/**
 * User: CHT
 * Date: 2020/5/8
 * Time: 14:01
 */

import {
  uuid,
  vector,
  mark
} from './utils'

import {
  direction,
  directionVector
} from './types'

export default class GraphLink {
  static distance = 15

  constructor (options, graph) {
    const {
      start,
      end = null,
      startAt = [0, 0],
      endAt = [0, 0],
      meta = null,
    } = options

    this.$options = options

    const id = options[mark.relationMark] || uuid('link')

    this.key = uuid('link')

    this[mark.relationMark] = id
    this.graph = graph
    this.start = start
    this.meta = meta

    this.end = end
    this.startDirection = directionVector[direction.top]
    this.endDirection = directionVector[direction.top]
    this.startAt = startAt
    this.endAt = endAt
  }

  get end () {
    return this._end
  }

  set end (node) {
    if (this.start === node) {
      return false
    } else {
      this._end = node
    }
  }

  get startAt () {
    return this._startAt
  }

  set startAt (offset) {
    const relative = this.start.relative(offset)
    this._startAt = relative.position
    this.startDirection = relative.direction
  }

  get endAt () {
    return this._endAt
  }

  set endAt (offset) {
    if (this.end) {
      const relative = this.end.relative(offset)
      this._endAt = relative.position
      this.endDirection = relative.direction
    } else {
      this._endAt = offset
    }
  }

  get movePosition () {
    return this._movePosition
  }

  set movePosition (offset) {
    this._movePosition = offset

    if (this.end) return

    const relative = this.start.relative(
      vector(offset)
        .minus(this.graph.origin)
        .minus(this.start.coordinate)
        .end
    )

    this.endDirection = vector(relative.direction)
      .multiply(-1)
      .end
  }

  get pathPointList () {
    const pointList = this.coordinateList()
      , xList = []
      , yList = []

    pointList.forEach(item => {
      xList.push(item[0])
      yList.push(item[1])
    })

    return {
      pointList,
      xList,
      yList,
      minX: Math.min(...xList),
      maxX: Math.max(...xList),
      minY: Math.min(...yList),
      maxY: Math.max(...yList)
    }
  }

  startCoordinate () {
    return vector(this.start.position)
      .add(this.startAt)
      .end
  }

  endCoordinate () {
    if (this.end) {
      return vector(this.end.position)
        .add(this.endAt)
        .end
    } else {
      return this.movePosition
    }
  }

  coordinateList (turnRatio = 0.5) {
    const entryPoint = this.startCoordinate()
    const exitPoint = this.endCoordinate()

    const entryDirection = this.startDirection
    let exitDirection = this.endDirection

    // 路径起点
    const startPoint = vector(entryDirection)
      .multiply(GraphLink.distance)
      .add(entryPoint)
      .end

    // 路径终点
    const endPoint = vector(exitDirection)
      .multiply(GraphLink.distance)
      .add(exitPoint)
      .end

    // 入口方向取反
    exitDirection = vector(exitDirection)
      .multiply(-1)
      .end

    // 终点 - 起点  垂直 水平向量
    const pathHorizontalVec = [endPoint[0] - startPoint[0], 0]
    const pathVerticalVec = [0, endPoint[1] - startPoint[1]]

    const startDirection = this.pathDirection(
      pathVerticalVec,
      pathHorizontalVec,
      entryDirection
    )
    const endDirection = this.pathDirection(
      pathVerticalVec,
      pathHorizontalVec,
      exitDirection
    )

    const splitNum = vector(startDirection)
      .dotProduct(endDirection)
      .end > 0 ? 2 : 1

    const pathMiddle = endDirection === pathHorizontalVec
      ? pathVerticalVec
      : pathHorizontalVec

    let points = []

    points.push(entryPoint, startPoint)

    if (splitNum === 1) {

      const point1 = vector(startPoint)
        .add(startDirection)
        .end

      const point2 = vector(point1)
        .add(endDirection)
        .end
      points.push(point1, point2)

    } else {
      const point1 = vector(startDirection)
        .multiply(turnRatio)
        .add(startPoint)
        .end

      const point2 = vector(point1)
        .add(pathMiddle)
        .end

      const point3 = vector(endDirection)
        .multiply(1 - turnRatio)
        .add(point2)
        .end

      points.push(point1, point2, point3)
    }

    points.push(exitPoint)

    return points
  }

  pathDirection (vertical, horizontal, direction) {
    if (
      vector(horizontal)
        .parallel(direction)
        .end
    ) {
      if (
        vector(horizontal)
          .dotProduct(direction)
          .end > 0
      ) {
        return horizontal
      } else {
        return vertical
      }
    } else {
      if (
        vector(vertical)
          .dotProduct(direction)
          .end > 0
      ) {
        return vertical
      } else {
        return horizontal
      }
    }
  }

  isPointInLink (position, pathPointList) {
    const {
      pointList,
      minX,
      minY,
      maxX,
      maxY
    } = pathPointList || this.pathPointList

    const n = 5

    if (
      position[0] < minX - n
      || position[0] > maxX + n
      || position[1] < minY - n
      || position[1] > maxY + n
    ) {
      return false
    }

    for (let i = 0; i < pointList.length - 2; i++) {
      const prev = pointList[i]
      const current = pointList[i + 1]

      const top = Math.min(prev[1], current[1]) - n
      const right = Math.max(prev[0], current[0]) + n
      const bottom = Math.max(prev[1], current[1]) + n
      const left = Math.min(prev[0], current[0]) - n

      const [x, y] = position

      if (x > left && x < right && y > top && y < bottom) {
        return true
      }
    }
    return false
  }

  remove () {
    return this.graph.removeLink(this)
  }

  toJSON () {
    return {
      [mark.relationMark]: this[mark.relationMark],
      [mark.startMark]: this.start[mark.relationMark],
      [mark.endMark]: this.end[mark.relationMark],
      startAt: this.startAt,
      endAt: this.endAt,
      meta: this.meta
    }
  }
}