(function (document, $) {
    "use strict";

	const MARKET_META_DATA_SELECTOR = 'meta[name="marketLayerOverride"]:not([data-marketlayer-submarket])';
	const SUB_MARKET_META_DATA_SELECTOR = 'meta[name="marketLayerOverride"][data-marketlayer-submarket]';
	const MARKET_SELECTOR_SELECTOR = '[data-mount="market-selector"] select';
	const POSITION_OPTION_APPEND = 'append';
	const POSITION_OPTION_PREPEND = 'prepend';
	const POSITION_OPTION_REPLACE = 'replace';
	const POSITION_OPTION_INNER_TEXT = 'innerText';
	const NOT_META_DATA_SPECIFIER = ':not([meta])';
	const OVERRIDE_OBJECT_ATTRIBUTES = [
		"data-marketlayer-submarket",
		"data-marketlayer-content",
		"data-marketlayer-selector",
		"data-marketlayer-position"
	];

	let $marketSelector = $(MARKET_SELECTOR_SELECTOR);
	let $marketMetaDataElements = $(MARKET_META_DATA_SELECTOR);
	let $subMarketMetaDataElements = $(SUB_MARKET_META_DATA_SELECTOR);
	let previousOverrides = [];

	/**
	 * Refines overrides to only page and sub market specific overrides.
	 * @param subMarket - current market selector sub market code.
	 */
	const refineOverrides = (subMarket) => {
		let overrideObjects = [];

		//Create all sub-market overrides.
		$subMarketMetaDataElements.each(function()  {

			let curOverrideSubMarket = $(this).attr(OVERRIDE_OBJECT_ATTRIBUTES[0]);

			//Sub market is the selected market or no sub market is required.
			if(curOverrideSubMarket == subMarket) {
				var newObject = {
					content: $(this).attr(OVERRIDE_OBJECT_ATTRIBUTES[1]),
					selector: $(this).attr(OVERRIDE_OBJECT_ATTRIBUTES[2]) + NOT_META_DATA_SPECIFIER,
					position: $(this).attr(OVERRIDE_OBJECT_ATTRIBUTES[3])
				};
				overrideObjects.push(newObject);
				console.log(newObject);	
			}
		});

		//Create market overrides that are not covered by sub-market overrides.
		$marketMetaDataElements.each(function() {
			let curContent = $(this).attr(OVERRIDE_OBJECT_ATTRIBUTES[1]);
			let curSelector = $(this).attr(OVERRIDE_OBJECT_ATTRIBUTES[2]) + NOT_META_DATA_SPECIFIER;
			let curPosition =  $(this).attr(OVERRIDE_OBJECT_ATTRIBUTES[3]);

			let isContained = false;

			for(let i = 0; i < overrideObjects.length; i++) {
				if(curSelector == overrideObjects[i].selector && curPosition == overrideObjects[i].position) {
					isContained = true;
					break;
				}
			}

			if(!isContained) {
				var newObject = {
					content: curContent,
					selector: curSelector,
					position: curPosition
				};
				overrideObjects.push(newObject);
			}
		});

		console.log(overrideObjects);
		return overrideObjects;
	}

	/**
	 * Appends content to specified selector element and adds to previous override list.
	 * @param override - object containing selector, content, and position.
	 */
	const appendContent = (override) => {
		$(override.selector).after(override.content);
		previousOverrides.push({
			'element': $(override.selector).next(),
			'action': 'remove',
			'content': ''
		});
	}

	/**
	 * Prepends content to specified selector element and adds to previous override list.
	 * @param override - object containing selector, content, and position.
	 */
	const prependContent = (override) => {
		$(override.selector).before(override.content);
		previousOverrides.push({
			'element': $(override.selector).prev(),
			'action': 'remove',
			'content': ''
		});
	}

	/**
	 * Replaces content with specified selector element and adds to previous override list.
	 * @param override - object containing selector, content, and position.
	 */
	const replaceWithContent = (override) => {
		let prevElement = $(override.selector);
		let newElement = $(override.content);
		prevElement.replaceWith(newElement);
		previousOverrides.push({
			'element': newElement,
			'action': 'replace',
			'content': prevElement
		});
	}

	/**
	 * Replaces text with specified selector element and adds to previous override list.
	 * @param override - object containing selector, content, and position.
	 */
	const replaceInnerTextWithContent = (override) => {
		let prevText = $(override.selector).text();
		$(override.selector).text(override.content);
		previousOverrides.push({
			'element': $(override.selector),
			'action': 'replace-text',
			'content': prevText
		});
	}

	/**
	 * Applies refined overrides using jqery. 
	 * @param overrideObjects - override objects with position, content, and selector.
	 */
	const applyOverrides = (overrideObjects) => {

		overrideObjects.forEach((override) => {
			if(override.position === POSITION_OPTION_APPEND) {
				appendContent(override);
			} else if (override.position === POSITION_OPTION_PREPEND) {
				prependContent(override);
			} else if (override.position === POSITION_OPTION_REPLACE) {
				replaceWithContent(override);
			} else if (override.position === POSITION_OPTION_INNER_TEXT) {
				replaceInnerTextWithContent(override);
			}
		});
	}

	/**
	 * Reverts all previous overrides before new market overrides are applied.
	 */
	const revertOverrides = () => {
		previousOverrides.forEach((override) => {
			if(override.action == 'remove') {
				override.element.remove();
			} else if(override.action == 'replace') {
				override.element.replaceWith(override.content);
			} else if(override.action == 'replace-text') {
				override.element.text(override.content);
			}
		});
		previousOverrides = [];
	}

	//Market Selector is used on the page.
	if($marketSelector.length) {
		let subMarket =  $marketSelector.find(":selected").val();
		
		//Refine override metadata and apply overrides.
		let overrideObjects = refineOverrides(subMarket);
		applyOverrides(overrideObjects);

		//When market selector is updated.
		$marketSelector.change(() => {
			let subMarket =  $marketSelector.find(":selected").val();

			//Revert previous overrides.
			revertOverrides();

			//Refine override metadata.
			let overrideObjects = refineOverrides(subMarket);

			//Apply overrides.
			applyOverrides(overrideObjects);
		});

	} else {

		//Refine override metadata and apply overrides.
		let overrideObjects = refineOverrides(null);
		applyOverrides(overrideObjects);
	}

})(document, $);