'use strict';
// Codex CLI 執行層：spawn `codex exec --json`，逐行解析 JSONL 事件。
// Windows 上 codex 是 .cmd shim（node codex.js 的包裝），直接解析出 codex.js
// 用 node 執行，避開 shell:true 的引號問題與 DEP0190 警告。
const { spawn, execSync } = require('child_process');
const fs = require('fs');
const path = require('path');

let cachedCommand = null;

// 在 PATH 中尋找 codex shim，回推 @openai/codex/bin/codex.js 的實際位置
function findCodexJs() {
  const dirs = (process.env.PATH || '').split(path.delimiter);
  for (const dir of dirs) {
    if (!dir) continue;
    const shim = path.join(dir, process.platform === 'win32' ? 'codex.cmd' : 'codex');
    if (!fs.existsSync(shim)) continue;
    const candidates = [
      path.join(dir, 'node_modules', '@openai', 'codex', 'bin', 'codex.js'),
      // unix 下 shim 是 symlink，指向 lib/node_modules 下的實體
      path.join(dir, '..', 'lib', 'node_modules', '@openai', 'codex', 'bin', 'codex.js'),
    ];
    for (const c of candidates) {
      if (fs.existsSync(c)) return c;
    }
  }
  // 最後手段：問 npm 全域 root
  try {
    const root = execSync('npm root -g', { encoding: 'utf-8', windowsHide: true }).trim();
    const c = path.join(root, '@openai', 'codex', 'bin', 'codex.js');
    if (fs.existsSync(c)) return c;
  } catch { /* ignore */ }
  return null;
}

// 回傳 { cmd, baseArgs, shell }：實際 spawn 的指令與前置參數
function resolveCodexCommand(config) {
  if (cachedCommand) return cachedCommand;
  const custom = config && config.codexPath;
  if (custom) {
    cachedCommand = custom.endsWith('.js')
      ? { cmd: process.execPath, baseArgs: [custom], shell: false }
      : { cmd: custom, baseArgs: [], shell: false };
    return cachedCommand;
  }
  if (process.platform === 'win32') {
    const js = findCodexJs();
    if (js) {
      cachedCommand = { cmd: process.execPath, baseArgs: [js], shell: false };
      return cachedCommand;
    }
    // 找不到實體時退回 shell（.cmd 需要 shell 才能執行）
    cachedCommand = { cmd: 'codex', baseArgs: [], shell: true };
    return cachedCommand;
  }
  cachedCommand = { cmd: 'codex', baseArgs: [], shell: false };
  return cachedCommand;
}

function killTree(proc) {
  if (process.platform === 'win32') {
    // node shim 的子程序（codex.exe）不會隨父程序死掉，要整棵砍
    try { execSync(`taskkill /pid ${proc.pid} /T /F`, { windowsHide: true, stdio: 'ignore' }); } catch { /* ignore */ }
  } else {
    try { proc.kill('SIGKILL'); } catch { /* ignore */ }
  }
}

const PROGRESS_LABELS = {
  command_execution: '⚙️ 執行指令',
  file_change: '✏️ 修改檔案',
  mcp_tool_call: '🔧 呼叫工具',
  web_search: '🔎 搜尋網路',
  reasoning: '🤔 思考中',
};

/**
 * 執行一輪 Codex 對話。
 * @param {object} opts
 * @param {object} opts.config      載入後的設定
 * @param {string} opts.prompt      使用者 prompt（走 stdin，任意內容都安全）
 * @param {string|null} opts.threadId  既有會話 id；null 表示開新會話
 * @param {string[]} [opts.images]  附圖檔案路徑
 * @param {(text: string) => void} [opts.onProgress]  進度回呼
 * @returns {Promise<{text: string, threadId: string|null, usage: object|null}>}
 */
function runCodex({ config, prompt, threadId, images = [], onProgress }) {
  return new Promise((resolve, reject) => {
    const { cmd, baseArgs, shell } = resolveCodexCommand(config);

    const args = [...baseArgs, 'exec'];
    if (threadId) args.push('resume', threadId);
    args.push('--json', '--skip-git-repo-check');
    if (threadId) {
      // resume 子指令不吃 -s / -m / --color，改走 -c 設定覆寫
      args.push('-c', `sandbox_mode="${config.sandbox}"`);
      if (config.model) args.push('-c', `model="${config.model}"`);
    } else {
      args.push('--color', 'never', '-s', config.sandbox);
      if (config.model) args.push('-m', config.model);
    }
    if (config.reasoningEffort) args.push('-c', `model_reasoning_effort="${config.reasoningEffort}"`);
    if (config.serviceTier) args.push('-c', `service_tier="${config.serviceTier}"`);
    for (const img of images) args.push('-i', img);
    args.push('-'); // prompt 從 stdin 讀

    const proc = spawn(cmd, args, {
      cwd: config.workDir,
      env: { ...process.env },
      shell,
      windowsHide: true,
      stdio: ['pipe', 'pipe', 'pipe'],
    });

    proc.stdin.write(prompt);
    proc.stdin.end();

    let buffer = '';
    let stderrTail = '';
    let resultThreadId = threadId || null;
    let usage = null;
    let turnCompleted = false;
    let turnFailedMessage = null;
    const messages = [];

    const timer = setTimeout(() => {
      killTree(proc);
      reject(new Error(`Codex 逾時（${config.timeoutMinutes} 分鐘）`));
    }, config.timeoutMinutes * 60 * 1000);

    const handleEvent = (event) => {
      const item = event.item;
      switch (event.type) {
        case 'thread.started':
          if (event.thread_id) resultThreadId = event.thread_id;
          break;
        case 'turn.completed':
          turnCompleted = true;
          usage = event.usage || null;
          break;
        case 'turn.failed':
          turnFailedMessage = event.error?.message || 'turn.failed（未提供原因）';
          break;
        case 'error':
          turnFailedMessage = event.message || event.error?.message || 'Codex 回報錯誤';
          break;
        case 'item.started':
        case 'item.updated': {
          if (!onProgress || !item) break;
          const label = PROGRESS_LABELS[item.type];
          if (!label) break;
          let detail = '';
          if (item.type === 'command_execution' && item.command) {
            detail = item.command.length > 300 ? item.command.slice(0, 300) + '...' : item.command;
          }
          onProgress(`${label}...${detail ? '\n' + detail : ''}`);
          break;
        }
        case 'item.completed': {
          if (!item) break;
          if (item.type === 'agent_message' && item.text) {
            messages.push(item.text);
            if (onProgress) {
              const t = item.text.trim();
              onProgress('💬 ' + (t.length > 600 ? t.slice(0, 600) + '...' : t));
            }
          } else if (item.type === 'error' && item.message) {
            turnFailedMessage = item.message;
          } else if (item.type === 'reasoning' && item.text && onProgress) {
            const t = item.text.trim();
            onProgress('🤔 ' + (t.length > 600 ? t.slice(0, 600) + '...' : t));
          }
          break;
        }
        default:
          break;
      }
    };

    proc.stdout.on('data', (chunk) => {
      buffer += chunk.toString();
      const lines = buffer.split('\n');
      buffer = lines.pop(); // 最後一段可能被截斷，留到下一批
      for (const line of lines) {
        if (!line.trim()) continue;
        try {
          handleEvent(JSON.parse(line));
        } catch { /* 非 JSON 行（log 雜訊）直接忽略 */ }
      }
    });

    proc.stderr.on('data', (chunk) => {
      stderrTail = (stderrTail + chunk.toString()).slice(-2000);
      if (process.env.DEBUG) console.error('[codex stderr]', chunk.toString());
    });

    proc.on('close', (code) => {
      clearTimeout(timer);
      if (turnFailedMessage) {
        return reject(new Error(`Codex 執行失敗：${turnFailedMessage}`));
      }
      if (turnCompleted || messages.length > 0) {
        return resolve({ text: messages.join('\n\n'), threadId: resultThreadId, usage });
      }
      const hint = stderrTail
        .split('\n')
        .filter((l) => l.trim() && !/^\d{4}-\d{2}-\d{2}T.*(ERROR|WARN) codex_models_manager/.test(l))
        .slice(-5)
        .join('\n');
      reject(new Error(`codex 結束（exit code ${code}）${hint ? '\n' + hint : ''}`));
    });

    proc.on('error', (err) => {
      clearTimeout(timer);
      reject(new Error(`無法啟動 codex：${err.message}（請確認已安裝 @openai/codex 並在 PATH 中）`));
    });
  });
}

module.exports = { runCodex, resolveCodexCommand, findCodexJs };