package com.hmdp.service.impl;import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;import javax.annotation.Resource;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;/*** <p>* 服务实现类* </p>** @author 虎哥* @since 2021-12-22*/
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {@Resourceprivate IUserService userService;@Resourceprivate StringRedisTemplate stringRedisTemplate;@Overridepublic Result queryHotBlog(Integer current) {// 根据用户查询Page<Blog> page = query().orderByDesc("liked").page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));// 获取当前页数据List<Blog> records = page.getRecords();// 查询用户records.forEach(blog ->{this.queryBlogUser(blog);this.isBlogLiked(blog);});return Result.ok(records);}@Overridepublic Result queryBlogById(Long id) {// 1.查询blogBlog blog = getById(id);if (blog == null) {return Result.fail("笔记不存在");}// 2.查询blog相关的用户queryBlogUser(blog);// 3.查询blog是否被点赞isBlogLiked(blog);return Result.ok(blog);}private void isBlogLiked(Blog blog) {// 0.获取登录用户UserDTO user = UserHolder.getUser();if(user == null){//用户未登录，无需查询是否点赞return;}Long userId = user.getId();// 1.判断当前登录用户是否已经点赞String key = BLOG_LIKED_KEY + blog.getId();Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());blog.setIsLike(score != null);}@Overridepublic Result likeBlog(Long id) {// 0.获取登录用户Long userId = UserHolder.getUser().getId();// 1.判断当前登录用户是否已经点赞String key = BLOG_LIKED_KEY + id;Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());if(score == null ){// 2.如果未点赞，可以点赞boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();if(isSuccess){stringRedisTemplate.opsForZSet().add(key, userId.toString(),System.currentTimeMillis());}}else {// 3.已点赞，取消点赞boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();if(isSuccess){stringRedisTemplate.opsForZSet().remove(key, userId.toString());}}return Result.ok();}@Overridepublic Result queryBlogLikes(Long id) {String key = BLOG_LIKED_KEY + id;// 1.查询top5的点赞用户 zrange key 0 4Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);if(top5 == null || top5.isEmpty()){return Result.ok(Collections.emptyList());}// 2.解析出其中的用户idList<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());String idStr = StrUtil.join(",",ids);// 3.根据用户id查询用户,得用ORDER BY FIELD(id,5,1)
// List<UserDTO> userDTOS = userService.listByIds(ids)List<UserDTO> userDTOS = userService.query().in("id",ids).last("ORDER BY FIELD(id,"+ idStr +")").list().stream().map(user -> BeanUtil.copyProperties(user, UserDTO.class)).collect(Collectors.toList());return Result.ok(userDTOS);}private void queryBlogUser(Blog blog) {Long userId = blog.getUserId();User user = userService.getById(userId);blog.setName(user.getNickName());blog.setIcon(user.getIcon());}
}