<template>
  <div
    :style="style"
    :class="[
      {
        [classNameActive]: enabled,
        [classNameDragging]: dragging,
        [classNameResizing]: resizing,
        [classNameDraggable]: draggable,
        [classNameResizable]: resizable,
      },
      className,
    ]"
    @mousedown="elementDown"
    @touchstart="elementTouchDown"
  >
    <div
      v-for="handle in actualHandles"
      :key="handle"
      :class="[classNameHandle, classNameHandle + '-' + handle]"
      :style="{ display: enabled ? 'block' : 'none' }"
      @mousedown.stop.prevent="handleDown(handle, $event)"
      @touchstart.stop.prevent="handleTouchDown(handle, $event)"
    >
      <slot :name="handle"></slot>
    </div>
    <slot></slot>
  </div>
</template>

<script>
import { matchesSelectorToParentElements, addEvent, removeEvent } from './util'

const events = {
  mouse: {
    start: 'mousedown',
    move: 'mousemove',
    stop: 'mouseup',
  },
  touch: {
    start: 'touchstart',
    move: 'touchmove',
    stop: 'touchend',
  },
}

const userSelectNone = {
  userSelect: 'none',
  MozUserSelect: 'none',
  WebkitUserSelect: 'none',
  MsUserSelect: 'none',
}

const userSelectAuto = {
  userSelect: 'auto',
  MozUserSelect: 'auto',
  WebkitUserSelect: 'auto',
  MsUserSelect: 'auto',
}

let eventsFor = events.mouse

export default {
  name: 'DragAndResizable',
  props: {
    className: {
      type: String,
      default: 'drag-and-resizable',
    },
    classNameDraggable: {
      type: String,
      default: 'draggable',
    },
    classNameResizable: {
      type: String,
      default: 'resizable',
    },
    classNameDragging: {
      type: String,
      default: 'dragging',
    },
    classNameResizing: {
      type: String,
      default: 'resizing',
    },
    classNameActive: {
      type: String,
      default: 'active',
    },
    classNameHandle: {
      type: String,
      default: 'handle',
    },
    disableUserSelect: {
      type: Boolean,
      default: true,
    },
    enableNativeDrag: {
      type: Boolean,
      default: false,
    },
    preventDeactivation: {
      type: Boolean,
      default: false,
    },
    active: {
      type: Boolean,
      default: false,
    },
    draggable: {
      type: Boolean,
      default: true,
    },
    resizable: {
      type: Boolean,
      default: true,
    },
    lockAspectRatio: {
      type: Boolean,
      default: false,
    },
    w: {
      type: Number,
      default: 200,
      validator: val => val > 0,
    },
    h: {
      type: Number,
      default: 200,
      validator: val => val > 0,
    },
    minWidth: {
      type: Number,
      default: 0,
      validator: val => val >= 0,
    },
    minHeight: {
      type: Number,
      default: 0,
      validator: val => val >= 0,
    },
    maxWidth: {
      type: Number,
      default: null,
      validator: val => val >= 0,
    },
    maxHeight: {
      type: Number,
      default: null,
      validator: val => val >= 0,
    },
    x: {
      type: Number,
      default: 0,
      validator: val => typeof val === 'number',
    },
    y: {
      type: Number,
      default: 0,
      validator: val => typeof val === 'number',
    },
    z: {
      type: [String, Number],
      default: 'auto',
      validator: val => (typeof val === 'string' ? val === 'auto' : val >= 0),
    },
    handles: {
      type: Array,
      default: () => ['tl', 'tm', 'tr', 'mr', 'br', 'bm', 'bl', 'ml'],
      validator: val => {
        const s = new Set(['tl', 'tm', 'tr', 'mr', 'br', 'bm', 'bl', 'ml'])

        return new Set(val.filter(h => s.has(h))).size === val.length
      },
    },
    dragHandle: {
      type: String,
      default: null,
    },
    dragCancel: {
      type: String,
      default: null,
    },
    axis: {
      type: String,
      default: 'both',
      validator: val => ['x', 'y', 'both'].includes(val),
    },
    grid: {
      type: Array,
      default: () => [1, 1],
    },
    parent: {
      type: Boolean,
      default: false,
    },
    onDragStart: {
      type: Function,
      default: null,
    },
    onResizeStart: {
      type: Function,
      default: null,
    },
  },

  data: function() {
    return {
      rawWidth: this.w,
      rawHeight: this.h,
      rawLeft: this.x,
      rawTop: this.y,
      rawRight: null,
      rawBottom: null,

      left: this.x,
      top: this.y,
      right: null,
      bottom: null,

      aspectFactor: this.w / this.h,

      parentWidth: null,
      parentHeight: null,

      minW: this.minWidth,
      minH: this.minHeight,

      maxW: this.maxWidth,
      maxH: this.maxHeight,

      handle: null,
      enabled: this.active,
      resizing: false,
      dragging: false,
      zIndex: this.z,
    }
  },
  computed: {
    style() {
      return {
        position: 'absolute',
        top: this.top + 'px',
        left: this.left + 'px',
        width: this.width + 'px',
        height: this.height + 'px',
        zIndex: this.zIndex,
        ...(this.dragging && this.disableUserSelect
          ? userSelectNone
          : userSelectAuto),
      }
    },
    actualHandles() {
      if (!this.resizable) {
        return []
      }

      return this.handles
    },
    width() {
      return this.parentWidth - this.left - this.right
    },
    height() {
      return this.parentHeight - this.top - this.bottom
    },
    resizingOnX() {
      return (
        Boolean(this.handle) &&
        (this.handle.includes('l') || this.handle.includes('r'))
      )
    },
    resizingOnY() {
      return (
        Boolean(this.handle) &&
        (this.handle.includes('t') || this.handle.includes('b'))
      )
    },
    isCornerHandle() {
      return (
        Boolean(this.handle) && ['tl', 'tr', 'br', 'bl'].includes(this.handle)
      )
    },
  },

  watch: {
    active(val) {
      this.enabled = val

      if (val) {
        this.$emit('activated')
      } else {
        this.$emit('deactivated')
      }
    },
    z(val) {
      if (val >= 0 || val === 'auto') {
        this.zIndex = val
      }
    },
    rawLeft(newLeft) {
      const bounds = this.bounds
      const aspectFactor = this.aspectFactor
      const lockAspectRatio = this.lockAspectRatio
      const left = this.left
      const top = this.top

      if (bounds.minLeft !== null && newLeft < bounds.minLeft) {
        newLeft = bounds.minLeft
      } else if (bounds.maxLeft !== null && bounds.maxLeft < newLeft) {
        newLeft = bounds.maxLeft
      }

      if (lockAspectRatio && this.resizingOnX) {
        this.rawTop = top - (left - newLeft) / aspectFactor
      }

      this.left = newLeft
    },
    rawRight(newRight) {
      const bounds = this.bounds
      const aspectFactor = this.aspectFactor
      const lockAspectRatio = this.lockAspectRatio
      const right = this.right
      const bottom = this.bottom

      if (bounds.minRight !== null && newRight < bounds.minRight) {
        newRight = bounds.minRight
      } else if (bounds.maxRight !== null && bounds.maxRight < newRight) {
        newRight = bounds.maxRight
      }

      if (lockAspectRatio && this.resizingOnX) {
        this.rawBottom = bottom - (right - newRight) / aspectFactor
      }

      this.right = newRight
    },
    rawTop(newTop) {
      const bounds = this.bounds
      const aspectFactor = this.aspectFactor
      const lockAspectRatio = this.lockAspectRatio
      const left = this.left
      const top = this.top

      if (bounds.minTop !== null && newTop < bounds.minTop) {
        newTop = bounds.minTop
      } else if (bounds.maxTop !== null && bounds.maxTop < newTop) {
        newTop = bounds.maxTop
      }

      if (lockAspectRatio && this.resizingOnY) {
        this.rawLeft = left - (top - newTop) * aspectFactor
      }

      this.top = newTop
    },
    rawBottom(newBottom) {
      const bounds = this.bounds
      const aspectFactor = this.aspectFactor
      const lockAspectRatio = this.lockAspectRatio
      const right = this.right
      const bottom = this.bottom

      if (bounds.minBottom !== null && newBottom < bounds.minBottom) {
        newBottom = bounds.minBottom
      } else if (bounds.maxBottom !== null && bounds.maxBottom < newBottom) {
        newBottom = bounds.maxBottom
      }

      if (lockAspectRatio && this.resizingOnY) {
        this.rawRight = right - (bottom - newBottom) * aspectFactor
      }

      this.bottom = newBottom
    },
    x() {
      if (this.resizing || this.dragging) {
        return
      }

      if (this.parent) {
        this.bounds = this.calcDragLimits()
      }

      const delta = this.x - this.left

      if (delta % this.grid[0] === 0) {
        this.rawLeft = this.x
        this.rawRight = this.right - delta
      }
    },
    y() {
      if (this.resizing || this.dragging) {
        return
      }

      if (this.parent) {
        this.bounds = this.calcDragLimits()
      }

      const delta = this.y - this.top

      if (delta % this.grid[1] === 0) {
        this.rawTop = this.y
        this.rawBottom = this.bottom - delta
      }
    },
    lockAspectRatio(val) {
      if (val) {
        this.aspectFactor = this.width / this.height
      } else {
        this.aspectFactor = undefined
      }
    },
    minWidth(val) {
      if (val > 0 && val <= this.width) {
        this.minW = val
      }
    },
    minHeight(val) {
      if (val > 0 && val <= this.height) {
        this.minH = val
      }
    },
    maxWidth(val) {
      this.maxW = val
    },
    maxHeight(val) {
      this.maxH = val
    },
    w() {
      if (this.resizing || this.dragging) {
        return
      }

      if (this.parent) {
        this.bounds = this.calcResizeLimits()
      }

      const delta = this.width - this.w

      if (delta % this.grid[0] === 0) {
        this.rawRight = this.right + delta
      }
    },
    h() {
      if (this.resizing || this.dragging) {
        return
      }

      if (this.parent) {
        this.bounds = this.calcResizeLimits()
      }

      const delta = this.height - this.h

      if (delta % this.grid[1] === 0) {
        this.rawBottom = this.bottom + delta
      }
    },
  },

  created: function() {
    if (this.maxWidth && this.minWidth > this.maxWidth) {
      console.warn(
        '[drag-and-resizable warn]: Invalid prop: minWidth cannot be greater than maxWidth'
      )
    }
    if (this.maxWidth && this.minHeight > this.maxHeight) {
      console.warn(
        '[drag-and-resizable warn]: Invalid prop: minHeight cannot be greater than maxHeight'
      )
    }

    this.resetBoundsAndMouseState()
  },
  mounted: function() {
    if (!this.enableNativeDrag) {
      this.$el.ondragstart = () => false
    }

    ;[this.parentWidth, this.parentHeight] = this.getParentSize()

    this.rawRight = this.parentWidth - this.rawWidth - this.rawLeft
    this.rawBottom = this.parentHeight - this.rawHeight - this.rawTop

    addEvent(document.documentElement, 'mousedown', this.deselect)
    addEvent(document.documentElement, 'touchend touchcancel', this.deselect)

    addEvent(window, 'resize', this.checkParentSize)
  },
  beforeDestroy: function() {
    removeEvent(document.documentElement, 'mousedown', this.deselect)
    removeEvent(document.documentElement, 'touchstart', this.handleUp)
    removeEvent(document.documentElement, 'mousemove', this.move)
    removeEvent(document.documentElement, 'touchmove', this.move)
    removeEvent(document.documentElement, 'mouseup', this.handleUp)
    removeEvent(document.documentElement, 'touchend touchcancel', this.deselect)

    removeEvent(window, 'resize', this.checkParentSize)
  },

  methods: {
    resetBoundsAndMouseState() {
      this.mouseClickPosition = { mouseX: 0, mouseY: 0, x: 0, y: 0, w: 0, h: 0 }

      this.bounds = {
        minLeft: null,
        maxLeft: null,
        minRight: null,
        maxRight: null,
        minTop: null,
        maxTop: null,
        minBottom: null,
        maxBottom: null,
      }
    },
    checkParentSize() {
      if (this.parent) {
        const [newParentWidth, newParentHeight] = this.getParentSize()

        const deltaX = this.parentWidth - newParentWidth
        const deltaY = this.parentHeight - newParentHeight

        this.rawRight -= deltaX
        this.rawBottom -= deltaY

        this.parentWidth = newParentWidth
        this.parentHeight = newParentHeight
      }
    },
    getParentSize() {
      if (this.parent) {
        const style = window.getComputedStyle(this.$el.parentNode, null)

        return [
          parseInt(style.getPropertyValue('width'), 10),
          parseInt(style.getPropertyValue('height'), 10),
        ]
      }

      return [null, null]
    },
    elementTouchDown(e) {
      eventsFor = events.touch

      this.elementDown(e)
    },
    elementDown(e) {
      const target = e.target || e.srcElement

      if (this.$el.contains(target)) {
        if (this.onDragStart && this.onDragStart(e) === false) {
          return
        }

        if (
          (this.dragHandle &&
            !matchesSelectorToParentElements(
              target,
              this.dragHandle,
              this.$el
            )) ||
          (this.dragCancel &&
            matchesSelectorToParentElements(target, this.dragCancel, this.$el))
        ) {
          return
        }

        if (!this.enabled) {
          this.enabled = true

          this.$emit('activated')
          this.$emit('update:active', true)
        }

        if (this.draggable) {
          this.dragging = true
        }

        this.mouseClickPosition.mouseX = e.touches
          ? e.touches[0].pageX
          : e.pageX
        this.mouseClickPosition.mouseY = e.touches
          ? e.touches[0].pageY
          : e.pageY

        this.mouseClickPosition.left = this.left
        this.mouseClickPosition.right = this.right
        this.mouseClickPosition.top = this.top
        this.mouseClickPosition.bottom = this.bottom

        if (this.parent) {
          this.bounds = this.calcDragLimits()
        }

        addEvent(document.documentElement, eventsFor.move, this.move)
        addEvent(document.documentElement, eventsFor.stop, this.handleUp)
      }
    },
    calcDragLimits() {
      return {
        minLeft: (this.parentWidth + this.left) % this.grid[0],
        maxLeft:
          Math.floor(
            (this.parentWidth - this.width - this.left) / this.grid[0]
          ) *
            this.grid[0] +
          this.left,
        minRight: (this.parentWidth + this.right) % this.grid[0],
        maxRight:
          Math.floor(
            (this.parentWidth - this.width - this.right) / this.grid[0]
          ) *
            this.grid[0] +
          this.right,
        minTop: (this.parentHeight + this.top) % this.grid[1],
        maxTop:
          Math.floor(
            (this.parentHeight - this.height - this.top) / this.grid[1]
          ) *
            this.grid[1] +
          this.top,
        minBottom: (this.parentHeight + this.bottom) % this.grid[1],
        maxBottom:
          Math.floor(
            (this.parentHeight - this.height - this.bottom) / this.grid[1]
          ) *
            this.grid[1] +
          this.bottom,
      }
    },
    deselect(e) {
      const target = e.target || e.srcElement
      const regex = new RegExp(this.className + '-([trmbl]{2})', '')

      if (!this.$el.contains(target) && !regex.test(target.className)) {
        if (this.enabled && !this.preventDeactivation) {
          this.enabled = false

          this.$emit('deactivated')
          this.$emit('update:active', false)
        }

        removeEvent(document.documentElement, eventsFor.move, this.handleMove)
      }

      this.resetBoundsAndMouseState()
    },
    handleTouchDown(handle, e) {
      eventsFor = events.touch

      this.handleDown(handle, e)
    },
    handleDown(handle, e) {
      if (this.onResizeStart && this.onResizeStart(handle, e) === false) {
        return
      }

      if (e.stopPropagation) {
        e.stopPropagation()
      }

      // Here we avoid a dangerous recursion by faking
      // corner handles as middle handles
      if (this.lockAspectRatio && !handle.includes('m')) {
        this.handle = 'm' + handle.substring(1)
      } else {
        this.handle = handle
      }

      this.resizing = true

      this.mouseClickPosition.mouseX = e.touches ? e.touches[0].pageX : e.pageX
      this.mouseClickPosition.mouseY = e.touches ? e.touches[0].pageY : e.pageY
      this.mouseClickPosition.left = this.left
      this.mouseClickPosition.right = this.right
      this.mouseClickPosition.top = this.top
      this.mouseClickPosition.bottom = this.bottom

      this.bounds = this.calcResizeLimits()

      addEvent(document.documentElement, eventsFor.move, this.handleMove)
      addEvent(document.documentElement, eventsFor.stop, this.handleUp)
    },
    calcResizeLimits() {
      let minW = this.minW
      let minH = this.minH
      let maxW = this.maxW
      let maxH = this.maxH

      const aspectFactor = this.aspectFactor
      const [gridX, gridY] = this.grid
      const width = this.width
      const height = this.height
      const left = this.left
      const top = this.top
      const right = this.right
      const bottom = this.bottom

      if (this.lockAspectRatio) {
        if (minW / minH > aspectFactor) {
          minH = minW / aspectFactor
        } else {
          minW = aspectFactor * minH
        }

        if (maxW && maxH) {
          maxW = Math.min(maxW, aspectFactor * maxH)
          maxH = Math.min(maxH, maxW / aspectFactor)
        } else if (maxW) {
          maxH = maxW / aspectFactor
        } else if (maxH) {
          maxW = aspectFactor * maxH
        }
      }

      maxW = maxW - (maxW % gridX)
      maxH = maxH - (maxH % gridY)

      const limits = {
        minLeft: null,
        maxLeft: null,
        minTop: null,
        maxTop: null,
        minRight: null,
        maxRight: null,
        minBottom: null,
        maxBottom: null,
      }

      if (this.parent) {
        limits.minLeft = (this.parentWidth + left) % gridX
        limits.maxLeft = left + Math.floor((width - minW) / gridX) * gridX
        limits.minTop = (this.parentHeight + top) % gridY
        limits.maxTop = top + Math.floor((height - minH) / gridY) * gridY
        limits.minRight = (this.parentWidth + right) % gridX
        limits.maxRight = right + Math.floor((width - minW) / gridX) * gridX
        limits.minBottom = (this.parentHeight + bottom) % gridY
        limits.maxBottom = bottom + Math.floor((height - minH) / gridY) * gridY

        if (maxW) {
          limits.minLeft = Math.max(
            limits.minLeft,
            this.parentWidth - right - maxW
          )
          limits.minRight = Math.max(
            limits.minRight,
            this.parentWidth - left - maxW
          )
        }

        if (maxH) {
          limits.minTop = Math.max(
            limits.minTop,
            this.parentHeight - bottom - maxH
          )
          limits.minBottom = Math.max(
            limits.minBottom,
            this.parentHeight - top - maxH
          )
        }

        if (this.lockAspectRatio) {
          limits.minLeft = Math.max(limits.minLeft, left - top * aspectFactor)
          limits.minTop = Math.max(limits.minTop, top - left / aspectFactor)
          limits.minRight = Math.max(
            limits.minRight,
            right - bottom * aspectFactor
          )
          limits.minBottom = Math.max(
            limits.minBottom,
            bottom - right / aspectFactor
          )
        }
      } else {
        limits.minLeft = null
        limits.maxLeft = left + Math.floor((width - minW) / gridX) * gridX
        limits.minTop = null
        limits.maxTop = top + Math.floor((height - minH) / gridY) * gridY
        limits.minRight = null
        limits.maxRight = right + Math.floor((width - minW) / gridX) * gridX
        limits.minBottom = null
        limits.maxBottom = bottom + Math.floor((height - minH) / gridY) * gridY

        if (maxW) {
          limits.minLeft = -(right + maxW)
          limits.minRight = -(left + maxW)
        }

        if (maxH) {
          limits.minTop = -(bottom + maxH)
          limits.minBottom = -(top + maxH)
        }

        if (this.lockAspectRatio && (maxW && maxH)) {
          limits.minLeft = Math.min(limits.minLeft, -(right + maxW))
          limits.minTop = Math.min(limits.minTop, -(maxH + bottom))
          limits.minRight = Math.min(limits.minRight, -left - maxW)
          limits.minBottom = Math.min(limits.minBottom, -top - maxH)
        }
      }

      return limits
    },
    move(e) {
      if (this.resizing) {
        this.handleMove(e)
      } else if (this.dragging) {
        this.elementMove(e)
      }
    },
    elementMove(e) {
      const axis = this.axis
      const grid = this.grid
      const mouseClickPosition = this.mouseClickPosition

      const tmpDeltaX =
        axis && axis !== 'y'
          ? mouseClickPosition.mouseX -
            (e.touches ? e.touches[0].pageX : e.pageX)
          : 0
      const tmpDeltaY =
        axis && axis !== 'x'
          ? mouseClickPosition.mouseY -
            (e.touches ? e.touches[0].pageY : e.pageY)
          : 0

      const [deltaX, deltaY] = this.snapToGrid(this.grid, tmpDeltaX, tmpDeltaY)

      this.rawTop = mouseClickPosition.top - deltaY
      this.rawBottom = mouseClickPosition.bottom + deltaY
      this.rawLeft = mouseClickPosition.left - deltaX
      this.rawRight = mouseClickPosition.right + deltaX

      this.$emit('dragging', this.left, this.top)
    },
    handleMove(e) {
      const handle = this.handle
      const mouseClickPosition = this.mouseClickPosition

      const tmpDeltaX =
        mouseClickPosition.mouseX - (e.touches ? e.touches[0].pageX : e.pageX)
      const tmpDeltaY =
        mouseClickPosition.mouseY - (e.touches ? e.touches[0].pageY : e.pageY)

      const [deltaX, deltaY] = this.snapToGrid(this.grid, tmpDeltaX, tmpDeltaY)

      if (handle.includes('b')) {
        this.rawBottom = mouseClickPosition.bottom + deltaY
      } else if (handle.includes('t')) {
        this.rawTop = mouseClickPosition.top - deltaY
      }

      if (handle.includes('r')) {
        this.rawRight = mouseClickPosition.right + deltaX
      } else if (handle.includes('l')) {
        this.rawLeft = mouseClickPosition.left - deltaX
      }

      this.$emit('resizing', this.left, this.top, this.width, this.height)
    },
    handleUp(e) {
      this.handle = null

      this.resetBoundsAndMouseState()

      this.rawTop = this.top
      this.rawBottom = this.bottom
      this.rawLeft = this.left
      this.rawRight = this.right

      if (this.resizing) {
        this.resizing = false
        this.$emit('resizestop', this.left, this.top, this.width, this.height)
      }
      if (this.dragging) {
        this.dragging = false
        this.$emit('dragstop', this.left, this.top)
      }

      removeEvent(document.documentElement, eventsFor.move, this.handleMove)
    },
    snapToGrid(grid, pendingX, pendingY) {
      const x = Math.round(pendingX / grid[0]) * grid[0]
      const y = Math.round(pendingY / grid[1]) * grid[1]

      return [x, y]
    },
  },
}
</script>

<style lang="scss" scoped>
.drag-and-resizable {
  position: absolute;
  box-sizing: border-box;
  touch-action: none;
}
.handle {
  position: absolute;
  width: 10px;
  height: 10px;
  background: #eee;
  border: 1px solid #333;
  box-sizing: border-box;
}
.handle-tl {
  top: -10px;
  left: -10px;
  cursor: nwse-resize;
}
.handle-tm {
  top: -10px;
  left: 50%;
  margin-left: -5px;
  cursor: ns-resize;
}
.handle-tr {
  top: -10px;
  right: -10px;
  cursor: nesw-resize;
}
.handle-ml {
  top: 50%;
  left: -10px;
  margin-top: -5px;
  cursor: ew-resize;
}
.handle-mr {
  top: 50%;
  right: -10px;
  margin-top: -5px;
  cursor: ew-resize;
}
.handle-bl {
  bottom: -10px;
  left: -10px;
  cursor: nesw-resize;
}
.handle-bm {
  bottom: -10px;
  left: 50%;
  margin-left: -5px;
  cursor: ns-resize;
}
.handle-br {
  right: -10px;
  bottom: -10px;
  cursor: nwse-resize;
}
@media only screen and (max-width: 768px) {
  [class*='handle-']:before {
    position: absolute;
    top: -10px;
    right: -10px;
    bottom: -10px;
    left: -10px;
    content: '';
  }
}
</style>
