/**
  * 關注用戶
  * @param id
  * @param isFollow
  * @return
  */
@PutMapping("/{id}/{isFollow}")
public Result follow(@PathVariable("id") Long id, @PathVariable("isFollow") Boolean isFollow){
    return followService.follow(id,isFollow);
}
 
/**
  * 判斷是否關注指定用戶
  * @param id
  * @return
  */
@GetMapping("/or/not/{id}")
public Result isFollow(@PathVariable("id") Long id){
    return followService.isFollow(id);
}

/**
  * 關注用戶
  * @param id 
  * @param isFollow
  * @return
  */
@Override
public Result follow(Long id, Boolean isFollow) {
    //獲取當前用戶id
    Long userId = UserHolder.getUser().getId();
    //判斷是關注操作還是取關操作
    if(BooleanUtil.isTrue(isFollow)){
        //關注操作
        Follow follow = new Follow();
        follow.setUserId(userId);
        follow.setFollowUserId(id);
        save(follow);
    }else{
        //取關操作
        remove(new QueryWrapper<Follow>().eq("user_id",userId).eq("follow_user_id",id));
    }
    return Result.ok();
}
 
/**
  * 判斷是否關注指定用戶
  * @param id
  * @return
  */
@Override
public Result isFollow(Long id) {
    //獲取當前用戶id
    Long userId = UserHolder.getUser().getId();
    Integer count = query().eq("user_id", userId).eq("follow_user_id", id).count();
    if(count>0){
        return Result.ok(true);
    }
    return Result.ok(false);
}

/**
  * 關注用戶
  * @param id
  * @param isFollow
  * @return
  */
@Override
public Result follow(Long id, Boolean isFollow) {
    //獲取當前用戶id
    Long userId = UserHolder.getUser().getId();
    String key = "follow:" + userId;
    //判斷是關注操作還是取關操作
    if(BooleanUtil.isTrue(isFollow)){
        //關注操作
        Follow follow = new Follow();
        follow.setUserId(userId);
        follow.setFollowUserId(id);
        boolean success = save(follow);
        if(success){
            //插入set集合中
            stringRedisTemplate.opsForSet().add(key,id.toString());
        }
    }else{
        //取關操作
        boolean success = remove(new QueryWrapper<Follow>().eq("user_id", userId).eq("follow_user_id", id));
        //從set集合中移除
        if(success){
            stringRedisTemplate.opsForSet().remove(key,id.toString());
        }
    }
    return Result.ok();
}

/**
  * 判斷是否關注指定用戶
  * @param id
  * @return
  */
@GetMapping("common/{id}")
public Result followCommons(@PathVariable("id") Long id){
    return followService.followCommons(id);
}

/**
  * 共同關注
  * @param id
  * @return
  */
@Override
public Result followCommons(Long id) {
    Long userId = UserHolder.getUser().getId();
    //當前用戶的key
    String key1 = "follow:" + userId;
    //指定用戶的key
    String key2 = "follow:" + id;
    //判斷兩個用戶的交集
    Set<String> intersect = stringRedisTemplate.opsForSet().intersect(key1, key2);
    if(intersect==null||intersect.isEmpty()){
        //說明沒有共同關注
        return Result.ok();
    }
    //如果有共同關注，則獲取這些用戶的信息
    List<Long> userIds = intersect.stream().map(Long::valueOf).collect(Collectors.toList());
    List<UserDTO> userDTOS = userService.listByIds(userIds).stream().map(item -> (BeanUtil.copyProperties(item, UserDTO.class))).collect(Collectors.toList());
    return Result.ok(userDTOS);
}

@Override
public Result saveBlog(Blog blog) {
    // 1.獲取登錄用戶
    UserDTO user = UserHolder.getUser();
    blog.setUserId(user.getId());
    // 2.保存探店筆記
    boolean isSuccess = save(blog);
    if(!isSuccess){
        return Result.fail("新增筆記失敗!");
    }
    // 3.查詢筆記作者的所有粉絲 select * from tb_follow where follow_user_id = ?
    List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
    // 4.推送筆記id給所有粉絲
    for (Follow follow : follows) {
        // 4.1.獲取粉絲id
        Long userId = follow.getUserId();
        // 4.2.推送
        String key = FEED_KEY + userId;
        stringRedisTemplate.opsForZSet().add(key, blog.getId().toString(), System.currentTimeMillis());
    }
    // 5.返回id
    return Result.ok(blog.getId());
}

@Data
public class ScrollResult {
    private List<?> list;
    private Long minTime;
    private Integer offset;
}

@GetMapping("/of/follow")
public Result queryBlogOfFollow(
    @RequestParam("lastId") Long max, @RequestParam(value = "offset", defaultValue = "0") Integer offset){
    return blogService.queryBlogOfFollow(max, offset);
}

@Override
public Result queryBlogOfFollow(Long max, Integer offset) {
    //獲取當前用戶
    Long userId = UserHolder.getUser().getId();
    //組裝key
    String key = RedisConstants.FEED_KEY + userId;
    //分頁查詢收件箱，一次查詢兩條 ZREVRANGEBYSCORE key Max Min LIMIT offset count
    Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet().reverseRangeByScoreWithScores(key, 0, max, offset, 2);
    //若收件箱為空則直接返回
    if (typedTuples == null || typedTuples.isEmpty()) {
        return Result.ok();
    }
    //通過上述數據獲取筆記id，偏移量和最小時間
    ArrayList<Long> ids = new ArrayList<>();
    long minTime = 0;
    //因為這里的偏移量是下一次要傳給前端的偏移量，所以初始值定為1
    int os = 1;
    for (ZSetOperations.TypedTuple<String> typedTuple : typedTuples) {
        //添加博客id
        ids.add(Long.valueOf(typedTuple.getValue()));
        //獲取時間戳
        long score = typedTuple.getScore().longValue();
        //由于數據是按時間戳倒序排列的，因此最后被賦值的就是最小時間
        if (minTime == score) {
            //如果有兩個數據時間戳相等，那么偏移量開始計數
            os++;
        } else {
            //如果當前數據的時間戳與已經記錄的最小時間戳不相等，則說明當前時間小于已記錄的最小時間戳，將其賦給minTime
            minTime = score;
            //偏移量重置
            os = 1;
        }
    }
    //需要考慮到時間戳相等的消息數量大于2的情況，這時候偏移量就需要加上上一頁查詢時的偏移量
    os = minTime == max ? os : os + offset;
 
    //根據id查詢blog
    String idStr = StrUtil.join(",", ids);
    //查詢時需要手動指定順序
    List<Blog> blogs = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
    //這里還需要查詢博客作者的相關信息，這里對比視頻中，用一次查詢代替了多次查詢，提高效率
    List<Long> blogUserIds = blogs.stream().map(blog -> blog.getUserId()).collect(Collectors.toList());
    String blogUserIdStr = StrUtil.join(",", blogUserIds);
    HashMap<Long, User> userHashMap = new HashMap<>();
    userService.query().in("id", blogUserIds).last("ORDER BY FIELD(id," + blogUserIdStr + ")").list().
        stream().forEach(user -> {
        userHashMap.put(user.getId(), user);
    });
    //為blog封裝數據
    Iterator<Blog> blogIterator = blogs.iterator();
    while (blogIterator.hasNext()) {
        Blog blog = blogIterator.next();
        User user = userHashMap.get(blog.getUserId());
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
        blog.setIsLike(isLikeBlog(blog.getId()));
    }
    //返回封裝數據
    ScrollResult scrollResult = new ScrollResult();
    scrollResult.setList(blogs);
    scrollResult.setMinTime(minTime);
    scrollResult.setOffset(os);
    return Result.ok(scrollResult);
}