WebCAD/src/Geometry/RegionParse.ts

import { Vector3 } from 'three';
import { arrayRemoveDuplicateBySort, arrayRemoveIf } from '../Common/ArrayExt';
import { Arc } from '../DatabaseServices/Entity/Arc';
import { Curve } from '../DatabaseServices/Entity/Curve';
import { Polyline } from '../DatabaseServices/Entity/Polyline';
import { Count } from './Count';
import { CurveMap } from './CurveMap';
import { angle, equalv3 } from './GeUtils';

//路线
export interface Route
{
    curve: Curve; //路线的曲线
    to: Stand;    //终点的点
}


//站台
export interface Stand
{
    //位置
    position: Vector3;
    //路径
    routes: Array<Route>;
}

//区域的路线表 表示了一个区域
type RegionRouteS = Array<Set<Route>>;

//区域搜索算法
export class RegionParse
{
    //曲线使用计数器
    private _CountCu = new Count();

    //区域列表 通常是外轮廓
    RegionsOutline: RegionRouteS = [];
    //区域列表 通常是内轮廓
    RegionsInternal: RegionRouteS = [];

    //碎线 曲线进入到这里会被炸开.
    ExpLineMap: Map<Curve, Curve[]> = new Map();

    /**
     * Creates an instance of RegionParse.
     * @param {Curve[]} cuList 请不要传递圆和椭圆.
     * @memberof RegionParse
     */
    constructor(cuList: Curve[], public fractionDigits = 3)
    {
        //需要搜索的站
        let needFinds = this.GenerateNodeMap(cuList);

        //搜索大轮廓.
        while (needFinds.size > 0)
        {
            //找到最小的站.
            let minStand = this.FindMinStand(needFinds);
            needFinds.delete(minStand);
            //逆时针+逆时针
            for (let i = minStand.routes.length; i--;)
            {
                let wayS = new Set<Stand>();
                let routeS = new Set<Route>();
                let isFind = this.FindRegion(minStand, minStand, undefined, wayS, routeS, 1);
                if (isFind)
                {
                    this.RegionsOutline.push(routeS);
                    //计数增加
                    for (let route of routeS)
                        this._CountCu.AddCount(route.curve, 1);
                    this.FindMinRegion(wayS);
                }
            }
        }
    }

    /**
     * 曲线是否已经被算法使用
     * @param cu 
     * @returns true if cueve used 
     */
    GetCueveUsed(cu: Curve): boolean
    {
        if (this.ExpLineMap.has(cu))
        {
            let use = this.ExpLineMap.get(cu).some(c => this._CountCu.GetCount(c) > 0);
            if (!use)
                this.ExpLineMap.delete(cu);
            return use;
        }
        else
            return this._CountCu.GetCount(cu) > 0;
    }

    /**
     * 使用类似涨潮的方式,从最低的地方,采用顺时针填充.
     * 算法允许搜索到的区域在外轮廓外.
     *
     * @param {Set<Stand>} standS 外轮廓站点
     * @memberof RegionAlg
     */
    private FindMinRegion(standS: Set<Stand>)
    {
        //需要搜索的.
        let needFinds = new Set<Stand>();
        standS.forEach(w => needFinds.add(w));
        //已经走过的
        let passingStands = new Set<Stand>();

        let regs: RegionRouteS = [];

        while (needFinds.size > 0)
        {
            //找到最小站
            let minStand = this.FindMinStand(needFinds);
            //添加为已经计算
            passingStands.add(minStand);
            needFinds.delete(minStand);

            //顺时针搜索
            for (let j = minStand.routes.length; j--;)
            {
                let route = minStand.routes[j];

                if (!needFinds.has(route.to))
                    continue;

                let wayS = new Set<Stand>();
                let routeS = new Set<Route>();

                routeS.add(route);
                wayS.add(route.to);

                let isFindMin = this.FindRegion(minStand, route.to, route.curve, wayS, routeS, 2);
                if (isFindMin)
                {
                    regs.push(routeS);

                    wayS.forEach(w =>
                    {
                        //站点拓展,如果该地点没有被走过,那么加入到需要搜寻的站点表
                        if (!passingStands.has(w))
                            needFinds.add(w);
                    });

                    for (let route of routeS)
                        this._CountCu.AddCount(route.curve, 1);
                }
            }
        }

        if (regs.length > 1)
            this.RegionsInternal.push(...regs);
    }

    /**
     * 找到左下角的站.
     *
     * @private
     * @param {Set<Stand>} standS
     * @returns
     * @memberof RegionAlg
     */
    private FindMinStand(standS: Set<Stand>)
    {
        let minStand: Stand;
        for (let stand of standS)
        {
            if (!minStand)
            {
                minStand = stand;
                continue;
            }
            if (minStand.position.y > stand.position.y)
            {
                minStand = stand;
            }
            else if (minStand.position.y === stand.position.y && minStand.position.x > stand.position.x)
            {
                minStand = stand;
            }
        }
        return minStand;
    }

    /**
     * 构造路线图. 每个节点对应下一个路口的路线表. 路口表使用逆时针排序,起始角度使用正x轴.
     * 
     * @private
     * @param {Curve[]} cuList 
     * @returns {Set<Stand>} 站点列表
     * @memberof RegionParse
     */
    private GenerateNodeMap(cuList: Curve[]): Set<Stand>
    {
        let curveMap = new CurveMap(this.fractionDigits);

        //将多段线炸开
        let plcus: Curve[] = [];
        arrayRemoveIf(cuList, c =>
        {
            if (c instanceof Polyline)
            {
                let cus = c.Explode();

                //如果为圆弧,提前打断
                let arcs: Arc[] = [];
                arrayRemoveIf(cus, c =>
                {
                    if (c instanceof Arc)
                    {
                        let arcBrs = this.BreakArc(c);
                        if (arcBrs.length > 1)
                        {
                            arcs.push(...arcBrs);
                            return true;
                        }
                    }
                    return false;
                });
                //加入到计算
                cus.push(...arcs);

                this.ExpLineMap.set(c, cus);
                plcus.push(...cus);
                return true;
            }
            return false;
        });
        cuList.push(...plcus);

        for (let cu of cuList)
        {
            //由于圆弧可能导致最低点计算错误的问题.
            if (cu instanceof Arc)
            {
                let arcs = this.BreakArc(cu);
                if (arcs.length > 1)
                {
                    arcs.forEach(a => curveMap.addCurveToMap(a));
                    this.ExpLineMap.set(cu, arcs);
                    continue;
                }
            }
            curveMap.addCurveToMap(cu);
        }

        //排序,根据角度逆时针排序.
        curveMap.m_NodeMap.forEach(s =>
        {
            s.routes.sort((r1, r2) =>
            {
                let a1: number, a2: number;
                if (equalv3(r1.curve.StartPoint, s.position))
                    a1 = angle(r1.curve.GetFistDeriv(0));
                else
                    a1 = angle(r1.curve.GetFistDeriv(r1.curve.EndParam).negate());

                if (equalv3(r2.curve.StartPoint, s.position))
                    a2 = angle(r2.curve.GetFistDeriv(0));
                else
                    a2 = angle(r2.curve.GetFistDeriv(r1.curve.EndParam).negate());

                return a1 - a2;
            });

            //移除重复的线
            arrayRemoveDuplicateBySort(s.routes, (r1, r2) =>
            {
                let isEqual = r1.to === r2.to && r1.curve.constructor.name === r2.curve.constructor.name;
                if (isEqual && r1.curve instanceof Arc)
                    return equalv3(r1.curve.GetPointAtParam(0.5), r2.curve.GetPointAtParam(0.5));
                return isEqual;
            });
        });

        return new Set(curveMap.Stands);
    }

    private BreakArc(arc: Arc)
    {
        let underPt = arc.Center.add(new Vector3(0, -arc.Radius));
        let param = arc.GetParamAtPoint(underPt);
        if (param > 0.01 && param < 0.99)
            return arc.GetSplitCurves(param);
        else
            return [arc];
    }

    //寻找闭合轮廓,下一站总是使用逆时针规划.
    private FindRegion(firstS: Stand,  //起点
        nowStand: Stand,       //当前站
        lastCurve: Curve,      //上一条线索引
        wayStands: Set<Stand>, //走过的站
        routeS: Set<Route>,    //走过的路
        cuMaximumCount: number,  //允许最大的行走次数
    )
    {
        let routeCount = nowStand.routes.length;
        //查找上一条线的索引.
        let lastIndex = -1;
        if (lastCurve)
        {
            for (let i = routeCount; i--;)//顺时针搜索.
            {
                if (nowStand.routes[i].curve === lastCurve)
                {
                    lastIndex = i;
                    break;
                }
            }
        }

        for (let i = 0; i < routeCount - 1; i++)
        {
            let index = lastIndex + i + 1;//转弯,逆时针
            if (index >= routeCount) index -= routeCount;

            //下一站
            let route = nowStand.routes[index];

            let usedCount = this._CountCu.GetCount(route.curve);
            if (usedCount >= cuMaximumCount)
                continue;

            //如果发现这条路已经走回去,中途回路
            if (wayStands.has(route.to))
            {
                return false;
                // for (let stand of wayStands)
                // {
                //     if (stand === route.to)
                //         break;
                //     wayStands.delete(stand);//删除不是回路的部分
                // }
                // return true;
            }

            //加入到已经走过的道路.
            wayStands.add(route.to);
            routeS.add(route);

            //已经回原地,此处不验证该轮廓的正确性.
            if (route.to === firstS)
                return true;

            //在下个路口试着往前走
            let isFind = this.FindRegion(firstS, route.to, route.curve, wayStands, routeS, cuMaximumCount);
            if (isFind)
                return true;
            else
            {
                wayStands.delete(route.to);//不走这条路
                routeS.delete(route);
            }
        }
        return false;
    }
}