import express from 'express';
import db from '../config/database.js';
import { authenticateToken, authorize } from '../middleware/auth.js';

const router = express.Router();

// Get all attendance records
router.get('/', authenticateToken, async (req, res) => {
  try {
    const { employeeId, startDate, endDate, status } = req.query;
    
    let query = `
      SELECT a.*, 
             e.name as employee_name, e.username as employee_username,
             s.name as supervisor_name,
             d.name as department_name,
             c.name as contractor_name
      FROM attendance a
      JOIN users e ON a.employee_id = e.id
      JOIN users s ON a.supervisor_id = s.id
      LEFT JOIN departments d ON e.department_id = d.id
      LEFT JOIN users c ON e.contractor_id = c.id
      WHERE 1=1
    `;
    const params = [];

    // Role-based filtering
    if (req.user.role === 'Supervisor') {
      query += ' AND a.supervisor_id = ?';
      params.push(req.user.id);
    } else if (req.user.role === 'Employee') {
      query += ' AND a.employee_id = ?';
      params.push(req.user.id);
    }

    if (employeeId) {
      query += ' AND a.employee_id = ?';
      params.push(employeeId);
    }

    if (startDate) {
      query += ' AND a.work_date >= ?';
      params.push(startDate);
    }

    if (endDate) {
      query += ' AND a.work_date <= ?';
      params.push(endDate);
    }

    if (status) {
      query += ' AND a.status = ?';
      params.push(status);
    }

    query += ' ORDER BY a.work_date DESC, a.check_in_time DESC';

    const [records] = await db.query(query, params);
    res.json(records);
  } catch (error) {
    console.error('Get attendance error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// Get attendance by ID
router.get('/:id', authenticateToken, async (req, res) => {
  try {
    const [records] = await db.query(
      `SELECT a.*, 
              e.name as employee_name, e.username as employee_username,
              s.name as supervisor_name,
              d.name as department_name,
              c.name as contractor_name
       FROM attendance a
       JOIN users e ON a.employee_id = e.id
       JOIN users s ON a.supervisor_id = s.id
       LEFT JOIN departments d ON e.department_id = d.id
       LEFT JOIN users c ON e.contractor_id = c.id
       WHERE a.id = ?`,
      [req.params.id]
    );

    if (records.length === 0) {
      return res.status(404).json({ error: 'Attendance record not found' });
    }

    res.json(records[0]);
  } catch (error) {
    console.error('Get attendance error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// Check in employee (Supervisor or SuperAdmin)
router.post('/check-in', authenticateToken, authorize('Supervisor', 'SuperAdmin'), async (req, res) => {
  try {
    const { employeeId, workDate } = req.body;

    if (!employeeId || !workDate) {
      return res.status(400).json({ error: 'Employee ID and work date required' });
    }

    // Verify employee exists (SuperAdmin can check in any employee, Supervisor only their department)
    let employeeQuery = 'SELECT * FROM users WHERE id = ? AND role = ?';
    let employeeParams = [employeeId, 'Employee'];
    
    if (req.user.role === 'Supervisor') {
      employeeQuery += ' AND department_id = ?';
      employeeParams.push(req.user.departmentId);
    }

    const [employees] = await db.query(employeeQuery, employeeParams);

    if (employees.length === 0) {
      return res.status(403).json({ error: 'Employee not found or not in your department' });
    }

    // Check if already checked in today
    const [existing] = await db.query(
      'SELECT * FROM attendance WHERE employee_id = ? AND work_date = ? AND status = ?',
      [employeeId, workDate, 'CheckedIn']
    );

    if (existing.length > 0) {
      return res.status(400).json({ error: 'Employee already checked in today' });
    }

    const checkInTime = new Date();
    
    const [result] = await db.query(
      'INSERT INTO attendance (employee_id, supervisor_id, check_in_time, work_date, status) VALUES (?, ?, ?, ?, ?)',
      [employeeId, req.user.id, checkInTime, workDate, 'CheckedIn']
    );

    const [newRecord] = await db.query(
      `SELECT a.*, 
              e.name as employee_name, e.username as employee_username,
              s.name as supervisor_name,
              d.name as department_name,
              c.name as contractor_name
       FROM attendance a
       JOIN users e ON a.employee_id = e.id
       JOIN users s ON a.supervisor_id = s.id
       LEFT JOIN departments d ON e.department_id = d.id
       LEFT JOIN users c ON e.contractor_id = c.id
       WHERE a.id = ?`,
      [result.insertId]
    );

    res.status(201).json(newRecord[0]);
  } catch (error) {
    console.error('Check in error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// Check out employee (Supervisor or SuperAdmin)
router.post('/check-out', authenticateToken, authorize('Supervisor', 'SuperAdmin'), async (req, res) => {
  try {
    const { employeeId, workDate } = req.body;

    if (!employeeId || !workDate) {
      return res.status(400).json({ error: 'Employee ID and work date required' });
    }

    // Find the check-in record (SuperAdmin can check out any, Supervisor only their own)
    let query = 'SELECT * FROM attendance WHERE employee_id = ? AND work_date = ? AND status = ?';
    let params = [employeeId, workDate, 'CheckedIn'];
    
    if (req.user.role === 'Supervisor') {
      query += ' AND supervisor_id = ?';
      params.push(req.user.id);
    }

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

    if (records.length === 0) {
      return res.status(404).json({ error: 'No check-in record found for today' });
    }

    const checkOutTime = new Date();
    
    await db.query(
      'UPDATE attendance SET check_out_time = ?, status = ? WHERE id = ?',
      [checkOutTime, 'CheckedOut', records[0].id]
    );

    const [updatedRecord] = await db.query(
      `SELECT a.*, 
              e.name as employee_name, e.username as employee_username,
              s.name as supervisor_name,
              d.name as department_name,
              c.name as contractor_name
       FROM attendance a
       JOIN users e ON a.employee_id = e.id
       JOIN users s ON a.supervisor_id = s.id
       LEFT JOIN departments d ON e.department_id = d.id
       LEFT JOIN users c ON e.contractor_id = c.id
       WHERE a.id = ?`,
      [records[0].id]
    );

    res.json(updatedRecord[0]);
  } catch (error) {
    console.error('Check out error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// Get attendance summary
router.get('/summary/stats', authenticateToken, async (req, res) => {
  try {
    const { startDate, endDate, departmentId } = req.query;
    
    let query = `
      SELECT 
        COUNT(DISTINCT a.employee_id) as total_employees,
        COUNT(DISTINCT CASE WHEN a.status = 'CheckedIn' THEN a.employee_id END) as checked_in,
        COUNT(DISTINCT CASE WHEN a.status = 'CheckedOut' THEN a.employee_id END) as checked_out,
        d.name as department_name
      FROM attendance a
      JOIN users e ON a.employee_id = e.id
      LEFT JOIN departments d ON e.department_id = d.id
      WHERE 1=1
    `;
    const params = [];

    if (req.user.role === 'Supervisor') {
      query += ' AND a.supervisor_id = ?';
      params.push(req.user.id);
    }

    if (startDate) {
      query += ' AND a.work_date >= ?';
      params.push(startDate);
    }

    if (endDate) {
      query += ' AND a.work_date <= ?';
      params.push(endDate);
    }

    if (departmentId) {
      query += ' AND e.department_id = ?';
      params.push(departmentId);
    }

    query += ' GROUP BY d.id, d.name';

    const [summary] = await db.query(query, params);
    res.json(summary);
  } catch (error) {
    console.error('Get attendance summary error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
});

export default router;