#!/bin/bash
#
# Copyright (c) [2026] SUSE LLC
#
# All Rights Reserved.
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the Free
# Software Foundation; either version 2 of the License, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, contact SUSE LLC.
#
# To contact SUSE LLC about this file by physical or electronic mail, you may
# find current contact information at www.suse.com.

# Helper script which prints the messages from the systemd journal with
# additional details like code location.

# All script arguments are passed to journalctl, you can use it to filter the
# displayed messages, e.g. filter by unit with '-u sshd.service', filter by time
# with '--since "5 minutes ago"' or show only errors and higher priority with
# '-p err'..

# The timestamps are printed in the local time, to print the UTC time
# run with TZ=UTC. Hint: You can set any time zone, e.g. TZ=America/New_York.

# It accepts special "--input-file <file>" parameter to load the data from
# previously saved journal in JSON format.


# Use colors if the output goes to a terminal
if [ -t 1 ]; then
  USE_COLORS="true"
else
  USE_COLORS="false"
fi

SHOW_MICROSECONDS="false"
INPUT_FILE=""
JOURNAL_ARGS=()

while [ $# -gt 0 ]; do
  case "$1" in
    # Allow using a JSON file as input
    --input-file)
      INPUT_FILE="$2"
      shift 2
      ;;
    --microseconds)
      SHOW_MICROSECONDS="true"
      shift
      ;;
    *)
      JOURNAL_ARGS+=("$1")
      shift
      ;;
  esac
done

process_logs() {
  if [ -n "$INPUT_FILE" ]; then
    cat "$INPUT_FILE"
  else
    journalctl -o json "$@"
  fi | jq --unbuffered --arg use_colors "$USE_COLORS" --arg show_microseconds "$SHOW_MICROSECONDS" -r '
  # Helper function to get color based on priority
  def get_color:
    {
      "0": "\u001b[1;91m", # Emergency - Bold Bright Red
      "1": "\u001b[1;91m", # Alert - Bold Bright Red
      "2": "\u001b[1;91m", # Critical - Bold Bright Red
      "3": "\u001b[1;31m", # Error - Bold Red
      "4": "\u001b[93m", # Warning - Bright Yellow
      "5": "\u001b[1m",  # Notice - Bold white
      "6": "",           # Informational - Default
      "7": "\u001b[90m"  # Debug - Grey
    }[tostring] // "";

  # Helper function to format timestamp
  def format_timestamp:
    # The journal time is in microseconds
    (tonumber / 1000000 | strflocaltime("%b %e %H:%M:%S"))
      + (if $show_microseconds == "true" then "." + (tostring | .[-6:]) else "" end);

  # Helper function to build the source code location string
  def format_location:
    [
      (.CODE_FILE | select(. != null and . != "") | tostring),
      (.CODE_FUNC | select(. != null and . != "") | "(" + tostring + ")"),
      (.CODE_LINE | select(. != null and . != "") | ":" + tostring + ":")
    ]
    | join("")
    | select(. != "");

  # Helper function to combine syslog identifier and PID
  def format_syslog_pid:
    [
      (.SYSLOG_IDENTIFIER | select(. != null and . != "")),
      (._PID | select(. != null and . != "") | "[" + tostring + "]:")
    ]
    | join("")
    | select(. != "");

  # Join the requested fields into a single line
  (.PRIORITY | get_color) as $color |
  [
    (.__REALTIME_TIMESTAMP | select(. != null and . != "") | format_timestamp),
    (.PRIORITY | select(. != null and . != "") | "<" + tostring + ">"),
    format_syslog_pid,
    format_location,
    (.ZYPP_GROUP | select(. != null and . != "") | "[" + tostring + "]"),
    (.MESSAGE | select(. != null and . != "") | tostring | if $use_colors == "true" and $color != "" then $color + . + "\u001b[0m" else . end)
  ]
  # Remove any missing/empty values and join them with a space
  | map(select(. != null and . != ""))
  | join(" ")
'
}

if [ "$USE_COLORS" = "true" ] && [ -n "$PAGER" ]; then
  process_logs "${JOURNAL_ARGS[@]}" | $PAGER
else
  process_logs "${JOURNAL_ARGS[@]}"
fi