import * as $ from 'jquery'
import * as moment from 'moment'
import { getEvIsTouch, diffByUnit, diffDayTime } from '../util'
import DateComponent from './DateComponent'
import GlobalEmitter from '../common/GlobalEmitter'


export default abstract class InteractiveDateComponent extends DateComponent {

  dateClickingClass: any
  dateSelectingClass: any
  eventPointingClass: any
  eventDraggingClass: any
  eventResizingClass: any
  externalDroppingClass: any

  dateClicking: any
  dateSelecting: any
  eventPointing: any
  eventDragging: any
  eventResizing: any
  externalDropping: any

  // self-config, overridable by subclasses
  segSelector: string = '.fc-event-container > *' // what constitutes an event element?

  // if defined, holds the unit identified (ex: "year" or "month") that determines the level of granularity
  // of the date areas. if not defined, assumes to be day and time granularity.
  // TODO: port isTimeScale into same system?
  largeUnit: any


  constructor(_view?, _options?) {
    super(_view, _options)

    if (this.dateSelectingClass) {
      this.dateClicking = new this.dateClickingClass(this)
    }

    if (this.dateSelectingClass) {
      this.dateSelecting = new this.dateSelectingClass(this)
    }

    if (this.eventPointingClass) {
      this.eventPointing = new this.eventPointingClass(this)
    }

    if (this.eventDraggingClass && this.eventPointing) {
      this.eventDragging = new this.eventDraggingClass(this, this.eventPointing)
    }

    if (this.eventResizingClass && this.eventPointing) {
      this.eventResizing = new this.eventResizingClass(this, this.eventPointing)
    }

    if (this.externalDroppingClass) {
      this.externalDropping = new this.externalDroppingClass(this)
    }
  }


  // Sets the container element that the view should render inside of, does global DOM-related initializations,
  // and renders all the non-date-related content inside.
  setElement(el) {
    super.setElement(el)

    if (this.dateClicking) {
      this.dateClicking.bindToEl(el)
    }

    if (this.dateSelecting) {
      this.dateSelecting.bindToEl(el)
    }

    this.bindAllSegHandlersToEl(el)
  }


  removeElement() {
    this.endInteractions()

    super.removeElement()
  }


  executeEventUnrender() {
    this.endInteractions()

    super.executeEventUnrender()
  }


  bindGlobalHandlers() {
    super.bindGlobalHandlers()

    if (this.externalDropping) {
      this.externalDropping.bindToDocument()
    }
  }


  unbindGlobalHandlers() {
    super.unbindGlobalHandlers()

    if (this.externalDropping) {
      this.externalDropping.unbindFromDocument()
    }
  }


  bindDateHandlerToEl(el, name, handler) {
    // attach a handler to the grid's root element.
    // jQuery will take care of unregistering them when removeElement gets called.
    this.el.on(name, (ev) => {
      if (
        !$(ev.target).is(
          this.segSelector + ':not(.fc-helper),' + // directly on an event element
          this.segSelector + ':not(.fc-helper) *,' + // within an event element
          '.fc-more,' + // a "more.." link
          'a[data-goto]' // a clickable nav link
        )
      ) {
        return handler.call(this, ev)
      }
    })
  }


  bindAllSegHandlersToEl(el) {
    [
      this.eventPointing,
      this.eventDragging,
      this.eventResizing
    ].forEach(function(eventInteraction) {
      if (eventInteraction) {
        eventInteraction.bindToEl(el)
      }
    })
  }


  bindSegHandlerToEl(el, name, handler) {
    el.on(name, this.segSelector, (ev) => {
      let segEl = $(ev.currentTarget)
      if (!segEl.is('.fc-helper')) {
        let seg = segEl.data('fc-seg') // grab segment data. put there by View::renderEventsPayload
        if (seg && !this.shouldIgnoreEventPointing()) {
          return handler.call(this, seg, ev) // context will be the Grid
        }
      }
    })
  }


  shouldIgnoreMouse() {
    // HACK
    // This will still work even though bindDateHandlerToEl doesn't use GlobalEmitter.
    return GlobalEmitter.get().shouldIgnoreMouse()
  }


  shouldIgnoreTouch() {
    let view = this._getView()

    // On iOS (and Android?) when a new selection is initiated overtop another selection,
    // the touchend never fires because the elements gets removed mid-touch-interaction (my theory).
    // HACK: simply don't allow this to happen.
    // ALSO: prevent selection when an *event* is already raised.
    return view.isSelected || view.selectedEvent
  }


  shouldIgnoreEventPointing() {
    // only call the handlers if there is not a drag/resize in progress
    return (this.eventDragging && this.eventDragging.isDragging) ||
      (this.eventResizing && this.eventResizing.isResizing)
  }


  canStartSelection(seg, ev) {
    return getEvIsTouch(ev) &&
      !this.canStartResize(seg, ev) &&
      (this.isEventDefDraggable(seg.footprint.eventDef) ||
        this.isEventDefResizable(seg.footprint.eventDef))
  }


  canStartDrag(seg, ev) {
    return !this.canStartResize(seg, ev) &&
      this.isEventDefDraggable(seg.footprint.eventDef)
  }


  canStartResize(seg, ev) {
    let view = this._getView()
    let eventDef = seg.footprint.eventDef

    return (!getEvIsTouch(ev) || view.isEventDefSelected(eventDef)) &&
      this.isEventDefResizable(eventDef) &&
      $(ev.target).is('.fc-resizer')
  }


  // Kills all in-progress dragging.
  // Useful for when public API methods that result in re-rendering are invoked during a drag.
  // Also useful for when touch devices misbehave and don't fire their touchend.
  endInteractions() {
    [
      this.dateClicking,
      this.dateSelecting,
      this.eventPointing,
      this.eventDragging,
      this.eventResizing
    ].forEach(function(interaction) {
      if (interaction) {
        interaction.end()
      }
    })
  }


  // Event Drag-n-Drop
  // ---------------------------------------------------------------------------------------------------------------


  // Computes if the given event is allowed to be dragged by the user
  isEventDefDraggable(eventDef) {
    return this.isEventDefStartEditable(eventDef)
  }


  isEventDefStartEditable(eventDef) {
    let isEditable = eventDef.isStartExplicitlyEditable()

    if (isEditable == null) {
      isEditable = this.opt('eventStartEditable')

      if (isEditable == null) {
        isEditable = this.isEventDefGenerallyEditable(eventDef)
      }
    }

    return isEditable
  }


  isEventDefGenerallyEditable(eventDef) {
    let isEditable = eventDef.isExplicitlyEditable()

    if (isEditable == null) {
      isEditable = this.opt('editable')
    }

    return isEditable
  }


  // Event Resizing
  // ---------------------------------------------------------------------------------------------------------------


  // Computes if the given event is allowed to be resized from its starting edge
  isEventDefResizableFromStart(eventDef) {
    return this.opt('eventResizableFromStart') && this.isEventDefResizable(eventDef)
  }


  // Computes if the given event is allowed to be resized from its ending edge
  isEventDefResizableFromEnd(eventDef) {
    return this.isEventDefResizable(eventDef)
  }


  // Computes if the given event is allowed to be resized by the user at all
  isEventDefResizable(eventDef) {
    let isResizable = eventDef.isDurationExplicitlyEditable()

    if (isResizable == null) {
      isResizable = this.opt('eventDurationEditable')

      if (isResizable == null) {
        isResizable = this.isEventDefGenerallyEditable(eventDef)
      }
    }
    return isResizable
  }


  // Event Mutation / Constraints
  // ---------------------------------------------------------------------------------------------------------------


  // Diffs the two dates, returning a duration, based on granularity of the grid
  // TODO: port isTimeScale into this system?
  diffDates(a, b): moment.Duration {
    if (this.largeUnit) {
      return diffByUnit(a, b, this.largeUnit)
    } else {
      return diffDayTime(a, b)
    }
  }


  // is it allowed, in relation to the view's validRange?
  // NOTE: very similar to isExternalInstanceGroupAllowed
  isEventInstanceGroupAllowed(eventInstanceGroup) {
    let view = this._getView()
    let dateProfile = this.dateProfile
    let eventFootprints = this.eventRangesToEventFootprints(eventInstanceGroup.getAllEventRanges())
    let i

    for (i = 0; i < eventFootprints.length; i++) {
      // TODO: just use getAllEventRanges directly
      if (!dateProfile.validUnzonedRange.containsRange(eventFootprints[i].componentFootprint.unzonedRange)) {
        return false
      }
    }

    return view.calendar.constraints.isEventInstanceGroupAllowed(eventInstanceGroup)
  }


  // NOTE: very similar to isEventInstanceGroupAllowed
  // when it's a completely anonymous external drag, no event.
  isExternalInstanceGroupAllowed(eventInstanceGroup) {
    let view = this._getView()
    let dateProfile = this.dateProfile
    let eventFootprints = this.eventRangesToEventFootprints(eventInstanceGroup.getAllEventRanges())
    let i

    for (i = 0; i < eventFootprints.length; i++) {
      if (!dateProfile.validUnzonedRange.containsRange(eventFootprints[i].componentFootprint.unzonedRange)) {
        return false
      }
    }

    for (i = 0; i < eventFootprints.length; i++) {
      // treat it as a selection
      // TODO: pass in eventInstanceGroup instead
      //  because we don't want calendar's constraint system to depend on a component's
      //  determination of footprints.
      if (!view.calendar.constraints.isSelectionFootprintAllowed(eventFootprints[i].componentFootprint)) {
        return false
      }
    }

    return true
  }

}