/**
 * keyhelper.js — 长驻 PowerShell 子进程。
 *
 * ⚠ 非生产代码 —— 当前没有任何主进程路径 require 它或调用它。
 * 历史：早期版本的「点选一条 → 自动粘贴到目标窗口」功能走这条路，
 * 需要 PowerShell 用 SendKeys 发 Ctrl+V。在 2026-07-30 那一轮把
 * 自动粘贴整体移除了（用户明确不想要自动粘贴触发的「窗口缩一下」
 * 动画），主进程只剩手动 Ctrl+V 这条路。
 *
 * 用途（保留作备用 / bug 复现）：
 *   - 在 Windows 上发 Ctrl+V（避开 robotjs/nut-js 之类的原生模块编译）
 *   - 通过 stdin/stdout JSON-RPC 与主进程通信，单进程常驻，延迟 ~5ms
 *
 * 不在 package.json 的 build.files 里 —— 打包后不会进用户机器。
 * 想恢复自动粘贴：把 require('./keyhelper') 加回 main.js，把发键的
 * 逻辑塞到 clips:movetop 处理器的"clipboard.writeText 之后、IPC 返回
 * 之前"那段窗口隐藏逻辑即可（参见 README「不自动粘贴」说明）。
 *
 * 协议：
 *   in :  {"id":1,"action":"sendCtrlV"}
 *   out:  {"id":1,"ok":true}
 */

'use strict';

const { spawn } = require('node:child_process');

const PS_SCRIPT = String.raw`
$ErrorActionPreference = 'Stop'
Add-Type -AssemblyName System.Windows.Forms
while ($true) {
  $line = [Console]::In.ReadLine()
  if ([string]::IsNullOrEmpty($line)) { continue }
  try {
    $req = $line | ConvertFrom-Json
    $id = $req.id
    switch ($req.action) {
      'sendCtrlV' {
        [System.Windows.Forms.SendKeys]::SendWait('^v')
        [Console]::Out.WriteLine(('{"id":' + $id + ',"ok":true}'))
      }
      default {
        [Console]::Out.WriteLine(('{"id":' + $id + ',"ok":false,"error":"unknown action"}'))
      }
    }
  } catch {
    [Console]::Out.WriteLine(('{"id":-1,"ok":false,"error":"' + ($_.Exception.Message -replace '"','\\"') + '"}'))
  }
}
`;

class KeyHelper {
  constructor() {
    this.id = 0;
    this.pending = new Map();
    this.buffer = '';
    this._reconnectTimer = null;
    this.disposed = false;
    this._spawn();
  }

  _spawn() {
    this.ps = spawn(
      'powershell.exe',
      ['-NoProfile', '-ExecutionPolicy', 'Bypass', '-Command', PS_SCRIPT],
      { stdio: ['pipe', 'pipe', 'pipe'], windowsHide: true }
    );

    this.ps.stdout.on('data', (chunk) => this._onStdout(chunk));
    this.ps.stderr.on('data', (chunk) => {
      console.error('[keyhelper stderr]', chunk.toString());
    });
    this.ps.on('exit', (code) => {
      console.error('[keyhelper] powershell exited with code', code);
      this._rejectAll(new Error('keyhelper exited'));
      this._reconnect();
    });
  }

  _reconnect(retryMs = 500) {
    if (this.disposed || this._reconnectTimer) return;
    const tryOnce = () => {
      this._reconnectTimer = null;
      if (this.disposed) return;
      try {
        this._spawn();
      } catch (e) {
        console.error('[keyhelper] respawn failed:', e.message);
        this._reconnectTimer = setTimeout(tryOnce, Math.min(retryMs * 2, 8000));
      }
    };
    this._reconnectTimer = setTimeout(tryOnce, retryMs);
  }

  _onStdout(chunk) {
    this.buffer += chunk.toString('utf8');
    let nl;
    while ((nl = this.buffer.indexOf('\n')) >= 0) {
      const line = this.buffer.slice(0, nl).trim();
      this.buffer = this.buffer.slice(nl + 1);
      if (!line) continue;
      try {
        const resp = JSON.parse(line);
        if (resp.id === -1) {
          console.error('[keyhelper error]', resp.error);
          continue;
        }
        const cb = this.pending.get(resp.id);
        if (cb) {
          this.pending.delete(resp.id);
          cb.resolve(resp);
        }
      } catch (e) {
        // ignore parse error
      }
    }
  }

  _send(action, params = {}, timeoutMs = 10000) {
    return new Promise((resolve, reject) => {
      if (!this.ps || !this.ps.stdin || this.ps.stdin.destroyed) {
        return reject(new Error('keyhelper not running'));
      }
      const id = ++this.id;
      let settled = false;
      const t = setTimeout(() => {
        if (settled) return;
        settled = true;
        this.pending.delete(id);
        reject(new Error('keyhelper timeout'));
      }, timeoutMs);
      // 定时器句柄要存下来：dispose() / 进程退出时必须能取消，
      // 否则挂起的请求会在 10 秒后抛一个没人接的 rejection，
      // 同时这个 timer 还会一直吊着事件循环。
      this.pending.set(id, {
        timer: t,
        resolve: (v) => { if (settled) return; settled = true; clearTimeout(t); resolve(v); },
        reject: (e) => { if (settled) return; settled = true; clearTimeout(t); reject(e); },
      });
      try {
        this.ps.stdin.write(JSON.stringify({ id, action, ...params }) + '\n');
      } catch (e) {
        if (settled) return;
        settled = true;
        clearTimeout(t);
        this.pending.delete(id);
        reject(e);
      }
    });
  }

  sendCtrlV() {
    return this._send('sendCtrlV');
  }

  _rejectAll(err) {
    for (const [, p] of this.pending) p.reject(err);
    this.pending.clear();
  }

  dispose() {
    this.disposed = true;
    if (this._reconnectTimer) { clearTimeout(this._reconnectTimer); this._reconnectTimer = null; }
    this._rejectAll(new Error('keyhelper disposed'));
    if (this.ps) {
      // 别再因为我们自己的 kill 触发重连
      this.ps.removeAllListeners('exit');
      try { this.ps.stdin.end(); } catch (e) {}
      try { this.ps.kill(); } catch (e) {}
    }
  }
}

module.exports = KeyHelper;