/* An abstract class from which other views inherit from
----------------------------------------------------------------------------------------------------------------------*/
// Newer methods should be written as prototype methods, not in the monster `View` function at the bottom.

View.prototype = {

	calendar: null, // owner Calendar object
	coordMap: null, // a CoordMap object for converting pixel regions to dates
	el: null, // the view's containing element. set by Calendar

	// important Moments
	start: null, // the date of the very first cell
	end: null, // the date after the very last cell
	intervalStart: null, // the start of the interval of time the view represents (1st of month for month view)
	intervalEnd: null, // the exclusive end of the interval of time the view represents

	// used for cell-to-date and date-to-cell calculations
	rowCnt: null, // # of weeks
	colCnt: null, // # of days displayed in a week

	isSelected: false, // boolean whether cells are user-selected or not

	// subclasses can optionally use a scroll container
	scrollerEl: null, // the element that will most likely scroll when content is too tall
	scrollTop: null, // cached vertical scroll value

	// classNames styled by jqui themes
	widgetHeaderClass: null,
	widgetContentClass: null,
	highlightStateClass: null,

	// document handlers, bound to `this` object
	documentMousedownProxy: null,
	documentDragStartProxy: null,


	// Serves as a "constructor" to suppliment the monster `View` constructor below
	init: function() {
		var tm = this.opt('theme') ? 'ui' : 'fc';

		this.widgetHeaderClass = tm + '-widget-header';
		this.widgetContentClass = tm + '-widget-content';
		this.highlightStateClass = tm + '-state-highlight';

		// save references to `this`-bound handlers
		this.documentMousedownProxy = $.proxy(this, 'documentMousedown');
		this.documentDragStartProxy = $.proxy(this, 'documentDragStart');
	},


	// Renders the view inside an already-defined `this.el`.
	// Subclasses should override this and then call the super method afterwards.
	render: function() {
		this.updateSize();
		this.trigger('viewRender', this, this, this.el);

		// attach handlers to document. do it here to allow for destroy/rerender
		$(document)
			.on('mousedown', this.documentMousedownProxy)
			.on('dragstart', this.documentDragStartProxy); // jqui drag
	},


	// Clears all view rendering, event elements, and unregisters handlers
	destroy: function() {
		this.unselect();
		this.trigger('viewDestroy', this, this, this.el);
		this.destroyEvents();
		this.el.empty(); // removes inner contents but leaves the element intact

		$(document)
			.off('mousedown', this.documentMousedownProxy)
			.off('dragstart', this.documentDragStartProxy);
	},


	// Used to determine what happens when the users clicks next/prev. Given -1 for prev, 1 for next.
	// Should apply the delta to `date` (a Moment) and return it.
	incrementDate: function(date, delta) {
		// subclasses should implement
	},


	/* Dimensions
	------------------------------------------------------------------------------------------------------------------*/


	// Refreshes anything dependant upon sizing of the container element of the grid
	updateSize: function(isResize) {
		if (isResize) {
			this.recordScroll();
		}
		this.updateHeight();
		this.updateWidth();
	},


	// Refreshes the horizontal dimensions of the calendar
	updateWidth: function() {
		// subclasses should implement
	},


	// Refreshes the vertical dimensions of the calendar
	updateHeight: function() {
		var calendar = this.calendar; // we poll the calendar for height information

		this.setHeight(
			calendar.getSuggestedViewHeight(),
			calendar.isHeightAuto()
		);
	},


	// Updates the vertical dimensions of the calendar to the specified height.
	// if `isAuto` is set to true, height becomes merely a suggestion and the view should use its "natural" height.
	setHeight: function(height, isAuto) {
		// subclasses should implement
	},


	// Given the total height of the view, return the number of pixels that should be used for the scroller.
	// Utility for subclasses.
	computeScrollerHeight: function(totalHeight) {
		var both = this.el.add(this.scrollerEl);
		var otherHeight; // cumulative height of everything that is not the scrollerEl in the view (header+borders)

		// fuckin IE8/9/10/11 sometimes returns 0 for dimensions. this weird hack was the only thing that worked
		both.css({
			position: 'relative', // cause a reflow, which will force fresh dimension recalculation
			left: -1 // ensure reflow in case the el was already relative. negative is less likely to cause new scroll
		});
		otherHeight = this.el.outerHeight() - this.scrollerEl.height(); // grab the dimensions
		both.css({ position: '', left: '' }); // undo hack

		return totalHeight - otherHeight;
	},


	// Called for remembering the current scroll value of the scroller.
	// Should be called before there is a destructive operation (like removing DOM elements) that might inadvertently
	// change the scroll of the container.
	recordScroll: function() {
		if (this.scrollerEl) {
			this.scrollTop = this.scrollerEl.scrollTop();
		}
	},


	// Set the scroll value of the scroller to the previously recorded value.
	// Should be called after we know the view's dimensions have been restored following some type of destructive
	// operation (like temporarily removing DOM elements).
	restoreScroll: function() {
		if (this.scrollTop !== null) {
			this.scrollerEl.scrollTop(this.scrollTop);
		}
	},


	/* Events
	------------------------------------------------------------------------------------------------------------------*/


	// Renders the events onto the view.
	// Should be overriden by subclasses. Subclasses should call the super-method afterwards.
	renderEvents: function(events) {
		this.segEach(function(seg) {
			this.trigger('eventAfterRender', seg.event, seg.event, seg.el);
		});
		this.trigger('eventAfterAllRender');
	},


	// Removes event elements from the view.
	// Should be overridden by subclasses. Should call this super-method FIRST, then subclass DOM destruction.
	destroyEvents: function() {
		this.segEach(function(seg) {
			this.trigger('eventDestroy', seg.event, seg.event, seg.el);
		});
	},


	// Given an event and the default element used for rendering, returns the element that should actually be used.
	// Basically runs events and elements through the eventRender hook.
	resolveEventEl: function(event, el) {
		var custom = this.trigger('eventRender', event, event, el);

		if (custom === false) { // means don't render at all
			el = null;
		}
		else if (custom && custom !== true) {
			el = $(custom);
		}

		return el;
	},


	// Hides all rendered event segments linked to the given event
	showEvent: function(event) {
		this.segEach(function(seg) {
			seg.el.css('visibility', '');
		}, event);
	},


	// Shows all rendered event segments linked to the given event
	hideEvent: function(event) {
		this.segEach(function(seg) {
			seg.el.css('visibility', 'hidden');
		}, event);
	},


	// Iterates through event segments. Goes through all by default.
	// If the optional `event` argument is specified, only iterates through segments linked to that event.
	// The `this` value of the callback function will be the view.
	segEach: function(func, event) {
		var segs = this.getSegs();
		var i;

		for (i = 0; i < segs.length; i++) {
			if (!event || segs[i].event._id === event._id) {
				func.call(this, segs[i]);
			}
		}
	},


	// Retrieves all the rendered segment objects for the view
	getSegs: function() {
		// subclasses must implement
	},


	/* Event Drag Visualization
	------------------------------------------------------------------------------------------------------------------*/


	// Renders a visual indication of an event hovering over the specified date.
	// `end` is a Moment and might be null.
	// `seg` might be null. if specified, it is the segment object of the event being dragged.
	//       otherwise, an external event from outside the calendar is being dragged.
	renderDrag: function(start, end, seg) {
		// subclasses should implement
	},


	// Unrenders a visual indication of event hovering
	destroyDrag: function() {
		// subclasses should implement
	},


	// Handler for accepting externally dragged events being dropped in the view.
	// Gets called when jqui's 'dragstart' is fired.
	documentDragStart: function(ev, ui) {
		var _this = this;
		var dropDate = null;
		var dragListener;

		if (this.opt('droppable')) { // only listen if this setting is on

			// listener that tracks mouse movement over date-associated pixel regions
			dragListener = new DragListener(this.coordMap, {
				cellOver: function(cell, date) {
					dropDate = date;
					_this.renderDrag(date);
				},
				cellOut: function() {
					dropDate = null;
					_this.destroyDrag();
				}
			});

			// gets called, only once, when jqui drag is finished
			$(document).one('dragstop', function(ev, ui) {
				_this.destroyDrag();
				if (dropDate) {
					_this.trigger('drop', ev.target, dropDate, ev, ui);
				}
			});

			dragListener.startDrag(ev); // start listening immediately
		}
	},


	/* Selection
	------------------------------------------------------------------------------------------------------------------*/


	// Selects a date range on the view. `start` and `end` are both Moments.
	// `ev` is the native mouse event that begin the interaction.
	select: function(start, end, ev) {
		this.unselect(ev);
		this.renderSelection(start, end);
		this.reportSelection(start, end, ev);
	},


	// Renders a visual indication of the selection
	renderSelection: function(start, end) {
		// subclasses should implement
	},


	// Called when a new selection is made. Updates internal state and triggers handlers.
	reportSelection: function(start, end, ev) {
		this.isSelected = true;
		this.trigger('select', null, start, end, ev);
	},


	// Undoes a selection. updates in the internal state and triggers handlers.
	// `ev` is the native mouse event that began the interaction.
	unselect: function(ev) {
		if (this.isSelected) {
			this.isSelected = false;
			this.destroySelection();
			this.trigger('unselect', null, ev);
		}
	},


	// Unrenders a visual indication of selection
	destroySelection: function() {
		// subclasses should implement
	},


	// Handler for unselecting when the user clicks something and the 'unselectAuto' setting is on
	documentMousedown: function(ev) {
		var ignore;

		// is there a selection, and has the user made a proper left click?
		if (this.isSelected && this.opt('unselectAuto') && isPrimaryMouseButton(ev)) {

			// only unselect if the clicked element is not identical to or inside of an 'unselectCancel' element
			ignore = this.opt('unselectCancel');
			if (!ignore || !$(ev.target).closest(ignore).length) {
				this.unselect(ev);
			}
		}
	}

};


// We are mixing JavaScript OOP design patterns here by putting methods and member variables in the closed scope of the
// constructor. Going forward, methods should be part of the prototype.
function View(calendar) {
	var t = this;
	
	// exports
	t.calendar = calendar;
	t.opt = opt;
	t.trigger = trigger;
	t.isEventDraggable = isEventDraggable;
	t.isEventResizable = isEventResizable;
	t.eventDrop = eventDrop;
	t.eventResize = eventResize;
	
	// imports
	var reportEventChange = calendar.reportEventChange;
	
	// locals
	var options = calendar.options;
	var nextDayThreshold = moment.duration(options.nextDayThreshold);


	t.init(); // the "constructor" that concerns the prototype methods
	
	
	function opt(name) {
		var v = options[name];
		if ($.isPlainObject(v) && !isForcedAtomicOption(name)) {
			return smartProperty(v, t.name);
		}
		return v;
	}

	
	function trigger(name, thisObj) {
		return calendar.trigger.apply(
			calendar,
			[name, thisObj || t].concat(Array.prototype.slice.call(arguments, 2), [t])
		);
	}
	


	/* Event Editable Boolean Calculations
	------------------------------------------------------------------------------*/

	
	function isEventDraggable(event) {
		var source = event.source || {};

		return firstDefined(
			event.startEditable,
			source.startEditable,
			opt('eventStartEditable'),
			event.editable,
			source.editable,
			opt('editable')
		);
	}
	
	
	function isEventResizable(event) {
		var source = event.source || {};

		return firstDefined(
			event.durationEditable,
			source.durationEditable,
			opt('eventDurationEditable'),
			event.editable,
			source.editable,
			opt('editable')
		);
	}
	
	
	
	/* Event Elements
	------------------------------------------------------------------------------*/


	// Compute the text that should be displayed on an event's element.
	// Based off the settings of the view. Possible signatures:
	//   .getEventTimeText(event, formatStr)
	//   .getEventTimeText(startMoment, endMoment, formatStr)
	//   .getEventTimeText(startMoment, null, formatStr)
	// `timeFormat` is used but the `formatStr` argument can be used to override.
	t.getEventTimeText = function(event, formatStr) {
		var start;
		var end;

		if (typeof event === 'object' && typeof formatStr === 'object') {
			// first two arguments are actually moments (or null). shift arguments.
			start = event;
			end = formatStr;
			formatStr = arguments[2];
		}
		else {
			// otherwise, an event object was the first argument
			start = event.start;
			end = event.end;
		}

		formatStr = formatStr || opt('timeFormat');

		if (end && opt('displayEventEnd')) {
			return calendar.formatRange(start, end, formatStr);
		}
		else {
			return calendar.formatDate(start, formatStr);
		}
	};

	
	
	/* Event Modification Reporting
	---------------------------------------------------------------------------------*/

	
	function eventDrop(el, event, newStart, ev) {
		var mutateResult = calendar.mutateEvent(event, newStart, null);

		trigger(
			'eventDrop',
			el,
			event,
			mutateResult.dateDelta,
			function() {
				mutateResult.undo();
				reportEventChange();
			},
			ev,
			{} // jqui dummy
		);

		reportEventChange();
	}


	function eventResize(el, event, newEnd, ev) {
		var mutateResult = calendar.mutateEvent(event, null, newEnd);

		trigger(
			'eventResize',
			el,
			event,
			mutateResult.durationDelta,
			function() {
				mutateResult.undo();
				reportEventChange();
			},
			ev,
			{} // jqui dummy
		);

		reportEventChange();
	}


	// ====================================================================================================
	// Utilities for day "cells"
	// ====================================================================================================
	// The "basic" views are completely made up of day cells.
	// The "agenda" views have day cells at the top "all day" slot.
	// This was the obvious common place to put these utilities, but they should be abstracted out into
	// a more meaningful class (like DayEventRenderer).
	// ====================================================================================================


	// For determining how a given "cell" translates into a "date":
	//
	// 1. Convert the "cell" (row and column) into a "cell offset" (the # of the cell, cronologically from the first).
	//    Keep in mind that column indices are inverted with isRTL. This is taken into account.
	//
	// 2. Convert the "cell offset" to a "day offset" (the # of days since the first visible day in the view).
	//
	// 3. Convert the "day offset" into a "date" (a Moment).
	//
	// The reverse transformation happens when transforming a date into a cell.


	// exports
	t.isHiddenDay = isHiddenDay;
	t.skipHiddenDays = skipHiddenDays;
	t.getCellsPerWeek = getCellsPerWeek;
	t.dateToCell = dateToCell;
	t.dateToDayOffset = dateToDayOffset;
	t.dayOffsetToCellOffset = dayOffsetToCellOffset;
	t.cellOffsetToCell = cellOffsetToCell;
	t.cellToDate = cellToDate;
	t.cellToCellOffset = cellToCellOffset;
	t.cellOffsetToDayOffset = cellOffsetToDayOffset;
	t.dayOffsetToDate = dayOffsetToDate;
	t.rangeToSegments = rangeToSegments;
	t.isMultiDayEvent = isMultiDayEvent;


	// internals
	var hiddenDays = opt('hiddenDays') || []; // array of day-of-week indices that are hidden
	var isHiddenDayHash = []; // is the day-of-week hidden? (hash with day-of-week-index -> bool)
	var cellsPerWeek;
	var dayToCellMap = []; // hash from dayIndex -> cellIndex, for one week
	var cellToDayMap = []; // hash from cellIndex -> dayIndex, for one week
	var isRTL = opt('isRTL');


	// initialize important internal variables
	(function() {

		if (opt('weekends') === false) {
			hiddenDays.push(0, 6); // 0=sunday, 6=saturday
		}

		// Loop through a hypothetical week and determine which
		// days-of-week are hidden. Record in both hashes (one is the reverse of the other).
		for (var dayIndex=0, cellIndex=0; dayIndex<7; dayIndex++) {
			dayToCellMap[dayIndex] = cellIndex;
			isHiddenDayHash[dayIndex] = $.inArray(dayIndex, hiddenDays) != -1;
			if (!isHiddenDayHash[dayIndex]) {
				cellToDayMap[cellIndex] = dayIndex;
				cellIndex++;
			}
		}

		cellsPerWeek = cellIndex;
		if (!cellsPerWeek) {
			throw 'invalid hiddenDays'; // all days were hidden? bad.
		}

	})();


	// Is the current day hidden?
	// `day` is a day-of-week index (0-6), or a Moment
	function isHiddenDay(day) {
		if (moment.isMoment(day)) {
			day = day.day();
		}
		return isHiddenDayHash[day];
	}


	function getCellsPerWeek() {
		return cellsPerWeek;
	}


	// Incrementing the current day until it is no longer a hidden day, returning a copy.
	// If the initial value of `date` is not a hidden day, don't do anything.
	// Pass `isExclusive` as `true` if you are dealing with an end date.
	// `inc` defaults to `1` (increment one day forward each time)
	function skipHiddenDays(date, inc, isExclusive) {
		var out = date.clone();
		inc = inc || 1;
		while (
			isHiddenDayHash[(out.day() + (isExclusive ? inc : 0) + 7) % 7]
		) {
			out.add(inc, 'days');
		}
		return out;
	}


	//
	// TRANSFORMATIONS: cell -> cell offset -> day offset -> date
	//

	// cell -> date (combines all transformations)
	// Possible arguments:
	// - row, col
	// - { row:#, col: # }
	function cellToDate() {
		var cellOffset = cellToCellOffset.apply(null, arguments);
		var dayOffset = cellOffsetToDayOffset(cellOffset);
		var date = dayOffsetToDate(dayOffset);
		return date;
	}

	// cell -> cell offset
	// Possible arguments:
	// - row, col
	// - { row:#, col:# }
	function cellToCellOffset(row, col) {
		var colCnt = t.colCnt;

		// rtl variables. wish we could pre-populate these. but where?
		var dis = isRTL ? -1 : 1;
		var dit = isRTL ? colCnt - 1 : 0;

		if (typeof row == 'object') {
			col = row.col;
			row = row.row;
		}
		var cellOffset = row * colCnt + (col * dis + dit); // column, adjusted for RTL (dis & dit)

		return cellOffset;
	}

	// cell offset -> day offset
	function cellOffsetToDayOffset(cellOffset) {
		var day0 = t.start.day(); // first date's day of week
		cellOffset += dayToCellMap[day0]; // normlize cellOffset to beginning-of-week
		return Math.floor(cellOffset / cellsPerWeek) * 7 + // # of days from full weeks
			cellToDayMap[ // # of days from partial last week
				(cellOffset % cellsPerWeek + cellsPerWeek) % cellsPerWeek // crazy math to handle negative cellOffsets
			] -
			day0; // adjustment for beginning-of-week normalization
	}

	// day offset -> date
	function dayOffsetToDate(dayOffset) {
		return t.start.clone().add(dayOffset, 'days');
	}


	//
	// TRANSFORMATIONS: date -> day offset -> cell offset -> cell
	//

	// date -> cell (combines all transformations)
	function dateToCell(date) {
		var dayOffset = dateToDayOffset(date);
		var cellOffset = dayOffsetToCellOffset(dayOffset);
		var cell = cellOffsetToCell(cellOffset);
		return cell;
	}

	// date -> day offset
	function dateToDayOffset(date) {
		return date.clone().stripTime().diff(t.start, 'days');
	}

	// day offset -> cell offset
	function dayOffsetToCellOffset(dayOffset) {
		var day0 = t.start.day(); // first date's day of week
		dayOffset += day0; // normalize dayOffset to beginning-of-week
		return Math.floor(dayOffset / 7) * cellsPerWeek + // # of cells from full weeks
			dayToCellMap[ // # of cells from partial last week
				(dayOffset % 7 + 7) % 7 // crazy math to handle negative dayOffsets
			] -
			dayToCellMap[day0]; // adjustment for beginning-of-week normalization
	}

	// cell offset -> cell (object with row & col keys)
	function cellOffsetToCell(cellOffset) {
		var colCnt = t.colCnt;

		// rtl variables. wish we could pre-populate these. but where?
		var dis = isRTL ? -1 : 1;
		var dit = isRTL ? colCnt - 1 : 0;

		var row = Math.floor(cellOffset / colCnt);
		var col = ((cellOffset % colCnt + colCnt) % colCnt) * dis + dit; // column, adjusted for RTL (dis & dit)
		return {
			row: row,
			col: col
		};
	}


	//
	// Converts a date range into an array of segment objects.
	// "Segments" are horizontal stretches of time, sliced up by row.
	// A segment object has the following properties:
	// - row
	// - cols
	// - isStart
	// - isEnd
	//
	function rangeToSegments(start, end) {

		var rowCnt = t.rowCnt;
		var colCnt = t.colCnt;
		var segments = []; // array of segments to return

		// day offset for given date range
		var dayRange = computeDayRange(start, end); // convert to a whole-day range
		var rangeDayOffsetStart = dateToDayOffset(dayRange.start);
		var rangeDayOffsetEnd = dateToDayOffset(dayRange.end); // an exclusive value

		// first and last cell offset for the given date range
		// "last" implies inclusivity
		var rangeCellOffsetFirst = dayOffsetToCellOffset(rangeDayOffsetStart);
		var rangeCellOffsetLast = dayOffsetToCellOffset(rangeDayOffsetEnd) - 1;

		// loop through all the rows in the view
		for (var row=0; row<rowCnt; row++) {

			// first and last cell offset for the row
			var rowCellOffsetFirst = row * colCnt;
			var rowCellOffsetLast = rowCellOffsetFirst + colCnt - 1;

			// get the segment's cell offsets by constraining the range's cell offsets to the bounds of the row
			var segmentCellOffsetFirst = Math.max(rangeCellOffsetFirst, rowCellOffsetFirst);
			var segmentCellOffsetLast = Math.min(rangeCellOffsetLast, rowCellOffsetLast);

			// make sure segment's offsets are valid and in view
			if (segmentCellOffsetFirst <= segmentCellOffsetLast) {

				// translate to cells
				var segmentCellFirst = cellOffsetToCell(segmentCellOffsetFirst);
				var segmentCellLast = cellOffsetToCell(segmentCellOffsetLast);

				// view might be RTL, so order by leftmost column
				var cols = [ segmentCellFirst.col, segmentCellLast.col ].sort();

				// Determine if segment's first/last cell is the beginning/end of the date range.
				// We need to compare "day offset" because "cell offsets" are often ambiguous and
				// can translate to multiple days, and an edge case reveals itself when we the
				// range's first cell is hidden (we don't want isStart to be true).
				var isStart = cellOffsetToDayOffset(segmentCellOffsetFirst) == rangeDayOffsetStart;
				var isEnd = cellOffsetToDayOffset(segmentCellOffsetLast) + 1 == rangeDayOffsetEnd;
				                                                   // +1 for comparing exclusively

				segments.push({
					row: row,
					leftCol: cols[0],
					rightCol: cols[1],
					isStart: isStart,
					isEnd: isEnd
				});
			}
		}

		return segments;
	}


	// Returns the date range of the full days the given range visually appears to occupy.
	// Returns object with properties `start` (moment) and `end` (moment, exclusive end).
	function computeDayRange(start, end) {
		var startDay = start.clone().stripTime(); // the beginning of the day the range starts
		var endDay;
		var endTimeMS;

		if (end) {
			endDay = end.clone().stripTime(); // the beginning of the day the range exclusively ends
			endTimeMS = +end.time(); // # of milliseconds into `endDay`

			// If the end time is actually inclusively part of the next day and is equal to or
			// beyond the next day threshold, adjust the end to be the exclusive end of `endDay`.
			// Otherwise, leaving it as inclusive will cause it to exclude `endDay`.
			if (endTimeMS && endTimeMS >= nextDayThreshold) {
				endDay.add(1, 'days');
			}
		}

		// If no end was specified, or if it is within `startDay` but not past nextDayThreshold,
		// assign the default duration of one day.
		if (!end || endDay <= startDay) {
			endDay = startDay.clone().add(1, 'days');
		}

		return { start: startDay, end: endDay };
	}


	// Does the given event visually appear to occupy more than one day?
	function isMultiDayEvent(event) {
		var range = computeDayRange(event.start, event.end);

		return range.end.diff(range.start, 'days') > 1;
	}

}