import 'dart:convert';
import '../http_util.dart';
import '../models.dart';
import '../sse.dart';
import 'webview_base_provider.dart';

/// Qwen chat (chat.qwen.ai). WAF is solved inside the hidden WebView.
class QwenChat extends WebViewBaseProvider {
  @override
  String get name => 'Qwen';

  @override
  bool get working => true;

  @override
  List<String> get models => ['qwen3.5-flash', 'qwen3.7-plus', 'qwen3-max-2026-01-23'];

  @override
  String get defaultModel => 'qwen3.5-flash';

  @override
  String get baseUrl => 'https://chat.qwen.ai/';

  @override
  String get apiEndpoint => 'https://chat.qwen.ai/api/v2/chat/completions';

  @override
  String buildJsFetchCode(String model, List<Message> messages, bool stream) {
    final modelJson = jsonEncode(models.contains(model) ? model : defaultModel);
    final promptJson = jsonEncode(getLastUserMessage(messages));
    return '''
      (async function() {
        for (let i = 0; i < 16; i++) {
          if (!document.documentElement.innerHTML.includes('aliyun_waf_aa')) break;
          await new Promise(r => setTimeout(r, 400));
        }
        const headers = {'Content-Type': 'application/json', 'source': 'web'};
        const created = await fetch('/api/v2/chats/new', {
          method: 'POST',
          headers,
          body: JSON.stringify({
            title: 'New Chat',
            models: [$modelJson],
            chat_mode: 'normal',
            chat_type: 't2t',
            timestamp: Date.now()
          })
        });
        const createdJson = await created.json();
        const chatId = createdJson.data && createdJson.data.id;
        if (!chatId) return JSON.stringify({error: createdJson});
        const resp = await fetch('/api/v2/chat/completions?chat_id=' + chatId, {
          method: 'POST',
          headers,
          body: JSON.stringify({
            stream: false,
            version: '2.1',
            incremental_output: false,
            chat_id: chatId,
            chat_mode: 'normal',
            model: $modelJson,
            messages: [{
              fid: crypto.randomUUID(),
              role: 'user',
              content: $promptJson,
              user_action: 'chat',
              files: [],
              timestamp: Date.now(),
              models: [$modelJson],
              chat_type: 't2t',
              extra: {meta: {subChatType: 't2t'}},
              sub_chat_type: 't2t'
            }],
            timestamp: Date.now()
          })
        });
        return await resp.text();
      })();
    ''';
  }

  @override
  String parseResponse(String rawResponse) {
    final sse = extractAllSseContent(rawResponse).join();
    if (looksLikeModelOutput(sse)) return sse;
    try {
      final json = jsonDecode(rawResponse);
      if (json is Map) {
        if (json['error'] != null) throw Exception(json['error']);
        final choices = json['choices'];
        if (choices is List && choices.isNotEmpty) {
          final c = choices.first;
          if (c is Map) {
            final msg = c['message'];
            if (msg is Map && msg['content'] is String) return msg['content'];
            final delta = c['delta'];
            if (delta is Map && delta['content'] is String) return delta['content'];
          }
        }
        final data = json['data'];
        if (data is Map && data['content'] is String) return data['content'];
      }
    } catch (e) {
      if (e.toString().startsWith('Exception:')) rethrow;
    }
    if (looksLikeModelOutput(rawResponse)) return rawResponse.trim();
    throw Exception('Failed to parse Qwen: ${rawResponse.substring(0, rawResponse.length.clamp(0, 180))}');
  }
}