/*
 * The MIT License (MIT)
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
*/

// derived from https://github.com/dryoma/postcss-media-query-parser

this.mediaQueryParser = (() => {

	/**
	 * Parses a media feature expression, e.g. `max-width: 10px`, `(color)`
	 *
	 * @param {string} string - the source expression string, can be inside parens
	 * @param {Number} index - the index of `string` in the overall input
	 *
	 * @return {Array} an array of Nodes, the first element being a media feature,
	 *    the second - its value (may be missing)
	 */

	function parseMediaFeature(string, index = 0) {
		const modesEntered = [{
			mode: "normal",
			character: null,
		}];
		const result = [];
		let lastModeIndex = 0, mediaFeature = "", colon = null, mediaFeatureValue = null, indexLocal = index;

		let stringNormalized = string;
		// Strip trailing parens (if any), and correct the starting index
		if (string[0] === "(" && string[string.length - 1] === ")") {
			stringNormalized = string.substring(1, string.length - 1);
			indexLocal++;
		}

		for (let i = 0; i < stringNormalized.length; i++) {
			const character = stringNormalized[i];

			// If entering/exiting a string
			if (character === "'" || character === "\"") {
				if (modesEntered[lastModeIndex].isCalculationEnabled === true) {
					modesEntered.push({
						mode: "string",
						isCalculationEnabled: false,
						character,
					});
					lastModeIndex++;
				} else if (modesEntered[lastModeIndex].mode === "string" &&
					modesEntered[lastModeIndex].character === character &&
					stringNormalized[i - 1] !== "\\"
				) {
					modesEntered.pop();
					lastModeIndex--;
				}
			}

			// If entering/exiting interpolation
			if (character === "{") {
				modesEntered.push({
					mode: "interpolation",
					isCalculationEnabled: true,
				});
				lastModeIndex++;
			} else if (character === "}") {
				modesEntered.pop();
				lastModeIndex--;
			}

			// If a : is met outside of a string, function call or interpolation, than
			// this : separates a media feature and a value
			if (modesEntered[lastModeIndex].mode === "normal" && character === ":") {
				const mediaFeatureValueStr = stringNormalized.substring(i + 1);
				mediaFeatureValue = {
					type: "value",
					before: /^(\s*)/.exec(mediaFeatureValueStr)[1],
					after: /(\s*)$/.exec(mediaFeatureValueStr)[1],
					value: mediaFeatureValueStr.trim(),
				};
				// +1 for the colon
				mediaFeatureValue.sourceIndex =
					mediaFeatureValue.before.length + i + 1 + indexLocal;
				colon = {
					type: "colon",
					sourceIndex: i + indexLocal,
					after: mediaFeatureValue.before,
					value: ":", // for consistency only
				};
				break;
			}

			mediaFeature += character;
		}

		// Forming a media feature node
		mediaFeature = {
			type: "media-feature",
			before: /^(\s*)/.exec(mediaFeature)[1],
			after: /(\s*)$/.exec(mediaFeature)[1],
			value: mediaFeature.trim(),
		};
		mediaFeature.sourceIndex = mediaFeature.before.length + indexLocal;
		result.push(mediaFeature);

		if (colon !== null) {
			colon.before = mediaFeature.after;
			result.push(colon);
		}

		if (mediaFeatureValue !== null) {
			result.push(mediaFeatureValue);
		}

		return result;
	}

	/**
	 * Parses a media query, e.g. `screen and (color)`, `only tv`
	 *
	 * @param {string} string - the source media query string
	 * @param {Number} index - the index of `string` in the overall input
	 *
	 * @return {Array} an array of Nodes and Containers
	 */

	function parseMediaQuery(string, index = 0) {
		const result = [];

		// How many times the parser entered parens/curly braces
		let localLevel = 0;
		// Has any keyword, media type, media feature expression or interpolation
		// ('element' hereafter) started
		let insideSomeValue = false, node;

		function resetNode() {
			return {
				before: "",
				after: "",
				value: "",
			};
		}

		node = resetNode();

		for (let i = 0; i < string.length; i++) {
			const character = string[i];
			// If not yet entered any element
			if (!insideSomeValue) {
				if (character.search(/\s/) !== -1) {
					// A whitespace
					// Don't form 'after' yet; will do it later
					node.before += character;
				} else {
					// Not a whitespace - entering an element
					// Expression start
					if (character === "(") {
						node.type = "media-feature-expression";
						localLevel++;
					}
					node.value = character;
					node.sourceIndex = index + i;
					insideSomeValue = true;
				}
			} else {
				// Already in the middle of some element
				node.value += character;

				// Here parens just increase localLevel and don't trigger a start of
				// a media feature expression (since they can't be nested)
				// Interpolation start
				if (character === "{" || character === "(") { localLevel++; }
				// Interpolation/function call/media feature expression end
				if (character === ")" || character === "}") { localLevel--; }
			}

			// If exited all parens/curlies and the next symbol
			if (insideSomeValue && localLevel === 0 &&
				(character === ")" || i === string.length - 1 ||
					string[i + 1].search(/\s/) !== -1)
			) {
				if (["not", "only", "and"].indexOf(node.value) !== -1) {
					node.type = "keyword";
				}
				// if it's an expression, parse its contents
				if (node.type === "media-feature-expression") {
					node.nodes = parseMediaFeature(node.value, node.sourceIndex);
				}
				result.push(Array.isArray(node.nodes) ?
					new Container(node) : new Node(node));
				node = resetNode();
				insideSomeValue = false;
			}
		}

		// Now process the result array - to specify undefined types of the nodes
		// and specify the `after` prop
		for (let i = 0; i < result.length; i++) {
			node = result[i];
			if (i > 0) { result[i - 1].after = node.before; }

			// Node types. Might not be set because contains interpolation/function
			// calls or fully consists of them
			if (node.type === undefined) {
				if (i > 0) {
					// only `and` can follow an expression
					if (result[i - 1].type === "media-feature-expression") {
						node.type = "keyword";
						continue;
					}
					// Anything after 'only|not' is a media type
					if (result[i - 1].value === "not" || result[i - 1].value === "only") {
						node.type = "media-type";
						continue;
					}
					// Anything after 'and' is an expression
					if (result[i - 1].value === "and") {
						node.type = "media-feature-expression";
						continue;
					}

					if (result[i - 1].type === "media-type") {
						// if it is the last element - it might be an expression
						// or 'and' depending on what is after it
						if (!result[i + 1]) {
							node.type = "media-feature-expression";
						} else {
							node.type = result[i + 1].type === "media-feature-expression" ?
								"keyword" : "media-feature-expression";
						}
					}
				}

				if (i === 0) {
					// `screen`, `fn( ... )`, `#{ ... }`. Not an expression, since then
					// its type would have been set by now
					if (!result[i + 1]) {
						node.type = "media-type";
						continue;
					}

					// `screen and` or `#{...} (max-width: 10px)`
					if (result[i + 1] &&
						(result[i + 1].type === "media-feature-expression" ||
							result[i + 1].type === "keyword")
					) {
						node.type = "media-type";
						continue;
					}
					if (result[i + 2]) {
						// `screen and (color) ...`
						if (result[i + 2].type === "media-feature-expression") {
							node.type = "media-type";
							result[i + 1].type = "keyword";
							continue;
						}
						// `only screen and ...`
						if (result[i + 2].type === "keyword") {
							node.type = "keyword";
							result[i + 1].type = "media-type";
							continue;
						}
					}
					if (result[i + 3]) {
						// `screen and (color) ...`
						if (result[i + 3].type === "media-feature-expression") {
							node.type = "keyword";
							result[i + 1].type = "media-type";
							result[i + 2].type = "keyword";
							continue;
						}
					}
				}
			}
		}
		return result;
	}

	/**
	 * Parses a media query list. Takes a possible `url()` at the start into
	 * account, and divides the list into media queries that are parsed separately
	 *
	 * @param {string} string - the source media query list string
	 *
	 * @return {Array} an array of Nodes/Containers
	 */

	function parseMediaList(string) {
		const result = [];
		let interimIndex = 0, levelLocal = 0;

		// Check for a `url(...)` part (if it is contents of an @import rule)
		const doesHaveUrl = /^(\s*)url\s*\(/.exec(string);
		if (doesHaveUrl !== null) {
			let i = doesHaveUrl[0].length;
			let parenthesesLv = 1;
			while (parenthesesLv > 0) {
				const character = string[i];
				if (character === "(") { parenthesesLv++; }
				if (character === ")") { parenthesesLv--; }
				i++;
			}
			result.unshift(new Node({
				type: "url",
				value: string.substring(0, i).trim(),
				sourceIndex: doesHaveUrl[1].length,
				before: doesHaveUrl[1],
				after: /^(\s*)/.exec(string.substring(i))[1],
			}));
			interimIndex = i;
		}

		// Start processing the media query list
		for (let i = interimIndex; i < string.length; i++) {
			const character = string[i];

			// Dividing the media query list into comma-separated media queries
			// Only count commas that are outside of any parens
			// (i.e., not part of function call params list, etc.)
			if (character === "(") { levelLocal++; }
			if (character === ")") { levelLocal--; }
			if (levelLocal === 0 && character === ",") {
				const mediaQueryString = string.substring(interimIndex, i);
				const spaceBefore = /^(\s*)/.exec(mediaQueryString)[1];
				result.push(new Container({
					type: "media-query",
					value: mediaQueryString.trim(),
					sourceIndex: interimIndex + spaceBefore.length,
					nodes: parseMediaQuery(mediaQueryString, interimIndex),
					before: spaceBefore,
					after: /(\s*)$/.exec(mediaQueryString)[1],
				}));
				interimIndex = i + 1;
			}
		}

		const mediaQueryString = string.substring(interimIndex);
		const spaceBefore = /^(\s*)/.exec(mediaQueryString)[1];
		result.push(new Container({
			type: "media-query",
			value: mediaQueryString.trim(),
			sourceIndex: interimIndex + spaceBefore.length,
			nodes: parseMediaQuery(mediaQueryString, interimIndex),
			before: spaceBefore,
			after: /(\s*)$/.exec(mediaQueryString)[1],
		}));

		return result;
	}

	function Container(opts) {
		this.constructor(opts);

		this.nodes = opts.nodes;

		if (this.after === undefined) {
			this.after = this.nodes.length > 0 ?
				this.nodes[this.nodes.length - 1].after : "";
		}

		if (this.before === undefined) {
			this.before = this.nodes.length > 0 ?
				this.nodes[0].before : "";
		}

		if (this.sourceIndex === undefined) {
			this.sourceIndex = this.before.length;
		}

		this.nodes.forEach(node => {
			node.parent = this; // eslint-disable-line no-param-reassign
		});
	}

	Container.prototype = Object.create(Node.prototype);
	Container.constructor = Node;

	/**
	 * Iterate over descendant nodes of the node
	 *
	 * @param {RegExp|string} filter - Optional. Only nodes with node.type that
	 *    satisfies the filter will be traversed over
	 * @param {function} cb - callback to call on each node. Takes these params:
	 *    node - the node being processed, i - it's index, nodes - the array
	 *    of all nodes
	 *    If false is returned, the iteration breaks
	 *
	 * @return (boolean) false, if the iteration was broken
	 */
	Container.prototype.walk = function walk(filter, cb) {
		const hasFilter = typeof filter === "string" || filter instanceof RegExp;
		const callback = hasFilter ? cb : filter;
		const filterReg = typeof filter === "string" ? new RegExp(filter) : filter;

		for (let i = 0; i < this.nodes.length; i++) {
			const node = this.nodes[i];
			const filtered = hasFilter ? filterReg.test(node.type) : true;
			if (filtered && callback && callback(node, i, this.nodes) === false) {
				return false;
			}
			if (node.nodes && node.walk(filter, cb) === false) { return false; }
		}
		return true;
	};

	/**
	 * Iterate over immediate children of the node
	 *
	 * @param {function} cb - callback to call on each node. Takes these params:
	 *    node - the node being processed, i - it's index, nodes - the array
	 *    of all nodes
	 *    If false is returned, the iteration breaks
	 *
	 * @return (boolean) false, if the iteration was broken
	 */
	Container.prototype.each = function each(cb = () => { }) {
		for (let i = 0; i < this.nodes.length; i++) {
			const node = this.nodes[i];
			if (cb(node, i, this.nodes) === false) { return false; }
		}
		return true;
	};

	/**
	 * A very generic node. Pretty much any element of a media query
	 */

	function Node(opts) {
		this.after = opts.after;
		this.before = opts.before;
		this.type = opts.type;
		this.value = opts.value;
		this.sourceIndex = opts.sourceIndex;
	}

	return {
		parseMediaList
	};

})();