package repository

import (
	"errors"
	"fmt"
	"joylink.club/rtsssimulation/repository/model/proto"
)

// 转换公里标
func convertKilometer(repo *Repository, km *proto.Kilometer, cs string, dir proto.Direction) (*proto.Kilometer, error) {
	if km.CoordinateSystem == cs {
		return km, nil
	}

	kc, err := repo.getKilometerConvert(km.CoordinateSystem, cs, km.Direction, dir)
	if err != nil {
		return nil, err
	}

	var sourceCsKm *proto.Kilometer
	var targetCsKm *proto.Kilometer
	if kc.KmA.CoordinateSystem == km.CoordinateSystem {
		sourceCsKm = kc.KmA
		targetCsKm = kc.KmB
	} else {
		sourceCsKm = kc.KmB
		targetCsKm = kc.KmA
	}
	offset := km.Value - sourceCsKm.Value
	var value int64
	if kc.SameTrend {
		value = targetCsKm.Value + offset
	} else {
		value = targetCsKm.Value - offset
	}
	if value < 0 {
		return nil, errors.New(fmt.Sprintf("公里标[%s]转换为坐标系[%s]的公里标的值[%d]小于0", km, cs, value))
	}
	return &proto.Kilometer{
		Value:            value,
		CoordinateSystem: cs,
		Direction:        dir,
	}, nil
}