from argparse import ArgumentParser
import logging
from pathlib import Path
import urllib.error
import urllib.request

from flask import Flask, send_file


def main():
    parser = ArgumentParser()
    parser.add_argument('--host', default='0.0.0.0', help='Server host (default: 0.0.0.0)')
    parser.add_argument('--port', type=int, default=8000, help='Server port (default: 8000)')
    parser.add_argument('--debug', action='store_true', help='Run in debug mode (auto-reload on change)')
    arguments = parser.parse_args()

    host: str = arguments.host
    port: int = arguments.port
    debug_mode: bool = arguments.debug
    del arguments

    app = Flask('map_server', static_folder='public', static_url_path='/')
    osm_timeout = 3
    http_code_ok = 200
    if not debug_mode:
        log = logging.getLogger('werkzeug')
        log.setLevel(logging.WARNING)

    @app.route('/')
    def _index():
        return app.send_static_file('index.html')

    @app.route('/<int:zoom>/<int:x>/<int:y>.png')
    def _tile(zoom: int, x: int, y: int):
        tile_path = Path('data', str(zoom), str(x), f'{y}.png')
        if tile_path.exists():
            return send_file(tile_path)
        if not tile_path.parent.exists():
            tile_path.parent.mkdir(parents=True, exist_ok=True)
        request = urllib.request.Request(f'https://tile.openstreetmap.org/{zoom}/{x}/{y}.png')
        request.add_header('User-Agent', 'Mozilla/5.0 (X11; Linux x86_64; rv:138.0) Gecko/20100101 Firefox/138.0')
        request.add_header('Accept', 'image/avif,image/webp,image/png,image/svg+xml,image/*;q=0.8,*/*;q=0.5')
        request.add_header('Accept-Language', 'en-US,en;q=0.5')
        request.add_header('Accept-Encoding', 'gzip, deflate, br, zstd')
        try:
            with urllib.request.urlopen(request, timeout=osm_timeout) as response:
                if response.status != http_code_ok:
                    return (f'tile.openstreetmap.org answer is not OK (status: {response.status}) : {response.read()}',
                            501)
                tile_path.write_bytes(response.read())
                return send_file(tile_path)
        except urllib.error.URLError as error:
            return f'Cannot retrieve tile: {error}', 501

    app.run(host=host, port=port, debug=debug_mode)


if __name__ == '__main__':
    main()