fullcalendar/src/ViewSpecManager.js

var ViewSpecManager = Class.extend({

	_calendar: null, // avoid
	optionsManager: null,
	viewSpecCache: null, // cache of view definitions (initialized in Calendar.js)


	constructor: function(optionsManager, _calendar) {
		this.optionsManager = optionsManager;
		this._calendar = _calendar;

		this.clearCache();
	},


	clearCache: function() {
		this.viewSpecCache = {};
	},


	// Gets information about how to create a view. Will use a cache.
	getViewSpec: function(viewType) {
		var cache = this.viewSpecCache;

		return cache[viewType] || (cache[viewType] = this.buildViewSpec(viewType));
	},


	// Given a duration singular unit, like "week" or "day", finds a matching view spec.
	// Preference is given to views that have corresponding buttons.
	getUnitViewSpec: function(unit) {
		var viewTypes;
		var i;
		var spec;

		if ($.inArray(unit, unitsDesc) != -1) {

			// put views that have buttons first. there will be duplicates, but oh well
			viewTypes = this._calendar.header.getViewsWithButtons(); // TODO: include footer as well?
			$.each(FC.views, function(viewType) { // all views
				viewTypes.push(viewType);
			});

			for (i = 0; i < viewTypes.length; i++) {
				spec = this.getViewSpec(viewTypes[i]);
				if (spec) {
					if (spec.singleUnit == unit) {
						return spec;
					}
				}
			}
		}
	},


	// Builds an object with information on how to create a given view
	buildViewSpec: function(requestedViewType) {
		var viewOverrides = this.optionsManager.overrides.views || {};
		var specChain = []; // for the view. lowest to highest priority
		var defaultsChain = []; // for the view. lowest to highest priority
		var overridesChain = []; // for the view. lowest to highest priority
		var viewType = requestedViewType;
		var spec; // for the view
		var overrides; // for the view
		var durationInput;
		var duration;
		var unit;

		// iterate from the specific view definition to a more general one until we hit an actual View class
		while (viewType) {
			spec = fcViews[viewType];
			overrides = viewOverrides[viewType];
			viewType = null; // clear. might repopulate for another iteration

			if (typeof spec === 'function') { // TODO: deprecate
				spec = { 'class': spec };
			}

			if (spec) {
				specChain.unshift(spec);
				defaultsChain.unshift(spec.defaults || {});
				durationInput = durationInput || spec.duration;
				viewType = viewType || spec.type;
			}

			if (overrides) {
				overridesChain.unshift(overrides); // view-specific option hashes have options at zero-level
				durationInput = durationInput || overrides.duration;
				viewType = viewType || overrides.type;
			}
		}

		spec = mergeProps(specChain);
		spec.type = requestedViewType;
		if (!spec['class']) {
			return false;
		}

		// fall back to top-level `duration` option
		durationInput = durationInput ||
			this.optionsManager.dynamicOverrides.duration ||
			this.optionsManager.overrides.duration;

		if (durationInput) {
			duration = moment.duration(durationInput);

			if (duration.valueOf()) { // valid?

				unit = computeDurationGreatestUnit(duration, durationInput);

				spec.duration = duration;
				spec.durationUnit = unit;

				// view is a single-unit duration, like "week" or "day"
				// incorporate options for this. lowest priority
				if (duration.as(unit) === 1) {
					spec.singleUnit = unit;
					overridesChain.unshift(viewOverrides[unit] || {});
				}
			}
		}

		spec.defaults = mergeOptions(defaultsChain);
		spec.overrides = mergeOptions(overridesChain);

		this.buildViewSpecOptions(spec);
		this.buildViewSpecButtonText(spec, requestedViewType);

		return spec;
	},


	// Builds and assigns a view spec's options object from its already-assigned defaults and overrides
	buildViewSpecOptions: function(spec) {
		var optionsManager = this.optionsManager;

		spec.options = mergeOptions([ // lowest to highest priority
			Calendar.defaults, // global defaults
			spec.defaults, // view's defaults (from ViewSubclass.defaults)
			optionsManager.dirDefaults,
			optionsManager.localeDefaults, // locale and dir take precedence over view's defaults!
			optionsManager.overrides, // calendar's overrides (options given to constructor)
			spec.overrides, // view's overrides (view-specific options)
			optionsManager.dynamicOverrides // dynamically set via setter. highest precedence
		]);
		populateInstanceComputableOptions(spec.options);
	},


	// Computes and assigns a view spec's buttonText-related options
	buildViewSpecButtonText: function(spec, requestedViewType) {
		var optionsManager = this.optionsManager;

		// given an options object with a possible `buttonText` hash, lookup the buttonText for the
		// requested view, falling back to a generic unit entry like "week" or "day"
		function queryButtonText(options) {
			var buttonText = options.buttonText || {};
			return buttonText[requestedViewType] ||
				// view can decide to look up a certain key
				(spec.buttonTextKey ? buttonText[spec.buttonTextKey] : null) ||
				// a key like "month"
				(spec.singleUnit ? buttonText[spec.singleUnit] : null);
		}

		// highest to lowest priority
		spec.buttonTextOverride =
			queryButtonText(optionsManager.dynamicOverrides) ||
			queryButtonText(optionsManager.overrides) || // constructor-specified buttonText lookup hash takes precedence
			spec.overrides.buttonText; // `buttonText` for view-specific options is a string

		// highest to lowest priority. mirrors buildViewSpecOptions
		spec.buttonTextDefault =
			queryButtonText(optionsManager.localeDefaults) ||
			queryButtonText(optionsManager.dirDefaults) ||
			spec.defaults.buttonText || // a single string. from ViewSubclass.defaults
			queryButtonText(Calendar.defaults) ||
			(spec.duration ? this._calendar.humanizeDuration(spec.duration) : null) || // like "3 days"
			requestedViewType; // fall back to given view name
	}

});