import 'dart:convert';
import 'package:http/http.dart' as http;
import '../http_client.dart';
import '../http_util.dart';
import '../models.dart';
import 'base_provider.dart';

/// Port of g4f HuggingSpace / CohereForAI C4AI Command (HF Space).
class CohereSpace extends BaseProvider {
  @override
  String get name => 'CohereSpace';

  @override
  bool get working => true;

  @override
  List<String> get models => [
        'command-a-03-2025',
        'command-r-plus-08-2024',
        'command-r-08-2024',
      ];

  @override
  String get defaultModel => 'command-a-03-2025';

  static const _url = 'https://coherelabs-c4ai-command.hf.space';

  @override
  Stream<String> createAsyncGenerator(
    String model,
    List<Message> messages, {
    bool stream = false,
  }) async* {
    final useModel = models.contains(model) ? model : defaultModel;
    final headers = browserHeaders(
      origin: _url,
      referer: '$_url/',
      contentType: 'application/json',
    );
    final conv = await g4fHttp
        .post(
          Uri.parse('$_url/conversation'),
          headers: headers,
          body: jsonEncode({
            'model': useModel,
            'preprompt': extractSystemMessage(messages),
          }),
        )
        .timeout(const Duration(seconds: 15));
    if (conv.statusCode != 200) {
      throw Exception('CohereSpace conv ${conv.statusCode}');
    }
    final convJson = jsonDecode(conv.body);
    final convId = (convJson is Map
            ? (convJson['conversationId'] ?? convJson['id'])
            : null)
        ?.toString();
    if (convId == null) throw Exception('CohereSpace no conversation');

    final cookie = cookieHeaderFromSetCookie(conv.headers['set-cookie']);
    final req = http.MultipartRequest('POST', Uri.parse('$_url/conversation/$convId'));
    req.headers.addAll({
      ...browserHeaders(origin: _url, referer: '$_url/'),
      if (cookie != null) 'Cookie': cookie,
    });
    req.fields['data'] = jsonEncode({
      'inputs': formatPrompt(messages.where((m) => m.role != Role.system).toList()),
      'id': 0,
      'is_retry': false,
      'is_continue': false,
      'web_search': false,
      'tools': [],
    });

    final res = await g4fHttp.send(req).timeout(requestTimeout);
      if (res.statusCode != 200) {
        throw Exception('CohereSpace chat ${res.statusCode}');
      }
      final raw = utf8.decode(await res.stream.toBytes().timeout(requestTimeout));
      final buf = StringBuffer();
      for (final line in raw.split(RegExp(r'\r?\n'))) {
        if (line.trim().isEmpty) continue;
        try {
          final data = jsonDecode(line);
          if (data is Map) {
            if (data['type'] == 'stream' && data['token'] is String) {
              buf.write((data['token'] as String).replaceAll('\u0000', ''));
            } else if (data['type'] == 'finalAnswer' && data['text'] is String) {
              if (buf.isEmpty) buf.write(data['text']);
            }
          }
        } catch (_) {}
      }
      final text = buf.toString().trim();
    if (!looksLikeModelOutput(text)) throw Exception('CohereSpace empty');
    yield text;
  }
}