const express = require('express');
const pool = require('../config/database');
const { validateRequest, validateParams } = require('../utils/validation');
const { updateUserSchema, idParamSchema } = require('../utils/validation');
const { requireOwnership } = require('../middleware/auth');
const { AppError } = require('../middleware/errorHandler');

const router = express.Router();

// @route   GET /api/users/profile
// @desc    Get current user profile
// @access  Private
router.get('/profile', async (req, res, next) => {
  try {
    const userResult = await pool.query(
      `SELECT u.id, u.email, u.first_name, u.last_name, u.role, u.created_at, u.updated_at,
              COUNT(p.id) as property_count
       FROM users u
       LEFT JOIN properties p ON u.id = p.user_id
       WHERE u.id = $1
       GROUP BY u.id`,
      [req.user.id]
    );

    if (userResult.rows.length === 0) {
      throw new AppError('User not found', 404);
    }

    const user = userResult.rows[0];

    res.json({
      success: true,
      data: {
        user: {
          id: user.id,
          email: user.email,
          firstName: user.first_name,
          lastName: user.last_name,
          role: user.role,
          propertyCount: parseInt(user.property_count),
          createdAt: user.created_at,
          updatedAt: user.updated_at
        }
      }
    });
  } catch (error) {
    next(error);
  }
});

// @route   PUT /api/users/profile
// @desc    Update current user profile
// @access  Private
router.put('/profile', validateRequest(updateUserSchema), async (req, res, next) => {
  try {
    const { firstName, lastName, email } = req.body;
    const userId = req.user.id;

    // Check if email is already taken by another user
    if (email) {
      const emailCheck = await pool.query(
        'SELECT id FROM users WHERE email = $1 AND id != $2',
        [email.toLowerCase(), userId]
      );

      if (emailCheck.rows.length > 0) {
        throw new AppError('Email is already taken by another user', 409);
      }
    }

    // Build dynamic update query
    const updates = [];
    const values = [];
    let paramCount = 1;

    if (firstName) {
      updates.push(`first_name = $${paramCount}`);
      values.push(firstName);
      paramCount++;
    }

    if (lastName) {
      updates.push(`last_name = $${paramCount}`);
      values.push(lastName);
      paramCount++;
    }

    if (email) {
      updates.push(`email = $${paramCount}`);
      values.push(email.toLowerCase());
      paramCount++;
    }

    if (updates.length === 0) {
      throw new AppError('No valid fields to update', 400);
    }

    updates.push(`updated_at = CURRENT_TIMESTAMP`);
    values.push(userId);

    const query = `
      UPDATE users 
      SET ${updates.join(', ')} 
      WHERE id = $${paramCount}
      RETURNING id, email, first_name, last_name, role, updated_at
    `;

    const result = await pool.query(query, values);
    const user = result.rows[0];

    res.json({
      success: true,
      message: 'Profile updated successfully',
      data: {
        user: {
          id: user.id,
          email: user.email,
          firstName: user.first_name,
          lastName: user.last_name,
          role: user.role,
          updatedAt: user.updated_at
        }
      }
    });
  } catch (error) {
    next(error);
  }
});

// @route   DELETE /api/users/account
// @desc    Delete current user account
// @access  Private
router.delete('/account', async (req, res, next) => {
  try {
    const userId = req.user.id;

    // Check if user has any ongoing applications
    const ongoingApps = await pool.query(
      `SELECT COUNT(*) as count 
       FROM application_plans 
       WHERE user_id = $1 AND status IN ('planned', 'in_progress')`,
      [userId]
    );

    if (parseInt(ongoingApps.rows[0].count) > 0) {
      throw new AppError('Cannot delete account with ongoing applications. Please complete or cancel them first.', 400);
    }

    // Delete user (cascading will handle related records)
    await pool.query('DELETE FROM users WHERE id = $1', [userId]);

    res.json({
      success: true,
      message: 'Account deleted successfully'
    });
  } catch (error) {
    next(error);
  }
});

// @route   GET /api/users/stats
// @desc    Get user statistics
// @access  Private
router.get('/stats', async (req, res, next) => {
  try {
    const userId = req.user.id;

    const statsQuery = `
      SELECT 
        (SELECT COUNT(*) FROM properties WHERE user_id = $1) as total_properties,
        (SELECT COUNT(*) FROM lawn_sections ls 
         JOIN properties p ON ls.property_id = p.id 
         WHERE p.user_id = $1) as total_sections,
        (SELECT COALESCE(SUM(ls.area), 0) FROM lawn_sections ls 
         JOIN properties p ON ls.property_id = p.id 
         WHERE p.user_id = $1) as total_area,
        (SELECT COUNT(*) FROM user_equipment WHERE user_id = $1) as total_equipment,
        (SELECT COUNT(*) FROM application_plans WHERE user_id = $1) as total_plans,
        (SELECT COUNT(*) FROM application_logs WHERE user_id = $1) as total_applications,
        (SELECT COUNT(*) FROM application_plans 
         WHERE user_id = $1 AND status = 'completed') as completed_plans,
        (SELECT COUNT(*) FROM application_plans 
         WHERE user_id = $1 AND planned_date >= CURRENT_DATE) as upcoming_plans
    `;

    const result = await pool.query(statsQuery, [userId]);
    const stats = result.rows[0];

    // Get recent activity
    const recentActivity = await pool.query(
      `SELECT 'application' as type, al.application_date as date, 
              ls.name as section_name, p.name as property_name
       FROM application_logs al
       JOIN lawn_sections ls ON al.lawn_section_id = ls.id
       JOIN properties p ON ls.property_id = p.id
       WHERE al.user_id = $1
       ORDER BY al.application_date DESC
       LIMIT 5`,
      [userId]
    );

    res.json({
      success: true,
      data: {
        stats: {
          totalProperties: parseInt(stats.total_properties),
          totalSections: parseInt(stats.total_sections),
          totalArea: parseFloat(stats.total_area),
          totalEquipment: parseInt(stats.total_equipment),
          totalPlans: parseInt(stats.total_plans),
          totalApplications: parseInt(stats.total_applications),
          completedPlans: parseInt(stats.completed_plans),
          upcomingPlans: parseInt(stats.upcoming_plans),
          completionRate: stats.total_plans > 0 ? 
            Math.round((stats.completed_plans / stats.total_plans) * 100) : 0
        },
        recentActivity: recentActivity.rows
      }
    });
  } catch (error) {
    next(error);
  }
});

module.exports = router;