import os
import sys
import json
import threading
from urllib.parse import urlparse, parse_qs, unquote

import webview


AUTH_USER_AGENT = (
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
    "AppleWebKit/537.36 (KHTML, like Gecko) "
    "Chrome/120.0.0.0 Safari/537.36 Edg/120.0.0.0"
)


def extract_token(url_string):
    token = None
    expires_in = 3600
    parsed = urlparse(url_string)

    if parsed.fragment:
        params = parse_qs(parsed.fragment)
    else:
        params = parse_qs(parsed.query)

    if 'access_token' in params:
        token = params['access_token'][0]
    if 'expires_in' in params:
        try:
            expires_in = int(params['expires_in'][0])
        except ValueError:
            pass

    if not token:
        start_marker = "access_token%253D"
        end_marker = "%25"

        start_index = url_string.find(start_marker)
        if start_index != -1:
            token_start_index = start_index + len(start_marker)
            remaining_url = url_string[token_start_index:]
            end_index = remaining_url.find(end_marker)

            if end_index != -1:
                raw_token = remaining_url[:end_index]
            else:
                amp_index = remaining_url.find('&')
                if amp_index != -1:
                    raw_token = remaining_url[:amp_index]
                else:
                    raw_token = remaining_url
            token = unquote(raw_token)

    return token, expires_in


def main_auth(auth_url, output_path):
    stop_polling = threading.Event()
    polling_started = threading.Event()

    def poll_url():
        while not stop_polling.wait(0.75):
            try:
                url = window.get_current_url()
            except Exception:
                continue
            if not url:
                continue

            token, expires_in = extract_token(url)
            if not token:
                continue

            stop_polling.set()
            data = {"token": token, "expires_in": expires_in}
            with open(output_path, "w", encoding="utf-8") as f:
                json.dump(data, f)
            try:
                window.destroy()
            except Exception:
                pass
            return

    def start_polling():
        if polling_started.is_set():
            return
        polling_started.set()
        thread = threading.Thread(target=poll_url, name="vk-auth-url-poller", daemon=True)
        thread.start()

    def on_loaded():
        start_polling()

    def on_closed():
        stop_polling.set()

    window = webview.create_window("VK Авторизация", auth_url)
    window.events.loaded += on_loaded
    try:
        window.events.closed += on_closed
    except Exception:
        pass
    webview.start(
        start_polling,
        gui="edgechromium" if os.name == "nt" else None,
        private_mode=True,
        storage_path=None,
        user_agent=AUTH_USER_AGENT,
    )
    stop_polling.set()


def main():
    # Supports both: `python auth_webview.py <auth_url> <output_path>`
    # and: `python auth_webview.py --auth <auth_url> <output_path>`
    args = sys.argv[1:]
    if len(args) == 3 and args[0] == "--auth":
        auth_url, output_path = args[1], args[2]
    elif len(args) == 2:
        auth_url, output_path = args[0], args[1]
    else:
        print("Usage: auth_webview.py [--auth] <auth_url> <output_path>")
        return 1

    main_auth(auth_url, output_path)
    return 0


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