package com.iplatform.recvideo;

import com.iplatform.model.po.Rc_video_t1;
import com.walker.infrastructure.utils.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * 把一个原视频对应的多个相似视频集合，根据图像相似度数量归并排序。<p></p>
 * 最终返回排序后的相似视频列表，用于写入到数据库中。
 * @author 时克英
 * @date 2022-09-24
 */
public class SimilarVideoOrder {

    // 参与运算的最大距离，超过该距离说明相似度很低，不再参与运算。
    private double maxDistance = 1.0;

    // 计算多个相似视频id，综合距离平均值, key = 相似视频ID
    private Map<String, List<Double>> simiVideoDistanceMap = new HashMap<>();
    // 最终排序用的相似视频集合结果, key = 相似视频ID
    private Map<String, SimilarVideoInfo> orderVideoList = new HashMap<>();

    public SimilarVideoOrder(List<Rc_video_t1> list){
        for(Rc_video_t1 e : list){
            this.addSimiVideoDistance(e.getSim_video_id(), e.getDistance());
            this.addOrderVideo(e.getSim_video_id());
        }
    }

    public List<SimilarVideoInfo> calculateOrder(){
        SimilarVideoInfo similarVideoInfo = null;
        double averageDistance = 0;
        for(Map.Entry<String, List<Double>> entry : this.simiVideoDistanceMap.entrySet()){
            similarVideoInfo = this.orderVideoList.get(entry.getKey());
            if(similarVideoInfo == null){
                throw new IllegalArgumentException("similarVideoInfo不存在，这不科学:(" + entry.getKey());
            }
            averageDistance = this.getAverageDistance(entry.getValue(), entry.getKey());
            similarVideoInfo.setDistance(averageDistance);
        }

        //
        List<SimilarVideoInfo> resultList = new ArrayList<>(32);

        for(SimilarVideoInfo e : this.orderVideoList.values()){
            e.getScore();
            resultList.add(e);
        }
        Collections.sort(resultList);
        return resultList;
    }

    private double getAverageDistance(List<Double> list, String simiVideoId){
        if(StringUtils.isEmptyList(list)){
            return 0;
        }
        double total = 0;
        for(double d : list){
            if(d > this.maxDistance){
//                logger.debug("distance过大，不参与排序运算:" + d + ", simiVideoId = " + simiVideoId);
                continue;
            }
            total += d;
        }
        return total/list.size();
    }

    private void addOrderVideo(String simiVideoId){
        SimilarVideoInfo v = this.orderVideoList.get(simiVideoId);
        if(v == null){
            v = new SimilarVideoInfo(simiVideoId, 0);
            this.orderVideoList.put(simiVideoId, v);
        }
        v.increase();
    }

    private void addSimiVideoDistance(String videoId, double distance){
        List<Double> v = this.simiVideoDistanceMap.get(videoId);
        if(v == null){
            v = new ArrayList<>(16);
            this.simiVideoDistanceMap.put(videoId, v);
        }
        v.add(distance);
    }

    protected final transient Logger logger = LoggerFactory.getLogger(this.getClass());
}