import 'dart:convert';
import 'package:http/http.dart' as http;
import 'package:flutter_dotenv/flutter_dotenv.dart';

import 'ai_service.dart';

class VolcanoAIService implements AiService {
  final String apiKey;
  static const String _baseUrl = 'https://ark.cn-beijing.volces.com/api/v3';
  static const String _chatEndpoint = '/chat/completions';

  VolcanoAIService() : apiKey = dotenv.env['VOLCANO_AI_API_KEY'] ?? '' {
    if (apiKey.isEmpty) {
      throw VolcanoAIException('火山AI配置信息不完整，请检查环境变量');
    }
  }

  // 生成个性化问候语
  Stream<String> generateGreeting({
    required String agentName,
    required String systemPrompt,
  }) {
    final messages = [
      {'role': 'system', 'content': systemPrompt},
      {'role': 'user', 'content': '请用一句简短的话向我打个招呼，要符合你的身份和性格特点，不要超过18个字。'},
    ];

    return sendMessageStream(
      messages: messages,
      systemPrompt: systemPrompt,
    );
  }

  // 非流式输出方法
  @override
  Future<String> sendMessage({
    required List<Map<String, String>> messages,
    String? systemPrompt,
    String? userProperties,
  }) async {
    final url = Uri.parse('$_baseUrl$_chatEndpoint');

    final fullMessages = [
      {'role': 'system', 'content': systemPrompt},
      ...messages,
    ];

    try {
      final response = await http.post(
        url,
        headers: {
          'Content-Type': 'application/json',
          'Authorization': 'Bearer $apiKey',
        },
        body: json.encode({
          'model': 'doubao-1-5-lite-32k-250115',
          'messages': fullMessages,
          'temperature': 0.7,
          'max_tokens': 2000,
          'stream': false,
        }),
      );

      if (response.statusCode == 200) {
        final data = json.decode(response.body);
        if (data['choices'] != null &&
            data['choices'].isNotEmpty &&
            data['choices'][0]['message'] != null) {
          return data['choices'][0]['message']['content'];
        }
        throw VolcanoAIException('Invalid response format');
      } else {
        final error = json.decode(response.body);
        throw VolcanoAIException(
          error['error']?['message'] ?? 'Unknown error occurred',
        );
      }
    } catch (e) {
      if (e is VolcanoAIException) rethrow;
      throw VolcanoAIException('Failed to communicate with AI service: $e');
    }
  }

  // 流式输出方法
  @override
  Stream<String> sendMessageStream({
    required List<Map<String, String>> messages,
    String? systemPrompt,
    String? userProperties,
  }) async* {
    final url = Uri.parse('$_baseUrl$_chatEndpoint');

    final fullMessages = [
      {'role': 'system', 'content': systemPrompt},
      ...messages,
    ];

    try {
      final request = http.Request('POST', url);
      request.headers.addAll({
        'Content-Type': 'application/json',
        'Authorization': 'Bearer $apiKey',
        'Accept': 'text/event-stream',
      });

      request.body = json.encode({
        'model': 'doubao-1-5-lite-32k-250115',
        'messages': fullMessages,
        'temperature': 0.7,
        'max_tokens': 2000,
        'stream': true,
      });

      final response = await http.Client().send(request);

      if (response.statusCode != 200) {
        final error = await response.stream.bytesToString();
        throw VolcanoAIException(json.decode(error)['error']?['message'] ??
            'Unknown error occurred');
      }

      await for (final chunk in response.stream
          .transform(utf8.decoder)
          .transform(const LineSplitter())) {
        if (chunk.isEmpty) continue;
        if (chunk.startsWith('data: ')) {
          final data = chunk.substring(6);
          if (data == '[DONE]') break;

          try {
            final jsonData = json.decode(data);
            if (jsonData['choices'] != null &&
                jsonData['choices'].isNotEmpty &&
                jsonData['choices'][0]['delta'] != null &&
                jsonData['choices'][0]['delta']['content'] != null) {
              yield jsonData['choices'][0]['delta']['content'] as String;
            }
          } catch (e) {
            // 忽略无效的JSON数据
            continue;
          }
        }
      }
    } catch (e) {
      if (e is VolcanoAIException) rethrow;
      throw VolcanoAIException('Failed to communicate with AI service: $e');
    }
  }
}

class VolcanoAIException implements Exception {
  final String message;
  VolcanoAIException(this.message);

  @override
  String toString() => message;
}