unsloth/install.sh

#!/bin/sh
# Unsloth Studio Installer
# Usage (curl):  curl -fsSL https://unsloth.ai/install.sh | sh
# Usage (wget):  wget -qO- https://unsloth.ai/install.sh | sh
# Usage (local): ./install.sh --local   (install from local repo instead of PyPI)
# Usage (no-torch): ./install.sh --no-torch  (skip PyTorch, GGUF-only mode)
# Usage (test):  ./install.sh --package roland-sloth  (install a different package name)
# Usage (py):    ./install.sh --python 3.12  (override auto-detected Python version)
#
# Env vars (priority: UNSLOTH_STUDIO_HOME > STUDIO_HOME > HOME-redirect > default):
#   UNSLOTH_STUDIO_HOME=/abs/path  -> install under that path
#   STUDIO_HOME=/abs/path          -> alias, same effect (UNSLOTH_STUDIO_HOME wins)
#   (DATA_DIR + unsloth CLI shim nest inside; no shell rc-file append.)
# Default ($HOME/.unsloth/studio) is preserved when no env var is set.
set -e

# ── Output style (aligned with studio/setup.sh) ──
RULE=""
_rule_i=0
while [ "$_rule_i" -lt 52 ]; do
    RULE="${RULE}─"
    _rule_i=$((_rule_i + 1))
done
if [ -n "${NO_COLOR:-}" ]; then
    C_TITLE= C_DIM= C_OK= C_WARN= C_ERR= C_RST=
elif [ -t 1 ] || [ -n "${FORCE_COLOR:-}" ]; then
    _ESC="$(printf '\033')"
    C_TITLE="${_ESC}[38;5;150m"
    C_DIM="${_ESC}[38;5;245m"
    C_OK="${_ESC}[38;5;108m"
    C_WARN="${_ESC}[38;5;136m"
    C_ERR="${_ESC}[91m"
    C_RST="${_ESC}[0m"
else
    C_TITLE= C_DIM= C_OK= C_WARN= C_ERR= C_RST=
fi

step()    { printf "  ${C_DIM}%-15.15s${C_RST}${3:-$C_OK}%s${C_RST}\n" "$1" "$2"; }
substep() { printf "  ${C_DIM}%-15s${2:-$C_DIM}%s${C_RST}\n" "" "$1"; }

# ── Parse flags ──
STUDIO_LOCAL_INSTALL=false
PACKAGE_NAME="unsloth"
TAURI_MODE=false
_USER_PYTHON=""
_NO_TORCH_FLAG=false
_VERBOSE=false
_SHORTCUTS_ONLY=false
_next_is_package=false
_next_is_python=false
for arg in "$@"; do
    if [ "$_next_is_package" = true ]; then
        PACKAGE_NAME="$arg"
        _next_is_package=false
        continue
    fi
    if [ "$_next_is_python" = true ]; then
        _USER_PYTHON="$arg"
        _next_is_python=false
        continue
    fi
    case "$arg" in
        --local) STUDIO_LOCAL_INSTALL=true ;;
        --package) _next_is_package=true ;;
        --tauri) TAURI_MODE=true ;;
        --python) _next_is_python=true ;;
        --no-torch) _NO_TORCH_FLAG=true ;;
        --verbose|-v) _VERBOSE=true ;;
        --shortcuts-only) _SHORTCUTS_ONLY=true ;;
    esac
done

if [ "$_VERBOSE" = true ]; then
    export UNSLOTH_VERBOSE=1
fi

# Custom Studio roots are not supported with --tauri (desktop app still
# resolves ~/.unsloth/studio). Pass through if the override == legacy default.
if [ "$TAURI_MODE" = true ]; then
    _tauri_override_var=""
    _tauri_override="${UNSLOTH_STUDIO_HOME:-}"
    if [ -n "$_tauri_override" ]; then
        _tauri_override_var="UNSLOTH_STUDIO_HOME"
    else
        _tauri_override="${STUDIO_HOME:-}"
        [ -n "$_tauri_override" ] && _tauri_override_var="STUDIO_HOME"
    fi
    # Strip whitespace so " " is treated as unset (matches Python .strip()).
    _tauri_override=$(printf '%s' "$_tauri_override" | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//')
    if [ -n "$_tauri_override" ]; then
        case "$_tauri_override" in
            "~") _tauri_override="$HOME" ;;
            "~/"*) _tauri_override="$HOME/${_tauri_override#'~/'}" ;;
        esac
        # Canonicalize both sides (CDPATH=, -P) so a CDPATH-set env or
        # symlinked $HOME doesn't break the legacy-equality comparison.
        if [ -d "$_tauri_override" ]; then
            _tauri_override_abs=$(CDPATH= cd -P -- "$_tauri_override" 2>/dev/null && pwd -P) \
                || _tauri_override_abs="$_tauri_override"
        else
            _tauri_override_abs="$_tauri_override"
        fi
        # Strip trailing separators so ".../studio/" matches ".../studio".
        while [ "$_tauri_override_abs" != "/" ] \
            && [ "${_tauri_override_abs%/}" != "$_tauri_override_abs" ]; do
            _tauri_override_abs=${_tauri_override_abs%/}
        done
        _tauri_legacy_root="$HOME/.unsloth/studio"
        if [ -d "$_tauri_legacy_root" ]; then
            _tauri_legacy_root=$(CDPATH= cd -P -- "$_tauri_legacy_root" 2>/dev/null && pwd -P) \
                || _tauri_legacy_root="$HOME/.unsloth/studio"
        fi
        while [ "$_tauri_legacy_root" != "/" ] \
            && [ "${_tauri_legacy_root%/}" != "$_tauri_legacy_root" ]; do
            _tauri_legacy_root=${_tauri_legacy_root%/}
        done
        if [ "$_tauri_override_abs" != "$_tauri_legacy_root" ]; then
            echo "ERROR: $_tauri_override_var is not supported with --tauri." >&2
            echo "       The desktop app still uses the legacy ~/.unsloth/studio root." >&2
            echo "       Run install.sh without --tauri for custom-root shell installs," >&2
            echo "       or unset the env var for default desktop installs." >&2
            exit 1
        fi
    fi
fi

_is_verbose() {
    [ "${UNSLOTH_VERBOSE:-0}" = "1" ]
}

run_maybe_quiet() {
    if _is_verbose; then
        "$@"
    else
        "$@" > /dev/null 2>&1
    fi
}

run_install_cmd() {
    _label="$1"
    shift
    if _is_verbose; then
        "$@" && return 0
        _rc=$?
        step "error" "$_label failed (exit code $_rc)" "$C_ERR" >&2
        return "$_rc"
    fi
    _log=$(mktemp)
    "$@" >"$_log" 2>&1 && { rm -f "$_log"; return 0; }
    _rc=$?
    step "error" "$_label failed (exit code $_rc)" "$C_ERR" >&2
    cat "$_log" >&2
    rm -f "$_log"
    return $_rc
}

# Install bitsandbytes on AMD ROCm hosts. Uses the continuous-release_main
# wheel for the ROCm 4-bit GEMV fix (bnb PR #1887, post-0.49.2); bnb <= 0.49.2
# NaNs at decode shape on every AMD GPU. Falls back to PyPI >=0.49.1 if the
# pre-release URL is unreachable. Drop the pin once bnb 0.50+ ships on PyPI.
_install_bnb_rocm() {
    _label="$1"
    _venv_py="$2"
    case "$_ARCH" in
        x86_64|amd64)
            _bnb_whl_url="https://github.com/bitsandbytes-foundation/bitsandbytes/releases/download/continuous-release_main/bitsandbytes-1.33.7.preview-py3-none-manylinux_2_24_x86_64.whl"
            ;;
        aarch64|arm64)
            _bnb_whl_url="https://github.com/bitsandbytes-foundation/bitsandbytes/releases/download/continuous-release_main/bitsandbytes-1.33.7.preview-py3-none-manylinux_2_24_aarch64.whl"
            ;;
        *)
            _bnb_whl_url=""
            ;;
    esac
    # uv rejects the continuous-release_main bitsandbytes wheel because the
    # filename version (1.33.7rc0) does not match the embedded metadata version
    # (0.50.0.dev0). pip accepts the mismatch, so bootstrap pip and use it.
    if ! "$_venv_py" -m pip --version >/dev/null 2>&1; then
        if ! run_maybe_quiet "$_venv_py" -m ensurepip --upgrade; then
            run_maybe_quiet uv pip install --python "$_venv_py" pip || \
                substep "[WARN] could not bootstrap pip; bitsandbytes install will likely fail" "$C_WARN"
        fi
    fi
    if [ -n "$_bnb_whl_url" ]; then
        substep "installing bitsandbytes for AMD ROCm (pre-release, PR #1887)..."
        _bnb_log=$(mktemp)
        if "$_venv_py" -m pip install \
            --disable-pip-version-check \
            --force-reinstall --no-cache-dir --no-deps \
            --retries 8 --timeout 90 \
            "$_bnb_whl_url" >"$_bnb_log" 2>&1; then
            rm -f "$_bnb_log"
            return 0
        fi
        _bnb_rc=$?
        if _is_verbose; then
            cat "$_bnb_log" >&2
        fi
        rm -f "$_bnb_log"
        step "warning" "$_label (pre-release) failed (exit code $_bnb_rc)" "$C_WARN" >&2
        substep "[WARN] bnb pre-release install failed; falling back to PyPI (4-bit decode broken on ROCm)" "$C_WARN"
    fi
    run_install_cmd "$_label (pypi fallback)" "$_venv_py" -m pip install \
        --force-reinstall --no-cache-dir --no-deps "bitsandbytes>=0.49.1"
}

if [ "$_next_is_package" = true ]; then
    echo "❌ ERROR: --package requires an argument." >&2
    exit 1
fi
if [ "$_next_is_python" = true ]; then
    echo "❌ ERROR: --python requires a version argument (e.g. --python 3.12)." >&2
    exit 1
fi

# Validate --package to prevent injection into shell/Python commands.
# Must start with a letter/digit (rejects leading dashes that uv would parse as flags).
case "$PACKAGE_NAME" in
    [!a-zA-Z0-9]*)
        echo "❌ ERROR: --package name must start with a letter or digit." >&2
        exit 1 ;;
    *[!a-zA-Z0-9._-]*)
        echo "❌ ERROR: --package name contains invalid characters (allowed: a-z A-Z 0-9 . _ -)" >&2
        exit 1 ;;
esac

# ── Tauri structured output ──
tauri_log() {
    if [ "$TAURI_MODE" = true ]; then
        echo "[TAURI:$1] $2"
    fi
}

tauri_diag_marker() {
    _diag_gpu_branch="${1:-unknown}"
    _diag_torch_index_family="${2:-none}"
    tauri_log "DIAG" "diag_schema=1 platform=${OS:-unknown} arch=${_ARCH:-unknown} python_version=${PYTHON_VERSION:-unknown} skip_torch=${SKIP_TORCH:-false} mac_intel=${MAC_INTEL:-false} gpu_branch=${_diag_gpu_branch} torch_index_family=${_diag_torch_index_family}"
}

_tauri_torch_index_family() {
    if [ "${SKIP_TORCH:-false}" = true ]; then
        echo "none"
        return
    fi
    _diag_url="${1:-}"
    case "$_diag_url" in
        */cu118) echo "cu118" ;;
        */cu124) echo "cu124" ;;
        */cu126) echo "cu126" ;;
        */cu128) echo "cu128" ;;
        */cu130) echo "cu130" ;;
        */cpu) echo "cpu" ;;
        */rocm[0-9]*.[0-9]*)
            _diag_family=${_diag_url##*/}
            case "$_diag_family" in
                rocm[0-9]*.[0-9]*) echo "$_diag_family" ;;
                *) echo "auto" ;;
            esac ;;
        # AMD arch-specific index (e.g. repo.amd.com/rocm/whl/gfx1151/) --
        # used for Strix Halo/Point where torch 2.11+rocm7.13 has the real fix.
        *repo.amd.com/rocm/whl/gfx*|*rocm/whl/gfx*) echo "rocm7.13" ;;
        "") echo "none" ;;
        *) echo "auto" ;;
    esac
}

_tauri_gpu_branch() {
    _diag_family="${1:-unknown}"
    _diag_radeon="${2:-false}"
    if [ "${SKIP_TORCH:-false}" = true ]; then
        echo "no_torch"
        return
    fi
    if [ "${OS:-}" = "macos" ]; then
        echo "mac"
        return
    fi
    case "$_diag_family" in
        cu*) echo "cuda" ;;
        rocm*)
            if [ "$_diag_radeon" = true ]; then
                echo "rocm_radeon"
            else
                echo "rocm"
            fi ;;
        radeon) echo "rocm_radeon" ;;
        cpu) echo "cpu" ;;
        none) echo "no_torch" ;;
        *) echo "unknown" ;;
    esac
}

PYTHON_VERSION=""  # resolved after platform detection

# Resolve install destinations: env override, HOME-redirect (best-effort
# via getent/dscl), or default. Env-var priority: UNSLOTH_STUDIO_HOME wins
# over STUDIO_HOME (the more specific signal beats the generic alias).
_resolve_studio_destinations() {
    _override_var=""
    _override="${UNSLOTH_STUDIO_HOME:-}"
    if [ -n "$_override" ]; then
        _override_var="UNSLOTH_STUDIO_HOME"
    else
        _override="${STUDIO_HOME:-}"
        [ -n "$_override" ] && _override_var="STUDIO_HOME"
    fi
    # Strip surrounding whitespace so " " is treated as unset (matches the
    # Python resolvers' .strip()), preventing install/runtime layout drift.
    _override=$(printf '%s' "$_override" | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//')
    # Tilde expansion: env vars are not subject to it when quoted on assignment.
    case "$_override" in
        "~") _override="$HOME" ;;
        "~/"*) _override="$HOME/${_override#'~/'}" ;;
    esac
    if [ -n "$_override" ]; then
        mkdir -p -- "$_override" 2>/dev/null || { echo "ERROR: $_override_var=$_override cannot be created." >&2; exit 1; }
        [ -w "$_override" ] || { echo "ERROR: $_override_var=$_override is not writable." >&2; exit 1; }
        STUDIO_HOME="$(CDPATH= cd -P -- "$_override" && pwd -P)" || exit 1
        DATA_DIR="$STUDIO_HOME/share"
        _LOCAL_BIN="$STUDIO_HOME/bin"
        _STUDIO_HOME_REDIRECT=env
        substep "custom $_override_var=$STUDIO_HOME"
        return 0
    fi
    _default_home=""
    if command -v getent >/dev/null 2>&1; then
        _default_home=$(getent passwd "${USER:-$(whoami)}" 2>/dev/null | cut -d: -f6)
    elif [ "$(uname)" = "Darwin" ] && command -v dscl >/dev/null 2>&1; then
        _default_home=$(dscl . -read "/Users/${USER:-$(whoami)}" NFSHomeDirectory 2>/dev/null | awk '{print $2}')
    fi
    # Canonicalize both sides so a trailing slash on $HOME (or symlink mismatch
    # with passwd-DB output) doesn't misfire the redirection branch.
    _home_canon="$HOME"
    if [ -d "$_home_canon" ]; then
        _home_canon=$(CDPATH= cd -P -- "$_home_canon" 2>/dev/null && pwd -P) || _home_canon="$HOME"
    fi
    _default_home_canon="$_default_home"
    if [ -n "$_default_home_canon" ] && [ -d "$_default_home_canon" ]; then
        _default_home_canon=$(CDPATH= cd -P -- "$_default_home_canon" 2>/dev/null && pwd -P) || _default_home_canon="$_default_home"
    fi
    if [ -n "$_default_home_canon" ] && [ "$_home_canon" != "$_default_home_canon" ]; then
        STUDIO_HOME="$HOME/.unsloth/studio"
        DATA_DIR="$HOME/.local/share/unsloth"
        _LOCAL_BIN="$HOME/.local/bin"
        _STUDIO_HOME_REDIRECT=home
        substep "HOME redirected ($HOME); install follows \$HOME"
        return 0
    fi
    STUDIO_HOME="$HOME/.unsloth/studio"
    DATA_DIR="$HOME/.local/share/unsloth"
    _LOCAL_BIN="$HOME/.local/bin"
    _STUDIO_HOME_REDIRECT=default
}
_resolve_studio_destinations
VENV_DIR="$STUDIO_HOME/unsloth_studio"
_VENV_ROLLBACK_DIR=""
_VENV_ROLLBACK_TARGET="$VENV_DIR"
_VENV_ROLLBACK_ACTIVE=false

_start_studio_venv_replacement() {
    _existing_dir="$1"
    _stamp=$(date +%Y%m%d%H%M%S 2>/dev/null || echo "time")
    _candidate="$STUDIO_HOME/unsloth_studio.rollback.$_stamp.$$"
    _suffix=0
    while [ -e "$_candidate" ]; do
        _suffix=$((_suffix + 1))
        _candidate="$STUDIO_HOME/unsloth_studio.rollback.$_stamp.$$.$_suffix"
    done
    mv "$_existing_dir" "$_candidate"
    _VENV_ROLLBACK_DIR="$_candidate"
    _VENV_ROLLBACK_TARGET="$_existing_dir"
    _VENV_ROLLBACK_ACTIVE=true
    substep "previous environment preserved for rollback"
}

_restore_studio_venv_replacement() {
    [ "$_VENV_ROLLBACK_ACTIVE" = true ] || return 0
    [ -n "$_VENV_ROLLBACK_DIR" ] && [ -d "$_VENV_ROLLBACK_DIR" ] || {
        _VENV_ROLLBACK_ACTIVE=false
        return 0
    }
    substep "restoring previous environment after failed install..." "$C_WARN"
    rm -rf "$_VENV_ROLLBACK_TARGET"
    if mv "$_VENV_ROLLBACK_DIR" "$_VENV_ROLLBACK_TARGET"; then
        substep "restored previous environment"
        _VENV_ROLLBACK_ACTIVE=false
        _VENV_ROLLBACK_DIR=""
    else
        echo "⚠️  Could not restore previous environment from $_VENV_ROLLBACK_DIR to $_VENV_ROLLBACK_TARGET" >&2
    fi
}

_commit_studio_venv_replacement() {
    [ "$_VENV_ROLLBACK_ACTIVE" = true ] || return 0
    if [ -n "$_VENV_ROLLBACK_DIR" ] && [ -d "$_VENV_ROLLBACK_DIR" ]; then
        rm -rf "$_VENV_ROLLBACK_DIR" || true
    fi
    _VENV_ROLLBACK_ACTIVE=false
    _VENV_ROLLBACK_DIR=""
}

_on_install_exit() {
    _status=$?
    if [ "$_status" -ne 0 ]; then
        _restore_studio_venv_replacement
    fi
    exit "$_status"
}
trap _on_install_exit EXIT

# ── Helper: download a URL to a file (supports curl and wget) ──
download() {
    if command -v curl >/dev/null 2>&1; then
        curl -LsSf "$1" -o "$2"
    elif command -v wget >/dev/null 2>&1; then
        wget -qO "$2" "$1"
    else
        echo "Error: neither curl nor wget found. Install one and re-run."
        exit 1
    fi
}

# ── Helper: check if a single package is available on the system ──
_is_pkg_installed() {
    case "$1" in
        build-essential) command -v gcc >/dev/null 2>&1 ;;
        libcurl4-openssl-dev)
            command -v dpkg >/dev/null 2>&1 && dpkg -s "$1" >/dev/null 2>&1 ;;
        pciutils)
            command -v lspci >/dev/null 2>&1 ;;
        *) command -v "$1" >/dev/null 2>&1 ;;
    esac
}

# ── Helper: install packages via apt, escalating to sudo only if needed ──
# Usage: _smart_apt_install pkg1 pkg2 pkg3 ...
_smart_apt_install() {
    _PKGS="$*"

    # Step 1: Try installing without sudo (works when already root)
    apt-get update -y </dev/null >/dev/null 2>&1 || true
    apt-get install -y $_PKGS </dev/null >/dev/null 2>&1 || true

    # Step 2: Check which packages are still missing
    _STILL_MISSING=""
    for _pkg in $_PKGS; do
        if ! _is_pkg_installed "$_pkg"; then
            _STILL_MISSING="$_STILL_MISSING $_pkg"
        fi
    done
    _STILL_MISSING=$(echo "$_STILL_MISSING" | sed 's/^ *//')

    if [ -z "$_STILL_MISSING" ]; then
        return 0
    fi

    # In Tauri mode, report needed packages and exit — Rust handles elevation
    if [ "$TAURI_MODE" = true ]; then
        tauri_log "NEED_SUDO" "$_STILL_MISSING"
        exit 2
    fi

    # Step 3: Escalate -- need elevated permissions for remaining packages
    if command -v sudo >/dev/null 2>&1; then
        echo ""
        echo "    !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
        echo "    WARNING: We require sudo elevated permissions to install:"
        echo "    $_STILL_MISSING"
        echo "    If you accept, we'll run sudo now, and it'll prompt your password."
        echo "    !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
        echo ""
        printf "    Accept? [Y/n] "
        if [ -r /dev/tty ]; then
            read -r REPLY </dev/tty || REPLY="y"
        else
            REPLY="y"
        fi
        case "$REPLY" in
            [nN]*)
                echo ""
                echo "    Please install these packages first, then re-run Unsloth Studio setup:"
                echo "    sudo apt-get update -y && sudo apt-get install -y $_STILL_MISSING"
                exit 1
                ;;
            *)
                sudo apt-get update -y </dev/null
                sudo apt-get install -y $_STILL_MISSING </dev/null
                ;;
        esac
    else
        echo ""
        echo "    sudo is not available on this system."
        echo "    Please install these packages as root, then re-run Unsloth Studio setup:"
        echo "    apt-get update -y && apt-get install -y $_STILL_MISSING"
        exit 1
    fi
}

# ── Helper: create desktop shortcuts and launcher script ──
# Usage: create_studio_shortcuts <unsloth_exe> <os>
# Creates ~/.local/share/unsloth/launch-studio.sh (shared launcher),
# plus platform-specific shortcuts (Linux .desktop / macOS .app bundle /
# WSL Windows Desktop+Start Menu .lnk).
create_studio_shortcuts() {
    _css_exe="$1"
    _css_os="$2"

    # Validate exe
    if [ ! -x "$_css_exe" ]; then
        echo "[WARN] Cannot create shortcuts: unsloth not found at $_css_exe"
        return 0
    fi

    # Resolve absolute path
    _css_exe_dir=$(cd "$(dirname "$_css_exe")" && pwd)
    _css_exe="$_css_exe_dir/$(basename "$_css_exe")"

    _css_data_dir="$DATA_DIR"
    _css_launcher="$_css_data_dir/launch-studio.sh"
    _css_icon_png="$_css_data_dir/unsloth-studio.png"
    _css_gem_png="$_css_data_dir/unsloth-gem.png"

    mkdir -p "$_css_data_dir"

    # Same-install discriminator: per-install opaque id written once at install
    # time and read by both this launcher and the backend (/api/health). Replaces
    # the older sha256(canonical $STUDIO_HOME) scheme to (a) avoid leaking the
    # install path on -H 0.0.0.0 deployments and (b) sidestep launcher/backend
    # canonicalization drift (cd -P vs Path.resolve() symlink/junction handling).
    # Lives at $STUDIO_HOME/share/ (not $DATA_DIR) so the backend can find it
    # via _STUDIO_ROOT_RESOLVED / "share" / "studio_install_id" regardless of
    # mode (in env-mode $STUDIO_HOME/share == $DATA_DIR; in default mode they
    # diverge but the backend only knows the studio_root). 32 bytes of urandom
    # -> 64 hex chars, byte-compatible with the prior digest so launcher
    # placeholder, _check_health, and tests stay length-agnostic.
    _css_id_dir="$STUDIO_HOME/share"
    mkdir -p "$_css_id_dir"
    _css_id_file="$_css_id_dir/studio_install_id"
    if [ ! -s "$_css_id_file" ]; then
        if [ -r /dev/urandom ]; then
            _css_new_id=$(od -An -N32 -tx1 /dev/urandom 2>/dev/null | tr -d ' \n')
        fi
        if [ -z "${_css_new_id:-}" ] && command -v python3 >/dev/null 2>&1; then
            _css_new_id=$(python3 -c 'import secrets; print(secrets.token_hex(32))' 2>/dev/null)
        fi
        if [ -z "${_css_new_id:-}" ]; then
            echo "[WARN] Cannot create launcher: no entropy source for studio_install_id" >&2
            return 1
        fi
        # Atomic write so a partial install can't leave a half-written id.
        _css_id_tmp="$_css_id_file.$$.tmp"
        printf '%s' "$_css_new_id" > "$_css_id_tmp" \
            && mv "$_css_id_tmp" "$_css_id_file"
        chmod 600 "$_css_id_file" 2>/dev/null || true
        unset _css_new_id _css_id_tmp
    fi
    _css_studio_root_id=$(cat "$_css_id_file" 2>/dev/null)
    if [ -z "$_css_studio_root_id" ]; then
        echo "[WARN] Cannot create launcher: failed to read $_css_id_file" >&2
        return 1
    fi
    _css_is_env_mode=false
    [ "$_STUDIO_HOME_REDIRECT" = "env" ] && _css_is_env_mode=true

    # ── Write launcher script ──
    # Single-quoted heredoc; @@DATA_DIR@@, @@STUDIO_ROOT_ID@@, and
    # @@INSTALLED_IS_ENV_MODE@@ are substituted via sed below.
    cat > "$_css_launcher" << 'LAUNCHER_EOF'
#!/usr/bin/env bash
# Unsloth Studio Launcher
# Auto-generated by install.sh -- do not edit manually.
set -euo pipefail

DATA_DIR='@@DATA_DIR@@'
_EXPECTED_STUDIO_ROOT_ID='@@STUDIO_ROOT_ID@@'
_INSTALLED_IS_ENV_MODE='@@INSTALLED_IS_ENV_MODE@@'

# Read exe path from config written at install time.
# Sourcing is safe: the config file is written by install.sh, not user input.
if [ -f "$DATA_DIR/studio.conf" ]; then
    . "$DATA_DIR/studio.conf"
fi
if [ -z "${UNSLOTH_EXE:-}" ] || [ ! -x "${UNSLOTH_EXE:-}" ]; then
    echo "Error: UNSLOTH_EXE not set or not executable. Re-run the installer." >&2
    exit 1
fi

BASE_PORT=8888
MAX_PORT_OFFSET=20
TIMEOUT_SEC=60
POLL_INTERVAL_SEC=0.25
LOG_FILE="$DATA_DIR/studio.log"
# why: in env-override mode multiple installs share an OS user; namespace the
# lock and remember our own healthy port so we never attach to an unrelated
# Studio listening on the global 8888..8908 range.
LOCK_DIR="${XDG_RUNTIME_DIR:-/tmp}/unsloth-studio-launcher-$(id -u).lock"
PORT_FILE=""
# why: gate on the install-time mode (baked above) instead of the runtime env
# var; sourcing a custom-root studio.conf in shell must not flip a default-mode
# launcher into env-mode behavior with stale state.
if [ "$_INSTALLED_IS_ENV_MODE" = "true" ]; then
    if command -v cksum >/dev/null 2>&1; then
        _LOCK_KEY=$(printf '%s' "$DATA_DIR" | cksum | awk '{print $1}')
    else
        _LOCK_KEY=""
    fi
    [ -n "$_LOCK_KEY" ] && LOCK_DIR="${XDG_RUNTIME_DIR:-/tmp}/unsloth-studio-launcher-$(id -u)-${_LOCK_KEY}.lock"
    PORT_FILE="$DATA_DIR/studio.port"
fi

# ── HTTP GET helper (supports curl and wget) ──
_http_get() {
    _url="$1"
    if command -v curl >/dev/null 2>&1; then
        curl -fsS --max-time 1 "$_url" 2>/dev/null
    elif command -v wget >/dev/null 2>&1; then
        wget -qO- --timeout=1 "$_url" 2>/dev/null
    else
        return 1
    fi
}

# ── Health check ──
_check_health() {
    _port=$1
    _resp=$(_http_get "http://127.0.0.1:$_port/api/health") || return 1
    case "$_resp" in
        *'"status"'*'"healthy"'*'"service"'*'"Unsloth UI Backend"'*) ;;
        *'"service"'*'"Unsloth UI Backend"'*'"status"'*'"healthy"'*) ;;
        *) return 1 ;;
    esac
    # why: verify the backend belongs to THIS install. Baked hex digest avoids
    # JSON-escape mismatches on paths with `\`/`"` and avoids leaking the raw
    # install path to unauthenticated callers.
    if [ -n "$_EXPECTED_STUDIO_ROOT_ID" ]; then
        case "$_resp" in
            *"\"studio_root_id\":\"$_EXPECTED_STUDIO_ROOT_ID\""*|*"\"studio_root_id\": \"$_EXPECTED_STUDIO_ROOT_ID\""*) return 0 ;;
            *) return 1 ;;
        esac
    fi
    return 0
}

# ── Port scanning ──
_candidate_ports() {
    echo "$BASE_PORT"
    _max_port=$((BASE_PORT + MAX_PORT_OFFSET))
    if command -v ss >/dev/null 2>&1; then
        ss -tlnH 2>/dev/null | awk '{print $4}' | grep -oE '[0-9]+$' | \
            awk -v lo="$BASE_PORT" -v hi="$_max_port" '$1 >= lo && $1 <= hi && $1 != lo {print}' || true
    elif command -v lsof >/dev/null 2>&1; then
        lsof -iTCP -sTCP:LISTEN -nP 2>/dev/null | awk '{print $9}' | grep -oE '[0-9]+$' | \
            awk -v lo="$BASE_PORT" -v hi="$_max_port" '$1 >= lo && $1 <= hi && $1 != lo {print}' || true
    else
        _offset=1
        while [ "$_offset" -le "$MAX_PORT_OFFSET" ]; do
            echo $((BASE_PORT + _offset))
            _offset=$((_offset + 1))
        done
    fi
}

_find_healthy_port() {
    if [ -n "$PORT_FILE" ] && [ -f "$PORT_FILE" ]; then
        # why: env-mode installs only attach to a port we previously launched
        # ourselves; never to a sibling Studio that happens to be healthy.
        _p=$(cat "$PORT_FILE" 2>/dev/null || true)
        case "$_p" in
            ''|*[!0-9]*) ;;
            *)
                if _check_health "$_p"; then
                    echo "$_p"
                    return 0
                fi
                rm -f "$PORT_FILE"
                ;;
        esac
        return 1
    fi
    if [ -n "$PORT_FILE" ]; then
        return 1
    fi
    for _p in $(_candidate_ports | sort -un); do
        if _check_health "$_p"; then
            echo "$_p"
            return 0
        fi
    done
    return 1
}

# ── Check if a port is busy ──
_is_port_busy() {
    _port=$1
    if command -v ss >/dev/null 2>&1; then
        ss -tlnH 2>/dev/null | awk '{print $4}' | grep -qE "[.:]$_port$"
    elif command -v lsof >/dev/null 2>&1; then
        lsof -iTCP:"$_port" -sTCP:LISTEN -nP >/dev/null 2>&1
    else
        return 1
    fi
}

# ── Find a free port in range ──
_find_launch_port() {
    _offset=0
    while [ "$_offset" -le "$MAX_PORT_OFFSET" ]; do
        _candidate=$((BASE_PORT + _offset))
        if ! _is_port_busy "$_candidate"; then
            echo "$_candidate"
            return 0
        fi
        _offset=$((_offset + 1))
    done
    return 1
}

# ── Open browser ──
_open_browser() {
    _url="$1"
    if [ "$(uname)" = "Darwin" ] && command -v open >/dev/null 2>&1; then
        open "$_url"
    elif grep -qi microsoft /proc/version 2>/dev/null; then
        # WSL: xdg-open is unreliable; use Windows browser via PowerShell or cmd
        if command -v powershell.exe >/dev/null 2>&1; then
            powershell.exe -NoProfile -Command "Start-Process '$_url'" >/dev/null 2>&1 &
        elif command -v cmd.exe >/dev/null 2>&1; then
            cmd.exe /c start "" "$_url" >/dev/null 2>&1 &
        elif command -v xdg-open >/dev/null 2>&1; then
            xdg-open "$_url" >/dev/null 2>&1 &
        else
            echo "Open in your browser: $_url" >&2
        fi
    elif command -v xdg-open >/dev/null 2>&1; then
        xdg-open "$_url" >/dev/null 2>&1 &
    else
        echo "Open in your browser: $_url" >&2
    fi
}

# ── Spawn terminal with studio command ──
_spawn_terminal() {
    _cmd="$1"
    _os=$(uname)
    if [ "$_os" = "Darwin" ]; then
        # AppleEvents are TCC-denied from unsigned .app bundles; spawn
        # Terminal via a .command file + Launch Services instead. Server
        # is nohup'd so warm relaunches hit the fast-path; watcher + trap
        # in the .command couple Terminal close <-> server shutdown.
        # `exec` keeps the recorded PID equal to the studio process so
        # signals reach studio directly rather than a wrapper shell.
        nohup sh -c "exec $_cmd" >> "$LOG_FILE" 2>&1 &
        _server_pid=$!
        _pid_file="$DATA_DIR/studio-$_launch_port.pid"
        printf '%d\n' "$_server_pid" > "$_pid_file" 2>/dev/null || true

        _cmd_file="$DATA_DIR/launch-terminal.command"
        _logfile_q=$(printf '%s' "$LOG_FILE" | sed "s/'/'\\\\''/g")
        _pidfile_q=$(printf '%s' "$_pid_file" | sed "s/'/'\\\\''/g")
        if {
            {
                printf '#!/bin/bash\n'
                printf "SERVER_PID=%s\n" "$_server_pid"
                printf "PID_FILE='%s'\n" "$_pidfile_q"
                # Wait up to 12s for graceful shutdown before SIGKILL.
                printf 'shutdown_studio() {\n'
                printf '  kill -TERM "$SERVER_PID" 2>/dev/null\n'
                printf '  _i=0\n'
                printf '  while kill -0 "$SERVER_PID" 2>/dev/null && [ "$_i" -lt 24 ]; do\n'
                printf '    sleep 0.5\n'
                printf '    _i=$((_i + 1))\n'
                printf '  done\n'
                printf '  kill -0 "$SERVER_PID" 2>/dev/null && kill -KILL "$SERVER_PID" 2>/dev/null\n'
                printf '  rm -f "$PID_FILE" 2>/dev/null\n'
                printf '}\n'
                printf "tail -n 100 -F '%s' &\n" "$_logfile_q"
                printf 'TAIL_PID=$!\n'
                # Server gone -> kill tail so bash exits cleanly.
                printf '(\n'
                printf '  while kill -0 "$SERVER_PID" 2>/dev/null; do sleep 1; done\n'
                printf '  kill "$TAIL_PID" 2>/dev/null\n'
                printf ') &\n'
                printf 'WATCHER_PID=$!\n'
                printf "trap 'shutdown_studio; kill \"\$WATCHER_PID\" \"\$TAIL_PID\" 2>/dev/null; exit' HUP INT TERM\n"
                printf "trap 'rm -f \"\$PID_FILE\" 2>/dev/null' EXIT\n"
                printf 'wait "$TAIL_PID" 2>/dev/null\n'
            } > "$_cmd_file" 2>/dev/null \
                && chmod +x "$_cmd_file" 2>/dev/null \
                && open -a Terminal "$_cmd_file" 2>/dev/null
        }; then
            # Foreground Terminal (Launch Services spawns us backgrounded).
            osascript -e 'tell application "Terminal" to activate' >/dev/null 2>&1 || true
            return 0
        fi
        # .command/open failed: kill orphan, fall through to generic fallback.
        kill -TERM "$_server_pid" 2>/dev/null || true
        _i=0
        while kill -0 "$_server_pid" 2>/dev/null && [ "$_i" -lt 6 ]; do
            sleep 0.5
            _i=$((_i + 1))
        done
        kill -0 "$_server_pid" 2>/dev/null && kill -KILL "$_server_pid" 2>/dev/null || true
        rm -f "$_pid_file" 2>/dev/null || true
        echo "[WARN] Could not open Terminal; falling back to background launch" >&2
    else
        for _term in gnome-terminal konsole xfce4-terminal mate-terminal lxterminal xterm; do
            if command -v "$_term" >/dev/null 2>&1; then
                case "$_term" in
                    gnome-terminal) "$_term" -- sh -c "$_cmd" & return 0 ;;
                    konsole)        "$_term" -e sh -c "$_cmd" & return 0 ;;
                    xterm)          "$_term" -e sh -c "$_cmd" & return 0 ;;
                    *)              "$_term" -e sh -c "$_cmd" & return 0 ;;
                esac
            fi
        done
    fi
    # Fallback: background with log
    echo "No terminal emulator found; running in background. Logs: $LOG_FILE" >&2
    nohup sh -c "$_cmd" >> "$LOG_FILE" 2>&1 &
    return 0
}

# ── Atomic directory-based single-instance guard ──
_acquire_lock() {
    if mkdir "$LOCK_DIR" 2>/dev/null; then
        echo "$$" > "$LOCK_DIR/pid"
        return 0
    fi

    # Lock dir exists -- check if owner is still alive
    _old_pid=$(cat "$LOCK_DIR/pid" 2>/dev/null || true)
    if [ -n "$_old_pid" ] && kill -0 "$_old_pid" 2>/dev/null; then
        # Another launcher is running; wait for it to bring Studio up
        _deadline=$(($(date +%s) + TIMEOUT_SEC))
        while [ "$(date +%s)" -lt "$_deadline" ]; do
            _port=$(_find_healthy_port) && {
                _open_browser "http://localhost:$_port"
                exit 0
            }
            sleep "$POLL_INTERVAL_SEC"
        done
        echo "Timed out waiting for other launcher (PID $_old_pid)" >&2
        exit 0
    fi

    # Stale lock -- reclaim
    rm -rf "$LOCK_DIR"
    mkdir "$LOCK_DIR" 2>/dev/null || return 1
    echo "$$" > "$LOCK_DIR/pid"
}

_release_lock() {
    [ -d "$LOCK_DIR" ] || return 0
    [ "$(cat "$LOCK_DIR/pid" 2>/dev/null)" = "$$" ] || return 0
    rm -rf "$LOCK_DIR"
}

# ── Main ──
# Fast path: already healthy
_port=$(_find_healthy_port) && {
    _open_browser "http://localhost:$_port"
    exit 0
}

_acquire_lock
trap '_release_lock' EXIT INT TERM

# Post-lock re-check (handles race with another launcher)
_port=$(_find_healthy_port) && {
    _open_browser "http://localhost:$_port"
    exit 0
}

# Find a free port in range
_launch_port=$(_find_launch_port) || {
    echo "No free port found in range ${BASE_PORT}-$((BASE_PORT + MAX_PORT_OFFSET))" >&2
    exit 1
}

if [ -t 1 ]; then
    # ── Foreground mode (TTY available) ──
    # Background subshell: wait for studio to become healthy, release the
    # single-instance lock, then open the browser. The lock stays held until
    # health is confirmed so a second launcher cannot race during startup.
    (
        _obwr_deadline=$(($(date +%s) + TIMEOUT_SEC))
        while [ "$(date +%s)" -lt "$_obwr_deadline" ]; do
            if _check_health "$_launch_port"; then
                [ -n "$PORT_FILE" ] && printf '%s\n' "$_launch_port" > "$PORT_FILE" 2>/dev/null || true
                _release_lock
                _open_browser "http://localhost:$_launch_port"
                exit 0
            fi
            sleep "$POLL_INTERVAL_SEC"
        done
        # Timed out -- release the lock anyway so future launches are not blocked
        _release_lock
    ) &
    # Clear traps so exec does not trigger _release_lock (the subshell owns it)
    trap - EXIT INT TERM
    exec "$UNSLOTH_EXE" studio -p "$_launch_port"
else
    # ── Background mode (no TTY) ──
    # Used by macOS .app and headless invocations.
    _launch_cmd=$(printf '%q ' "$UNSLOTH_EXE" studio -p "$_launch_port")
    _launch_cmd=${_launch_cmd% }
    _spawn_terminal "$_launch_cmd"

    # Poll for health on the specific port we launched on
    _deadline=$(($(date +%s) + TIMEOUT_SEC))
    while [ "$(date +%s)" -lt "$_deadline" ]; do
        if _check_health "$_launch_port"; then
            [ -n "$PORT_FILE" ] && printf '%s\n' "$_launch_port" > "$PORT_FILE" 2>/dev/null || true
            _open_browser "http://localhost:$_launch_port"
            exit 0
        fi
        sleep "$POLL_INTERVAL_SEC"
    done

    echo "Unsloth Studio did not become healthy within ${TIMEOUT_SEC}s." >&2
    echo "Check logs at: $LOG_FILE" >&2
    exit 1
fi
LAUNCHER_EOF

    # why: bake non-user-controlled placeholders FIRST so a literal
    # `@@STUDIO_ROOT_ID@@` inside $DATA_DIR cannot be rewritten below.
    sed -e "s|@@STUDIO_ROOT_ID@@|$_css_studio_root_id|g" \
        -e "s|@@INSTALLED_IS_ENV_MODE@@|$_css_is_env_mode|g" \
        "$_css_launcher" > "$_css_launcher.tmp" \
        && mv "$_css_launcher.tmp" "$_css_launcher"

    # Env-mode bakes an absolute DATA_DIR (root fixed at install time);
    # default / HOME-redirect keeps the literal $HOME/.local/share/unsloth
    # so behavior is byte-identical to pre-override.
    if [ "$_STUDIO_HOME_REDIRECT" = "env" ]; then
        # Two-stage escape: (1) `'` -> `'\''` for shell single-quote embedding,
        # (2) backslash/&/| escape so the value survives the s|...|VALUE| sed
        # below. Verified end-to-end with apostrophes, spaces, &, |, $.
        _sq_escaped=$(printf '%s' "$DATA_DIR" | sed "s/'/'\\\\''/g")
        _sed_safe=$(printf '%s' "$_sq_escaped" | sed 's/[\\&|]/\\&/g')
        sed "s|@@DATA_DIR@@|$_sed_safe|g" "$_css_launcher" > "$_css_launcher.tmp" \
            && mv "$_css_launcher.tmp" "$_css_launcher"
    else
        sed "s|DATA_DIR='@@DATA_DIR@@'|DATA_DIR=\"\$HOME/.local/share/unsloth\"|" \
            "$_css_launcher" > "$_css_launcher.tmp" \
            && mv "$_css_launcher.tmp" "$_css_launcher"
    fi

    chmod +x "$_css_launcher"

    # studio.conf: exe path + (env-mode only) persisted env vars so fresh
    # shells launch the right install without re-exporting.
    _css_quoted_exe=$(printf '%s' "$_css_exe" | sed "s/'/'\\\\''/g")
    {
        printf '%s\n' "UNSLOTH_EXE='$_css_quoted_exe'"
        if [ "$_STUDIO_HOME_REDIRECT" = "env" ]; then
            # When an override resolves to the legacy default, llama.cpp
            # still lives at ~/.unsloth/llama.cpp (one shared build).
            # Canonicalize the legacy side so a symlinked $HOME doesn't
            # break the comparison.
            _css_legacy_studio="$HOME/.unsloth/studio"
            if [ -d "$_css_legacy_studio" ]; then
                _css_legacy_studio=$(CDPATH= cd -P -- "$_css_legacy_studio" 2>/dev/null && pwd -P) \
                    || _css_legacy_studio="$HOME/.unsloth/studio"
            fi
            if [ "$STUDIO_HOME" = "$_css_legacy_studio" ]; then
                _css_llama_path="$HOME/.unsloth/llama.cpp"
            else
                _css_llama_path="$STUDIO_HOME/llama.cpp"
            fi
            _css_quoted_home=$(printf '%s' "$STUDIO_HOME" | sed "s/'/'\\\\''/g")
            _css_quoted_llama=$(printf '%s' "$_css_llama_path" | sed "s/'/'\\\\''/g")
            printf '%s\n' "export UNSLOTH_STUDIO_HOME='$_css_quoted_home'"
            # UNSLOTH_LLAMA_CPP_PATH is a pre-existing user-controlled
            # llama.cpp dir override; only default it if unset.
            printf '%s\n' 'if [ -z "${UNSLOTH_LLAMA_CPP_PATH:-}" ]; then'
            printf '%s\n' "    export UNSLOTH_LLAMA_CPP_PATH='$_css_quoted_llama'"
            printf '%s\n' 'fi'
        fi
    } > "$_css_data_dir/studio.conf"

    # ── Icon: try bundled, then download ──
    # rounded-512.png used for both Linux and macOS icons
    _css_script_dir=""
    if [ -n "${0:-}" ] && [ -f "$0" ]; then
        _css_script_dir=$(cd "$(dirname "$0")" 2>/dev/null && pwd) || true
    fi

    # Try to find rounded-512.png from installed package (site-packages) or local repo
    _css_found_icon=""
    _css_venv_dir=$(dirname "$(dirname "$_css_exe")")
    # Check site-packages
    for _sp in "$_css_venv_dir"/lib/python*/site-packages/unsloth/studio/frontend/public; do
        if [ -f "$_sp/rounded-512.png" ]; then
            _css_found_icon="$_sp/rounded-512.png"
        fi
    done
    # Check local repo (when running from clone)
    if [ -z "$_css_found_icon" ] && [ -n "$_css_script_dir" ] && [ -f "$_css_script_dir/studio/frontend/public/rounded-512.png" ]; then
        _css_found_icon="$_css_script_dir/studio/frontend/public/rounded-512.png"
    fi

    # Copy or download rounded-512.png (used for both Linux icon and macOS icns)
    if [ -n "$_css_found_icon" ]; then
        cp "$_css_found_icon" "$_css_icon_png" 2>/dev/null || true
        cp "$_css_found_icon" "$_css_gem_png" 2>/dev/null || true
    else
        download "https://raw.githubusercontent.com/unslothai/unsloth/main/studio/frontend/public/rounded-512.png" "$_css_icon_png" 2>/dev/null || true
        cp "$_css_icon_png" "$_css_gem_png" 2>/dev/null || true
    fi

    # Validate PNG header (first 4 bytes: \x89PNG)
    _css_validate_png() {
        [ -f "$1" ] || return 1
        _hdr=$(od -An -tx1 -N4 "$1" 2>/dev/null | tr -d ' ')
        [ "$_hdr" = "89504e47" ]
    }
    if [ -f "$_css_icon_png" ] && ! _css_validate_png "$_css_icon_png"; then
        rm -f "$_css_icon_png"
    fi
    if [ -f "$_css_gem_png" ] && ! _css_validate_png "$_css_gem_png"; then
        rm -f "$_css_gem_png"
    fi

    # ── Platform-specific shortcuts ──
    # Env-mode installs are workspace-scoped: skip persistent desktop /
    # Start-Menu / dock launchers that may point at a deleted workspace.
    # Runtime launcher + studio.conf + icon are still written above.
    if [ "$_STUDIO_HOME_REDIRECT" = "env" ]; then
        substep "wrote launcher at $_css_launcher (persistent shortcuts skipped in env-override mode)"
        return 0
    fi

    _css_created=0

    if [ "$_css_os" = "linux" ]; then
        # ── Linux: .desktop file ──
        _css_app_dir="$HOME/.local/share/applications"
        mkdir -p "$_css_app_dir"

        _css_desktop="$_css_app_dir/unsloth-studio.desktop"
        # Escape backslashes and double-quotes for .desktop Exec= field
        _css_exec_escaped=$(printf '%s' "$_css_launcher" | sed 's/\\/\\\\/g; s/"/\\"/g')
        _css_icon_escaped=$(printf '%s' "$_css_icon_png" | sed 's/\\/\\\\/g; s/"/\\"/g')
        cat > "$_css_desktop" << DESKTOP_EOF
[Desktop Entry]
Version=1.0
Type=Application
Name=Unsloth Studio
Comment=Launch Unsloth Studio
Exec="$_css_exec_escaped"
Icon=$_css_icon_escaped
Terminal=true
StartupNotify=true
Categories=Development;Science;
DESKTOP_EOF
        chmod +x "$_css_desktop"

        # Copy to ~/Desktop if it exists
        if [ -d "$HOME/Desktop" ]; then
            cp "$_css_desktop" "$HOME/Desktop/unsloth-studio.desktop" 2>/dev/null || true
            chmod +x "$HOME/Desktop/unsloth-studio.desktop" 2>/dev/null || true
            # Mark as trusted so GNOME/Nautilus allows launching via double-click
            if command -v gio >/dev/null 2>&1; then
                gio set "$HOME/Desktop/unsloth-studio.desktop" metadata::trusted true 2>/dev/null || true
            fi
        fi

        # Best-effort update database
        update-desktop-database "$_css_app_dir" 2>/dev/null || true
        _css_created=1

    elif [ "$_css_os" = "macos" ]; then
        # ── macOS: .app bundle ──
        _css_app="$HOME/Applications/Unsloth Studio.app"
        _css_contents="$_css_app/Contents"
        _css_macos_dir="$_css_contents/MacOS"
        _css_res_dir="$_css_contents/Resources"
        # Recreate bundle if root or any subpath is a symlink (mkdir -p follows them).
        if [ -L "$_css_app" ] || [ -L "$_css_contents" ] \
            || [ -L "$_css_macos_dir" ] || [ -L "$_css_res_dir" ]; then
            rm -rf "$_css_app" 2>/dev/null || {
                echo "[ERROR] $_css_app contains a symlinked bundle path; remove manually and re-run install" >&2
                return 1
            }
        elif [ -e "$_css_app" ] && [ ! -d "$_css_app" ]; then
            echo "[ERROR] $_css_app exists but is not a directory; remove manually and re-run install" >&2
            return 1
        fi
        mkdir -p "$_css_macos_dir" "$_css_res_dir"

        # Info.plist
        cat > "$_css_contents/Info.plist" << 'PLIST_EOF'
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>CFBundleIdentifier</key>
    <string>ai.unsloth.studio</string>
    <key>CFBundleName</key>
    <string>Unsloth Studio</string>
    <key>CFBundleDisplayName</key>
    <string>Unsloth Studio</string>
    <key>CFBundleExecutable</key>
    <string>launch-studio</string>
    <key>CFBundleIconFile</key>
    <string>AppIcon</string>
    <key>CFBundlePackageType</key>
    <string>APPL</string>
    <key>CFBundleVersion</key>
    <string>1.0</string>
    <key>CFBundleShortVersionString</key>
    <string>1.0</string>
    <key>LSMinimumSystemVersion</key>
    <string>10.15</string>
    <key>NSHighResolutionCapable</key>
    <true/>
</dict>
</plist>
PLIST_EOF

        # Executable stub: same single-quoted-heredoc + sed-substitute
        # pattern as launch-studio.sh so $-vars in $_css_data_dir don't
        # expand at .app launch time.
        _css_sq_dir=$(printf '%s' "$_css_data_dir" | sed "s/'/'\\\\''/g")
        _css_sed_dir=$(printf '%s' "$_css_sq_dir" | sed 's/[\\&|]/\\&/g')
        cat > "$_css_macos_dir/launch-studio" << 'STUB_EOF'
#!/bin/sh
exec '@@DATA_DIR@@/launch-studio.sh' "$@"
STUB_EOF
        sed "s|@@DATA_DIR@@|$_css_sed_dir|g" "$_css_macos_dir/launch-studio" \
            > "$_css_macos_dir/launch-studio.tmp" \
            && mv "$_css_macos_dir/launch-studio.tmp" "$_css_macos_dir/launch-studio"
        chmod +x "$_css_macos_dir/launch-studio"

        # Build AppIcon.icns from unsloth-gem.png (2240x2240)
        if [ -f "$_css_gem_png" ] && command -v sips >/dev/null 2>&1 && command -v iconutil >/dev/null 2>&1; then
            _css_tmpdir=$(mktemp -d 2>/dev/null)
            if [ -d "$_css_tmpdir" ]; then
                _css_iconset="$_css_tmpdir/AppIcon.iconset"
                mkdir -p "$_css_iconset"
                _css_icon_ok=true
                for _sz in 16 32 128 256 512; do
                    _sz2=$((_sz * 2))
                    sips -z "$_sz" "$_sz" "$_css_gem_png" --out "$_css_iconset/icon_${_sz}x${_sz}.png" >/dev/null 2>&1 || _css_icon_ok=false
                    sips -z "$_sz2" "$_sz2" "$_css_gem_png" --out "$_css_iconset/icon_${_sz}x${_sz}@2x.png" >/dev/null 2>&1 || _css_icon_ok=false
                done
                if [ "$_css_icon_ok" = "true" ]; then
                    iconutil -c icns "$_css_iconset" -o "$_css_res_dir/AppIcon.icns" 2>/dev/null || true
                fi
                rm -rf "$_css_tmpdir"
            fi
        fi
        # Fallback: copy PNG as icon
        if [ ! -f "$_css_res_dir/AppIcon.icns" ] && [ -f "$_css_icon_png" ]; then
            cp "$_css_icon_png" "$_css_res_dir/AppIcon.icns" 2>/dev/null || true
        fi

        # Touch so Finder indexes it
        touch "$_css_app"

        # Symlink on Desktop
        if [ -d "$HOME/Desktop" ]; then
            ln -sf "$_css_app" "$HOME/Desktop/Unsloth Studio" 2>/dev/null || true
        fi
        _css_created=1

    elif [ "$_css_os" = "wsl" ]; then
        # ── WSL: create Windows Desktop and Start Menu shortcuts ──
        # Detect current WSL distro for targeted shortcut
        _css_distro="${WSL_DISTRO_NAME:-}"

        # Build the wsl.exe arguments.
        # Double-quote distro name and launcher path for Windows command line
        # parsing so values with spaces (e.g. "Ubuntu Preview") are kept as
        # single arguments.
        _css_wsl_args=""
        if [ -n "$_css_distro" ]; then
            _css_wsl_args="-d \"$_css_distro\" "
        fi
        _css_wsl_args="${_css_wsl_args}-- bash -l -c \"exec \\\"$_css_launcher\\\"\""

        # Detect whether Windows Terminal (wt.exe) is available (better UX)
        _css_use_wt=false
        if command -v wt.exe >/dev/null 2>&1; then
            _css_use_wt=true
        fi

        if [ "$_css_use_wt" = true ]; then
            _css_sc_target='wt.exe'
            _css_sc_args="wsl.exe $_css_wsl_args"
        else
            _css_sc_target='wsl.exe'
            _css_sc_args="$_css_wsl_args"
        fi

        # Escape single quotes for PowerShell single-quoted string embedding
        _css_sc_args_ps=$(printf '%s' "$_css_sc_args" | sed "s/'/''/g")

        # Create shortcuts via a temp PowerShell script to avoid escaping issues
        _css_ps1_tmp=$(mktemp /tmp/unsloth-shortcut-XXXXXX.ps1 2>/dev/null) || true
        if [ -n "$_css_ps1_tmp" ]; then
            cat > "$_css_ps1_tmp" << WSLPS1_EOF
\$WshShell = New-Object -ComObject WScript.Shell
\$targetExe = (Get-Command '$_css_sc_target' -ErrorAction SilentlyContinue).Source
if (-not \$targetExe) { exit 1 }
\$locations = @(
    [Environment]::GetFolderPath('Desktop'),
    (Join-Path \$env:APPDATA 'Microsoft\Windows\Start Menu\Programs')
)
foreach (\$dir in \$locations) {
    if (-not \$dir -or -not (Test-Path \$dir)) { continue }
    \$linkPath = Join-Path \$dir 'Unsloth Studio.lnk'
    \$shortcut = \$WshShell.CreateShortcut(\$linkPath)
    \$shortcut.TargetPath = \$targetExe
    \$shortcut.Arguments = '$_css_sc_args_ps'
    \$shortcut.Description = 'Launch Unsloth Studio'
    \$shortcut.Save()
}
WSLPS1_EOF

            # Convert WSL path to Windows path for powershell.exe
            _css_ps1_win=$(wslpath -w "$_css_ps1_tmp" 2>/dev/null)
            if [ -n "$_css_ps1_win" ]; then
                powershell.exe -NoProfile -ExecutionPolicy Bypass -File "$_css_ps1_win" >/dev/null 2>&1 && _css_created=1
            fi
            rm -f "$_css_ps1_tmp"
        fi
    fi

    if [ "$_css_created" -eq 1 ]; then
        substep "Created Unsloth Studio shortcut"
    fi
}

echo ""
printf "  ${C_TITLE}%s${C_RST}\n" "🦥 Unsloth Studio Installer"
printf "  ${C_DIM}%s${C_RST}\n" "$RULE"
echo ""

# ── Detect platform ──
tauri_log "STEP" "Detecting platform"
OS="linux"
if [ "$(uname)" = "Darwin" ]; then
    OS="macos"
elif grep -qi microsoft /proc/version 2>/dev/null; then
    OS="wsl"
fi
step "platform" "$OS"

# Regen launcher/shortcuts only; used by `unsloth studio update`.
if [ "$_SHORTCUTS_ONLY" = true ]; then
    # Tauri owns its own shortcuts.
    if [ "$TAURI_MODE" != true ]; then
        VENV_ABS_BIN="$VENV_DIR/bin"
        if [ ! -x "$VENV_ABS_BIN/unsloth" ]; then
            echo "ERROR: unsloth binary missing at '$VENV_ABS_BIN/unsloth'; run install.sh first." >&2
            exit 1
        fi
        create_studio_shortcuts "$VENV_ABS_BIN/unsloth" "$OS"
    fi
    exit 0
fi

# ── Architecture detection & Python version ──
_ARCH=$(uname -m)
MAC_INTEL=false
if [ "$OS" = "macos" ] && [ "$_ARCH" = "x86_64" ]; then
    # Guard against Apple Silicon running under Rosetta (reports x86_64).
    # sysctl hw.optional.arm64 returns "1" on Apple Silicon even in Rosetta.
    if [ "$(sysctl -in hw.optional.arm64 2>/dev/null || echo 0)" = "1" ]; then
        echo ""
        echo "  WARNING: Apple Silicon detected, but this shell is running under Rosetta (x86_64)."
        echo "  Re-run install.sh from a native arm64 terminal for full PyTorch support."
        echo "  Continuing in GGUF-only mode for now."
        echo ""
    fi
    MAC_INTEL=true
fi

if [ -n "$_USER_PYTHON" ]; then
    PYTHON_VERSION="$_USER_PYTHON"
    echo "  Using user-specified Python $PYTHON_VERSION (--python override)"
elif [ "$MAC_INTEL" = true ]; then
    PYTHON_VERSION="3.12"
else
    PYTHON_VERSION="3.13"
fi

if [ "$MAC_INTEL" = true ]; then
    echo ""
    echo "  NOTE: Intel Mac (x86_64) detected."
    echo "  PyTorch is unavailable for this platform (dropped Jan 2024)."
    echo "  Studio will install in GGUF-only mode."
    echo "  Chat, inference via GGUF, and data recipes will work."
    echo "  Training requires Apple Silicon or Linux with GPU."
    echo ""
fi

# ── Unified SKIP_TORCH: --no-torch flag OR Intel Mac auto-detection ──
SKIP_TORCH=false
if [ "$_NO_TORCH_FLAG" = true ] || [ "$MAC_INTEL" = true ]; then
    SKIP_TORCH=true
fi

# Apple Silicon: override mlx-vlm / mlx-lm's transformers pin (see overrides file).
if [ "$OS" = "macos" ] && [ "$_ARCH" = "arm64" ]; then
    _OVERRIDES_FILE="$(cd "$(dirname "$0" 2>/dev/null || echo ".")" && pwd)/studio/backend/requirements/single-env/overrides-darwin-arm64.txt"
    if [ -f "$_OVERRIDES_FILE" ]; then
        export UV_OVERRIDE="$_OVERRIDES_FILE"
    fi
fi

_TAURI_INITIAL_GPU_BRANCH="unknown"
if [ "$SKIP_TORCH" = true ]; then
    _TAURI_INITIAL_GPU_BRANCH="no_torch"
elif [ "$OS" = "macos" ]; then
    _TAURI_INITIAL_GPU_BRANCH="mac"
fi
tauri_diag_marker "$_TAURI_INITIAL_GPU_BRANCH" "none"

# ── Check system dependencies ──
# cmake and git are needed by unsloth studio setup to build the GGUF inference
# engine (llama.cpp). build-essential and libcurl-dev are also needed on Linux.
tauri_log "STEP" "Checking system dependencies"
MISSING=""

command -v cmake >/dev/null 2>&1 || MISSING="$MISSING cmake"
command -v git   >/dev/null 2>&1 || MISSING="$MISSING git"

case "$OS" in
    macos)
        # Xcode Command Line Tools provide the C/C++ compiler
        if ! xcode-select -p >/dev/null 2>&1; then
            echo ""
            echo "==> Xcode Command Line Tools are required."
            echo "    Installing (a system dialog will appear)..."
            xcode-select --install </dev/null 2>/dev/null || true
            echo "    After the installation completes, please re-run this script."
            exit 1
        fi
        ;;
    linux|wsl)
        # curl or wget is needed for downloads; check both
        if ! command -v curl >/dev/null 2>&1 && ! command -v wget >/dev/null 2>&1; then
            MISSING="$MISSING curl"
        fi
        command -v gcc  >/dev/null 2>&1 || MISSING="$MISSING build-essential"
        # libcurl dev headers for llama.cpp HTTPS support
        command -v curl-config >/dev/null 2>&1 || MISSING="$MISSING libcurl4-openssl-dev"
        ;;
esac

MISSING=$(echo "$MISSING" | sed 's/^ *//')

if [ -n "$MISSING" ]; then
    echo ""
    step "deps" "missing: $MISSING" "$C_WARN"
    substep "These are needed to build the GGUF inference engine."

    case "$OS" in
        macos)
            if ! command -v brew >/dev/null 2>&1; then
                echo ""
                echo "    Homebrew is required to install them."
                echo "    Install Homebrew from https://brew.sh then re-run this script."
                exit 1
            fi
            brew install $MISSING </dev/null
            ;;
        linux|wsl)
            if command -v apt-get >/dev/null 2>&1; then
                _smart_apt_install $MISSING
            else
                echo "    Automatic system package installation is supported on apt-based"
                echo "    Linux distributions (Ubuntu/Debian) only. Please install the"
                echo "    missing dependencies with your package manager, then re-run setup:"
                echo "    $MISSING"
                echo ""
                echo "    Examples:"
                echo "      Fedora/RHEL: sudo dnf install cmake git gcc gcc-c++ make libcurl-devel"
                echo "      Arch:       sudo pacman -S --needed cmake git base-devel curl"
                echo "      openSUSE:   sudo zypper install cmake git gcc gcc-c++ make libcurl-devel"
                exit 1
            fi
            ;;
    esac
    echo ""
else
    step "deps" "all system dependencies found"
fi

# ── Install uv ──
tauri_log "STEP" "Installing uv package manager"
UV_MIN_VERSION="0.7.14"

version_ge() {
    # returns 0 if $1 >= $2
    _a=$1
    _b=$2

    while [ -n "$_a" ] || [ -n "$_b" ]; do
        _a_part=${_a%%.*}
        _b_part=${_b%%.*}

        [ "$_a" = "$_a_part" ] && _a="" || _a=${_a#*.}
        [ "$_b" = "$_b_part" ] && _b="" || _b=${_b#*.}

        [ -z "$_a_part" ] && _a_part=0
        [ -z "$_b_part" ] && _b_part=0

        if [ "$_a_part" -gt "$_b_part" ]; then
            return 0
        fi
        if [ "$_a_part" -lt "$_b_part" ]; then
            return 1
        fi
    done

    return 0
}

_uv_version_ok() {
    _raw=$("$1" --version 2>/dev/null | awk '{print $2}') || return 1
    [ -n "$_raw" ] || return 1
    _ver=${_raw%%[-+]*}
    case "$_ver" in
        ''|*[!0-9.]*) return 1 ;;
    esac
    version_ge "$_ver" "$UV_MIN_VERSION" || return 1
    # Prerelease of the exact minimum (e.g. 0.7.14-rc1) is still below stable 0.7.14
    [ "$_ver" = "$UV_MIN_VERSION" ] && [ "$_raw" != "$_ver" ] && return 1
    return 0
}

if ! command -v uv >/dev/null 2>&1 || ! _uv_version_ok uv; then
    substep "installing uv package manager..."
    _uv_tmp=$(mktemp)
    download "https://astral.sh/uv/install.sh" "$_uv_tmp"
    run_maybe_quiet sh "$_uv_tmp" </dev/null
    rm -f "$_uv_tmp"
    if [ -f "$HOME/.local/bin/env" ]; then
        . "$HOME/.local/bin/env"
    fi
    export PATH="$HOME/.local/bin:$PATH"
fi

# ── Create venv (migrate old layout if possible, otherwise fresh) ──
tauri_log "STEP" "Creating virtual environment"
mkdir -p "$STUDIO_HOME"

_MIGRATED=false

if [ -x "$VENV_DIR/bin/python" ]; then
    # why: matching guard to the .venv branch below -- in env-mode
    # $STUDIO_HOME is a user-chosen workspace, so refuse to nuke an
    # existing $STUDIO_HOME/unsloth_studio that lacks Studio sentinels.
    # Accept the in-VENV ownership marker so partial-install retries are
    # not blocked. Sentinels must be regular files: -f follows symlinks
    # to files (the legitimate ln -s shim shape) but rejects directories
    # and broken/dir-targeted symlinks.
    if [ "$_STUDIO_HOME_REDIRECT" = "env" ] \
       && [ ! -f "$VENV_DIR/.unsloth-studio-owned" ] \
       && [ ! -f "$STUDIO_HOME/share/studio.conf" ] \
       && [ ! -f "$STUDIO_HOME/bin/unsloth" ]; then
        echo "ERROR: $VENV_DIR already exists but does not look like an Unsloth Studio install." >&2
        echo "       Move it aside or choose an empty UNSLOTH_STUDIO_HOME." >&2
        exit 1
    fi
    # New layout already exists — replace only after preserving rollback copy.
    substep "preserving existing environment for rollback..."
    _start_studio_venv_replacement "$VENV_DIR"
elif [ "$_STUDIO_HOME_REDIRECT" != "env" ] && [ -x "$STUDIO_HOME/.venv/bin/python" ]; then
    # Old layout exists — validate before migrating.
    # Skip in env-mode so we don't rm -rf an unrelated .venv at the
    # workspace root (e.g. user's existing project Python venv).
    # In no-torch mode, a missing torch package is expected; validate Python only.
    substep "found legacy Studio environment, validating..."
    _legacy_ok=false
    if [ "$SKIP_TORCH" = true ]; then
        if "$STUDIO_HOME/.venv/bin/python" -c "import sys; print(sys.executable)" >/dev/null 2>&1; then
            _legacy_ok=true
        fi
    elif "$STUDIO_HOME/.venv/bin/python" -c "
import torch
device = 'cuda' if torch.cuda.is_available() else 'cpu'
A = torch.ones((10, 10), device=device)
B = torch.ones((10, 10), device=device)
C = torch.ones((10, 10), device=device)
D = A + B
E = D @ C
torch.testing.assert_close(torch.unique(E), torch.tensor((20,), device=E.device, dtype=E.dtype))
" >/dev/null 2>&1; then
        _legacy_ok=true
    fi
    if [ "$_legacy_ok" = true ]; then
        echo "✅ Legacy environment is healthy — migrating..."
        mv "$STUDIO_HOME/.venv" "$VENV_DIR"
        echo "   Moved ~/.unsloth/studio/.venv → $VENV_DIR"
        _MIGRATED=true
    else
        echo "⚠️  Legacy environment failed validation — creating fresh environment"
        _invalid_venv="$STUDIO_HOME/.venv.invalid.$(date +%Y%m%d%H%M%S 2>/dev/null || echo time).$$"
        mv "$STUDIO_HOME/.venv" "$_invalid_venv" 2>/dev/null || true
    fi
fi

# If an Intel Mac has a stale 3.13 venv from a previous failed install, recreate
# (skip when the user explicitly chose a version via --python)
if [ "$SKIP_TORCH" = true ] && [ "$MAC_INTEL" = true ] && [ -z "$_USER_PYTHON" ] && [ -x "$VENV_DIR/bin/python" ]; then
    _PY_MM=$("$VENV_DIR/bin/python" -c \
        "import sys; print('{}.{}'.format(*sys.version_info[:2]))" 2>/dev/null || echo "")
    if [ "$_PY_MM" != "3.12" ]; then
        echo "  Recreating Intel Mac environment with Python 3.12 (was $_PY_MM)..."
        rm -rf "$VENV_DIR"
    fi
fi

if [ ! -x "$VENV_DIR/bin/python" ]; then
    step "venv" "creating Python ${PYTHON_VERSION} virtual environment"
    substep "$VENV_DIR"
    run_install_cmd "create venv" uv venv "$VENV_DIR" --python "$PYTHON_VERSION"
fi

# Mark the freshly-created venv as Studio-owned so a partial install can be
# repaired by re-running install.sh; the env-mode deletion guard above accepts
# this marker as the primary sentinel.
if [ -x "$VENV_DIR/bin/python" ]; then
    : > "$VENV_DIR/.unsloth-studio-owned" 2>/dev/null || true
fi

# Guard against Python 3.13.8 torch import bug on Apple Silicon
# (skip when the user explicitly chose a version via --python)
if [ -z "$_USER_PYTHON" ] && [ "$OS" = "macos" ] && [ "$_ARCH" = "arm64" ]; then
    _PY_VER=$("$VENV_DIR/bin/python" -c \
        "import sys; print('{}.{}.{}'.format(*sys.version_info[:3]))" 2>/dev/null || echo "")
    if [ "$_PY_VER" = "3.13.8" ]; then
        echo "  WARNING: Python 3.13.8 has a known torch import bug."
        echo "  Recreating venv with Python 3.12..."
        rm -rf "$VENV_DIR"
        PYTHON_VERSION="3.12"
        run_install_cmd "recreate venv" uv venv "$VENV_DIR" --python "$PYTHON_VERSION"
        if [ -x "$VENV_DIR/bin/python" ]; then
            : > "$VENV_DIR/.unsloth-studio-owned" 2>/dev/null || true
        fi
    fi
fi

if [ -x "$VENV_DIR/bin/python" ]; then
    step "venv" "using environment"
    substep "${VENV_DIR}"
fi

# Default torch constraint -- tightened for Python 3.13+ on arm64 macOS
# (torch <2.6 has no cp313 macOS arm64 wheels)
TORCH_CONSTRAINT="torch>=2.4,<2.11.0"
if [ "$SKIP_TORCH" = false ] && [ "$OS" = "macos" ] && [ "$_ARCH" = "arm64" ]; then
    _PY_MINOR=$("$VENV_DIR/bin/python" -c \
        "import sys; print(sys.version_info.minor)" 2>/dev/null || echo "0")
    if [ "$_PY_MINOR" -ge 13 ] 2>/dev/null; then
        TORCH_CONSTRAINT="torch>=2.6,<2.11.0"
    fi
fi

# ── Resolve repo root (for --local installs) ──
_REPO_ROOT="$(cd "$(dirname "$0" 2>/dev/null || echo ".")" && pwd)"

# ── Helper: find no-torch-runtime.txt (local repo or site-packages) ──
_find_no_torch_runtime() {
    # Check local repo first (for --local installs)
    if [ -f "$_REPO_ROOT/studio/backend/requirements/no-torch-runtime.txt" ]; then
        echo "$_REPO_ROOT/studio/backend/requirements/no-torch-runtime.txt"
        return
    fi
    # Check inside installed package
    _rt=$(find "$VENV_DIR" -path "*/studio/backend/requirements/no-torch-runtime.txt" -print -quit 2>/dev/null || echo "")
    if [ -n "$_rt" ]; then
        echo "$_rt"
        return
    fi
}

# ── AMD ROCm GPU detection helper ──
# Returns 0 if an AMD GPU is present. Checks rocminfo, amd-smi, then sysfs
# KFD topology (env-var-independent fallback for when HIP/ROCR_VISIBLE_DEVICES hides devices).
_has_amd_rocm_gpu() {
    if command -v rocminfo >/dev/null 2>&1 && \
       rocminfo 2>/dev/null | awk '/Name:[[:space:]]*gfx[1-9][0-9]/{found=1} END{exit !found}'; then
        return 0
    elif command -v amd-smi >/dev/null 2>&1 && \
         amd-smi list 2>/dev/null | awk '/^GPU[[:space:]]*[:\[][[:space:]]*[0-9]/{ found=1 } END{ exit !found }'; then
        return 0
    elif [ -e /dev/kfd ] && \
         awk '/gpu_id/{ if ($2+0 > 0) found=1 } END{ exit !found }' \
             /sys/class/kfd/kfd/topology/nodes/*/properties 2>/dev/null; then
        return 0
    fi
    return 1
}

# ── NVIDIA usable-GPU helper ──
# Returns 0 (true) only if nvidia-smi is present AND actually lists a GPU.
# Prevents AMD-only hosts with a stale nvidia-smi on PATH from being routed
# into the CUDA branch.
_has_usable_nvidia_gpu() {
    _nvsmi=""
    if command -v nvidia-smi >/dev/null 2>&1; then
        _nvsmi="nvidia-smi"
    elif [ -x "/usr/bin/nvidia-smi" ]; then
        _nvsmi="/usr/bin/nvidia-smi"
    else
        return 1
    fi
    "$_nvsmi" -L 2>/dev/null | awk '/^GPU[[:space:]]+[0-9]+:/{found=1} END{exit !found}'
}

# ── Detect GPU and choose PyTorch index URL ──
# Mirrors Get-TorchIndexUrl in install.ps1.
# On CPU-only machines this returns the cpu index, avoiding the solver
# dead-end where --torch-backend=auto resolves to unsloth==2024.8.
get_torch_index_url() {
    _base="${UNSLOTH_PYTORCH_MIRROR:-https://download.pytorch.org/whl}"
    _base="${_base%/}"
    # macOS: always CPU (no CUDA support)
    case "$(uname -s)" in Darwin) echo "$_base/cpu"; return ;; esac
    # Try nvidia-smi -- require the binary to actually list a usable GPU.
    # Presence of the binary alone (container leftovers, stale driver
    # packages) is not sufficient: otherwise an AMD-only host would
    # silently install CUDA wheels.
    _smi=""
    if _has_usable_nvidia_gpu; then
        if command -v nvidia-smi >/dev/null 2>&1; then
            _smi="nvidia-smi"
        elif [ -x "/usr/bin/nvidia-smi" ]; then
            _smi="/usr/bin/nvidia-smi"
        fi
    fi
    if [ -z "$_smi" ]; then
        # No NVIDIA GPU -- check for AMD ROCm GPU.
        # PyTorch only publishes ROCm wheels for linux-x86_64; skip the
        # ROCm branch entirely on aarch64 / arm64 / other architectures
        # so non-x86_64 Linux hosts fall back cleanly to CPU wheels.
        case "$(uname -m)" in
            x86_64|amd64) : ;;
            *) echo "$_base/cpu"; return ;;
        esac
        if ! _has_amd_rocm_gpu; then
            echo "$_base/cpu"; return
        fi
        # AMD GPU confirmed -- detect ROCm version
        _rocm_tag=""
        _rocm_tag=$({ command -v amd-smi >/dev/null 2>&1 && \
            amd-smi version 2>/dev/null | awk -F'ROCm version: ' \
                'NF>1{gsub(/[^0-9.]/, "", $2); split($2,a,"."); print "rocm"a[1]"."a[2]; ok=1; exit} END{exit !ok}'; } || \
            { [ -r /opt/rocm/.info/version ] && \
                awk -F. '{print "rocm"$1"."$2; exit}' /opt/rocm/.info/version; } || \
            { command -v hipconfig >/dev/null 2>&1 && \
                hipconfig --version 2>/dev/null | awk 'NR==1 && /^[0-9]/{split($1,a,"."); if(a[1]+0>0){print "rocm"a[1]"."a[2]; found=1}} END{exit !found}'; } || \
            { command -v dpkg-query >/dev/null 2>&1 && \
                ver="$(dpkg-query -W -f='${Version}\n' rocm-core 2>/dev/null)" && \
                [ -n "$ver" ] && \
                printf '%s\n' "$ver" | sed 's/^[0-9]*://' | awk -F'[.-]' '{print "rocm"$1"."$2; exit}'; } || \
            { command -v rpm >/dev/null 2>&1 && \
                ver="$(rpm -q --qf '%{VERSION}\n' rocm-core 2>/dev/null)" && \
                [ -n "$ver" ] && \
                printf '%s\n' "$ver" | awk -F'[.-]' '{print "rocm"$1"."$2; exit}'; }) 2>/dev/null
        # Validate _rocm_tag: must match "rocmX.Y" with major >= 1
        case "$_rocm_tag" in
            rocm[1-9]*.[0-9]*) : ;;  # valid (major >= 1)
            *) _rocm_tag="" ;;        # reject malformed (empty, garbled, or major=0)
        esac
        if [ -n "$_rocm_tag" ]; then
            # Minimum supported: ROCm 6.0 (no PyTorch wheels exist for older)
            case "$_rocm_tag" in
                rocm[1-5].*)
                    echo "[WARN] ROCm $_rocm_tag detected but PyTorch ROCm wheels require ROCm 6.0+ -- falling back to CPU-only PyTorch" >&2
                    echo "[WARN] Upgrade ROCm: https://rocm.docs.amd.com/en/latest/deploy/linux/index.html" >&2
                    echo "$_base/cpu"; return ;;
            esac
            # Supported tags; 6.5+ clips to rocm6.4, 7.3+ caps to rocm7.2.
            # PyTorch publishes major.minor URLs only (no patch level), so
            # rocm7.2.1 / rocm6.0.2 / etc. must normalise to rocm7.2 / rocm6.0.
            case "$_rocm_tag" in
                rocm6.0|rocm6.0.*) echo "$_base/rocm6.0" ;;
                rocm6.1|rocm6.1.*) echo "$_base/rocm6.1" ;;
                rocm6.2|rocm6.2.*) echo "$_base/rocm6.2" ;;
                rocm6.3|rocm6.3.*) echo "$_base/rocm6.3" ;;
                rocm6.4|rocm6.4.*) echo "$_base/rocm6.4" ;;
                rocm7.0|rocm7.0.*) echo "$_base/rocm7.0" ;;
                rocm7.1|rocm7.1.*) echo "$_base/rocm7.1" ;;
                rocm7.2|rocm7.2.*) echo "$_base/rocm7.2" ;;
                rocm6.*)
                    # ROCm 6.5+ (no published PyTorch wheels): clip down
                    # to the last supported 6.x wheel set.
                    echo "$_base/rocm6.4" ;;
                *)
                    # ROCm 7.3+ (future): cap to rocm7.2 (latest known)
                    echo "$_base/rocm7.2" ;;
            esac
            return
        fi
        # AMD GPU confirmed by rocminfo/amd-smi but ROCm version could not be
        # read from any source (amd-smi, /opt/rocm/.info/version, hipconfig,
        # dpkg, rpm).  Warn explicitly rather than silently installing CPU PyTorch.
        echo "[WARN] AMD GPU detected but ROCm version could not be determined -- falling back to CPU-only PyTorch" >&2
        echo "[WARN] Ensure one of the following is accessible: amd-smi, hipconfig, /opt/rocm/.info/version, rocm-core package" >&2
        echo "[WARN] To install ROCm: https://rocm.docs.amd.com/en/latest/deploy/linux/index.html" >&2
        echo "$_base/cpu"; return
    fi
    # Parse CUDA version from nvidia-smi output (POSIX-safe, no grep -P).
    # Newer NVIDIA drivers (e.g. 610.x) print "CUDA UMD Version: X.Y" instead
    # of the legacy "CUDA Version: X.Y"; accept both with two BRE expressions
    # (POSIX sed does not support "?" without -E).  The two patterns are
    # mutually exclusive per line, so head -1 picks the first emitted match.
    _cuda_ver=$(LC_ALL=C $_smi 2>/dev/null \
        | sed -n \
            -e 's/.*CUDA UMD Version:[[:space:]]*\([0-9][0-9]*\.[0-9][0-9]*\).*/\1/p' \
            -e 's/.*CUDA Version:[[:space:]]*\([0-9][0-9]*\.[0-9][0-9]*\).*/\1/p' \
        | head -1)
    if [ -z "$_cuda_ver" ]; then
        echo "[WARN] Could not determine CUDA version from nvidia-smi, defaulting to cu126" >&2
        echo "$_base/cu126"; return
    fi
    _major=${_cuda_ver%%.*}
    _minor=${_cuda_ver#*.}
    if [ "$_major" -ge 13 ]; then echo "$_base/cu130"
    elif [ "$_major" -eq 12 ] && [ "$_minor" -ge 8 ]; then echo "$_base/cu128"
    elif [ "$_major" -eq 12 ] && [ "$_minor" -ge 6 ]; then echo "$_base/cu126"
    elif [ "$_major" -ge 12 ]; then echo "$_base/cu124"
    elif [ "$_major" -ge 11 ]; then echo "$_base/cu118"
    else echo "$_base/cpu"; fi
}

get_radeon_wheel_url() {
    # Only meaningful on Linux. Picks a repo.radeon.com base URL whose listing
    # contains torch wheels. Tries paths like rocm-rel-7.2.1/, rocm-rel-7.2/,
    # rocm-rel-7.1.1/, rocm-rel-7.1/ (AMD publishes both M.m and M.m.p dirs).
    # Accepts both X.Y and X.Y.Z host versions since /opt/rocm/.info/version
    # and hipconfig --version can return either shape.
    case "$(uname -s)" in Linux) ;; *) echo ""; return ;; esac

    # Detect ROCm version (X.Y or X.Y.Z) -- try amd-smi, then
    # /opt/rocm/.info/version, then hipconfig.
    _full_ver=""
    _full_ver=$({ command -v amd-smi >/dev/null 2>&1 && \
        amd-smi version 2>/dev/null | awk -F'ROCm version: ' \
            'NF>1{if(match($2,/[0-9]+\.[0-9]+(\.[0-9]+)?/)){print substr($2,RSTART,RLENGTH); ok=1; exit}} END{exit !ok}'; } || \
        { [ -r /opt/rocm/.info/version ] && \
            awk 'match($0,/[0-9]+\.[0-9]+(\.[0-9]+)?/){print substr($0,RSTART,RLENGTH); found=1; exit} END{exit !found}' /opt/rocm/.info/version; } || \
        { command -v hipconfig >/dev/null 2>&1 && \
            hipconfig --version 2>/dev/null | awk 'NR==1 && match($0,/[0-9]+\.[0-9]+(\.[0-9]+)?/){print substr($0,RSTART,RLENGTH); found=1} END{exit !found}'; }) 2>/dev/null

    # Validate: must be X.Y or X.Y.Z with X >= 1
    case "$_full_ver" in
        [1-9]*.[0-9]*.[0-9]*) : ;;  # X.Y.Z
        [1-9]*.[0-9]*) : ;;          # X.Y
        *) echo ""; return ;;
    esac
    echo "https://repo.radeon.com/rocm/manylinux/rocm-rel-${_full_ver}/"
}

# ── Radeon repo wheel selection helpers ──────────────────────────────────────
# Fetches the Radeon repo directory listing once into _RADEON_LISTING (global).
# _RADEON_PYTAG holds the CPython tag for the running interpreter (e.g. cp312).
# _RADEON_BASE_URL holds the base URL for relative-href resolution.
_RADEON_LISTING=""
_RADEON_PYTAG=""
_RADEON_BASE_URL=""

_radeon_fetch_listing() {
    # Usage: _radeon_fetch_listing BASE_URL
    # Populates _RADEON_LISTING, _RADEON_PYTAG, _RADEON_BASE_URL.
    _RADEON_BASE_URL="$1"
    _RADEON_PYTAG=$("$_VENV_PY" -c "
import sys
print('cp{}{}'.format(sys.version_info.major, sys.version_info.minor))
" 2>/dev/null) || return 1
    if command -v curl >/dev/null 2>&1; then
        _RADEON_LISTING=$(curl -fsSL --max-time 20 "$_RADEON_BASE_URL" 2>/dev/null)
    elif command -v wget >/dev/null 2>&1; then
        _RADEON_LISTING=$(wget -qO- --timeout=20 "$_RADEON_BASE_URL" 2>/dev/null)
    fi
    [ -n "$_RADEON_LISTING" ] || return 1
}

_pick_radeon_wheel() {
    # Usage: _pick_radeon_wheel PACKAGE_NAME
    # Scans $_RADEON_LISTING for the newest wheel whose filename starts exactly
    # with PACKAGE_NAME- and matches _RADEON_PYTAG + linux_x86_64.
    # Prints the full URL (resolving relative hrefs against _RADEON_BASE_URL).
    #
    # POSIX-compliant pipeline: all href parsing, filtering, and version
    # selection is done inside a single awk script rather than reaching
    # for GNU extensions (grep -o, sort -V) that would break under BSD
    # or BusyBox coreutils.
    _pkg="$1"
    [ -n "$_RADEON_LISTING" ] || return 1
    [ -n "$_RADEON_PYTAG"   ] || return 1
    _tag="$_RADEON_PYTAG"
    _href=$(printf '%s\n' "$_RADEON_LISTING" \
        | awk -v pkg="$_pkg" -v tag="$_tag" '
            BEGIN { max_pad = ""; max_url = "" }
            {
                line = $0
                while (match(line, /href="[^"]*"/)) {
                    # Strip the leading href=" (6 chars) and trailing " (1 char)
                    url = substr(line, RSTART + 6, RLENGTH - 7)
                    line = substr(line, RSTART + RLENGTH)

                    # Extract basename, strip query / fragment
                    n = split(url, p, "/")
                    base = p[n]
                    sub(/[?#].*/, "", base)

                    prefix = pkg "-"
                    # Match cpXY-cpXY or cpXY-abi3 with any linux x86_64
                    # platform tag (linux_x86_64, manylinux_2_28_x86_64,
                    # manylinux2014_x86_64, etc.)
                    if (substr(base, 1, length(prefix)) == prefix &&
                            index(base, "-" tag "-") > 0 &&
                            match(base, /x86_64\.whl$/)) {
                        # Extract the version component (first
                        # dotted-number run) and pad each piece so a
                        # plain lexical comparison gives us the newest.
                        if (match(base, /[0-9]+\.[0-9]+(\.[0-9]+)?/)) {
                            ver = substr(base, RSTART, RLENGTH)
                            m = split(ver, v, ".")
                            pad = ""
                            for (i = 1; i <= m; i++)
                                pad = pad sprintf("%08d", v[i])
                            if (pad > max_pad) {
                                max_pad = pad
                                max_url = url
                            }
                        }
                    }
                }
            }
            END { if (max_url != "") print max_url }')
    [ -z "$_href" ] && return 1
    case "$_href" in
        http*) printf '%s\n' "$_href" ;;
        *)     printf '%s\n' "${_RADEON_BASE_URL%/}/${_href#/}" ;;
    esac
}

TORCH_INDEX_URL=$(get_torch_index_url)

# rocm7.2 ships torch 2.11.0 -- adjust the constraint to allow it.
# All other ROCm tags and CUDA stay within <2.11.0.
case "$TORCH_INDEX_URL" in
    */rocm7.2) TORCH_CONSTRAINT="torch>=2.11.0,<2.12.0" ;;
esac

# Auto-detect GPU for AMD ROCm based
# get_torch_index_url must have chosen */rocm*
# (gfx in rocminfo or amd-smi list). Then require rocminfo "Marketing Name:.*Radeon".
_amd_gpu_radeon=false
case "$TORCH_INDEX_URL" in
    */rocm*)
        if _has_amd_rocm_gpu && command -v rocminfo >/dev/null 2>&1 && \
           rocminfo 2>/dev/null | grep -q 'Marketing Name:.*Radeon'; then
            _amd_gpu_radeon=true
        fi
        ;;
esac
# ── Strix Halo / Strix Point: force rocm7.2 wheels, bypass Radeon repo ───────
# gfx1151 (Strix Halo) and gfx1150 (Strix Point) have a ROCm 7.1 driver bug
# that causes a segfault in torch._grouped_mm (moe_utils.py line 167).
# The Radeon repo now ships cp313 wheels for rocm-rel-7.1, so when
# _amd_gpu_radeon=true the installer silently lands on the broken combo.
# Detect these GPUs when TORCH_INDEX_URL is rocm7.1 and override to rocm7.2.
case "$TORCH_INDEX_URL" in
    */rocm7.1|*/rocm7.1.*)
        # Collect every gfx token in rocminfo / amd-smi enumeration order
        # (skip duplicates), then index by HIP_VISIBLE_DEVICES /
        # ROCR_VISIBLE_DEVICES so a mixed Strix iGPU + non-Strix dGPU box
        # where the user selected the dGPU does NOT get rerouted to the
        # Strix per-gfx index.
        _gfx_all=""
        if command -v rocminfo >/dev/null 2>&1; then
            _gfx_all=$(rocminfo 2>/dev/null | grep -oE 'gfx[1-9][0-9a-z]{2,3}')
        fi
        if [ -z "$_gfx_all" ] && command -v amd-smi >/dev/null 2>&1; then
            _gfx_all=$(amd-smi list 2>/dev/null | grep -oE 'gfx[1-9][0-9a-z]{2,3}')
            # PowerShell paths also probe `amd-smi static --asic`; mirror it
            # so a host with hipinfo-less amd-smi reports the gfx target.
            if [ -z "$_gfx_all" ]; then
                _gfx_all=$(amd-smi static --asic 2>/dev/null | grep -oE 'gfx[1-9][0-9a-z]{2,3}')
            fi
        fi
        _runtime_gfx=""
        if [ -n "$_gfx_all" ]; then
            _vis="${HIP_VISIBLE_DEVICES:-${ROCR_VISIBLE_DEVICES:-}}"
            _idx=0
            if [ -n "$_vis" ] && [ "$_vis" != "-1" ]; then
                _first=${_vis%%,*}
                case "$_first" in
                    ''|*[!0-9]*) _idx=0 ;;
                    *) _idx=$_first ;;
                esac
            fi
            _runtime_gfx=$(printf '%s\n' "$_gfx_all" | awk -v idx="$_idx" '
                NF && !seen[$0]++ { vals[n++] = $0 }
                END {
                    if (idx < 0 || idx >= n) idx = 0
                    if (n > 0) print vals[idx]
                }')
        fi
        _strix_gfx=""
        case "$_runtime_gfx" in
            gfx1151|gfx1150) _strix_gfx="$_runtime_gfx" ;;
        esac
        if [ -n "$_strix_gfx" ]; then
            echo "" >&2
            echo "  [WARN] $_strix_gfx (Strix) + ROCm 7.1 detected -- known _grouped_mm segfault" >&2
            echo "  [WARN] ROCm 7.1 wheels are broken for gfx1150/gfx1151 (moe_utils.py:167)" >&2
            echo "  [WARN] Routing to AMD arch-specific index (torch 2.11+rocm7.13 has the real fix)" >&2
            echo "  [WARN] Upgrade ROCm to 7.2+ to use the standard index:" >&2
            echo "  [WARN]   https://rocm.docs.amd.com/en/latest/deploy/linux/index.html" >&2
            echo "" >&2
            # AMD's arch-specific index serves torch 2.11.0+rocm7.13.0 which has AMD's
            # actual fix for the gfx1151/gfx1150 _grouped_mm kernel bug -- preferred
            # over the pytorch.org rocm7.2 fallback because it exercises the real GPU
            # kernel path. Set UNSLOTH_AMD_ROCM_MIRROR to override for air-gapped installs.
            _amd_strix_base="${UNSLOTH_AMD_ROCM_MIRROR:-https://repo.amd.com/rocm/whl}"
            # Strip ALL trailing slashes to match Python's .rstrip("/") -- a
            # double-/triple-slash mirror URL would otherwise produce 404s on
            # strict pip proxies (artifactory, sonatype).
            while [ "${_amd_strix_base%/}" != "$_amd_strix_base" ]; do
                _amd_strix_base="${_amd_strix_base%/}"
            done
            TORCH_INDEX_URL="${_amd_strix_base}/${_strix_gfx}/"
            TORCH_CONSTRAINT="torch>=2.11.0,<2.12.0"
            _amd_gpu_radeon=false
        fi
        ;;
esac
_TAURI_TORCH_INDEX_FAMILY=$(_tauri_torch_index_family "$TORCH_INDEX_URL")
if [ "$_amd_gpu_radeon" = true ] && [ "$SKIP_TORCH" = false ]; then
    _TAURI_TORCH_INDEX_FAMILY="radeon"
fi
_TAURI_GPU_BRANCH=$(_tauri_gpu_branch "$_TAURI_TORCH_INDEX_FAMILY" "$_amd_gpu_radeon")
tauri_diag_marker "$_TAURI_GPU_BRANCH" "$_TAURI_TORCH_INDEX_FAMILY"

# ── GPU detection summary (mirrors install.ps1 step "gpu" block) ──
if _has_usable_nvidia_gpu; then
    step "gpu" "NVIDIA GPU detected"
elif case "$TORCH_INDEX_URL" in */rocm*|*/gfx*) true ;; *) false ;; esac; then
    # Probe gfx arch for the display label, honouring HIP_VISIBLE_DEVICES
    _gpu_disp_gfx_all=""
    _gpu_disp_mkt=""
    if command -v rocminfo >/dev/null 2>&1; then
        _gpu_disp_gfx_all=$(rocminfo 2>/dev/null | grep -oE 'gfx[1-9][0-9a-z]{2,3}' || true)
        _gpu_disp_mkt=$(rocminfo 2>/dev/null | awk -F': ' \
            '/Marketing Name:/{gsub(/^[[:space:]]+|[[:space:]]+$/,"", $2); if($2){print $2; exit}}' || true)
    fi
    if [ -z "$_gpu_disp_gfx_all" ] && command -v amd-smi >/dev/null 2>&1; then
        _gpu_disp_gfx_all=$(amd-smi list 2>/dev/null | grep -oE 'gfx[1-9][0-9a-z]{2,3}' || true)
        [ -z "$_gpu_disp_gfx_all" ] && \
            _gpu_disp_gfx_all=$(amd-smi static --asic 2>/dev/null | grep -oE 'gfx[1-9][0-9a-z]{2,3}' || true)
    fi
    if [ -z "$_gpu_disp_mkt" ] && command -v amd-smi >/dev/null 2>&1; then
        _gpu_disp_mkt=$(amd-smi static --asic 2>/dev/null | awk -F'[:|]' \
            '/[Mm]arket.?[Nn]ame/{gsub(/^[[:space:]]+|[[:space:]]+$/,"", $2); if($2){print $2; exit}}' || true)
    fi
    _gpu_vis="${HIP_VISIBLE_DEVICES:-${ROCR_VISIBLE_DEVICES:-}}"
    _gpu_vis_idx=0
    if [ -n "$_gpu_vis" ] && [ "$_gpu_vis" != "-1" ]; then
        _gpu_first="${_gpu_vis%%,*}"
        case "$_gpu_first" in ''|*[!0-9]*) ;; *) _gpu_vis_idx=$_gpu_first ;; esac
    fi
    _gpu_disp_gfx=$(printf '%s\n' "$_gpu_disp_gfx_all" | awk -v idx="$_gpu_vis_idx" \
        'NF && !seen[$0]++ { a[n++]=$0 } END { if(idx>=n) idx=0; if(n>0) print a[idx] }')
    # UNSLOTH_ROCM_GFX_ARCH env override (mirrors install.ps1)
    if [ -n "${UNSLOTH_ROCM_GFX_ARCH:-}" ]; then
        _gpu_disp_gfx="${UNSLOTH_ROCM_GFX_ARCH}"
        substep "gfx arch from UNSLOTH_ROCM_GFX_ARCH env override: $_gpu_disp_gfx"
    # Name-based arch inference when tools don't report gfx (mirrors install.ps1 nameArchTable)
    elif [ -z "$_gpu_disp_gfx" ] && [ -n "$_gpu_disp_mkt" ]; then
        case "$_gpu_disp_mkt" in
            *"9070 XT"*|*9080*)                                                     _gpu_disp_gfx="gfx1201" ;;  # RDNA 4
            *9070*|*9060*)                                                          _gpu_disp_gfx="gfx1200" ;;  # RDNA 4
            *"8060S"*|*"890M"*|*"Strix Halo"*|*"HX 37"*|*"HX 38"*|*"AI 9 HX"*)  _gpu_disp_gfx="gfx1151" ;;  # RDNA 3.5 iGPU
            *"880M"*|*"Strix Point"*|*"AI 9 36"*|*"AI 7 35"*|*"AI 5 34"*)        _gpu_disp_gfx="gfx1150" ;;  # RDNA 3.5 iGPU
            *"RX 7900"*|*"RX 7800"*|*"RX 7700"*)                                  _gpu_disp_gfx="gfx1100" ;;  # RDNA 3 desktop
            *"RX 7600"*)                                                           _gpu_disp_gfx="gfx1102" ;;  # RDNA 3
            *"780M"*|*"760M"*|*"740M"*|*"Phoenix"*)                               _gpu_disp_gfx="gfx1103" ;;  # RDNA 3 iGPU
        esac
        if [ -n "$_gpu_disp_gfx" ]; then
            substep "gfx arch inferred from GPU name: $_gpu_disp_gfx"
            substep "Tip: set UNSLOTH_ROCM_GFX_ARCH=$_gpu_disp_gfx to skip inference next time"
        fi
    fi
    # ROCm version via hipconfig, then amd-smi
    _gpu_rocm_ver=""
    if command -v hipconfig >/dev/null 2>&1; then
        _gpu_rocm_ver=$(hipconfig --version 2>/dev/null | awk 'NR==1 && /^[0-9]/{print; exit}' || true)
    fi
    if [ -z "$_gpu_rocm_ver" ] && command -v amd-smi >/dev/null 2>&1; then
        _gpu_rocm_ver=$(amd-smi version 2>/dev/null | awk -F'ROCm version: ' \
            'NF>1{gsub(/[[:space:]]/,"", $2); print $2; exit}' || true)
    fi
    if [ -n "$_gpu_disp_gfx" ]; then
        step "gpu" "AMD ROCm ($_gpu_disp_gfx)"
    else
        step "gpu" "AMD ROCm"
    fi
    _rocm_root="${ROCM_PATH:-${HIP_PATH:-/opt/rocm}}"
    substep "ROCm: $_rocm_root"
    [ -n "$_gpu_rocm_ver" ] && substep "hipconfig: $_gpu_rocm_ver"
    [ -n "$_gpu_disp_mkt" ] && [ -n "$_gpu_disp_gfx" ] && substep "GPU: $_gpu_disp_mkt"
else
    step "gpu" "none (CPU-only)" "$C_WARN"
fi

# ── PyTorch wheel index note ──
case "$TORCH_INDEX_URL" in
    */cpu)
        if [ "$SKIP_TORCH" = false ] && [ "$OS" != "macos" ]; then
            substep "No GPU detected -- installing CPU-only PyTorch." "$C_WARN"
            substep "AMD ROCm users: see https://docs.unsloth.ai/get-started/install-and-update/amd"
            substep "Re-run with --no-torch for GGUF-only (faster, no PyTorch):"
            substep "  curl -fsSL https://unsloth.ai/install.sh | sh -s -- --no-torch"
        fi
        ;;
    */rocm*|*/gfx*)
        if [ "$_amd_gpu_radeon" = true ]; then
            substep "wheels: repo.radeon.com (Radeon)"
        else
            substep "wheels: $TORCH_INDEX_URL"
        fi
        ;;
esac

# ── Install unsloth directly into the venv (no activation needed) ──
tauri_log "STEP" "Installing PyTorch"
_VENV_PY="$VENV_DIR/bin/python"
if [ "$_MIGRATED" = true ]; then
    # Migrated env: force-reinstall unsloth+unsloth-zoo to ensure clean state
    # in the new venv location, while preserving existing torch/CUDA
    substep "upgrading unsloth in migrated environment..."
    if [ "$SKIP_TORCH" = true ]; then
        # No-torch: install unsloth + unsloth-zoo with --no-deps (current
        # PyPI metadata still declares torch as a hard dep), then install
        # runtime deps (typer, safetensors, transformers, etc.) with --no-deps
        # to prevent transitive torch resolution.
        run_install_cmd "install unsloth (migrated no-torch)" uv pip install --python "$_VENV_PY" --no-deps \
            --reinstall-package unsloth --reinstall-package unsloth-zoo \
            "unsloth>=2026.5.8" unsloth-zoo
        # Resolve pydantic WITH deps so pip pins pydantic-core to the
        # matching version (no-torch-runtime.txt below is --no-deps).
        # All transitive deps are torch-free.
        run_install_cmd "install pydantic (with deps for compatible core)" \
            uv pip install --python "$_VENV_PY" pydantic
        _NO_TORCH_RT="$(_find_no_torch_runtime)"
        if [ -n "$_NO_TORCH_RT" ]; then
            run_install_cmd "install no-torch runtime deps" uv pip install --python "$_VENV_PY" --no-deps -r "$_NO_TORCH_RT"
        fi
    else
        run_install_cmd "install unsloth (migrated)" uv pip install --python "$_VENV_PY" \
            --reinstall-package unsloth --reinstall-package unsloth-zoo \
            "unsloth>=2026.5.8" unsloth-zoo
    fi
    if [ "$STUDIO_LOCAL_INSTALL" = true ]; then
        substep "overlaying local repo (editable)..."
        run_install_cmd "overlay local repo" uv pip install --python "$_VENV_PY" -e "$_REPO_ROOT" --no-deps
        substep "overlaying unsloth-zoo from git main..."
        run_install_cmd "overlay unsloth-zoo (git main)" uv pip install --python "$_VENV_PY" \
            --no-deps --reinstall-package unsloth-zoo \
            "unsloth-zoo @ git+https://github.com/unslothai/unsloth-zoo"
    fi
    # AMD ROCm: install bitsandbytes even in migrated environments so
    # existing ROCm installs gain the AMD bitsandbytes build without a
    # fresh reinstall.
    if [ "$SKIP_TORCH" = false ]; then
        case "$TORCH_INDEX_URL" in
            */rocm*)
                _install_bnb_rocm "install bitsandbytes (AMD)" "$_VENV_PY"
                # Repair ROCm torch if overwritten during migrated install
                _has_hip=$("$_VENV_PY" -c "import torch; print(getattr(torch.version,'hip','') or '')" 2>/dev/null || true)
                if [ -z "$_has_hip" ]; then
                    substep "repairing ROCm torch (overwritten by dependency resolution)..."
                    run_install_cmd "repair ROCm torch" uv pip install --python "$_VENV_PY" \
                        "$TORCH_CONSTRAINT" torchvision torchaudio \
                        --index-url "$TORCH_INDEX_URL" \
                        --force-reinstall
                fi
                ;;
        esac
    fi
elif [ -n "$TORCH_INDEX_URL" ]; then
    # Fresh: Step 1 - install torch from explicit index (skip when --no-torch or Intel Mac)
    if [ "$SKIP_TORCH" = true ]; then
        substep "skipping PyTorch (--no-torch or Intel Mac x86_64)." "$C_WARN"
    elif [ "$_amd_gpu_radeon" = true ]; then
        _radeon_url=$(get_radeon_wheel_url)
        if [ -n "$_radeon_url" ]; then
            _radeon_listing_ok=false
            if _radeon_fetch_listing "$_radeon_url" 2>/dev/null; then
                _radeon_listing_ok=true
            else
                # Try shorter X.Y path (AMD publishes both X.Y.Z and X.Y dirs)
                _radeon_url_short=$(printf '%s\n' "$_radeon_url" \
                    | sed 's|rocm-rel-\([0-9]*\)\.\([0-9]*\)\.[0-9]*/|rocm-rel-\1.\2/|')
                if [ "$_radeon_url_short" != "$_radeon_url" ] && \
                   _radeon_fetch_listing "$_radeon_url_short" 2>/dev/null; then
                    _radeon_listing_ok=true
                fi
            fi

            if [ "$_radeon_listing_ok" = true ]; then
                # Require torch, torchvision, torchaudio wheels to all resolve
                # from the Radeon listing. If any is missing for this Python
                # tag, fall through to the standard ROCm index instead of
                # silently mixing Radeon wheels with PyPI defaults.
                _torch_whl=$(_pick_radeon_wheel "torch"       2>/dev/null) || _torch_whl=""
                _tv_whl=$(_pick_radeon_wheel    "torchvision" 2>/dev/null) || _tv_whl=""
                _ta_whl=$(_pick_radeon_wheel    "torchaudio"  2>/dev/null) || _ta_whl=""
                _tri_whl=$(_pick_radeon_wheel   "triton"      2>/dev/null) || _tri_whl=""
                # Sanity-check torch / torchvision / torchaudio are a
                # matching release. The Radeon repo publishes multiple
                # generations simultaneously, so picking the highest-version
                # wheel for each package independently can assemble a
                # mismatched trio (e.g. torch 2.9.1 + torchvision 0.23.0 +
                # torchaudio 2.9.0 from the current rocm-rel-7.2.1 index).
                # Check that torch and torchaudio share the same X.Y public
                # version prefix, and that torchvision's minor correctly
                # pairs with torch's minor (torchvision = torch.minor - 5
                # since torch 2.4 -> torchvision 0.19 -> torch 2.9 ->
                # torchvision 0.24).
                # URL-decode each wheel name so %2B -> + before version
                # extraction. Real Radeon wheel hrefs are percent-encoded
                # (torch-2.10.0%2Brocm7.2.0...), so a plain [+-] terminator
                # in the sed regex below would never match and
                # _radeon_versions_match would stay false for every real
                # listing, silently forcing a fallback to the generic
                # ROCm index.
                _torch_ver=""
                _tv_ver=""
                _ta_ver=""
                if [ -n "$_torch_whl" ]; then
                    _torch_name=$(printf '%s' "${_torch_whl##*/}" | sed 's/%2[Bb]/+/g')
                    _torch_ver=$(printf '%s\n' "$_torch_name" | sed -n 's|^torch-\([0-9][0-9]*\.[0-9][0-9]*\)\(\.[0-9][0-9]*\)\{0,1\}[+-].*|\1|p')
                fi
                if [ -n "$_tv_whl" ]; then
                    _tv_name=$(printf '%s' "${_tv_whl##*/}" | sed 's/%2[Bb]/+/g')
                    _tv_ver=$(printf '%s\n' "$_tv_name" | sed -n 's|^torchvision-\([0-9][0-9]*\.[0-9][0-9]*\)\(\.[0-9][0-9]*\)\{0,1\}[+-].*|\1|p')
                fi
                if [ -n "$_ta_whl" ]; then
                    _ta_name=$(printf '%s' "${_ta_whl##*/}" | sed 's/%2[Bb]/+/g')
                    _ta_ver=$(printf '%s\n' "$_ta_name" | sed -n 's|^torchaudio-\([0-9][0-9]*\.[0-9][0-9]*\)\(\.[0-9][0-9]*\)\{0,1\}[+-].*|\1|p')
                fi
                _radeon_versions_match=false
                if [ -n "$_torch_ver" ] && [ -n "$_tv_ver" ] && [ -n "$_ta_ver" ]; then
                    _torch_major=${_torch_ver%%.*}
                    _torch_minor=${_torch_ver#*.}
                    _ta_major=${_ta_ver%%.*}
                    _ta_minor=${_ta_ver#*.}
                    _tv_major=${_tv_ver%%.*}
                    _tv_minor=${_tv_ver#*.}
                    # torchvision expected minor (e.g. torch 2.9 -> 0.24)
                    _expected_tv_minor=$((_torch_minor + 15))
                    if [ "$_torch_major" = "$_ta_major" ] && \
                       [ "$_torch_minor" = "$_ta_minor" ] && \
                       [ "$_tv_major" = "0" ] && \
                       [ "$_tv_minor" = "$_expected_tv_minor" ]; then
                        _radeon_versions_match=true
                    fi
                fi
                if [ -z "$_torch_whl" ] || [ -z "$_tv_whl" ] || [ -z "$_ta_whl" ] || \
                   [ "$_radeon_versions_match" != true ]; then
                    substep "[WARN] Radeon repo lacks a compatible wheel set for this Python; falling back to ROCm index ($TORCH_INDEX_URL)" "$C_WARN"
                    run_install_cmd "install PyTorch" uv pip install --python "$_VENV_PY" \
                        "$TORCH_CONSTRAINT" torchvision torchaudio \
                        --index-url "$TORCH_INDEX_URL"
                else
                    substep "installing PyTorch from Radeon repo (${_RADEON_BASE_URL})..."
                    # Pass explicit wheel URLs so the matched trio is
                    # installed together. --find-links lets uv discover
                    # the Radeon listing for any local lookup, and PyPI
                    # (not disabled) provides transitive deps like
                    # filelock / sympy / networkx which are not in the
                    # Radeon listing.
                    if [ -n "$_tri_whl" ]; then
                        run_install_cmd "install triton + PyTorch" uv pip install --python "$_VENV_PY" \
                            --find-links "$_RADEON_BASE_URL" \
                            "$_tri_whl" "$_torch_whl" "$_tv_whl" "$_ta_whl"
                    else
                        run_install_cmd "install PyTorch" uv pip install --python "$_VENV_PY" \
                            --find-links "$_RADEON_BASE_URL" \
                            "$_torch_whl" "$_tv_whl" "$_ta_whl"
                    fi
                fi
            else
                substep "[WARN] Radeon repo unavailable; falling back to ROCm index ($TORCH_INDEX_URL)" "$C_WARN"
                run_install_cmd "install PyTorch" uv pip install --python "$_VENV_PY" \
                    "$TORCH_CONSTRAINT" torchvision torchaudio \
                    --index-url "$TORCH_INDEX_URL"
            fi
        else
            substep "[WARN] Radeon GPU detected but could not detect full ROCm version; falling back to ROCm index" "$C_WARN"
            run_install_cmd "install PyTorch" uv pip install --python "$_VENV_PY" \
                "$TORCH_CONSTRAINT" torchvision torchaudio \
                --index-url "$TORCH_INDEX_URL"
        fi
    else
        substep "installing PyTorch ($TORCH_INDEX_URL)..."
        run_install_cmd "install PyTorch" uv pip install --python "$_VENV_PY" "$TORCH_CONSTRAINT" torchvision torchaudio \
            --index-url "$TORCH_INDEX_URL"
    fi
    # AMD ROCm: install bitsandbytes (once, after torch, for all ROCm paths).
    # Gate on SKIP_TORCH=false so a user running with --no-torch on a ROCm
    # host stays in GGUF-only mode rather than pulling in bitsandbytes,
    # which is only useful once torch is present for training.
    if [ "$SKIP_TORCH" = false ]; then
        case "$TORCH_INDEX_URL" in
            */rocm*)
                _install_bnb_rocm "install bitsandbytes (AMD)" "$_VENV_PY"
                ;;
        esac
    fi
    # Fresh: Step 2 - install unsloth, preserving pre-installed torch
    tauri_log "STEP" "Installing Unsloth"
    substep "installing unsloth (this may take a few minutes)..."
    if [ "$SKIP_TORCH" = true ]; then
        # No-torch: install unsloth + unsloth-zoo with --no-deps, then
        # runtime deps (typer, safetensors, transformers, etc.) with --no-deps.
        run_install_cmd "install unsloth (no-torch)" uv pip install --python "$_VENV_PY" --no-deps \
            --upgrade-package unsloth --upgrade-package unsloth-zoo \
            "unsloth>=2026.5.8" unsloth-zoo
        # Same pydantic-with-deps trick as the migrated branch.
        run_install_cmd "install pydantic (with deps for compatible core)" \
            uv pip install --python "$_VENV_PY" pydantic
        _NO_TORCH_RT="$(_find_no_torch_runtime)"
        if [ -n "$_NO_TORCH_RT" ]; then
            run_install_cmd "install no-torch runtime deps" uv pip install --python "$_VENV_PY" --no-deps -r "$_NO_TORCH_RT"
        fi
        if [ "$STUDIO_LOCAL_INSTALL" = true ]; then
            substep "overlaying local repo (editable)..."
            run_install_cmd "overlay local repo" uv pip install --python "$_VENV_PY" -e "$_REPO_ROOT" --no-deps
            substep "overlaying unsloth-zoo from git main..."
            run_install_cmd "overlay unsloth-zoo (git main)" uv pip install --python "$_VENV_PY" \
                --no-deps --reinstall-package unsloth-zoo \
                "unsloth-zoo @ git+https://github.com/unslothai/unsloth-zoo"
        fi
    elif [ "$STUDIO_LOCAL_INSTALL" = true ]; then
        run_install_cmd "install unsloth (local)" uv pip install --python "$_VENV_PY" \
            --upgrade-package unsloth "unsloth>=2026.5.8" unsloth-zoo
        substep "overlaying local repo (editable)..."
        run_install_cmd "overlay local repo" uv pip install --python "$_VENV_PY" -e "$_REPO_ROOT" --no-deps
        substep "overlaying unsloth-zoo from git main..."
        run_install_cmd "overlay unsloth-zoo (git main)" uv pip install --python "$_VENV_PY" \
            --no-deps --reinstall-package unsloth-zoo \
            "unsloth-zoo @ git+https://github.com/unslothai/unsloth-zoo"
    else
        run_install_cmd "install unsloth" uv pip install --python "$_VENV_PY" \
            --upgrade-package unsloth -- "$PACKAGE_NAME"
    fi
    # AMD ROCm: repair torch if the unsloth/unsloth-zoo install pulled in
    # CUDA torch from PyPI, overwriting the ROCm wheels installed in Step 1.
    if [ "$SKIP_TORCH" = false ]; then
        case "$TORCH_INDEX_URL" in
            */rocm*)
                _has_hip=$("$_VENV_PY" -c "import torch; print(getattr(torch.version,'hip','') or '')" 2>/dev/null || true)
                if [ -z "$_has_hip" ]; then
                    substep "repairing ROCm torch (overwritten by dependency resolution)..."
                    run_install_cmd "repair ROCm torch" uv pip install --python "$_VENV_PY" \
                        "$TORCH_CONSTRAINT" torchvision torchaudio \
                        --index-url "$TORCH_INDEX_URL" \
                        --force-reinstall
                fi
                ;;
        esac
    fi
else
    # Fallback: GPU detection failed to produce a URL -- let uv resolve torch
    tauri_log "STEP" "Installing Unsloth"
    substep "installing unsloth (this may take a few minutes)..."
    if [ "$STUDIO_LOCAL_INSTALL" = true ]; then
        run_install_cmd "install unsloth (auto torch backend)" uv pip install --python "$_VENV_PY" unsloth-zoo "unsloth>=2026.5.8" --torch-backend=auto
        substep "overlaying local repo (editable)..."
        run_install_cmd "overlay local repo" uv pip install --python "$_VENV_PY" -e "$_REPO_ROOT" --no-deps
        substep "overlaying unsloth-zoo from git main..."
        run_install_cmd "overlay unsloth-zoo (git main)" uv pip install --python "$_VENV_PY" \
            --no-deps --reinstall-package unsloth-zoo \
            "unsloth-zoo @ git+https://github.com/unslothai/unsloth-zoo"
    else
        run_install_cmd "install unsloth (auto torch backend)" uv pip install --python "$_VENV_PY" --torch-backend=auto -- "$PACKAGE_NAME"
    fi
fi

# ── Run studio setup ──
tauri_log "STEP" "Running Studio setup"
# When --local, use the repo's own setup.sh directly.
# Otherwise, find it inside the installed package.
SETUP_SH=""
if [ "$STUDIO_LOCAL_INSTALL" = true ] && [ -f "$_REPO_ROOT/studio/setup.sh" ]; then
    SETUP_SH="$_REPO_ROOT/studio/setup.sh"
fi

if [ -z "$SETUP_SH" ] || [ ! -f "$SETUP_SH" ]; then
    SETUP_SH=$("$VENV_DIR/bin/python" -c "
import importlib.resources
print(importlib.resources.files('studio') / 'setup.sh')
" 2>/dev/null || echo "")
fi

# Fallback: search site-packages
if [ -z "$SETUP_SH" ] || [ ! -f "$SETUP_SH" ]; then
    SETUP_SH=$(find "$VENV_DIR" -path "*/studio/setup.sh" -print -quit 2>/dev/null || echo "")
fi

if [ -z "$SETUP_SH" ] || [ ! -f "$SETUP_SH" ]; then
    tauri_log "ERROR" "Could not find studio/setup.sh in the installed package"
    echo "❌ ERROR: Could not find studio/setup.sh in the installed package."
    exit 1
fi

# Ensure the venv's Python is on PATH so setup.sh can find it.
VENV_ABS_BIN="$(cd "$VENV_DIR/bin" && pwd)"
if [ -n "$VENV_ABS_BIN" ]; then
    export PATH="$VENV_ABS_BIN:$PATH"
fi

if ! command -v bash >/dev/null 2>&1; then
    step "setup" "bash is required to run studio setup" "$C_ERR"
    substep "Please install bash and re-run install.sh"
    exit 1
fi

step "setup" "running unsloth studio update..."
_SKIP_BASE=1
_SETUP_EXIT=0
# Tauri desktop app bundles its own frontend — skip Node/npm/frontend build
_SKIP_FRONTEND=0
if [ "$TAURI_MODE" = true ]; then
    _SKIP_FRONTEND=1
fi
# Prepend UNSLOTH_STUDIO_HOME=$STUDIO_HOME to "$@" for env-override installs
# without word-splitting on whitespace paths.
_run_setup_with_studio_home() {
    if [ "$_STUDIO_HOME_REDIRECT" = "env" ]; then
        UNSLOTH_STUDIO_HOME="$STUDIO_HOME" "$@"
    else
        "$@"
    fi
}
if [ "$STUDIO_LOCAL_INSTALL" = true ]; then
    _run_setup_with_studio_home env \
    SKIP_STUDIO_BASE="$_SKIP_BASE" \
    SKIP_STUDIO_FRONTEND="$_SKIP_FRONTEND" \
    STUDIO_PACKAGE_NAME="$PACKAGE_NAME" \
    STUDIO_LOCAL_INSTALL=1 \
    STUDIO_LOCAL_REPO="$_REPO_ROOT" \
    UNSLOTH_NO_TORCH="$SKIP_TORCH" \
    bash "$SETUP_SH" </dev/null || _SETUP_EXIT=$?
else
    # Explicitly reset STUDIO_LOCAL_INSTALL / STUDIO_LOCAL_REPO so a stale
    # value inherited from the parent shell (e.g. a previous --local run in
    # the same session) does not silently flip a normal install onto the
    # local-dev path in setup.sh and install_python_stack.py. Mirrors the
    # reset already done in install.ps1 for PowerShell.
    _run_setup_with_studio_home env \
    SKIP_STUDIO_BASE="$_SKIP_BASE" \
    SKIP_STUDIO_FRONTEND="$_SKIP_FRONTEND" \
    STUDIO_PACKAGE_NAME="$PACKAGE_NAME" \
    STUDIO_LOCAL_INSTALL=0 \
    STUDIO_LOCAL_REPO= \
    UNSLOTH_NO_TORCH="$SKIP_TORCH" \
    bash "$SETUP_SH" </dev/null || _SETUP_EXIT=$?
fi

# ── Make 'unsloth' available via $_LOCAL_BIN (resolved earlier) ──
# Env-mode: $_LOCAL_BIN is $STUDIO_HOME/bin; skip shell-rc PATH append so we
# don't pollute the user's profile with a workspace-scoped path.
mkdir -p "$_LOCAL_BIN"
# ln -sf into an existing dir creates link inside it. Refuse to delete a
# real directory at the shim path -- that could destroy unrelated user data.
_shim_path="$_LOCAL_BIN/unsloth"
if [ -d "$_shim_path" ] && [ ! -L "$_shim_path" ]; then
    echo "ERROR: $_shim_path is a directory; refusing to delete it." >&2
    echo "       Move or remove it manually, then re-run the installer." >&2
    exit 1
fi
# why: -sfn is atomic and -n prevents descent into a symlink-to-directory at
# the shim path (the directory guard above already rejects a real directory).
ln -sfn "$VENV_DIR/bin/unsloth" "$_shim_path"

case ":$PATH:" in
    *":$_LOCAL_BIN:"*) ;;  # already on PATH
    *)
        if [ "$_STUDIO_HOME_REDIRECT" = "env" ]; then
            export PATH="$_LOCAL_BIN:$PATH"
            step "path" "exported $_LOCAL_BIN for this session (no rc-file append in env-override mode)"
        else
            _SHELL_PROFILE=""
            if [ -n "${ZSH_VERSION:-}" ] || [ "$(basename "${SHELL:-}")" = "zsh" ]; then
                _SHELL_PROFILE="$HOME/.zshrc"
            elif [ -f "$HOME/.bashrc" ]; then
                _SHELL_PROFILE="$HOME/.bashrc"
            elif [ -f "$HOME/.profile" ]; then
                _SHELL_PROFILE="$HOME/.profile"
            fi
            if [ -n "$_SHELL_PROFILE" ]; then
                if ! grep -q '\.local/bin' "$_SHELL_PROFILE" 2>/dev/null; then
                    echo '' >> "$_SHELL_PROFILE"
                    echo '# Added by Unsloth installer' >> "$_SHELL_PROFILE"
                    echo 'export PATH="$HOME/.local/bin:$PATH"' >> "$_SHELL_PROFILE"
                    step "path" "added ~/.local/bin to PATH in $_SHELL_PROFILE"
                fi
            fi
            export PATH="$_LOCAL_BIN:$PATH"
        fi
        ;;
esac

# Non-Tauri installs keep shortcuts even if setup reports failure.
# create_studio_shortcuts gates persistent menu shortcuts on env-mode;
# launcher + studio.conf + icon are always written.
if [ "$TAURI_MODE" != true ]; then
    create_studio_shortcuts "$VENV_ABS_BIN/unsloth" "$OS"
fi

# If setup.sh failed, report and exit now.
# PATH and shortcuts are already set up so the user can fix and retry.
if [ "$_SETUP_EXIT" -ne 0 ]; then
    echo ""
    step "error" "studio setup failed (exit code $_SETUP_EXIT)" "$C_ERR"
    echo ""
    exit "$_SETUP_EXIT"
fi

_commit_studio_venv_replacement

# ── Tauri mode: done, skip shortcuts and auto-launch ──
if [ "$TAURI_MODE" = true ]; then
    tauri_log "DONE" ""
    exit 0
fi

# Warn if another 'unsloth' wins on PATH (different venv, system pip, etc).
# Users typing `unsloth studio` later would hit that binary instead of the
# one just installed; the runtime now falls back via UNSLOTH_STUDIO_HOME
# but the absolute path is still the most reliable launch.
# Uses the venv python (just created above) for path canonicalization so
# this works on macOS (BSD readlink has no -f) as well as Linux/WSL.
_installed_bin="$VENV_DIR/bin/unsloth"
_path_unsloth=$(command -v unsloth 2>/dev/null || true)
if [ -n "$_path_unsloth" ] && [ -x "$VENV_DIR/bin/python" ]; then
    # Canonicalize via the venv python (BSD readlink lacks -f on macOS).
    # If either side fails to resolve, skip the check entirely rather than
    # comparing raw paths (which would false-trigger on symlink targets).
    _canon() {
        "$VENV_DIR/bin/python" -c \
            'import os, sys; print(os.path.realpath(sys.argv[1]))' \
            "$1" 2>/dev/null
    }
    _installed_real=$(_canon "$_installed_bin")
    _path_real=$(_canon "$_path_unsloth")
    if [ -n "$_installed_real" ] && [ -n "$_path_real" ] \
        && [ "$_installed_real" != "$_path_real" ]; then
        echo ""
        step "warning" "another 'unsloth' wins on PATH:" "$C_WARN"
        substep "$_path_unsloth"
        substep "this installer's binary is at:"
        substep "$_installed_bin"
        substep "to use this install, run the absolute path above,"
        substep "alias unsloth, or put its dir earlier on PATH."
        echo ""
    fi
fi

echo ""
printf "  ${C_TITLE}%s${C_RST}\n" "Unsloth Studio installed!"
printf "  ${C_DIM}%s${C_RST}\n" "$RULE"
echo ""

# In interactive terminals, ask the user before starting Studio.
# In non-interactive environments (Docker, CI, cloud-init) just print instructions.
if [ -t 1 ]; then
    echo ""
    printf "  Start Unsloth Studio now? [Y/n] "
    if [ -r /dev/tty ]; then
        read -r _reply </dev/tty || _reply="y"
    else
        _reply="y"
    fi
    case "${_reply:-y}" in
        [Yy]*|"")
            step "launch" "starting Unsloth Studio..."
            "$VENV_DIR/bin/unsloth" studio -p 8888
            _LAUNCH_EXIT=$?
            if [ "$_LAUNCH_EXIT" -ne 0 ] && [ "$_MIGRATED" = true ]; then
                echo ""
                echo "⚠️  Unsloth Studio failed to start after migration."
                echo "   Your migrated environment may be incompatible."
                echo "   To fix, remove the environment and reinstall:"
                echo ""
                echo "   rm -rf $VENV_DIR"
                echo "   curl -fsSL https://unsloth.ai/install.sh | sh"
                echo ""
            fi
            exit "$_LAUNCH_EXIT"
            ;;
        *)
            step "launch" "to start later, run:"
            substep "unsloth studio -p 8888"
            substep "(add -H 0.0.0.0 to allow network / cloud access)"
            echo ""
            ;;
    esac
else
    step "launch" "manual commands:"
    # Single-quote-escape so paths with spaces / apostrophes copy-paste cleanly.
    _li_shim_q="'$(printf '%s' "${_LOCAL_BIN}/unsloth" | sed "s/'/'\\\\''/g")'"
    _li_act_q="'$(printf '%s' "${VENV_DIR}/bin/activate" | sed "s/'/'\\\\''/g")'"
    if [ "$_STUDIO_HOME_REDIRECT" = "env" ]; then
        # Env-mode skips the rc PATH append, so print the absolute shim path.
        substep "$_li_shim_q studio -p 8888"
        substep "or activate env first:"
        substep "source $_li_act_q"
        substep "unsloth studio -p 8888"
    else
        substep "unsloth studio -p 8888"
        substep "or activate env first:"
        substep "source $_li_act_q"
        substep "unsloth studio -p 8888"
    fi
    substep "(add -H 0.0.0.0 to allow network / cloud access)"
    echo ""
fi