package model

import (
	"fmt"
	"io"
)

type RR = io.Writer

// 轨道
type Link interface {
	TwoPortsPipeElement
	IsEquals(pla *PipeLink, plb *PipeLink) bool
}

// 轨道连接点
type LinkNode interface {
	Turnout() Turnout
	ThreePortsPipeElement
}

var _ Link = (*LinkImpl)(nil)
var _ LinkNode = (*LinkNodeImpl)(nil)

type LinkImpl struct {
	*TwoPortsPipeElementImpl
}

type LinkNodeImpl struct {
	turnout Turnout
	*ThreePortsPipeElementImpl
}

func NewLink(pla *PipeLink, plb *PipeLink) *LinkImpl {
	uid := buildLinkUid(pla, plb)
	return &LinkImpl{
		TwoPortsPipeElementImpl: &TwoPortsPipeElementImpl{
			uid: uid,
		},
	}
}

func NewLinkNode(turnout Turnout) *LinkNodeImpl {
	if turnout == nil {
		panic("构造LinkNode错误: 道岔不能为空")
	}
	return &LinkNodeImpl{
		turnout: turnout,
		ThreePortsPipeElementImpl: &ThreePortsPipeElementImpl{
			uid: turnout.Uid(),
		},
	}
}

func (l *LinkImpl) IsEquals(pla *PipeLink, plb *PipeLink) bool {
	return l.uid == buildLinkUid(pla, plb) || l.uid == buildLinkUid(plb, pla)
}

func (n *LinkNodeImpl) Turnout() Turnout {
	return n.turnout
}

func buildLinkUid(pla *PipeLink, plb *PipeLink) string {
	if pla == nil && plb == nil {
		panic("构造link Uid错误: pla和plb不能同时为空")
	}
	if pla == nil {
		return fmt.Sprintf("end->%s(%s)", plb.Pipe.Uid(), plb.Port)
	}
	if plb == nil {
		return fmt.Sprintf("%s(%s)->end", pla.Pipe.Uid(), pla.Port)
	}
	return fmt.Sprintf("%s(%s)->%s(%s)", pla.Pipe.Uid(), pla.Port, plb.Pipe.Uid(), plb.Port)
}