import express from 'express';
import { Parser } from 'json2csv';
import bcrypt from 'bcrypt';
import jwt from 'jsonwebtoken';
import { v4 as uuidv4 } from 'uuid';

export default function(db) {
  const router = express.Router();

  // Middleware to authenticate and authorize managers
  const authenticateJWT = (req, res, next) => {
    const authHeader = req.headers.authorization;
    if (authHeader) {
      const token = authHeader.split(' ')[1];
      jwt.verify(token, process.env.JWT_SECRET, (err, user) => {
        if (err || user.role !== 'manager') {
          return res.status(403).json({ message: 'Forbidden' });
        }
        req.user = user;
        next();
      });
    } else {
      res.status(401).json({ message: 'Unauthorized' });
    }
  };
  router.use(authenticateJWT);

  // --- START: Date Management Routes ---
  router.get('/enabled-dates', async (req, res) => {
    try {
      const [rows] = await db.execute('SELECT YEAR(enabled_date) as year, MONTH(enabled_date) as month, DAY(enabled_date) as day FROM enabled_dates');
      // Format date safely using components from the database to avoid timezone shifts
      const dates = rows.map(r => `${r.year}-${String(r.month).padStart(2, '0')}-${String(r.day).padStart(2, '0')}`);
      res.json(dates);
    } catch (error) {
      console.error('Error fetching enabled dates:', error);
      res.status(500).json({ message: 'Database error fetching enabled dates.' });
    }
  });

// Definitive version using a dedicated database connection
  router.post('/enabled-dates/update', async (req, res) => {
    let connection; // Define connection here to ensure it's accessible in the 'finally' block
    try {
      const { datesToEnable, datesToDisable } = req.body;

      if (!Array.isArray(datesToEnable) || !Array.isArray(datesToDisable)) {
        return res.status(400).json({ message: 'Invalid input format.' });
      }

      // 1. Get a single, dedicated connection from the pool
      connection = await db.getConnection();

      // 2. Process all deletions sequentially on the dedicated connection
      for (const date of datesToDisable) {
        await connection.execute('DELETE FROM enabled_dates WHERE enabled_date = ?', [date]);
      }

      // 3. Process all insertions sequentially on the dedicated connection
      for (const date of datesToEnable) {
        await connection.execute('INSERT IGNORE INTO enabled_dates (enabled_date) VALUES (?)', [date]);
      }

      res.status(200).json({ message: 'Work schedule updated successfully.' });

    } catch (error) {
      console.error('Error updating work schedule:', error);
      res.status(500).json({ message: 'Database error during schedule update.' });
    } finally {
      // 4. Ensure the dedicated connection is always released back to the pool
      if (connection) {
        connection.release();
      }
    }
  });
  // --- END: Date Management Routes ---

  // --- ATTENDANCE & REPORTING ---

  router.get('/failed-records', async (req, res) => {
    try {
      const { search = '', startDate, endDate } = req.query;
      if (!startDate || !endDate) {
        return res.status(400).json({ message: 'Start date and end date are required.' });
      }

      const searchTerm = `%${search}%`;
      const params = [startDate, `${endDate} 23:59:59`];

      let searchQuery = '';
      if (search) {
        searchQuery = `AND (w.full_name LIKE ? OR w.department LIKE ?)`;
        params.push(searchTerm, searchTerm);
      }

      const query = `
        SELECT cr.worker_id, w.full_name, COUNT(*) as count
        FROM clock_records cr
        JOIN workers w ON cr.worker_id = w.id
        WHERE cr.event_type = 'failed'
          AND cr.timestamp BETWEEN ? AND ?
          ${searchQuery}
        GROUP BY cr.worker_id, w.full_name
        ORDER BY count DESC
      `;

      const [rows] = await db.execute(query, params);
      res.json(rows);
    } catch (error) {
      console.error('Failed records summary error:', error);
      res.status(500).json({ message: 'Database error fetching failed records summary.', details: error.message });
    }
  });

  router.get('/failed-records/details', async (req, res) => {
    try {
      const { workerId, startDate, endDate } = req.query;
      if (!workerId || !startDate || !endDate) {
        return res.status(400).json({ message: 'Worker ID, start date, and end date are required.' });
      }

      const query = `
        SELECT cr.id, cr.timestamp, cr.event_type, COALESCE(qc.name, 'N/A') as qrCodeUsedName, cr.notes
        FROM clock_records cr
        LEFT JOIN qr_codes qc ON cr.qr_code_id = qc.id
        WHERE cr.worker_id = ?
          AND cr.event_type = 'failed'
          AND cr.timestamp BETWEEN ? AND ?
        ORDER BY cr.timestamp DESC
      `;

      const params = [workerId, startDate, `${endDate} 23:59:59`];
      const [rows] = await db.execute(query, params);
      res.json(rows);
    } catch (error) {
      console.error('Failed records details error:', error);
      res.status(500).json({ message: 'Database error fetching failed records details.', details: error.message });
    }
  });

  // GET attendance records with a modified query to avoid the MySQL 5.7 bug
  router.get('/attendance-records/export-raw', async (req, res) => {
    try {
      const { workerIds, startDate, endDate } = req.query;
      if (!startDate || !endDate) {
        return res.status(400).json({ message: 'Start date and end date are required.' });
      }

      let workerIdClause = '';
      const params = [startDate, `${endDate} 23:59:59`];

      if (workerIds) {
        const idsArray = workerIds.split(',').map(Number).filter(id => !isNaN(id));
        if (idsArray.length > 0) {
          workerIdClause = `AND cr.worker_id IN (${idsArray.join(',')})`;
        }
      }

      const query = `
        SELECT w.username, w.full_name, cr.event_type, cr.timestamp, COALESCE(qc.name, 'Manual Entry') as qr_code_name, cr.notes
        FROM clock_records cr
        JOIN workers w ON cr.worker_id = w.id
        LEFT JOIN qr_codes qc ON cr.qr_code_id = qc.id
        WHERE cr.timestamp BETWEEN ? AND ? ${workerIdClause}
        ORDER BY cr.timestamp DESC
      `;

      const [rows] = await db.execute(query, params);

      const json2csvParser = new Parser({ fields: ['username', 'full_name', 'event_type', 'timestamp', 'qr_code_name', 'notes'] });
      const csv = json2csvParser.parse(rows);
      res.header('Content-Type', 'text/csv').attachment(`raw_attendance_${startDate}_to_${endDate}.csv`).send(csv);

    } catch (error) {
      console.error('Raw attendance export error:', error);
      res.status(500).json({ message: 'Database error exporting raw attendance.', details: error.message });
    }
  });

  router.post('/add-record', authenticateJWT, async (req, res) => {
    try {
      const { workerId, eventType, timestamp, notes } = req.body

      if (!workerId || !eventType || !timestamp) {
        return res
          .status(400)
          .json({ message: 'Worker ID, event type, and timestamp are required.' })
      }

      // Check last event to prevent adding a duplicate event type
      const [lastEventRows] = await db.execute(
        'SELECT event_type FROM clock_records WHERE worker_id = ? ORDER BY timestamp DESC LIMIT 1',
        [workerId],
      )

      if (lastEventRows.length > 0 && lastEventRows[0].event_type === eventType) {
        const status = eventType === 'clock_in' ? 'in' : 'out'
        return res.status(409).json({ message: `Worker is already clocked ${status}.` })
      }
      // --- THIS IS THE FIX ---
      const sanitizedTimestamp = timestamp.replace('T', ' ')

      await db.execute(
        'INSERT INTO clock_records (worker_id, event_type, timestamp, notes, qr_code_id, latitude, longitude) VALUES (?, ?, ?, ?, NULL, NULL, NULL)',
        [workerId, eventType, sanitizedTimestamp, notes],
      )

      res.status(201).json({ message: 'Manual record added successfully.' })
    } catch (error) {
      console.error('Add manual record error:', error)
      res.status(500).json({ message: 'Database error adding manual record.' })
    }
  })

  router.get('/attendance-records/export', async (req, res) => {
    try {
      const { workerIds, startDate, endDate } = req.query;
      if (!startDate || !endDate) {
        return res.status(400).json({ message: 'Start date and end date are required.' });
      }

      let workerIdClause = '';
      const params = [startDate, `${endDate} 23:59:59`];

      if (workerIds) {
        const idsArray = workerIds.split(',').map(Number).filter(id => !isNaN(id));
        if (idsArray.length > 0) {
          workerIdClause = `AND cr.worker_id IN (${idsArray.join(',')})`;
        }
      }

      const query = `
        SELECT cr.worker_id, w.username, w.full_name, cr.event_type, cr.timestamp
        FROM clock_records cr
        JOIN workers w ON cr.worker_id = w.id
        WHERE cr.timestamp BETWEEN ? AND ? ${workerIdClause}
        ORDER BY cr.worker_id, cr.timestamp ASC
      `;

      const [rows] = await db.execute(query, params);

      const workHoursByWorkerAndDay = {};

      rows.forEach(row => {
        const day = new Date(row.timestamp).toISOString().split('T')[0];
        if (!workHoursByWorkerAndDay[row.worker_id]) {
          workHoursByWorkerAndDay[row.worker_id] = {
            username: row.username,
            full_name: row.full_name,
            days: {}
          };
        }
        if (!workHoursByWorkerAndDay[row.worker_id].days[day]) {
          workHoursByWorkerAndDay[row.worker_id].days[day] = [];
        }
        workHoursByWorkerAndDay[row.worker_id].days[day].push({
          type: row.event_type,
          time: new Date(row.timestamp)
        });
      });

      const csvData = [];
      for (const workerId in workHoursByWorkerAndDay) {
        const workerData = workHoursByWorkerAndDay[workerId];
        for (const day in workerData.days) {
          const events = workerData.days[day];
          let dailyTotalSeconds = 0;
          let lastClockIn = null;

          events.forEach(event => {
            if (event.type === 'clock_in') {
              lastClockIn = event.time;
            } else if (event.type === 'clock_out' && lastClockIn) {
              dailyTotalSeconds += (event.time - lastClockIn) / 1000;
              lastClockIn = null;
            }
          });

          csvData.push({
            username: workerData.username,
            full_name: workerData.full_name,
            date: day,
            work_hours: (dailyTotalSeconds / 3600).toFixed(2)
          });
        }
      }

      const json2csvParser = new Parser({ fields: ['username', 'full_name', 'date', 'work_hours'] });
      const csv = json2csvParser.parse(csvData);
      res.header('Content-Type', 'text/csv').attachment(`work_hours_${startDate}_to_${endDate}.csv`).send(csv);

    } catch (error) {
      console.error('Work hours export error:', error);
      res.status(500).json({ message: 'Database error exporting work hours.', details: error.message });
    }
  });

  router.get('/attendance-records', async (req, res) => {
    try {
      const { workerIds, startDate, endDate, format } = req.query;
      if (!workerIds) {
        return res.status(400).json({ message: 'Worker IDs are required.' });
      }

      // Ensure all IDs are numbers to prevent SQL injection.
      const idsArray = workerIds.split(',').map(Number).filter(id => !isNaN(id));
      if (idsArray.length === 0) {
        return res.json([]);
      }

      // --- MODIFICATION START ---
      // Instead of using a '?' placeholder for the IN clause, we build it directly.
      // This is safe because we have already sanitized idsArray to be only numbers.
      // This change is intended to bypass the specific bug in your MySQL version.
      const inClause = idsArray.join(',');
      let query = `
        SELECT cr.id, w.full_name, cr.event_type, cr.timestamp,
               COALESCE(qc.name, 'Manual Entry') as qrCodeUsedName,
               cr.latitude, cr.longitude, cr.notes
        FROM clock_records cr
        JOIN workers w ON cr.worker_id = w.id
        LEFT JOIN qr_codes qc ON cr.qr_code_id = qc.id
        WHERE cr.worker_id IN (${inClause})`; // Placeholder is replaced here

      const params = [];
      // --- MODIFICATION END ---

      if (startDate && endDate) {
        query += ' AND cr.timestamp BETWEEN ? AND ?';
        const endOfDay = new Date(endDate);
        endOfDay.setHours(23, 59, 59, 999);
        params.push(startDate, endOfDay);
      }
      query += ' ORDER BY w.full_name, cr.timestamp DESC';

      const [rows] = await db.execute(query, params);

      if (format === 'csv') {
        const json2csvParser = new Parser({ fields: ['full_name', 'event_type', 'timestamp', 'qrCodeUsedName', 'notes'] });
        const csv = json2csvParser.parse(rows);
        res.header('Content-Type', 'text/csv').attachment('attendance.csv').send(csv);
      } else {
        res.json(rows);
      }
    } catch (error) {
      console.error('Attendance records error:', error);
      res.status(500).json({ message: 'Database error fetching attendance records.', details: error.message });
    }
  });


  // --- All other manager routes remain the same ---

  // GET all workers with filtering and pagination
  router.get('/workers', async (req, res) => {
    try {
      const { search = '', page = 1, limit = 20 } = req.query;
      const offset = (parseInt(page) - 1) * parseInt(limit);
      const searchTerm = `%${search}%`;

      let baseQuery = `
        SELECT w.id, w.username, w.full_name, w.department, w.position, w.created_at
        FROM workers w
      `;
      let countQuery = `SELECT COUNT(w.id) as totalCount FROM workers w`;

      const params = [];
      const countParams = [];
      let whereClauses = ["w.role = 'worker'"];

      if (search) {
        whereClauses.push(`(w.full_name LIKE ? OR w.department LIKE ?)`);
        params.push(searchTerm, searchTerm);
        countParams.push(searchTerm, searchTerm);
      }

      if (whereClauses.length > 0) {
        const whereString = ` WHERE ${whereClauses.join(' AND ')}`;
        baseQuery += whereString;
        countQuery += whereString;
      }

      baseQuery += ` ORDER BY w.created_at DESC LIMIT ? OFFSET ?`;
      params.push(parseInt(limit), offset);

      const [workers] = await db.execute(baseQuery, params);
      const [[{ totalCount }]] = await db.execute(countQuery, countParams);

      res.json({ workers, totalCount });
    } catch (error) {
      console.error('Get workers error:', error);
      res.status(500).json({ message: 'Database error fetching workers.', details: error.message });
    }
  });

  // POST (add) a new worker
  router.post('/workers', async (req, res) => {
    try {
      const { username, password, fullName, department, position, role = 'worker' } = req.body;
      if (!username || !password || !fullName) {
        return res.status(400).json({ message: 'Username, password, and full name are required.' });
      }
      const hashedPassword = await bcrypt.hash(password, 10);
      const [result] = await db.execute(
        'INSERT INTO workers (username, password_hash, full_name, role, department, position) VALUES (?, ?, ?, ?, ?, ?)',
        [username, hashedPassword, fullName, role, department, position]
      );
      res.status(201).json({ id: result.insertId, username, fullName, role, department, position });
    } catch (error) {
      console.error('Add worker error:', error);
      if (error.code === 'ER_DUP_ENTRY') {
        return res.status(409).json({ message: 'Username already exists.' });
      }
      res.status(500).json({ message: 'Database error adding worker.', details: error.message });
    }
  });

  // DELETE a worker
  router.delete('/workers/:id', async (req, res) => {
    try {
      const { id } = req.params;
      const [result] = await db.execute("DELETE FROM workers WHERE id = ? AND role = 'worker'", [id]);
      if (result.affectedRows === 0) {
        return res.status(404).json({ message: 'Worker not found.' });
      }
      res.status(204).send();
    } catch (error) {
      console.error('Delete worker error:', error);
      res.status(500).json({ message: 'Database error deleting worker.', details: error.message });
    }
  });

  // PUT (update) a worker's password
  router.put('/workers/:workerId/password', async (req, res) => {
    try {
      const { workerId } = req.params;
      const { newPassword } = req.body;
      if (!newPassword || newPassword.length < 6) {
        return res.status(400).json({ message: 'Password must be at least 6 characters long.' });
      }
      const hashedPassword = await bcrypt.hash(newPassword, 10);
      const [result] = await db.execute("UPDATE workers SET password_hash = ? WHERE id = ? AND role = 'worker'", [hashedPassword, workerId]);
      if (result.affectedRows === 0) {
        return res.status(404).json({ message: 'Worker not found.' });
      }
      res.status(200).json({ message: 'Password updated successfully.' });
    } catch (error) {
      console.error('Update password error:', error);
      res.status(500).json({ message: 'Database error updating password.', details: error.message });
    }
  });

  // PUT (clear) a worker's device UUID
  router.put('/workers/:workerId/reset-device', async (req, res) => {
    try {
      const { workerId } = req.params;
      const [result] = await db.execute("UPDATE workers SET device_uuid = NULL WHERE id = ?", [workerId]);
      if (result.affectedRows === 0) {
        return res.status(404).json({ message: 'Worker not found.' });
      }
      res.status(200).json({ message: 'Device registration cleared.' });
    } catch (error) {
      console.error('Reset device error:', error);
      res.status(500).json({ message: 'Database error resetting device.', details: error.message });
    }
  });


  // Geofence Management Routes
  router.get('/geofences', async (req, res) => {
    try {
      const [rows] = await db.execute(
        'SELECT id, name, coordinates, is_active, created_at FROM geofences ORDER BY created_at DESC'
      );
      const geofences = rows.map(row => ({
        ...row,
        coordinates: JSON.parse(row.coordinates || '[]')
      }));
      res.json(geofences);
    } catch (error) {
      console.error('Get geofences error:', error);
      res.status(500).json({ message: 'Database error fetching geofences.', details: error.message });
    }
  });

  router.post('/geofences', async (req, res) => {
    try {
      const { name, coordinates } = req.body;
      if (!name || !coordinates) {
        return res.status(400).json({ message: 'Geofence name and coordinates are required.' });
      }

      const [result] = await db.execute(
        'INSERT INTO geofences (name, coordinates, is_active) VALUES (?, ?, ?)',
        [name, JSON.stringify(coordinates), true]
      );

      const newGeofence = {
        id: result.insertId,
        name,
        coordinates,
        is_active: true,
      };
      res.status(201).json(newGeofence);
    } catch (error) {
      console.error('Add geofence error:', error);
      res.status(500).json({ message: 'Database error adding geofence.', details: error.message });
    }
  });

  router.put('/geofences/:id', async (req, res) => {
    try {
      const { id } = req.params;
      const { is_active } = req.body;

      if (typeof is_active !== 'boolean') {
        return res.status(400).json({ message: 'is_active must be a boolean.' });
      }

      const [result] = await db.execute(
        'UPDATE geofences SET is_active = ? WHERE id = ?',
        [is_active, id]
      );

      if (result.affectedRows === 0) {
        return res.status(404).json({ message: 'Geofence not found.' });
      }

      res.json({ id, is_active });
    } catch (error) {
      console.error('Update geofence error:', error);
      res.status(500).json({ message: 'Database error updating geofence.', details: error.message });
    }
  });

  router.delete('/geofences/:id', async (req, res) => {
    try {
      const { id } = req.params;
      const [result] = await db.execute('DELETE FROM geofences WHERE id = ?', [id]);

      if (result.affectedRows === 0) {
        return res.status(404).json({ message: 'Geofence not found.' });
      }

      res.status(204).send();
    } catch (error) {
      console.error('Delete geofence error:', error);
      res.status(500).json({ message: 'Database error deleting geofence.', details: error.message });
    }
  });


  // QR Code Management Routes
  router.get('/qr-codes', authenticateJWT, async (req, res) => {
    try {
      const [rows] = await db.execute(
        'SELECT id, name, is_active, created_at FROM qr_codes ORDER BY created_at DESC'
      );
      res.json(rows);
    } catch (error) {
      console.error('Get QR codes error:', error);
      res.status(500).json({ message: 'Database error fetching QR codes.' });
    }
  });

  router.post('/qr-codes', authenticateJWT, async (req, res) => {
    try {
      const { name } = req.body;
      if (!name) return res.status(400).json({ message: 'QR Code name is required.' });

      const newQrCode = {
        id: uuidv4(),
        name,
        is_active: true
      };

      await db.execute(
        'INSERT INTO qr_codes (id, name, is_active) VALUES (?, ?, ?)',
        [newQrCode.id, newQrCode.name, newQrCode.is_active]
      );

      res.status(201).json(newQrCode);
    } catch (error) {
      console.error('Add QR code error:', error);
      res.status(500).json({ message: 'Database error adding QR code.' });
    }
  });

  router.put('/qr-codes/:id', authenticateJWT, async (req, res) => {
    try {
      const { id } = req.params;
      // Handle both isActive (camelCase) and is_active (snake_case)
      const is_active = req.body.is_active ?? req.body.isActive;

      if (typeof is_active !== 'boolean') {
        return res.status(400).json({ message: 'Status must be a boolean value.' });
      }

      const [result] = await db.execute(
        'UPDATE qr_codes SET is_active = ? WHERE id = ?',
        [is_active, id]
      );

      if (result.affectedRows === 0) {
        return res.status(404).json({ message: 'QR Code not found.' });
      }

      res.json({ id, is_active });
    } catch (error) {
      console.error('Update QR code error:', error);
      res.status(500).json({ message: 'Database error updating QR code.' });
    }
  });

  router.delete('/qr-codes/:id', authenticateJWT, async (req, res) => {
    try {
      const { id } = req.params;
      const [result] = await db.execute(
        'DELETE FROM qr_codes WHERE id = ?',
        [id]
      );

      if (result.affectedRows === 0) {
        return res.status(404).json({ message: 'QR Code not found.' });
      }

      res.status(204).send();
    } catch (error) {
      console.error('Delete QR code error:', error);
      res.status(500).json({ message: 'Database error deleting QR code.' });
    }
  });

  return router;
}