package com.sf.service.impl;

import com.google.gson.Gson;
import com.sf.cons.RedisKeyConst;
import com.sf.dto.resp.BookRankRespDto;
import com.sf.entity.BookInfo;
import com.sf.mapper.BookInfoMapper;
import com.sf.service.IBookRankService;
import lombok.RequiredArgsConstructor;
import org.springframework.beans.BeanUtils;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Set;

// 基于redis
@Service("bookRankServiceByRedis")
@RequiredArgsConstructor
public class BookRankByRedisServiceImpl implements IBookRankService {
    // 数据初始化
    private final BookInfoMapper bookInfoMapper;
    private final RedisTemplate redisTemplate;
    private final Gson gson;

    @Override
    public List<BookRankRespDto> listVisitRankBooks() {
        return getRankDataByRedis(RedisKeyConst.VISIT_ZSET);
    }

    @Override
    public List<BookRankRespDto> listNewestRankBooks() {
        return getRankDataByRedis(RedisKeyConst.NEW_ZSET);
    }

    @Override
    public List<BookRankRespDto> listUpdateRankBooks() {
        return getRankDataByRedis(RedisKeyConst.UPDATE_ZSET);
    }

    private List<BookRankRespDto> getRankDataByRedis(String key){
        ZSetOperations zSetOperations = redisTemplate.opsForZSet();
        Set<String> set = zSetOperations.reverseRange(key, 0, 29);
        return set.stream().map(str -> {
            // 将map中的每一个元素 转化为BookRankRespDto
            BookInfo bookInfo = gson.fromJson(str, BookInfo.class);
            BookRankRespDto bookRankRespDto = new BookRankRespDto();
            BeanUtils.copyProperties(bookInfo, bookRankRespDto);
            return bookRankRespDto;
        }).toList();
    }

    // 数据初始化
//    private void initData() {
//        List<BookInfo> bookInfos = bookInfoMapper.selectList(null);
//        ZSetOperations zSetOperations = redisTemplate.opsForZSet();
//        for (BookInfo bookInfo : bookInfos) {
//            Long visitCount = bookInfo.getVisitCount();
//            String bookInfoJson = gson.toJson(bookInfo);
//            zSetOperations.add(RedisKeyConst.VISIT_ZSET, bookInfoJson, visitCount);
//        }
//    }


    // 这是实时榜单的处理逻辑
    @Override
    public void updateVisitRank(Long bookId) {
        BookInfo bookInfo = bookInfoMapper.selectById(bookId);
        String json = gson.toJson(bookInfo);
        // 此时的问题 是json中包含了访问量参数 而访问量会频繁变化
        ZSetOperations zSetOperations = redisTemplate.opsForZSet();
        // 每一次更新访问量 就将旧的数据移除  新的数据添加进去  保证数据的统一
        zSetOperations.remove(RedisKeyConst.VISIT_ZSET, json);
        bookInfo.setVisitCount(bookInfo.getVisitCount() + 1);
        zSetOperations.add(RedisKeyConst.VISIT_ZSET, gson.toJson(bookInfo), bookInfo.getVisitCount());
    }
}