const db = require('../config/database');
const bcrypt = require('bcryptjs');
const User = require('../models/User');

class AdminService {
    static async getUsers(params) {
        const { page = 1, limit = 10, search = '', role = '' } = params;
        const offset = (page - 1) * limit;
        
        let queryStr = 'SELECT id, name, role, class, created_at FROM users WHERE 1=1';
        let queryParams = [];
        
        if (search) {
            queryStr += ' AND (id LIKE ? OR name LIKE ? OR class LIKE ?)';
            const searchTerm = `%${search}%`;
            queryParams.push(searchTerm, searchTerm, searchTerm);
        }
        
        if (role) {
            queryStr += ' AND role = ?';
            queryParams.push(role);
        }
        
        // Count
        const countSql = queryStr.replace('SELECT id, name, role, class, created_at', 'SELECT COUNT(*) as total');
        const countRows = await db.query(countSql, queryParams);
        const total = countRows[0].total;
        
        // Data
        queryStr += ' ORDER BY created_at DESC LIMIT ? OFFSET ?';
        queryParams.push(parseInt(limit), parseInt(offset));
        
        const users = await db.query(queryStr, queryParams);
        
        return {
            data: users,
            pagination: {
                page: parseInt(page),
                limit: parseInt(limit),
                total,
                pages: Math.ceil(total / limit)
            }
        };
    }

    static async createUser(userData) {
        const { id } = userData;
        
        // 检查 ID
        const existingUser = await User.findById(id);
        if (existingUser) {
            throw new Error('用户ID已存在');
        }

        // 创建用户
        return await User.create(userData);
    }
}

module.exports = AdminService;