package top.haijunit.train.simulation.domain;

import cn.hutool.core.util.StrUtil;
import liquibase.util.StringUtil;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.RequiredArgsConstructor;
import top.haijunit.train.domain.constant.DirectionEnum;
import top.haijunit.train.domain.entity.SignStopEntity;
import top.haijunit.train.utils.NumberUtil;

import java.math.BigDecimal;
import java.util.HashMap;
import java.util.List;
import java.util.Optional;

/**
 * @author zhanghaijun
 * @date 2023/12/17 21:30
 * @description [一句话描述该类的功能]
 * @version 1.0
 */
@Data
public class TrainTravel {

    // 可行驶的区段集合
    private final List<SectionItem> sectionList;
    // 停车标的位置
    private final HashMap<Long, SignStopEntity> signStopMap;

    public TrainTravel(List<SectionItem> sectionList, List<SignStopEntity> signStopEntityList) {
        this.sectionList = sectionList;
        this.signStopMap = signStopEntityList.stream().collect(HashMap::new, (map, entity) -> map.put(entity.getSelectionId(), entity), HashMap::putAll);
    }

    public TrainTravel(List<SectionItem> sectionList, HashMap<Long, SignStopEntity> signStopMap) {
        this.sectionList = sectionList;
        this.signStopMap = signStopMap;
    }

    public TravelItem travel(TrainItem train, BigDecimal distance) {
        Optional<SectionItem> sectionOptional = sectionList.stream().filter(item -> {
            return item.getSectionId().equals(train.getBlockId()) && item.getDirection().equals(train.getDirection());
        }).findFirst();
        return sectionOptional.map(sectionItem -> travel(sectionItem.getId(), train.getOffset(), distance)).orElse(null);
    }

    /**
     * 列车行驶
     * @param section 当前区段
     * @param offset 偏移量
     * @param distance 行驶距离
     * @return 行驶后的位置
     */
    public TravelItem travel(String id, BigDecimal offset, BigDecimal distance) {
        Optional<SectionItem> sectionOptional = sectionList.stream().filter(item -> StrUtil.equals(item.getId(), id)).findFirst();
        if (sectionOptional.isEmpty()) {
            return null;
        }
        SectionItem sectionItem = sectionOptional.get();
        if (null == offset) {
            // 偏移量为当前区段长度 上行的开始位置是区段的末端
            offset = sectionItem.getSectionLength();
        }
        BigDecimal travelDistance = NumberUtil.mul(sectionItem.getDirection().getFactor(), distance.abs());
        BigDecimal travelOffset = NumberUtil.add(offset, travelDistance);
        // 计算停车标
        SignStopEntity stopEntity = signStopMap.get(sectionItem.getSectionId());
        if (null != stopEntity) {
            BigDecimal minInclude = NumberUtil.min(offset.abs(), travelOffset);
            BigDecimal maxInclude = NumberUtil.max(offset.abs(), travelOffset);
            Boolean isStop = switch (sectionItem.getDirection()) {
                case UP -> NumberUtil.isGreaterOrEqual(stopEntity.getSelectionOff().abs(), minInclude) && NumberUtil.isLess(stopEntity.getSelectionOff().abs(), maxInclude);
                case DOWN -> NumberUtil.isGreater(stopEntity.getSelectionOff().abs(), minInclude) && NumberUtil.isLessOrEqual(stopEntity.getSelectionOff().abs(), maxInclude);
            };
            if (isStop) {
                return new TravelItem(sectionItem, stopEntity.getSelectionOff().abs(), true);
            }
        }
        if (NumberUtil.isLess(travelOffset, BigDecimal.ZERO)) {
            // <0 上行 行驶到下一个区段
            return travel(sectionItem.getNextId(), null, travelOffset.abs());
        } else if (NumberUtil.isGreaterOrEqual(travelOffset, sectionItem.getSectionLength())) {
            // >= 区段的长度 下行 实行到下一个区段
            return travel(sectionItem.getNextId(), BigDecimal.ZERO, travelOffset.subtract(sectionItem.getSectionLength()));
        } else {
            // 行驶后的位置在当前区段
            return new TravelItem(sectionItem, travelOffset, false);
        }
    }

    @Data
    @AllArgsConstructor
    public static class TravelItem {
        // 区段
        private SectionItem section;
        // 偏移量
        private BigDecimal offset;
        // 是否停车
        private boolean isStop;
    }
}