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

const router = express.Router();

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

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

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

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

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

    query += ' ORDER BY wa.assigned_date DESC, wa.created_at DESC';

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

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

    if (allocations.length === 0) {
      return res.status(404).json({ error: 'Work allocation not found' });
    }

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

// Create work allocation (Supervisor or SuperAdmin)
router.post('/', authenticateToken, authorize('Supervisor', 'SuperAdmin'), async (req, res) => {
  try {
    const { employeeId, contractorId, subDepartmentId, activity, description, assignedDate, rate, units, totalAmount, departmentId } = req.body;

    if (!employeeId || !contractorId || !assignedDate) {
      return res.status(400).json({ error: 'Missing required fields' });
    }

    // SuperAdmin can create for any department, Supervisor only for their own
    let targetDepartmentId = req.user.role === 'SuperAdmin' ? departmentId : req.user.departmentId;

    // Verify employee exists (SuperAdmin can assign any employee, Supervisor only their department)
    let employeeQuery = 'SELECT * FROM users WHERE id = ?';
    let employeeParams = [employeeId];
    
    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' });
    }

    // Use provided rate or get contractor's current rate
    let finalRate = rate;
    if (!finalRate) {
      const [rates] = await db.query(
        'SELECT rate FROM contractor_rates WHERE contractor_id = ? ORDER BY effective_date DESC LIMIT 1',
        [contractorId]
      );
      finalRate = rates.length > 0 ? rates[0].rate : null;
    }

    const [result] = await db.query(
      `INSERT INTO work_allocations 
       (employee_id, supervisor_id, contractor_id, sub_department_id, activity, description, assigned_date, rate, units, total_amount) 
       VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
      [employeeId, req.user.id, contractorId, subDepartmentId || null, activity || null, description || null, assignedDate, finalRate, units || null, totalAmount || null]
    );

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

    res.status(201).json(newAllocation[0]);
  } catch (error) {
    console.error('Create work allocation error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// Update work allocation status (Supervisor or SuperAdmin)
router.put('/:id/status', authenticateToken, authorize('Supervisor', 'SuperAdmin'), async (req, res) => {
  try {
    const { status, completionDate } = req.body;

    if (!status) {
      return res.status(400).json({ error: 'Status required' });
    }

    // SuperAdmin can update any allocation, Supervisor only their own
    let query = 'SELECT * FROM work_allocations WHERE id = ?';
    let params = [req.params.id];
    
    if (req.user.role === 'Supervisor') {
      query += ' AND supervisor_id = ?';
      params.push(req.user.id);
    }

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

    if (allocations.length === 0) {
      return res.status(403).json({ error: 'Work allocation not found or access denied' });
    }

    await db.query(
      'UPDATE work_allocations SET status = ?, completion_date = ? WHERE id = ?',
      [status, completionDate || null, req.params.id]
    );

    const [updatedAllocation] = await db.query(
      `SELECT wa.*, 
              e.name as employee_name, e.username as employee_username,
              s.name as supervisor_name,
              c.name as contractor_name,
              sd.name as sub_department_name,
              d.name as department_name
       FROM work_allocations wa
       JOIN users e ON wa.employee_id = e.id
       JOIN users s ON wa.supervisor_id = s.id
       JOIN users c ON wa.contractor_id = c.id
       LEFT JOIN sub_departments sd ON wa.sub_department_id = sd.id
       LEFT JOIN departments d ON e.department_id = d.id
       WHERE wa.id = ?`,
      [req.params.id]
    );

    res.json(updatedAllocation[0]);
  } catch (error) {
    console.error('Update work allocation error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// Delete work allocation (Supervisor or SuperAdmin)
router.delete('/:id', authenticateToken, authorize('Supervisor', 'SuperAdmin'), async (req, res) => {
  try {
    // SuperAdmin can delete any allocation, Supervisor only their own
    let query = 'SELECT * FROM work_allocations WHERE id = ?';
    let params = [req.params.id];
    
    if (req.user.role === 'Supervisor') {
      query += ' AND supervisor_id = ?';
      params.push(req.user.id);
    }

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

    if (allocations.length === 0) {
      return res.status(403).json({ error: 'Work allocation not found or access denied' });
    }

    await db.query('DELETE FROM work_allocations WHERE id = ?', [req.params.id]);
    res.json({ message: 'Work allocation deleted successfully' });
  } catch (error) {
    console.error('Delete work allocation error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
});

export default router;