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

/// HuggingChat (huggingface.co/chat). Guest REST is blocked; WebView carries cookies.
class HuggingChat extends WebViewBaseProvider {
  @override
  String get name => 'HuggingChat';

  @override
  bool get working => true;

  @override
  List<String> get models => [
        'omni',
        'meta-llama/Llama-3.1-8B-Instruct',
        'Qwen/Qwen3.8-27B',
        'zai-org/GLM-5.3-Flash',
      ];

  @override
  String get defaultModel => 'omni';

  @override
  String get baseUrl => 'https://huggingface.co/chat/';

  @override
  String get apiEndpoint => 'https://huggingface.co/chat/api/v2/conversations';

  @override
  String buildJsFetchCode(String model, List<Message> messages, bool stream) {
    final modelJson = jsonEncode(models.contains(model) ? model : defaultModel);
    final promptJson = jsonEncode(formatPrompt(messages));
    return '''
      (async function() {
        const headers = {'Content-Type': 'application/json', 'Accept': 'application/json'};
        let convRes = await fetch('/chat/api/v2/conversations', {
          method: 'POST',
          headers,
          body: JSON.stringify({ model: $modelJson })
        });
        if (!convRes.ok) {
          convRes = await fetch('/chat/conversation', {
            method: 'POST',
            headers,
            body: JSON.stringify({ model: $modelJson })
          });
        }
        if (!convRes.ok) {
          return JSON.stringify({error: 'HuggingChat login required: ' + convRes.status + ' ' + await convRes.text()});
        }
        const text = await convRes.text(); const conv = text ? JSON.parse(text) : {};
        const id = conv.json?.id || conv.id || conv.conversationId;
        if (!id) return JSON.stringify({error: 'no conversation id', raw: conv});

        const payload = {
          id: crypto.randomUUID(),
          inputs: $promptJson,
          is_retry: false,
          is_continue: false,
          web_search: false,
          tools: []
        };
        let msgRes = await fetch('/chat/api/v2/conversations/' + id, {
          method: 'POST',
          headers: {'Content-Type': 'application/json', 'Accept': 'text/event-stream'},
          body: JSON.stringify(payload)
        });
        if (!msgRes.ok) {
          msgRes = await fetch('/chat/conversation/' + id, {
            method: 'POST',
            headers: {'Content-Type': 'application/json', 'Accept': 'text/event-stream'},
            body: JSON.stringify(payload)
          });
        }
        const body = await msgRes.text();
        return JSON.stringify({status: msgRes.status, body});
      })();
    ''';
  }

  @override
  String parseResponse(String rawResponse) {
    try {
      final json = jsonDecode(rawResponse);
      if (json is Map && json['error'] != null) {
        throw Exception(json['error']);
      }
      final body = json is Map ? (json['body']?.toString() ?? rawResponse) : rawResponse;
      final sse = extractAllSseContent(body).join();
      if (looksLikeModelOutput(sse)) return sse;
      // chat-ui tokens: {"type":"stream","token":"..."}
      final tokens = <String>[];
      for (final line in body.split('\n')) {
        try {
          final m = jsonDecode(line);
          if (m is Map) {
            final token = m['token'] ?? m['text'] ?? m['generated_text'];
            if (token is String && token.isNotEmpty) tokens.add(token);
          }
        } catch (_) {}
      }
      final joined = tokens.join();
      if (looksLikeModelOutput(joined)) return joined;
      if (looksLikeModelOutput(body)) return body.trim();
      throw Exception('HuggingChat unusable: ${body.substring(0, body.length.clamp(0, 180))}');
    } catch (e) {
      if (looksLikeModelOutput(rawResponse)) return rawResponse.trim();
      throw Exception('Failed to parse HuggingChat: $e');
    }
  }
}