import 'dart:io';

import 'package:cronet_http/cronet_http.dart';
import 'package:flutter/foundation.dart';
import 'package:http/http.dart' as http;

import 'cookie_jar.dart';
import 'http_util.dart';

/// Shared HTTP stack for every G4F provider.
///
/// Python g4f uses `curl_cffi(impersonate="chrome")` plus a session cookie
/// jar. On Android the closest TLS equivalent is Cronet; cookies are kept
/// in [g4fCookies] because Cronet does not expose a Dart cookie store.
http.Client createG4fClient() {
  if (!kIsWeb && Platform.isAndroid) {
    final engine = CronetEngine.build(
      cacheMode: CacheMode.memory,
      cacheMaxSize: 4 * 1024 * 1024,
      userAgent: kDesktopUserAgent,
      enableHttp2: true,
      enableBrotli: true,
      enableQuic: true,
    );
    return CronetClient.fromCronetEngine(engine);
  }
  return http.Client();
}

final G4fCookieJar g4fCookies = G4fCookieJar();

final http.Client g4fHttp = CookieClient(createG4fClient(), g4fCookies);

class CookieClient extends http.BaseClient {
  CookieClient(this._inner, this.jar);

  final http.Client _inner;
  final G4fCookieJar jar;

  @override
  Future<http.StreamedResponse> send(http.BaseRequest request) async {
    final fromJar = jar.headerFor(request.url);
    if (fromJar.isNotEmpty) {
      final existing = request.headers['cookie'];
      if (existing == null || existing.isEmpty) {
        request.headers['cookie'] = fromJar;
      } else {
        request.headers['cookie'] = '$existing; $fromJar';
      }
    }
    final response = await _inner.send(request);
    jar.absorb(request.url, response.headers);
    return response;
  }

  @override
  void close() => _inner.close();
}

final Set<String> _warmedOrigins = {};

/// GET the provider origin once so Cloudflare/session cookies land in [g4fCookies].
Future<void> warmupOrigin(String url) async {
  if (url.isEmpty) return;
  final uri = Uri.tryParse(url);
  if (uri == null || !uri.hasScheme || uri.host.isEmpty) return;
  final origin = uri.origin;
  if (_warmedOrigins.contains(origin)) return;
  _warmedOrigins.add(origin);
  try {
    await g4fHttp
        .get(
          uri,
          headers: browserHeaders(
            desktop: true,
            accept:
                'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
            referer: '$origin/',
          ),
        )
        .timeout(const Duration(seconds: 12));
  } catch (_) {}
}