refactor(backend): 重构动物相关 API 接口

- 更新了动物数据结构和相关类型定义
- 优化了动物列表、详情、创建、更新和删除接口
- 新增了更新动物状态接口
- 移除了与认领记录相关的接口
-调整了 API 响应结构

backend/src/services/admin/systemStats.js

@@ -0,0 +1,164 @@
+// 系统统计服务
+const database = require('../../config/database');
+
+class SystemStatsService {
+  /**
+   * 获取系统统计数据
+   * @returns {Promise<Object>} 系统统计数据
+   */
+  async getSystemStats() {
+    try {
+      // 获取用户总数
+      const userCountResult = await database.query('SELECT COUNT(*) as count FROM users');
+      const userCount = userCountResult[0].count;
+
+      // 获取商家总数
+      const merchantCountResult = await database.query('SELECT COUNT(*) as count FROM merchants');
+      const merchantCount = merchantCountResult[0].count;
+
+      // 获取旅行计划总数
+      const travelCountResult = await database.query('SELECT COUNT(*) as count FROM travel_plans');
+      const travelCount = travelCountResult[0].count;
+
+      // 获取动物总数
+      const animalCountResult = await database.query('SELECT COUNT(*) as count FROM animals');
+      const animalCount = animalCountResult[0].count;
+
+      // 获取订单总数
+      const orderCountResult = await database.query('SELECT COUNT(*) as count FROM orders');
+      const orderCount = orderCountResult[0].count;
+
+      // 获取今日新增用户数
+      const todayUserCountResult = await database.query(
+        'SELECT COUNT(*) as count FROM users WHERE DATE(created_at) = CURDATE()'
+      );
+      const todayUserCount = todayUserCountResult[0].count;
+
+      // 获取今日新增订单数
+      const todayOrderCountResult = await database.query(
+        'SELECT COUNT(*) as count FROM orders WHERE DATE(ordered_at) = CURDATE()'
+      );
+      const todayOrderCount = todayOrderCountResult[0].count;
+
+      return {
+        userCount,
+        merchantCount,
+        travelCount,
+        animalCount,
+        orderCount,
+        todayUserCount,
+        todayOrderCount
+      };
+    } catch (error) {
+      throw new Error(`获取系统统计数据失败: ${error.message}`);
+    }
+  }
+
+  /**
+   * 获取用户统计信息
+   * @returns {Promise<Object>} 用户统计数据
+   */
+  async getUserStats() {
+    try {
+      // 用户总数
+      const totalResult = await database.query('SELECT COUNT(*) as total FROM users');
+      
+      // 按用户类型统计
+      const byTypeResult = await database.query(`
+        SELECT 
+          user_type,
+          COUNT(*) as count
+        FROM users 
+        GROUP BY user_type
+      `);
+      
+      // 按注册时间统计（近7天）
+      const byDateResult = await database.query(`
+        SELECT 
+          DATE(created_at) as date,
+          COUNT(*) as count
+        FROM users 
+        WHERE created_at >= DATE_SUB(NOW(), INTERVAL 7 DAY) 
+        GROUP BY DATE(created_at)
+        ORDER BY date ASC
+      `);
+      
+      return {
+        total: totalResult[0].total,
+        byType: byTypeResult,
+        byDate: byDateResult
+      };
+    } catch (error) {
+      throw new Error(`获取用户统计数据失败: ${error.message}`);
+    }
+  }
+
+  /**
+   * 获取订单统计信息
+   * @returns {Promise<Object>} 订单统计数据
+   */
+  async getOrderStats() {
+    try {
+      // 订单总数和总金额
+      const totalResult = await database.query(`
+        SELECT 
+          COUNT(*) as total,
+          COALESCE(SUM(total_amount), 0) as totalAmount
+        FROM orders
+      `);
+      
+      // 按状态统计
+      const byStatusResult = await database.query(`
+        SELECT 
+          status,
+          COUNT(*) as count
+        FROM orders
+        GROUP BY status
+      `);
+      
+      // 按日期统计（近7天）
+      const byDateResult = await database.query(`
+        SELECT 
+          DATE(ordered_at) as date,
+          COUNT(*) as count,
+          COALESCE(SUM(total_amount), 0) as amount
+        FROM orders 
+        WHERE ordered_at >= DATE_SUB(NOW(), INTERVAL 7 DAY)
+        GROUP BY DATE(ordered_at)
+        ORDER BY date ASC
+      `);
+      
+      return {
+        total: totalResult[0].total,
+        totalAmount: parseFloat(totalResult[0].totalAmount || 0),
+        byStatus: byStatusResult,
+        byDate: byDateResult
+      };
+    } catch (error) {
+      throw new Error(`获取订单统计数据失败: ${error.message}`);
+    }
+  }
+
+  /**
+   * 获取系统信息
+   * @returns {Promise<Object>} 系统信息
+   */
+  async getSystemInfo() {
+    try {
+      // 数据库信息
+      const dbInfo = await database.query('SELECT VERSION() as version');
+      
+      return {
+        nodeVersion: process.version,
+        platform: process.platform,
+        arch: process.arch,
+        uptime: Math.floor(process.uptime()),
+        databaseVersion: dbInfo[0].version
+      };
+    } catch (error) {
+      throw new Error(`获取系统信息失败: ${error.message}`);
+    }
+  }
+}
+
+module.exports = new SystemStatsService();