import json
import os
import shutil
import subprocess
import textwrap
from pathlib import Path

import pytest

WORKDIR = Path(__file__).resolve().parents[2]


def _source_path(relative_path: str) -> Path:
    direct = WORKDIR / relative_path
    if direct.exists():
        return direct
    return WORKDIR / "unsloth_repo" / relative_path


PRESET_POLICY = _source_path("studio/frontend/src/features/chat/presets/preset-policy.ts")
RUNTIME_TYPES = _source_path("studio/frontend/src/features/chat/types/runtime.ts")
TEMP = WORKDIR / "temp" / "chat_preset_builtin_invariants"


def _require_node():
    if shutil.which("node") is None:
        pytest.skip("node not available")
    if not PRESET_POLICY.exists() or not RUNTIME_TYPES.exists():
        pytest.skip("studio chat sources not present")
    result = subprocess.run(
        ["node", "--experimental-strip-types", "--version"],
        capture_output = True,
        text = True,
        timeout = 5,
    )
    if result.returncode != 0:
        pytest.skip("node --experimental-strip-types not available")


def _ensure_harness():
    TEMP.mkdir(parents = True, exist_ok = True)
    (TEMP / "register.mjs").write_text(
        "import { register } from 'node:module';\nregister('./loader.mjs', import.meta.url);\n"
    )
    (TEMP / "loader.mjs").write_text(
        "export function resolve(specifier, context, next) {\n"
        "  if (specifier.endsWith('/types/runtime')) return next(specifier + '.ts', context);\n"
        "  return next(specifier, context);\n"
        "}\n"
    )


def _run(script: str):
    _require_node()
    _ensure_harness()
    script_path = TEMP / "run.mts"
    script_path.write_text(script)
    env = dict(os.environ, NODE_NO_WARNINGS = "1")
    result = subprocess.run(
        [
            "node",
            "--experimental-strip-types",
            "--import=./register.mjs",
            "--no-warnings",
            "run.mts",
        ],
        cwd = str(TEMP),
        capture_output = True,
        text = True,
        timeout = 30,
        env = env,
    )
    assert result.returncode == 0, f"stderr: {result.stderr}\nstdout: {result.stdout}"
    last = [line for line in result.stdout.strip().splitlines() if line.strip()][-1]
    return json.loads(last)


def _policy_path():
    return os.path.relpath(PRESET_POLICY, TEMP).replace("\\", "/")


def _runtime_path():
    return os.path.relpath(RUNTIME_TYPES, TEMP).replace("\\", "/")


def test_default_builtin_matches_default_inference_params():
    out = _run(
        textwrap.dedent(
            f"""
            // @ts-nocheck
            import {{ BUILTIN_PRESETS, isSamePresetConfig }} from "{_policy_path()}";
            import {{ DEFAULT_INFERENCE_PARAMS }} from "{_runtime_path()}";
            const def = BUILTIN_PRESETS.find((p) => p.name === "Default");
            console.log(JSON.stringify({{
                found: !!def,
                matches: def ? isSamePresetConfig(def.params, DEFAULT_INFERENCE_PARAMS) : null,
            }}));
            """
        )
    )
    assert out["found"] is True
    assert out["matches"] is True


def test_is_same_preset_config_detects_temperature_edit():
    out = _run(
        textwrap.dedent(
            f"""
            // @ts-nocheck
            import {{ BUILTIN_PRESETS, isSamePresetConfig }} from "{_policy_path()}";
            const def = BUILTIN_PRESETS.find((p) => p.name === "Default");
            const edited = {{ ...def.params, temperature: def.params.temperature + 0.1 }};
            console.log(JSON.stringify({{ same: isSamePresetConfig(def.params, edited) }}));
            """
        )
    )
    assert out["same"] is False


def test_is_same_preset_config_detects_system_prompt_edit():
    out = _run(
        textwrap.dedent(
            f"""
            // @ts-nocheck
            import {{ BUILTIN_PRESETS, isSamePresetConfig }} from "{_policy_path()}";
            const def = BUILTIN_PRESETS.find((p) => p.name === "Default");
            const edited = {{ ...def.params, systemPrompt: "you are a pirate" }};
            console.log(JSON.stringify({{ same: isSamePresetConfig(def.params, edited) }}));
            """
        )
    )
    assert out["same"] is False


def test_is_same_preset_config_ignores_checkpoint_difference():
    out = _run(
        textwrap.dedent(
            f"""
            // @ts-nocheck
            import {{ BUILTIN_PRESETS, isSamePresetConfig }} from "{_policy_path()}";
            const def = BUILTIN_PRESETS.find((p) => p.name === "Default");
            const withCheckpoint = {{ ...def.params, checkpoint: "meta-llama/Llama-3-8B" }};
            console.log(JSON.stringify({{ same: isSamePresetConfig(def.params, withCheckpoint) }}));
            """
        )
    )
    assert out["same"] is True


def test_is_same_preset_config_ignores_model_owned_fields():
    out = _run(
        textwrap.dedent(
            f"""
            // @ts-nocheck
            import {{ BUILTIN_PRESETS, isSamePresetConfig }} from "{_policy_path()}";
            const def = BUILTIN_PRESETS.find((p) => p.name === "Default");
            const edited = {{
                ...def.params,
                maxSeqLength: def.params.maxSeqLength + 1024,
                trustRemoteCode: !def.params.trustRemoteCode,
            }};
            console.log(JSON.stringify({{ same: isSamePresetConfig(def.params, edited) }}));
            """
        )
    )
    assert out["same"] is True


def test_preset_owned_config_key_ignores_model_owned_fields():
    out = _run(
        textwrap.dedent(
            f"""
            // @ts-nocheck
            import {{ BUILTIN_PRESETS, getPresetOwnedConfigKey }} from "{_policy_path()}";
            const def = BUILTIN_PRESETS.find((p) => p.name === "Default");
            const edited = {{
                ...def.params,
                checkpoint: "foo/bar",
                maxSeqLength: def.params.maxSeqLength + 1024,
                trustRemoteCode: !def.params.trustRemoteCode,
            }};
            console.log(JSON.stringify({{
                same: getPresetOwnedConfigKey(def.params) === getPresetOwnedConfigKey(edited),
            }}));
            """
        )
    )
    assert out["same"] is True


def test_to_preset_params_strips_model_owned_fields():
    out = _run(
        textwrap.dedent(
            f"""
            // @ts-nocheck
            import {{ toPresetParams }} from "{_policy_path()}";
            const sanitized = toPresetParams({{
                temperature: 0.9,
                topP: 0.8,
                topK: 40,
                minP: 0.05,
                repetitionPenalty: 1.1,
                presencePenalty: 0.4,
                maxSeqLength: 16384,
                maxTokens: 2048,
                systemPrompt: "hello",
                checkpoint: "foo/bar",
                trustRemoteCode: true,
            }});
            console.log(JSON.stringify({{
                checkpoint: sanitized.checkpoint,
                trustRemoteCode: sanitized.trustRemoteCode,
                maxSeqLength: sanitized.maxSeqLength,
                maxTokens: sanitized.maxTokens,
                systemPrompt: sanitized.systemPrompt,
            }}));
            """
        )
    )
    assert out["checkpoint"] == ""
    assert out["trustRemoteCode"] is False
    assert out["maxSeqLength"] == 4096
    assert out["maxTokens"] == 2048
    assert out["systemPrompt"] == "hello"


def test_apply_preset_params_preserves_model_owned_fields():
    out = _run(
        textwrap.dedent(
            f"""
            // @ts-nocheck
            import {{ applyPresetParams }} from "{_policy_path()}";
            const samplingPreset = {{
                temperature: 1.5,
                topP: 1,
                topK: 0,
                minP: 0.1,
                repetitionPenalty: 1,
                presencePenalty: 0,
                maxSeqLength: 4096,
                maxTokens: 2048,
                systemPrompt: "",
                checkpoint: "",
                trustRemoteCode: false,
            }};
            const applied = applyPresetParams(
                {{
                    temperature: 0.6,
                    topP: 0.95,
                    topK: 20,
                    minP: 0.01,
                    repetitionPenalty: 1.0,
                    presencePenalty: 0.0,
                    maxSeqLength: 16384,
                    maxTokens: 8192,
                    systemPrompt: "keep me?",
                    checkpoint: "foo/bar",
                    trustRemoteCode: true,
                }},
                samplingPreset,
            );
            console.log(JSON.stringify({{
                checkpoint: applied.checkpoint,
                trustRemoteCode: applied.trustRemoteCode,
                maxSeqLength: applied.maxSeqLength,
                temperature: applied.temperature,
                topK: applied.topK,
            }}));
            """
        )
    )
    assert out["checkpoint"] == "foo/bar"
    assert out["trustRemoteCode"] is True
    assert out["maxSeqLength"] == 16384
    assert out["temperature"] == 1.5
    assert out["topK"] == 0


def test_default_is_only_builtin_preset():
    out = _run(
        textwrap.dedent(
            f"""
            // @ts-nocheck
            import {{ BUILTIN_PRESETS }} from "{_policy_path()}";
            console.log(JSON.stringify({{
                names: BUILTIN_PRESETS.map((p) => p.name),
            }}));
            """
        )
    )
    assert out["names"] == ["Default"]