/**
 * 节点执行器（H4/H5）。
 * - nativeExecute：原生内置 worker（确定性，不冒充 LLM），独立工作目录
 * - makeAdapterExecute：兼容转化层，把外部执行器包成统一协议
 *     kind=cmd  本地白名单命令
 *     kind=http 任意 OpenAI 兼容端点（真实大模型 worker）
 *     kind=codex codex CLI 子进程（真实，需本机装 codex；Windows 已兼容 .cmd shim）
 *     kind=cli  任意本地 agent CLI（--cli 指定，{prompt} 占位符）
 * 安全：危险关键词拦截、独立 workspace、spawn 参数数组（无 shell 注入）。
 */
import { spawn } from "node:child_process";
import { mkdirSync, writeFileSync, rmSync, readFileSync, existsSync } from "node:fs";
import { resolve, join, dirname } from "node:path";
import { tmpdir } from "node:os";
import { isDangerousTask } from "../security.js";
import { chatComplete, llmConfig } from "../llm.js";
import { WorkspaceManager } from "../worktree.js";

// 产物回传上限：过小会把长文（如白皮书章节）截断导致内容永久丢失（历史教训：
// task-mt9focod-zj852h 第二部分在 slice(0,2000) 处被切掉尾部）。可用 GW_ARTIFACT_MAX 覆盖。
const ARTIFACT_MAX = Number(process.env.GW_ARTIFACT_MAX) || 20_000;

// 可选：设置 GW_WORKTREE=1 即每任务独立 git worktree（失败自动回退普通目录并记录原因）
const wtEnabled = process.env.GW_WORKTREE === "1";
const wm = wtEnabled
  ? new WorkspaceManager({
      repoRoot: process.env.GW_REPO_ROOT || resolve(process.cwd(), "workspace-repo"),
      workspaceRoot: process.env.GW_WORKSPACE_ROOT || resolve(process.cwd(), "workspace"),
    })
  : null;

let seq = 0;
function taskWorkspace(tag, taskId) {
  const dir = resolve(tmpdir(), "gw-live-nodes", `${tag}-${process.pid}`, `${taskId}-${++seq}`);
  mkdirSync(dir, { recursive: true });
  return dir;
}

function assertSafe(task) {
  const d = isDangerousTask(task);
  if (d.dangerous) throw new Error(`blocked: dangerous pattern "${d.keyword}"`);
  // 压测故障注入标记
  if (String(task.prompt || "").includes("__FAIL__")) throw new Error("injected-failure");
}

/** native 直连节点执行器。 */
export async function nativeExecute(task) {
  assertSafe(task);
  let ws, wtInfo = null;
  if (wm) {
    wtInfo = wm.acquire(task.id); // {path,mode:'worktree'|'dir',fallbackReason?}
    ws = wtInfo.path;
  } else {
    ws = taskWorkspace("native", task.id);
  }
  try {
    const text = String(task.prompt || task.title || "");
    const words = (text.match(/[\w一-龿]+/g) || []).length;
    const artifact = `# ${task.title}\n\n${text}\n\n---\nnative worker @ ${new Date().toISOString()}\n词数 ${words}\n`;
    writeFileSync(join(ws, "result.md"), artifact);
    await new Promise((r) => setTimeout(r, 3 + Math.random() * 10));
    return {
      output: artifact.slice(0, ARTIFACT_MAX),
      evidence: {
        workspace: ws,
        artifact: "result.md",
        words,
        isolation: wtInfo ? wtInfo : "temp-dir",
      },
      executor: "native-builtin",
    };
  } finally {
    // git worktree 保留供审计/diff 取证；临时目录直接清理
    if (!wtInfo) {
      try {
        rmSync(ws, { recursive: true, force: true });
      } catch {}
    }
  }
}

/** Windows：npm 的 .cmd 是跳板，解析出真实 exe/js 直接调用（绕开 cmd.exe 兼容坑）。 */
async function _resolveShimTarget(cmdPath) {
  try {
    const txt = readFileSync(cmdPath, "utf8");
    // shim 里可能先出现 "%dp0%\node.exe"（探测分支），优先取 node_modules 下的真实入口
    const re = /"%dp0%\\([^"]+?)"/g;
    let m, hit = null, last = null;
    while ((m = re.exec(txt))) {
      last = m[1];
      if (/node_modules/i.test(m[1])) { hit = m[1]; break; }
    }
    const rel = hit || last;
    if (!rel) return null;
    const target = join(dirname(cmdPath), rel);
    return existsSync(target) ? target : null;
  } catch {
    return null;
  }
}

/** 解析可执行文件的真实路径（Windows npm 全局是 .cmd shim，裸 spawn 会失败）。 */
const _binCache = new Map();
export async function resolveBin(bin) {
  if (_binCache.has(bin)) return _binCache.get(bin);
  const isWin = process.platform === "win32";
  let abs = bin;
  try {
    const { out } = await runCmd(isWin ? "where" : "which", [bin], null, 5_000);
    const hits = out.split(/\r?\n/).map((s) => s.trim()).filter(Boolean);
    // where 会把无扩展名的 bash shim 排在前面，cmd.exe 无法执行它——优先可执行扩展名
    let hit = isWin ? hits.find((h) => /\.(cmd|exe|bat)$/i.test(h)) || hits[0] : hits[0];
    if (hit && isWin && /\.cmd$/i.test(hit)) {
      const real = await _resolveShimTarget(hit);
      if (real) hit = real; // claude→claude.exe；codex/gemini→node 脚本
    }
    if (hit) abs = hit;
  } catch {}
  _binCache.set(bin, abs);
  return abs;
}

/**
 * 运行外部 agent CLI（binAbs 来自 resolveBin：真实 exe 或 node 脚本）。
 * js 脚本用当前 node 直启；exe 直接 spawn——全程不经 cmd.exe（其控制台句柄会挂起部分 CLI）。
 */
export function runCli(binAbs, argv, input, timeoutMs = 180_000, extraEnv = null) {
  const isScript = /\.(js|cjs|mjs)$/i.test(binAbs);
  const cmd = isScript ? process.execPath : binAbs;
  const finalArgs = isScript ? [binAbs, ...argv] : argv;
  return new Promise((resolveP, rejectP) => {
    const child = spawn(cmd, finalArgs, {
      shell: false,
      // 自定义模型接入点：extraEnv 覆盖同名变量（如 ANTHROPIC_BASE_URL/ANTHROPIC_MODEL/OPENAI_API_KEY）
      env: extraEnv && Object.keys(extraEnv).length ? { ...process.env, ...extraEnv } : undefined,
    });
    let out = "", err = "";
    const t = setTimeout(() => { child.kill(9); rejectP(new Error("cli-timeout")); }, timeoutMs);
    child.stdout.on("data", (d) => (out += d));
    child.stderr.on("data", (d) => (err += d));
    child.on("error", (e) => { clearTimeout(t); rejectP(e); });
    child.on("close", (code) => {
      clearTimeout(t);
      code === 0 ? resolveP({ out, err }) : rejectP(new Error("exit " + code + ": " + err.slice(0, 300)));
    });
    // 所有平台都要写完立即关闭 stdin：部分 CLI（如 claude -p）会等待 EOF 才开始处理
    if (input != null) { try { child.stdin.write(input); } catch {} }
    try { child.stdin.end(); } catch {}
  });
}

function runCmd(command, args, input, timeoutMs = 30_000) {
  return new Promise((resolveP, rejectP) => {
    const child = spawn(command, args, { shell: false });
    let out = "",
      err = "";
    const t = setTimeout(() => {
      child.kill(9);
      rejectP(new Error("cmd-timeout"));
    }, timeoutMs);
    child.stdout.on("data", (d) => (out += d));
    child.stderr.on("data", (d) => (err += d));
    child.on("error", (e) => {
      clearTimeout(t);
      rejectP(e);
    });
    child.on("close", (code) => {
      clearTimeout(t);
      code === 0 ? resolveP({ out, err }) : rejectP(new Error(`exit ${code}: ${err.slice(0, 200)}`));
    });
    if (input != null) {
      child.stdin.write(input);
      child.stdin.end();
    }
  });
}

/** 兼容转化层执行器工厂。 */
export function makeAdapterExecute(kind, opts = {}) {
  return async function adapterExecute(task) {
    assertSafe(task);

    if (kind === "fast") {
      // 转化层包装的"外部快速执行单元"（压测用；证明协议转换而非吞吐瓶颈）
      await new Promise((r) => setTimeout(r, 2 + Math.random() * 8));
      return {
        output: `[adapter-fast] processed: ${String(task.prompt || "").slice(0, 60)}`,
        evidence: { adapter: "fast" },
        executor: "adapter-fast",
      };
    }

    if (kind === "cmd") {
      const ws = taskWorkspace("adapter-cmd", task.id);
      writeFileSync(join(ws, "input.txt"), String(task.prompt || ""));
      const isWin = process.platform === "win32";
      const { out } = await runCmd(
        isWin ? "cmd" : "sh",
        isWin
          ? ["/c", "echo", `[adapter-cmd] ${task.id}`]
          : ["-c", `echo '[adapter-cmd] ${task.id}'`],
        null,
        10_000,
      );
      return { output: out.trim(), evidence: { adapter: "cmd", workspace: ws }, executor: "adapter-cmd" };
    }

    if (kind === "http") {
      const cfg = llmConfig();
      const r = await chatComplete([
        { role: "system", content: "你是子任务执行者，用 2-3 句中文给出结果。" },
        { role: "user", content: String(task.prompt || task.title) },
      ]);
      if (!r.ok) throw new Error(`upstream ${r.status}/${r.httpStatus}`);
      return {
        output: r.text.slice(0, ARTIFACT_MAX),
        evidence: { adapter: "http", model: cfg.model, latencyMs: r.latencyMs, usage: r.usage },
        executor: "adapter-http-llm",
      };
    }

    if (kind === "codex") {
      const bin = await resolveBin(opts.codexBin || "codex");
      const t0 = Date.now();
      // prompt 作为参数传入（跨平台免 stdin；Windows 的 .cmd 经 cmd.exe 包装也能收到）
      const { out } = await runCli(
        bin,
        ["exec", "--skip-git-repo-check", String(task.prompt || task.title)],
        null,
        Number(process.env.GW_CLI_TIMEOUT) || 120_000,
        opts.cliEnv,
      );
      return { output: out.slice(0, ARTIFACT_MAX), evidence: { adapter: "codex-cli", bin, latencyMs: Date.now() - t0 }, executor: "adapter-codex" };
    }

    if (kind === "cli") {
      // 通用 CLI 适配器：任意「提示词进、文本出」的本地 CLI 都能包成节点
      // opts.cli 可执行名；opts.cliArgs 支持 {prompt} 占位符（如 "-p {prompt}"），缺省把 prompt 作为最后一个参数
      const rawBin = opts.cli || process.env.GW_CLI_BIN;
      if (!rawBin) throw new Error("adapter-cli: 缺少 --cli <可执行名>");
      const bin = await resolveBin(rawBin);
      const prompt = String(task.prompt || task.title || "");
      const tmpl = String(opts.cliArgs ?? "").trim();
      let argv;
      if (tmpl.includes("{prompt}")) {
        argv = tmpl.split("{prompt}").length === 2
          ? [tmpl.split("{prompt}")[0].trim(), prompt, tmpl.split("{prompt}")[1].trim()].filter(Boolean)
          : tmpl.split(/\s+/);
      } else {
        argv = [...(tmpl ? tmpl.split(/\s+/) : []), prompt];
      }
      const t0 = Date.now();
      const { out, err } = await runCli(bin, argv, prompt, Number(process.env.GW_CLI_TIMEOUT) || 180_000, opts.cliEnv);
      return {
        output: (out || err).slice(0, ARTIFACT_MAX),
        evidence: { adapter: "cli", bin, args: argv.map((a) => (String(a).length > 60 ? "[prompt]" : a)), latencyMs: Date.now() - t0 },
        executor: "cli:" + bin.split(/[\\/]/).pop(),
      };
    }

    throw new Error(`unknown adapter kind: ${kind}`);
  };
}