#!/usr/bin/env python3
"""
Fix JRiver date imported fields to use the earliest date for each album.
"""

import sys
from pathlib import Path, PureWindowsPath


def get_album_path(line: str) -> str:
    """Extract and return the album directory path from a filename field."""
    filename = line.lstrip('<Field Name="Filename">').rstrip('</Field>\n')
    path = PureWindowsPath(filename)
    return str(path.parent)


def get_date(line: str) -> int:
    """Extract and return the date imported value from a date field."""
    date = line.lstrip('<Field Name="Date Imported">').rstrip('</Field>\n')
    return int(date)


def main() -> None:
    """Main function to process JRiver library file."""
    if len(sys.argv) != 3:
        print("Usage: jriver-fix-date-imported <input_file> <output_file>", file=sys.stderr)
        sys.exit(1)

    in_file = Path(sys.argv[1])
    out_file = Path(sys.argv[2])

    if not in_file.exists():
        print(f"[ERROR] Input file '{in_file}' does not exist.", file=sys.stderr)
        sys.exit(1)

    # Read input file
    with open(in_file, "r", encoding="utf-8") as f:
        lines = f.readlines()

    # Build album to tracks mapping
    albums: dict[str, list[tuple[int, int]]] = {}
    current_album: str | None = None
    
    for lnum, line in enumerate(lines):
        if '<Field Name="Filename">' in line:
            current_album = get_album_path(line)
        elif '<Field Name="Date Imported">' in line:
            date = get_date(line)
            if current_album:
                albums.setdefault(current_album, []).append((lnum, date))

    # Update lines with earliest date for each album
    for _, tracks in albums.items():
        earliest_date: int = min(tracks, key=lambda t: t[1])[1]
        for lnum, _ in tracks:
            lines[lnum] = f'<Field Name="Date Imported">{earliest_date}</Field>\n'

    # Write output file
    with open(out_file, 'w', encoding="utf-8") as f:
        f.writelines(lines)

    print(f"[SUCCESS] Processed {len(albums)} albums. Output written to '{out_file}'.")


if __name__ == "__main__":
    main()