meta-server/src/get-router/get-router.service.ts

import { Injectable } from '@nestjs/common';
import { CacheService } from 'src/cache/cache.service';

@Injectable()
export class GetRouterService {
  constructor(private cacheService: CacheService) {}

  async searchRoad(appId, startPointId, clicking_point) {
    //表示终点
    let endPoint;

    const keys = await this.cacheService.keys(`breakpoints:app_id:${appId}*`);
    let minDis = null;
    for (let i = 0; i < keys.length; ++i) {
      const breakPointRes = await this.cacheService.get(keys[i]);
      const breakPoint = JSON.parse(breakPointRes);
      if (breakPoint.breakPointId == startPointId) {
        continue;
      }
      const position = breakPoint.position;
      if (minDis == null) {
        minDis = this.getDistance(clicking_point, position);
        endPoint = breakPoint;
      } else if (minDis > this.getDistance(clicking_point, position)) {
        endPoint = breakPoint;
        minDis = this.getDistance(clicking_point, position);
      }
    }

    if (minDis > 100) {
      return [];
    }

    const startPointRes = await this.cacheService.get(
      'breakpoints:app_id:' + appId + ':break_point_id:' + startPointId,
    );
    const startPoint = JSON.parse(startPointRes);

    // const endPointRes = await this.cacheService.get(
    //   'breakpoints:app_id:' + appId + ':break_point_id:' + endPointId,
    // );
    // const endPoint = JSON.parse(endPointRes);

    const openList = [], //开启列表
      closeList = []; //关闭列表
    let result = []; //结果数组
    let result_index: number; //结果数组在开启列表中的序号

    //openList.push({x:startPoint.x,y:startPoint.y,G:0});//把当前点加入到开启列表中，并且G是0
    openList.push({ breakPointId: startPointId, G: 0 }); //把当前点加入到开启列表中，并且G是0

    do {
      const currentPointInfo = openList.pop();
      const currentPointRes = await this.cacheService.get(
        'breakpoints:app_id:' +
          appId +
          ':break_point_id:' +
          currentPointInfo.breakPointId,
      );
      const currentPoint = JSON.parse(currentPointRes);
      closeList.push(currentPointInfo);

      //读redis里的数据
      const breakPointRes = await this.cacheService.get(
        'breakpoints:app_id:' +
          appId +
          ':break_point_id:' +
          currentPointInfo.breakPointId,
      );
      let surroundPoint = [];
      const _breakPoint = JSON.parse(breakPointRes);
      surroundPoint = _breakPoint.contact;

      for (let i = 0; i < surroundPoint.length; ++i) {
        const neighPointId = surroundPoint[i];
        const itemRes = await this.cacheService.get(
          'breakpoints:app_id:' + appId + ':break_point_id:' + neighPointId,
        );
        const item = JSON.parse(itemRes);
        //g 到父节点的位置
        const g =
          currentPointInfo.G +
          this.getDistance(currentPoint.position, item.position);
        if (this.existList(item, openList) == -1) {
          //如果不在开启列表中
          item['H'] = 0;
          item['G'] = g;
          item['F'] = item.H + item.G;
          item['parent'] = currentPoint;
          openList.push(item);
        } else {
          //存在在开启列表中，比较目前的g值和之前的g的大小
          const index = this.existList(item, openList);
          //如果当前点的g更小
          if (g < openList[index].G) {
            openList[index].parent = currentPoint;
            openList[index].G = g;
            openList[index].F = g + openList[index].H;
          }
        }
      }
      //如果开启列表空了，没有通路，结果为空
      if (openList.length == 0) {
        break;
      }

      openList.sort(this.sortF); //这一步是为了循环回去的时候，找出 F 值最小的, 将它从 "开启列表" 中移掉
    } while ((result_index = this.existList(endPoint, openList)) == -1);

    //判断结果列表是否为空
    if (result_index == -1) {
      result = [];
    } else {
      let currentObj = openList[result_index];
      do {
        //把路劲节点添加到result当中
        result.unshift(currentObj.breakPointId);
        currentObj = currentObj.parent;
        // debugger
      } while (
        currentObj.position.x != startPoint.position.x ||
        currentObj.position.y != startPoint.position.y
      );
    }
    result.unshift(startPointId);
    return result;
  }

  //用F值对数组排序
  sortF(a, b) {
    return b.F - a.F;
  }

  //获取周围点
  async SurroundPoint(appId, curPointId, endPoint) {
    //读redis里的数据
    const breakPointRes = await this.cacheService.get(
      'breakpoints:app_id:' + appId + ':break_point_id:' + curPointId,
    );
    const breakPoint = JSON.parse(breakPointRes);
    if (this.getDistance(breakPoint.position, endPoint.position) < 1) {
      breakPoint.contact.push(endPoint.breakPointId);
    }
    return breakPoint.contact;
  }

  //判断点是否存在在列表中，是的话返回的是序列号
  existList(point, list) {
    for (let i = 0; i < list.length; ++i) {
      if (point.breakPointId == list[i].breakPointId) {
        return i;
      }
    }
    return -1;
  }

  getDistance(position1, position2) {
    return Math.sqrt(
      (position1.x - position2.x) * (position1.x - position2.x) +
        (position1.y - position2.y) * (position1.y - position2.y),
    );
  }
}