const express = require('express');
const { exec, execFile } = require('child_process');
const path = require('path');
const fs = require('fs');

const app = express();
const PORT = process.env.PORT || 3789;

// Windows 版：crontab 內容存在本地檔案，由內建排程器執行
const CRONTAB_FILE = process.env.CRONTAB_FILE || path.join(__dirname, 'crontab.txt');
const LOG_DIR = process.env.LOG_DIR || path.join(__dirname, 'logs');

app.use(express.json());
app.use(express.static(path.join(__dirname, 'public')));

// ── 判斷是否為 cron 格式 ──────────────────────────────────
function isCronFormat(content) {
  if (!content) return false;
  if (content.startsWith('@')) return /^@\w+\s+\S/.test(content);
  return /^[\d\*\/\-,]+\s+[\d\*\/\-,]+\s+[\d\*\/\-,]+\s+[\d\*\/\-,]+\s+[\d\*\/\-,]+\s+\S/.test(content);
}

// ── 解析 crontab 文字 ─────────────────────────────────────
function parseCrontab(raw) {
  const lines = raw.split('\n');
  const labelLineSet = new Set(); // 屬於某個 cron 任務的 label 行

  // 第一輪：標記所有緊接在 cron 行前面的連續 comment 行
  for (let i = 0; i < lines.length; i++) {
    const trimmed = lines[i].trim();
    if (!trimmed) continue;
    const disabled = trimmed.startsWith('#');
    const content = disabled ? trimmed.replace(/^#+\s*/, '').trim() : trimmed;
    if (!isCronFormat(content)) continue;

    // 往前找所有連續的 comment 行（中間沒有空行）
    let j = i - 1;
    while (j >= 0) {
      const t = lines[j].trim();
      if (!t) break; // 空行就停
      if (t.startsWith('#') && !isCronFormat(t.replace(/^#+\s*/, '').trim())) {
        labelLineSet.add(j);
        j--;
      } else {
        break;
      }
    }
  }

  // 第二輪：建立 entries
  const entries = [];
  for (let i = 0; i < lines.length; i++) {
    const line = lines[i];
    const trimmed = line.trim();
    if (!trimmed) continue;
    if (labelLineSet.has(i)) continue; // label 行由 cron entry 帶走

    const disabled = trimmed.startsWith('#');
    const content = disabled ? trimmed.replace(/^#+\s*/, '').trim() : trimmed;

    if (isCronFormat(content)) {
      const entry = parseCronLine(i, line, content, disabled);

      // 收集緊接在上方的 label 行（由小到大排列）
      const labelIndices = [];
      let j = i - 1;
      while (j >= 0 && labelLineSet.has(j)) {
        labelIndices.unshift(j);
        j--;
      }
      if (labelIndices.length > 0) {
        entry.label = labelIndices
          .map(idx => lines[idx].trim().replace(/^#+\s*/, ''))
          .join('\n');
        entry.labelIndices = labelIndices;
      }

      entries.push(entry);
    } else {
      entries.push({ index: i, type: 'comment', raw: line, text: trimmed });
    }
  }

  return entries;
}

function parseCronLine(index, raw, content, disabled) {
  let schedule, command, scheduleDesc;

  if (content.startsWith('@')) {
    const spaceIdx = content.indexOf(' ');
    schedule = content.slice(0, spaceIdx);
    command = content.slice(spaceIdx + 1).trim();
    const macros = {
      '@reboot': '開機時執行', '@yearly': '每年', '@annually': '每年',
      '@monthly': '每月1日', '@weekly': '每週日', '@daily': '每天',
      '@midnight': '每天', '@hourly': '每小時',
    };
    scheduleDesc = macros[schedule] || schedule;
  } else {
    const parts = content.split(/\s+/);
    const [min, hour, day, month, weekday, ...rest] = parts;
    schedule = `${min} ${hour} ${day} ${month} ${weekday}`;
    command = rest.join(' ');
    scheduleDesc = describeSchedule(min, hour, day, month, weekday);
  }

  return { index, type: 'cron', raw, schedule, command, scheduleDesc, disabled, label: '', labelIndices: [] };
}

function describeSchedule(min, hour, day, month, weekday) {
  const wd = ['日', '一', '二', '三', '四', '五', '六'];
  const parts = [];
  if (weekday !== '*') {
    parts.push(`每週${weekday.split(',').map(n => wd[parseInt(n)] || n).join('、')}`);
  } else if (day !== '*') {
    parts.push(`每月 ${day} 日`);
  } else {
    parts.push('每天');
  }
  if (hour !== '*' && min !== '*') parts.push(`${hour}:${String(min).padStart(2, '0')}`);
  else if (hour !== '*') parts.push(`${hour} 時`);
  else if (min !== '*') parts.push(`每小時第 ${min} 分`);
  if (month !== '*') parts.unshift(`${month} 月`);
  return parts.join(' ');
}

// ── 內建排程器 ────────────────────────────────────────────
// macro → 5 欄位（@reboot 於伺服器啟動時執行）
const MACRO_MAP = {
  '@yearly': '0 0 1 1 *', '@annually': '0 0 1 1 *',
  '@monthly': '0 0 1 * *', '@weekly': '0 0 * * 0',
  '@daily': '0 0 * * *', '@midnight': '0 0 * * *',
  '@hourly': '0 * * * *',
};

// 解析單一 cron 欄位（*、*/n、a-b、a-b/n、a,b,c），回傳允許值 Set；null 表示格式錯誤
function parseField(field, min, max) {
  const values = new Set();
  for (const part of field.split(',')) {
    const m = part.match(/^(\*|\d+(?:-\d+)?)(?:\/(\d+))?$/);
    if (!m) return null;
    const step = m[2] ? parseInt(m[2]) : 1;
    if (step < 1) return null;
    let lo, hi;
    if (m[1] === '*') { lo = min; hi = max; }
    else if (m[1].includes('-')) { [lo, hi] = m[1].split('-').map(Number); }
    else { lo = hi = parseInt(m[1]); if (m[2]) hi = max; } // "a/n" 視為 a-max/n
    if (lo < min || hi > max || lo > hi) return null;
    for (let v = lo; v <= hi; v += step) values.add(v);
  }
  return values;
}

function cronMatches(schedule, date) {
  const fields = schedule.trim().split(/\s+/);
  if (fields.length !== 5) return false;
  const [min, hour, day, month, weekday] = fields;
  const fMin = parseField(min, 0, 59);
  const fHour = parseField(hour, 0, 23);
  const fDay = parseField(day, 1, 31);
  const fMonth = parseField(month, 1, 12);
  const fWd = parseField(weekday, 0, 7);
  if (!fMin || !fHour || !fDay || !fMonth || !fWd) return false;
  if (fWd.has(7)) fWd.add(0); // 7 也代表週日

  if (!fMin.has(date.getMinutes())) return false;
  if (!fHour.has(date.getHours())) return false;
  if (!fMonth.has(date.getMonth() + 1)) return false;

  // 標準 cron 規則：day 與 weekday 都有限制時，符合其一即可
  const dayRestricted = day !== '*';
  const wdRestricted = weekday !== '*';
  const dayOk = fDay.has(date.getDate());
  const wdOk = fWd.has(date.getDay());
  if (dayRestricted && wdRestricted) return dayOk || wdOk;
  if (dayRestricted) return dayOk;
  if (wdRestricted) return wdOk;
  return true;
}

function cronLog(message) {
  const line = `[${new Date().toLocaleString('sv-SE')}] ${message}\n`;
  try {
    if (!fs.existsSync(LOG_DIR)) fs.mkdirSync(LOG_DIR, { recursive: true });
    fs.appendFileSync(path.join(LOG_DIR, 'cron.log'), line);
  } catch {}
  console.log(line.trim());
}

function runJob(schedule, command) {
  cronLog(`▶ 執行 [${schedule}] ${command}`);
  exec(command, { windowsHide: true, maxBuffer: 10 * 1024 * 1024 }, (err, stdout, stderr) => {
    const out = [stdout, stderr].filter(s => s && s.trim()).join('\n').trim();
    if (err) cronLog(`✖ 失敗 [${command}]：${err.message}${out ? '\n' + out : ''}`);
    else cronLog(`✔ 完成 [${command}]${out ? '\n' + out : ''}`);
  });
}

// 取得目前啟用中的 cron 任務
function activeJobs() {
  return parseCrontab(readCrontabRaw())
    .filter(e => e.type === 'cron' && !e.disabled)
    .map(e => ({
      schedule: MACRO_MAP[e.schedule] || e.schedule,
      isReboot: e.schedule === '@reboot',
      command: e.command,
    }));
}

let lastMinuteKey = '';
function schedulerTick() {
  const now = new Date();
  const key = `${now.getFullYear()}-${now.getMonth()}-${now.getDate()} ${now.getHours()}:${now.getMinutes()}`;
  if (key === lastMinuteKey) return; // 同一分鐘不重複執行
  lastMinuteKey = key;

  for (const job of activeJobs()) {
    if (job.isReboot) continue;
    if (cronMatches(job.schedule, now)) runJob(job.schedule, job.command);
  }
}

function startScheduler() {
  // @reboot：伺服器啟動時執行一次
  for (const job of activeJobs()) {
    if (job.isReboot) runJob('@reboot', job.command);
  }
  lastMinuteKey = ''; // 啟動當下這一分鐘也要檢查
  setInterval(schedulerTick, 5000);
  schedulerTick();
}

// ── 工具 ─────────────────────────────────────────────────
function readCrontabRaw() {
  try {
    return fs.readFileSync(CRONTAB_FILE, 'utf-8');
  } catch {
    return '';
  }
}

function getCrontabLines(cb) {
  cb(readCrontabRaw().split('\n'));
}

function applyLines(lines, res) {
  const content = lines.join('\n');
  console.log('[applyLines] writing crontab:');
  lines.forEach((l, i) => console.log(`  [${i}] ${JSON.stringify(l)}`));

  try {
    fs.writeFileSync(CRONTAB_FILE, content);
    res.json({ success: true });
  } catch (e) {
    console.error('[applyLines] error:', e.message);
    res.status(500).json({ error: e.message });
  }
}

// label 文字 → 陣列的 # 行
function labelToLines(label) {
  if (!label || !label.trim()) return [];
  return label.split('\n').filter(l => l.trim()).map(l => `# ${l.trim()}`);
}

// ── GET /api/crontab ──────────────────────────────────────
app.get('/api/crontab', (req, res) => {
  const raw = readCrontabRaw();
  res.json({ raw, entries: parseCrontab(raw) });
});

// ── POST /api/crontab/toggle ──────────────────────────────
app.post('/api/crontab/toggle', (req, res) => {
  const { index } = req.body;
  if (index === undefined) return res.status(400).json({ error: 'index required' });
  getCrontabLines((lines) => {
    if (index < 0 || index >= lines.length) return res.status(404).json({ error: 'not found' });
    const t = lines[index].trim();
    lines[index] = t.startsWith('#') ? t.replace(/^#+\s*/, '') : '# ' + lines[index];
    applyLines(lines, res);
  });
});

// ── DELETE /api/crontab/:index ────────────────────────────
// body: { labelIndices?: number[] }
app.delete('/api/crontab/:index', (req, res) => {
  const cronIndex = parseInt(req.params.index);
  const labelIndices = req.body?.labelIndices || [];

  getCrontabLines((lines) => {
    if (isNaN(cronIndex) || cronIndex < 0 || cronIndex >= lines.length)
      return res.status(404).json({ error: 'not found' });

    const toDelete = [...labelIndices, cronIndex].sort((a, b) => b - a);
    toDelete.forEach(idx => { if (idx >= 0 && idx < lines.length) lines.splice(idx, 1); });
    applyLines(lines, res);
  });
});

// ── PUT /api/crontab/:index ───────────────────────────────
// body: { schedule, command, label, labelIndices?: number[] }
app.put('/api/crontab/:index', (req, res) => {
  const cronIndex = parseInt(req.params.index);
  const { schedule, command, label, labelIndices = [] } = req.body;
  console.log('[PUT] index=%d schedule=%j command=%j label=%j labelIndices=%j',
    cronIndex, schedule, command, label, labelIndices);
  if (!schedule || !command) return res.status(400).json({ error: 'schedule and command required' });

  getCrontabLines((lines) => {
    if (isNaN(cronIndex) || cronIndex < 0 || cronIndex >= lines.length)
      return res.status(404).json({ error: 'not found' });

    const wasDisabled = lines[cronIndex].trim().startsWith('#');
    const newCronLine = wasDisabled ? `# ${schedule} ${command}` : `${schedule} ${command}`;

    // 所有要移除的行（倒序）
    const allRemove = [...labelIndices, cronIndex].sort((a, b) => b - a);
    const insertAt = Math.min(...allRemove);
    allRemove.forEach(idx => lines.splice(idx, 1));

    // 重建：新 label 行 + cron 行
    const newLines = [...labelToLines(label), newCronLine];
    lines.splice(insertAt, 0, ...newLines);

    applyLines(lines, res);
  });
});

// ── POST /api/crontab/add ─────────────────────────────────
// body: { schedule, command, label? }
app.post('/api/crontab/add', (req, res) => {
  const { schedule, command, label } = req.body;
  if (!schedule || !command) return res.status(400).json({ error: 'schedule and command required' });

  getCrontabLines((lines) => {
    while (lines.length && !lines[lines.length - 1].trim()) lines.pop();
    labelToLines(label).forEach(l => lines.push(l));
    lines.push(`${schedule} ${command}`);
    lines.push('');
    applyLines(lines, res);
  });
});

// ── GET /api/pm2 ─────────────────────────────────────────
app.get('/api/pm2', (req, res) => {
  exec('pm2 jlist', { windowsHide: true }, (err, stdout) => {
    if (err) return res.json({ processes: [], error: err.message });
    try {
      // pm2 jlist 前面可能夾雜非 JSON 訊息，從第一個 [ 開始取
      const jsonStart = stdout.indexOf('[');
      const list = JSON.parse(jsonStart >= 0 ? stdout.slice(jsonStart) : '[]');
      const processes = list.map(p => ({
        id:       p.pm_id,
        name:     p.name,
        status:   p.pm2_env?.status || 'unknown',
        pid:      p.pid,
        cpu:      p.monit?.cpu ?? '-',
        memory:   p.monit?.memory ?? 0,
        restarts: p.pm2_env?.restart_time ?? 0,
        uptime:   p.pm2_env?.pm_uptime ?? null,
        mode:     p.pm2_env?.exec_mode || 'fork',
        script:   p.pm2_env?.pm_exec_path || p.pm2_env?.script || '',
        ports:    [],
      }));

      const pids = new Set(processes.filter(p => p.pid).map(p => String(p.pid)));
      if (pids.size === 0) return res.json({ processes });

      // 用 netstat 取得所有 LISTENING port，再依 PID 對應
      exec('netstat -ano', { windowsHide: true, maxBuffer: 10 * 1024 * 1024 }, (e2, netOut) => {
        const portMap = {}; // pid → [port, ...]
        (netOut || '').split('\n').forEach(line => {
          // 格式: TCP  0.0.0.0:3789  0.0.0.0:0  LISTENING  12345
          const m = line.trim().match(/^TCP\s+\S+:(\d+)\s+\S+\s+LISTENING\s+(\d+)/);
          if (!m) return;
          const port = m[1];
          const pid = m[2];
          if (pids.has(pid)) {
            if (!portMap[pid]) portMap[pid] = [];
            if (!portMap[pid].includes(port)) portMap[pid].push(port);
          }
        });

        processes.forEach(p => {
          if (portMap[String(p.pid)]) p.ports = portMap[String(p.pid)];
        });
        res.json({ processes });
      });
    } catch (e) {
      res.json({ processes: [], error: e.message });
    }
  });
});

// ── POST /api/pm2/:action ─────────────────────────────────
// action: start | stop | restart | delete
app.post('/api/pm2/:action', (req, res) => {
  const { action } = req.params;
  const { name } = req.body;
  if (!name) return res.status(400).json({ error: 'name required' });
  const allowed = ['start', 'stop', 'restart', 'delete'];
  if (!allowed.includes(action)) return res.status(400).json({ error: 'invalid action' });

  exec(`pm2 ${action} ${JSON.stringify(name)}`, { windowsHide: true }, (err, stdout) => {
    if (err) return res.status(500).json({ error: stdout || err.message });
    res.json({ success: true });
  });
});

// ── GET /api/node ─────────────────────────────────────────
app.get('/api/node', (req, res) => {
  const script = `Get-CimInstance Win32_Process | Where-Object { $_.Name -match '^(node|bun)' } | ` +
    `Select-Object ProcessId, CommandLine, ` +
    `@{n='MemMB';e={[math]::Round($_.WorkingSetSize/1MB,1)}}, ` +
    `@{n='Started';e={if ($_.CreationDate) {$_.CreationDate.ToString('MM/dd HH:mm')} else {'-'}}} | ` +
    `ConvertTo-Json -Compress`;
  execFile('powershell.exe', ['-NoProfile', '-Command', script], { windowsHide: true, maxBuffer: 10 * 1024 * 1024 }, (err, stdout) => {
    if (err) return res.json({ processes: [], error: err.message });
    let list = [];
    try {
      const parsed = JSON.parse(stdout.trim() || '[]');
      list = Array.isArray(parsed) ? parsed : [parsed];
    } catch {}
    const processes = list.map(p => ({
      pid: String(p.ProcessId),
      cpu: '-',
      mem: `${p.MemMB}MB`,
      started: p.Started || '-',
      time: '-',
      cmd: p.CommandLine || '',
    })).filter(p => p.pid && p.pid !== String(process.pid)); // 排除自己
    res.json({ processes });
  });
});

// ── POST /api/node/kill ───────────────────────────────────
app.post('/api/node/kill', (req, res) => {
  const { pid, force } = req.body;
  if (!pid) return res.status(400).json({ error: 'pid required' });
  const args = force ? `/F /T /PID ${parseInt(pid)}` : `/PID ${parseInt(pid)}`;
  exec(`taskkill ${args}`, { windowsHide: true }, (err, stdout, stderr) => {
    if (err) return res.status(500).json({ error: (stderr || stdout || err.message).trim() });
    res.json({ success: true });
  });
});

// ── GET /api/docker ──────────────────────────────────────
app.get('/api/docker', (req, res) => {
  const format = '{{json .}}';
  exec(`docker ps -a --format ${JSON.stringify(format)}`, { windowsHide: true }, (err, stdout) => {
    if (err) return res.json({ containers: [], error: (stdout || '').trim() || err.message });

    try {
      const containers = (stdout || '')
        .split('\n')
        .filter(Boolean)
        .map(line => JSON.parse(line))
        .map(container => ({
          id: container.ID,
          name: container.Names,
          image: container.Image,
          status: container.Status,
          state: (container.State || 'unknown').toLowerCase(),
          ports: container.Ports || '',
          command: container.Command || '',
          createdAt: container.CreatedAt || '',
          runningFor: container.RunningFor || '',
        }));

      res.json({ containers });
    } catch (e) {
      res.json({ containers: [], error: e.message });
    }
  });
});

// ── POST /api/docker/:action ─────────────────────────────
// action: start | stop | restart
app.post('/api/docker/:action', (req, res) => {
  const { action } = req.params;
  const { id } = req.body;
  const allowed = ['start', 'stop', 'restart'];
  if (!allowed.includes(action)) return res.status(400).json({ error: 'invalid action' });
  if (!id) return res.status(400).json({ error: 'id required' });

  exec(`docker ${action} ${JSON.stringify(id)}`, { windowsHide: true }, (err, stdout) => {
    if (err) return res.status(500).json({ error: (stdout || '').trim() || err.message });
    res.json({ success: true });
  });
});

// ── Log API ───────────────────────────────────────────────
app.get('/api/logs', (req, res) => {
  try {
    if (!fs.existsSync(LOG_DIR)) return res.json([]);
    const files = fs.readdirSync(LOG_DIR)
      .filter(f => f.endsWith('.log'))
      .map(f => {
        const stat = fs.statSync(path.join(LOG_DIR, f));
        return { name: f, size: stat.size, mtime: stat.mtimeMs };
      })
      .sort((a, b) => b.mtime - a.mtime);
    res.json(files);
  } catch (err) {
    res.status(500).json({ error: err.message });
  }
});

app.get('/api/logs/:filename', (req, res) => {
  const filename = path.basename(req.params.filename); // 防止路徑穿越
  const filepath = path.join(LOG_DIR, filename);
  if (!filepath.startsWith(LOG_DIR)) return res.status(403).json({ error: 'forbidden' });
  try {
    if (!fs.existsSync(filepath)) return res.status(404).json({ error: '找不到檔案' });
    const lines = parseInt(req.query.lines) || 200;
    const content = fs.readFileSync(filepath, 'utf-8');
    const allLines = content.split('\n');
    const tail = allLines.slice(-lines).join('\n');
    res.json({ filename, lines: allLines.length, content: tail });
  } catch (err) {
    res.status(500).json({ error: err.message });
  }
});

app.use('/api', (req, res) => {
  res.status(404).json({ error: `API not found: ${req.method} ${req.originalUrl}` });
});

app.listen(PORT, () => {
  console.log(`✅ Crontab UI (Windows) 已啟動：http://localhost:${PORT}`);
  console.log(`   排程檔：${CRONTAB_FILE}`);
  console.log(`   Log 目錄：${LOG_DIR}`);
  startScheduler();
});