#!/usr/bin/env python3
# This file is part of ISO Scalpel.
# Copyright (C) 2025 Jeremy Anderson <info@dcos.net>
#
# 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, see <https://www.gnu.org/licenses/>
# or write to the Free Software Foundation, Inc., 51 Franklin Street,
# Fifth Floor, Boston, MA  02110-1301 USA.
"""ISO Scalpel -- entry point.

A PySide6 disc-image editor built on pycdlib, supporting ISO9660, Rock
Ridge, Joliet, UDF and El Torito boot images.

Usage:
    python main.py [file.iso]
    python main.py --check-deps        # report missing deps and exit
    python main.py --no-install-deps   # never prompt to install
    python main.py --reset-layout      # clear saved window/splitter settings and exit
    python main.py --debug-layout      # start the GUI with verbose widget-tree logging
"""
from __future__ import annotations

import os
import sys

# Make the package importable when run directly.
sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))

# Verify third-party dependencies BEFORE importing the GUI layer, so a
# missing package produces a friendly, actionable message instead of a raw
# traceback.  In an interactive terminal the user is offered to install
# the missing packages (with explicit consent for any sudo fallback).
from iso_scalpel._deps import (
    check_dependencies,
    ensure_dependencies,
    format_missing_report,
)

# Recognised long options and the flag key they set.  A flat lookup table
# replaces the if/elif chain so adding a new switch is a one-line edit.
_FLAG_TABLE: dict[str, str] = {
    "--check-deps": "check_only",
    "--no-install-deps": "no_install",
    "--reset-layout": "reset_layout",
    "--debug-layout": "debug_layout",
}


def _parse_flags(argv: list[str]) -> tuple[list[str], dict[str, bool]]:
    """Separate our own flags from argv; return (positional, flags_dict).

    Unknown arguments are treated as positional and returned for the GUI
    layer (which honours a single ISO path argument).
    """
    flags = dict.fromkeys(_FLAG_TABLE.values(), False)
    rest: list[str] = []
    for arg in argv:
        flag_key = _FLAG_TABLE.get(arg)
        if flag_key is not None:
            flags[flag_key] = True
        else:
            rest.append(arg)
    return rest, flags


def _reset_layout() -> int:
    """Delete the saved settings file so the next launch uses defaults."""
    from iso_scalpel.config import _config_path
    path = _config_path()
    if os.path.exists(path):
        try:
            os.remove(path)
            print(f"Removed saved settings: {path}")
        except OSError as exc:
            sys.stderr.write(f"Could not remove {path}: {exc}\n")
            return 1
    else:
        print(f"No saved settings at {path} -- nothing to reset.")
    print("Re-run `python main.py` to launch with default layout.")
    return 0


def main() -> int:
    argv = list(sys.argv)
    argv, flags = _parse_flags(argv)

    if flags["check_only"]:
        missing = check_dependencies()
        if missing:
            sys.stderr.write(format_missing_report(missing) + "\n")
            return 1
        print("All dependencies satisfied.")
        return 0

    if flags["reset_layout"]:
        return _reset_layout()

    ensure_dependencies(auto_install=not flags["no_install"])

    from iso_scalpel.app import run
    # If a file was passed on the command line, defer opening it to the
    # main window after it is constructed.  Handled in run() via argv.
    return run(argv, debug_layout=flags["debug_layout"])


if __name__ == "__main__":
    raise SystemExit(main())