// ═══════════════════════════════════════
// 铸渊开发Agent · 大模型调用模块
// 支持 OpenAI 兼容 API → DeepSeek/千问/等
// ═══════════════════════════════════════

const https = require("https");

function getConfig() {
  const key = process.env.MODEL_API_KEY;
  const base = process.env.MODEL_API_BASE || "https://api.deepseek.com/v1";
  const model = process.env.MODEL_NAME || "deepseek-chat";

  if (!key) {
    console.warn("[ModelCaller] MODEL_API_KEY 未配置");
    return null;
  }
  return { key, base, model };
}

/**
 * 调用大模型
 * @param {string} prompt - 输入提示
 * @param {object} opts - { max_tokens, temperature }
 * @returns {Promise<string>} 模型回复文本
 */
async function call(prompt, opts = {}) {
  const config = getConfig();
  if (!config) throw new Error("MODEL_API_KEY 未配置");

  const body = JSON.stringify({
    model: config.model,
    messages: [
      { role: "system", content: "你是一个技术开发Agent。回答要精确、结构化、可执行。" },
      { role: "user", content: prompt }
    ],
    max_tokens: opts.max_tokens || 4096,
    temperature: opts.temperature || 0.3
  });

  return new Promise((resolve, reject) => {
    const url = new URL(config.base + "/chat/completions");
    const req = https.request({
      hostname: url.hostname,
      path: url.pathname,
      method: "POST",
      headers: {
        "Authorization": "Bearer " + config.key,
        "Content-Type": "application/json"
      }
    }, (res) => {
      let data = "";
      res.on("data", (c) => data += c);
      res.on("end", () => {
        try {
          const json = JSON.parse(data);
          if (json.error) return reject(new Error(json.error.message || "API错误"));
          resolve(json.choices?.[0]?.message?.content || "");
        } catch (e) {
          reject(new Error("解析失败: " + data.slice(0, 200)));
        }
      });
    });

    req.on("error", reject);
    req.write(body);
    req.end();
  });
}

module.exports = { call };