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/*
 * Copyright (c) 2021 yizzuide All rights Reserved.
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package com.github.yizzuide.milkomeda.light;

import lombok.extern.slf4j.Slf4j;

import java.io.Serializable;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

/**
 * SortDiscard
 *
 * 抽象的字段排序方案
 *
 * @since 1.8.0
 * @version 3.12.10
 * @author yizzuide
 * 

 * Create at 2019/06/28 16:32
 */
@Slf4j
public abstract class SortDiscard implements Discard {

    @Override
    @SuppressWarnings("unchecked")
    public Spot deform(String key, Spot spot, long expire) {
        SortSpot sortSpot = null;
        try {
            sortSpot = spotClazz().newInstance();
            sortSpot.setView(spot.getView());
            sortSpot.setData(spot.getData());
            sortSpot.setKey(key);
        } catch (Exception e) {
            log.error("SortDiscard:- 创建类实例失败：{}", e.getMessage(), e);
        }
        return sortSpot;
    }

    @Override
    @SuppressWarnings("unchecked")
    public void discard(Map> cacheMap, float l1DiscardPercent) {
        Comparator> comparator = comparator();
        // 不支持排序丢弃，直接返回
        if (comparator == null) {
            return;
        }
        List> list = cacheMap.values()
                .stream()
                .map(spot -> (SortSpot)spot)
                .sorted((Comparator>) comparator)
                .collect(Collectors.toList());
        int size = list.size();
        int discardCount = Math.round(size * l1DiscardPercent);
        // 一级缓存百分比太小，直接返回
        if (discardCount == 0) {
            return;
        }
        if (discardCount >= size) {
            discardCount = size - 1;
        }
        Map> newCacheMap = new HashMap<>(size);
        for (int i = discardCount; i < size; i++) {
            String key = list.get(i).getKey();
            newCacheMap.put(key, cacheMap.get(key));
        }
        cacheMap.clear();
        cacheMap.putAll(newCacheMap);
    }

    /**
     * 排序比较器
     * @return Comparator
     */
    protected abstract Comparator> comparator();
}