const { Categories, Subject } = require('../models');
const { cacheUtils } = require('../config/redis');

/**
 * Categories Controller - Quản lý danh mục
 */
class CategoryController {
  /**
   * Get all categories with pagination and caching
   */
  async getAllCategories(req, res, next) {
    try {
      const { page = 1, limit = 50, is_active } = req.query;
      const offset = (page - 1) * limit;
      
      // Generate cache key
      const cacheKey = `categories:list:${page}:${limit}:${is_active || 'all'}`;
      
      // Try to get from cache first
      const cached = await cacheUtils.get(cacheKey);
      if (cached) {
        return res.json({
          success: true,
          data: cached,
          cached: true,
        });
      }
      
      // Build query conditions
      const where = {};
      if (is_active !== undefined) where.is_active = is_active === 'true';
      
      // Query from database (through ProxySQL)
      const { count, rows } = await Categories.findAndCountAll({
        where,
        limit: parseInt(limit),
        offset: parseInt(offset),
        order: [['category_code', 'ASC']],
      });
      
      const result = {
        categories: rows,
        pagination: {
          total: count,
          page: parseInt(page),
          limit: parseInt(limit),
          totalPages: Math.ceil(count / limit),
        },
      };
      
      // Cache the result
      await cacheUtils.set(cacheKey, result, 7200); // Cache for 2 hours
      
      res.json({
        success: true,
        data: result,
        cached: false,
      });
    } catch (error) {
      next(error);
    }
  }

  /**
   * Get category by ID with caching
   */
  async getCategoryById(req, res, next) {
    try {
      const { id } = req.params;
      const cacheKey = `category:${id}`;
      
      // Try cache first
      const cached = await cacheUtils.get(cacheKey);
      if (cached) {
        return res.json({
          success: true,
          data: cached,
          cached: true,
        });
      }
      
      // Query from database
      const category = await Categories.findByPk(id);
      
      if (!category) {
        return res.status(404).json({
          success: false,
          message: 'Category not found',
        });
      }
      
      // Cache the result
      await cacheUtils.set(cacheKey, category, 7200); // Cache for 2 hours
      
      res.json({
        success: true,
        data: category,
        cached: false,
      });
    } catch (error) {
      next(error);
    }
  }

  /**
   * Get category by code with caching
   */
  async getCategoryByCode(req, res, next) {
    try {
      const { code } = req.params;
      const cacheKey = `category:code:${code}`;
      
      // Try cache first
      const cached = await cacheUtils.get(cacheKey);
      if (cached) {
        return res.json({
          success: true,
          data: cached,
          cached: true,
        });
      }
      
      // Query from database
      const category = await Categories.findOne({
        where: { category_code: code },
      });
      
      if (!category) {
        return res.status(404).json({
          success: false,
          message: 'Category not found',
        });
      }
      
      // Cache the result
      await cacheUtils.set(cacheKey, category, 7200); // Cache for 2 hours
      
      res.json({
        success: true,
        data: category,
        cached: false,
      });
    } catch (error) {
      next(error);
    }
  }

  /**
   * Create new category
   */
  async createCategory(req, res, next) {
    try {
      const categoryData = req.body;
      
      const category = await Categories.create(categoryData);
      
      await cacheUtils.deletePattern('categories:list:*');
      
      res.status(201).json({
        success: true,
        message: 'Category created successfully',
        data: category,
      });
    } catch (error) {
      next(error);
    }
  }

  /**
   * Update category
   */
  async updateCategory(req, res, next) {
    try {
      const { id } = req.params;
      const updates = req.body;
      
      const category = await Categories.findByPk(id);
      
      if (!category) {
        return res.status(404).json({
          success: false,
          message: 'Category not found',
        });
      }
      
      await category.update(updates);
      
      await cacheUtils.delete(`category:${id}`);
      await cacheUtils.deletePattern('categories:list:*');
      
      res.json({
        success: true,
        message: 'Category updated successfully',
        data: category,
      });
    } catch (error) {
      next(error);
    }
  }

  /**
   * Delete category
   */
  async deleteCategory(req, res, next) {
    try {
      const { id } = req.params;
      
      const category = await Categories.findByPk(id);
      
      if (!category) {
        return res.status(404).json({
          success: false,
          message: 'Category not found',
        });
      }
      
      await category.destroy();
      
      await cacheUtils.delete(`category:${id}`);
      await cacheUtils.deletePattern('categories:list:*');
      
      res.json({
        success: true,
        message: 'Category deleted successfully',
      });
    } catch (error) {
      next(error);
    }
  }

  /**
   * Get active categories (frequently used)
   */
  async getActiveCategories(req, res, next) {
    try {
      const cacheKey = 'categories:active';
      
      // Try cache first
      const cached = await cacheUtils.get(cacheKey);
      if (cached) {
        return res.json({
          success: true,
          data: cached,
          cached: true,
        });
      }
      
      // Query from database
      const categories = await Categories.findAll({
        where: { is_active: true },
        order: [['category_code', 'ASC']],
      });
      
      // Cache for 4 hours (this data changes infrequently)
      await cacheUtils.set(cacheKey, categories, 14400);
      
      res.json({
        success: true,
        data: categories,
        cached: false,
      });
    } catch (error) {
      next(error);
    }
  }

  /**
   * Get category datatypes
   */
  async getCategoryDatatypes(req, res, next) {
    try {
      const datatypes = Categories.rawAttributes;
      res.json({
        success: true,
        data: datatypes,
      });
    } catch (error) {
      next(error);
    }
  }

  /**
   * Get subjects by category ID
   */
  async getSubjectsByCategory(req, res, next) {
    try {
      const { id } = req.params;
      const { page = 1, limit = 50, is_active } = req.query;
      const offset = (page - 1) * limit;

      // Generate cache key
      const cacheKey = `category:${id}:subjects:${page}:${limit}:${is_active || 'all'}`;

      // Try cache first
      const cached = await cacheUtils.get(cacheKey);
      if (cached) {
        return res.json({
          success: true,
          data: cached,
          cached: true,
        });
      }

      // Check if category exists
      const category = await Categories.findByPk(id);
      if (!category) {
        return res.status(404).json({
          success: false,
          message: 'Category not found',
        });
      }

      // Build query conditions
      const where = { category_id: id };
      if (is_active !== undefined) where.is_active = is_active === 'true';

      // Query subjects
      const { count, rows } = await Subject.findAndCountAll({
        where,
        limit: parseInt(limit),
        offset: parseInt(offset),
        order: [['subject_code', 'ASC']],
      });

      const result = {
        category: {
          id: category.id,
          category_code: category.category_code,
          category_name: category.category_name,
        },
        subjects: rows,
        pagination: {
          total: count,
          page: parseInt(page),
          limit: parseInt(limit),
          totalPages: Math.ceil(count / limit),
        },
      };

      // Cache the result
      await cacheUtils.set(cacheKey, result, 3600); // Cache for 1 hour

      res.json({
        success: true,
        data: result,
        cached: false,
      });
    } catch (error) {
      next(error);
    }
  }
}

module.exports = new CategoryController();