package model

import (
	"fmt"
	"io"
	"math"
)

type RR = io.Writer

// 轨道
// 默认坐标系为以A端为起点，B端为终点的单轴坐标系
type Link interface {
	TwoPortsPipeElement
	IsEquals(pla *PipeLink, plb *PipeLink) bool
	// 获取轨道长度，单位：毫米mm
	GetLength() int64
}

// 轨道连接点(使用的是道岔岔心)，然后有三个方向A/B/C，还是使用PipePort枚举，但表示的含义是方向，而不是道岔的三个端口
type LinkNode interface {
	Turnout() Turnout
	ThreePortsPipeElement
}

type LinkDirection int

const (
	LinkDirectionB2A LinkDirection = -1
	LinkDirectionA2B LinkDirection = 1
)

// link位置
type LinkPosition struct {
	link Link
	pos  int64
}

func NewLinkPosition(link Link, pos int64) *LinkPosition {
	return &LinkPosition{
		link: link,
		pos:  pos,
	}
}

func (lp *LinkPosition) Link() Link {
	return lp.link
}

func (lp *LinkPosition) Position() int64 {
	return lp.pos
}

func (lp *LinkPosition) IsIn(linkRange LinkRange) bool {
	return lp.link.Uid() == linkRange.link.Uid() && lp.IsInRange(linkRange.start, linkRange.end)
}

func (lp *LinkPosition) IsInRange(a int64, b int64) bool {
	start := int64(math.Min(float64(a), float64(b)))
	end := int64(math.Max(float64(a), float64(b)))
	return lp.pos >= start && lp.pos <= end
}

// 移动位置
func (lp *LinkPosition) Move(len uint32, direction LinkDirection) (overflow bool) {
	lp.pos += int64(len) * int64(direction)
	if lp.pos > lp.link.GetLength() || lp.pos < 0 {
		overflow = true
	}
	return
}

// link范围
type LinkRange struct {
	link  Link
	start int64
	end   int64
}

// 构造link范围
// link: 轨道 不能为nil
// a: 起始位置，b: 结束位置，单位：毫米mm，a和b不能相等
func NewLinkRange(link Link, a int64, b int64) *LinkRange {
	if link == nil {
		panic("构造LinkRange错误: link不能为空")
	}
	if a == b {
		panic("构造LinkRange错误: a和b不能相等")
	}
	start := int64(math.Min(float64(a), float64(b)))
	end := int64(math.Max(float64(a), float64(b)))
	return &LinkRange{
		link:  link,
		start: start,
		end:   end,
	}
}

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

type LinkImpl struct {
	*TwoPortsPipeElementImpl
	len int64
}

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 (l *LinkImpl) GetLength() int64 {
	return l.len
}

func (l *LinkImpl) SetLength(len int64) {
	l.len = len
}

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)
}