// dsh-plugin-mcn MCP stdio 客户端（复用已验证方案；拆分自 index.js）
import { homedir } from "node:os";
import { join, isAbsolute, resolve } from "node:path";
import { spawn } from "node:child_process";
import { NPX_CMD, MCP_PACKAGE, MCP_ENV } from "./config.js";

function dshHome() {
  const configured = process.env.DSH_HOME?.trim();
  if (!configured) return join(homedir(), ".dsh");
  return isAbsolute(configured) ? configured : resolve(configured);
}

function callMcpTool(toolName, args = {}) {
  return new Promise((resolvePromise, reject) => {
    const reqs = [
      JSON.stringify({ jsonrpc: "2.0", id: 1, method: "initialize", params: { protocolVersion: "2024-11-05", capabilities: {}, clientInfo: { name: "dsh-plugin-mcn", version: "0.1.0" } } }),
      JSON.stringify({ jsonrpc: "2.0", method: "notifications/initialized" }),
      JSON.stringify({ jsonrpc: "2.0", id: 2, method: "tools/call", params: { name: toolName, arguments: args } }),
    ].join("\n") + "\n";

    const child = spawn(NPX_CMD, ["-y", MCP_PACKAGE], {
      env: { ...process.env, ...MCP_ENV },
      shell: true,
      stdio: ["pipe", "pipe", "inherit"],
    });
    let stdout = "";
    let settled = false;
    const timer = setTimeout(() => {
      if (!settled) { settled = true; child.kill(); reject(new Error("MCP 调用超时")); }
    }, 120000);

    child.stdout.on("data", (chunk) => { stdout += chunk.toString("utf8"); });
    child.on("close", (code) => {
      if (settled) return;
      settled = true;
      clearTimeout(timer);
      try {
        // 找到 id=2 的响应
        const lines = stdout.split("\n");
        for (const line of lines) {
          if (!line.includes('"id":2')) continue;
          const msg = JSON.parse(line);
          if (msg.result?.isError) { reject(new Error(msg.result.content?.[0]?.text || "MCP 工具报错")); return; }
          // 优先 structuredContent（结构化数据）；无则回退 text（格式化文本）
          const sc = msg.result?.structuredContent;
          const text = msg.result?.content?.[0]?.text ?? "";
          resolvePromise({ structured: sc ?? null, text });
          return;
        }
        reject(new Error("未找到 MCP 工具响应"));
      } catch (e) {
        reject(new Error("解析 MCP 响应失败: " + e.message));
      }
    });
    child.stdin.write(reqs);
    child.stdin.end();
    child.on("error", (e) => { if (!settled) { settled = true; clearTimeout(timer); reject(new Error("MCP 进程启动失败: " + e.message)); } });
  });
}

export { dshHome, callMcpTool };