"""Build a single-file GUI executable for the current OS with PyInstaller.

    python build.py                      # -> dist/FFmpegWrapper(.exe)
    python build.py --ffmpeg-dir DIR     # also copy ffmpeg + ffprobe from DIR next to the exe,
                                         #    plus ffmpeg's LICENSE from DIR or its parent,
                                         #    and pack everything into a .zip / .tar.gz

PyInstaller cannot cross-compile: run this on Windows to get the .exe and on
Linux to get the Linux binary (or use the CI workflow, which does both).
"""

from __future__ import annotations

import argparse
import shutil
import sys
from pathlib import Path

ROOT = Path(__file__).resolve().parent
NAME = "FFmpegWrapper"
IS_WINDOWS = sys.platform.startswith("win")
EXE = ".exe" if IS_WINDOWS else ""


def find_ffmpeg_license(ffmpeg_dir: Path) -> Path | None:
    """ffmpeg's license file. BtbN and gyan.dev builds keep it one level above bin/."""
    for folder in (ffmpeg_dir, ffmpeg_dir.parent):
        for name in ("LICENSE.txt", "LICENSE", "ffmpeg-LICENSE.txt"):
            if (folder / name).is_file():
                return folder / name
    return None


def main() -> int:
    ap = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
    ap.add_argument("--ffmpeg-dir", type=Path, help="folder containing ffmpeg and ffprobe to bundle")
    ap.add_argument("--onedir", action="store_true", help="build a folder instead of a single file (faster start-up)")
    args = ap.parse_args()

    if args.ffmpeg_dir:
        # Check before the slow PyInstaller run: ffmpeg is GPL, so its license must ship with it.
        ffmpeg_license = find_ffmpeg_license(args.ffmpeg_dir)
        if ffmpeg_license is None:
            print(f"error: no ffmpeg license (LICENSE.txt or LICENSE) in {args.ffmpeg_dir} or its parent "
                  "folder. ffmpeg is GPL, so the license has to be packaged with it.", file=sys.stderr)
            return 1

    import PyInstaller.__main__

    from ffwrap import __version__

    sep = ";" if IS_WINDOWS else ":"
    pyi_args = [
        str(ROOT / "run.py"),
        "--name", NAME,
        "--windowed",
        "--noconfirm",
        "--clean",
        "--onedir" if args.onedir else "--onefile",
        "--icon", str(ROOT / "assets" / "icon.ico"),
        "--add-data", f"{ROOT / 'assets' / 'icon.png'}{sep}assets",
        "--distpath", str(ROOT / "dist"),
        "--workpath", str(ROOT / "build"),
        "--specpath", str(ROOT / "build"),
        # Not needed and only add weight.
        "--exclude-module", "tkinter",
        "--exclude-module", "unittest",
        "--exclude-module", "pydoc",
    ]
    PyInstaller.__main__.run(pyi_args)

    dist = ROOT / "dist"
    built = dist / NAME if args.onedir else dist / f"{NAME}{EXE}"
    print(f"\nBuilt {built}")

    if args.ffmpeg_dir:
        # Stage <exe or onedir tree> + ffmpeg + ffprobe + ffmpeg's license in one folder and archive it.
        stage = dist / "package" / NAME
        shutil.rmtree(stage.parent, ignore_errors=True)
        if args.onedir:
            shutil.copytree(built, stage)
        else:
            stage.mkdir(parents=True)
            shutil.copy2(built, stage)
        for tool in ("ffmpeg", "ffprobe"):
            src = args.ffmpeg_dir / f"{tool}{EXE}"
            if not src.is_file():
                print(f"error: {src} not found", file=sys.stderr)
                return 1
            shutil.copy2(src, stage)
        shutil.copy2(ffmpeg_license, stage / "ffmpeg-LICENSE.txt")
        plat ="windows-x64" if IS_WINDOWS else "linux-x64"
        archive = shutil.make_archive(
            str(dist / f"{NAME}-{__version__}-{plat}"), "zip" if IS_WINDOWS else "gztar",
            root_dir=stage.parent, base_dir=NAME)
        print(f"Packed {archive}")
    return 0


if __name__ == "__main__":
    sys.exit(main())