completeStream method

Implementation

@override
Stream<AIStreamChunk> completeStream(
  List<AIMessage> messages, {
  int? maxTokens,
  double? temperature,
  List<AITool>? tools,
}) async* {
  final body = _buildRequestBody(messages, maxTokens, temperature,
      stream: true, tools: tools);

  final request =
      http.Request('POST', Uri.parse('$_baseUrl/chat/completions'));
  request.headers.addAll(_headers());
  request.body = jsonEncode(body);

  final streamedResponse = await _httpClient.send(request);

  if (streamedResponse.statusCode != 200) {
    final responseBody = await streamedResponse.stream.bytesToString();
    final json = jsonDecode(responseBody) as Map<String, dynamic>;
    throw _parseError(streamedResponse.statusCode, json);
  }

  await for (final chunk in streamedResponse.stream
      .transform(utf8.decoder)
      .transform(const LineSplitter())) {
    if (chunk.isEmpty || chunk == 'data: [DONE]') continue;
    if (!chunk.startsWith('data: ')) continue;

    final jsonStr = chunk.substring(6);
    try {
      final json = jsonDecode(jsonStr) as Map<String, dynamic>;
      final choices = json['choices'] as List;
      if (choices.isEmpty) continue;

      final delta = (choices.first as Map<String, dynamic>)['delta']
          as Map<String, dynamic>?;
      final finishReason =
          (choices.first as Map<String, dynamic>)['finish_reason'];
      final content = delta?['content'] as String? ?? '';

      if (content.isNotEmpty || finishReason != null) {
        yield AIStreamChunk(
          text: content,
          isComplete: finishReason != null,
          finishReason: finishReason as String?,
          provider: name,
          model: json['model'] as String?,
        );
      }
    } on FormatException catch (_) {
      // Skip malformed SSE chunks (e.g. partial JSON)
      continue;
    }
  }
}