package com.yanzuoguang.util.vo;

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

/**
 * 数据库操作对象
 *
 * @param <T>
 * @author 颜佐光
 */
public class DataDaoVo<T> {
    private List<T> creates = new ArrayList<>();
    private List<T> updates = new ArrayList<>();
    private List<T> removes = new ArrayList<>();
    private Map<String, T> mapNow = new HashMap<>();

    /**
     * 将历史数据映射为HashMap
     *
     * @param hisitories 历史数据
     * @param keyFunc    　获取主键函数
     * @param <T>
     * @return
     */
    private static <T> Map<String, T> getMapHistory(List<T> hisitories, DataDaoKey<T> keyFunc) {
        // 定义缓存集合
        Map<String, T> mapHistory = new HashMap<>(10);
        // 历史数据处理
        if (hisitories != null) {
            for (T his : hisitories) {
                String key = keyFunc.getKey(his);
                mapHistory.put(key, his);
            }
        }
        return mapHistory;
    }

    /**
     * 获取结果
     *
     * @param mapHistory 历史数据映射
     * @param nows       　当前数据
     * @param keyFunc    　获取主键函数
     * @param <T>
     * @return
     */
    private static <T> DataDaoVo<T> getResult(Map<String, T> mapHistory, List<T> nows, DataDaoKey<T> keyFunc) {
        DataDaoVo<T> res = new DataDaoVo<T>();
        // 返回集
        if (nows != null) {
            for (T now : nows) {
                String key = keyFunc.getKey(now);
                T his = mapHistory.get(key);
                if (his == null) {
                    res.creates.add(now);
                    res.mapNow.put(key, now);
                } else {
                    mapHistory.remove(key);
                    boolean isChange = keyFunc.set(his, now);
                    if (isChange) {
                        res.updates.add(his);
                    }
                    res.mapNow.put(key, his);
                }
            }
        }
        res.removes.addAll(mapHistory.values());
        return res;
    }

    /**
     * 初始话对象
     *
     * @param hisitories
     * @param nows
     * @param keyFunc
     */
    public static <T> DataDaoVo<T> init(List<T> hisitories, List<T> nows, DataDaoKey<T> keyFunc) {
        Map<String, T> mapHistory = getMapHistory(hisitories, keyFunc);
        DataDaoVo<T> res = getResult(mapHistory, nows, keyFunc);
        return res;
    }


    /**
     * 初始话对象
     *
     * @param hisitories
     * @param nows
     * @param keyFunc
     */
    public static <T, M> DataDaoVo<T> init(List<T> hisitories, List<M> nows, DataDaoKeyConvert<T, M> keyFunc) {
        Map<String, T> mapHistory = getMapHistory(hisitories, keyFunc);
        List<T> toNows = new ArrayList<>(10);
        if (nows != null) {
            for (M m : nows) {
                T t = keyFunc.convert(mapHistory, m);
                toNows.add(t);
            }
        }
        DataDaoVo<T> res = getResult(mapHistory, toNows, keyFunc);
        return res;
    }

    /**
     * 需要创建的对象
     *
     * @return
     */
    public List<T> getCreates() {
        return creates;
    }

    /**
     * 需要修改的对象
     *
     * @return
     */
    public List<T> getUpdates() {
        return updates;
    }

    /**
     * 需要删除的对象
     *
     * @return
     */
    public List<T> getRemoves() {
        return removes;
    }

    /**
     * 所有需要修改和更新的对象
     *
     * @return
     */
    public Map<String, T> getMapNow() {
        return mapNow;
    }
}