Class OpenAiEngine

src/engine/openAi.ts:12–90

export interface OpenAiConfig extends AiEngineConfig {}

export class OpenAiEngine implements AiEngine {
  config: OpenAiConfig;
  client: OpenAI;

  constructor(config: OpenAiConfig) {
    this.config = config;

    const clientOptions: OpenAI.ClientOptions = {
      apiKey: config.apiKey
    };

    if (config.baseURL) {
      clientOptions.baseURL = config.baseURL;
    }

    const proxy = config.proxy;
    if (proxy) {
      clientOptions.httpAgent = new HttpsProxyAgent(proxy);
    }

    if (config.customHeaders) {
      const headers = parseCustomHeaders(config.customHeaders);
      if (Object.keys(headers).length > 0) {
        clientOptions.defaultHeaders = headers;
      }
    }

    // The OpenAI SDK's internal fetch may resolve before globalThis.fetch is
    // available in some Node.js versions, causing premature connection errors.
    // Explicitly binding globalThis.fetch here defers resolution to call time,
    // ensuring the runtime's native fetch is used instead of the SDK's bundled
    // undici — which also avoids double-initialisation in newer Node (>=18).
    if (!clientOptions.fetch && typeof globalThis.fetch === 'function') {
      clientOptions.fetch = (...args) => globalThis.fetch(...args);
    }

    this.client = new OpenAI(clientOptions);
  }

  public generateCommitMessage = async (
    messages: Array<OpenAI.Chat.Completions.ChatCompletionMessageParam>
  ): Promise<string | null> => {
    const isReasoningModel = /^(o[1-9]|gpt-5)/.test(this.config.model);

    const params = {
      model: this.config.model,
      messages,
      ...(isReasoningModel
        ? { max_completion_tokens: this.config.maxTokensOutput }
        : {
            temperature: 0,
            top_p: 0.1,
            max_tokens: this.config.maxTokensOutput
          })
    };

    try {
      const REQUEST_TOKENS = messages