/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/
var loaderUtils = require("loader-utils");
var Parser = require("fastparse");

function errorMatch(message, newParserMode) {
	return function(match) {
		var index = arguments[arguments.length - 1];
		var nextLine = this.source.indexOf("\n", index);
		var splittedSource = this.source.substr(0, index).split("\n");
		var line = splittedSource.length;
		var lineBeforeError = splittedSource.pop();
		var lineAfterError = this.source.substr(index, nextLine);
		this.errors.push("Unexpected '" + match + "' in line " + (line + 1) + ", " + message + "\n" +
			lineBeforeError + lineAfterError + "\n" + lineBeforeError.replace(/[^\\s]/g, " ") + "^");
		return newParserMode;
	};
}

function urlMatch(match, textBeforeUrl, replacedText, url, index) {
	this.urls.push({
		url: url,
		raw: replacedText,
		start: index + textBeforeUrl.length,
		length: replacedText.length
	});
}

function importMatch(match, url, mediaQuery, index) {
	this.imports.push({
		url: url,
		mediaQuery: mediaQuery,
		start: index,
		length: match.length
	});
}

function rulesStartMatch() {
	this.blockMode = this.mode;
	return "firstRule";
}

function rulesEndMatch() {
	this.mode = null;
	this.activeSelectors = [];
	return "source";
}

function nextSelectorMatch() {
	this.mode = null;
}

function enableLocal(match, whitespace, index) {
	this.remove.push({
		start: index + whitespace.length,
		length: match.length - whitespace.length
	});
	this.mode = "local";
}

function enableGlobal(match, whitespace, index) {
	this.remove.push({
		start: index + whitespace.length,
		length: match.length - whitespace.length
	});
	this.mode = "global";
}

function localStart(match, whitespace, index) {
	this.remove.push({
		start: index + whitespace.length,
		length: match.length - whitespace.length
	});
	this.bracketStatus = 0;
	return "local";
}

function globalStart(match, whitespace, index) {
	this.remove.push({
		start: index + whitespace.length,
		length: match.length - whitespace.length
	});
	this.bracketStatus = 0;
	return "global";
}

function withMode(mode, fn) {
	return function() {
		var oldMode = this.mode;
		this.mode = mode;
		var newParserMode = fn.apply(this, arguments);
		this.mode = oldMode;
		return newParserMode;
	};
}

function jump(newParserMode, fn) {
	return function() {
		fn.apply(this, arguments);
		return newParserMode;
	};
}

function innerBracketIn() {
	this.bracketStatus++;
}

function innerBracketOut(match, index) {
	if(this.bracketStatus-- === 0) {
		this.remove.push({
			start: index,
			length: match.length
		});
		return "source";
	}
}

function selectorMatch(match, prefix, name, index) {
	var selector = {
		name: name,
		prefix: prefix,
		start: index,
		length: match.length,
		mode: this.mode
	};
	this.selectors.push(selector);
	this.activeSelectors.push(selector);
}

function ruleScopedMatch() {
	this.mode = this.blockMode;
	return "ruleScoped";
}

function extendsStartMatch(match, index) {
	this.remove.push({
		start: index,
		length: 0
	});
	this.activeExtends = [];
	return "extends";
}

function extendsEndMatch(match, index) {
	var lastRemove = this.remove[this.remove.length - 1];
	lastRemove.length = index + match.length - lastRemove.start;
	if(this.activeExtends.length === 0) {
		errorMatch("expected class names")(match, index);
		return "rule";
	}
	return "firstRule";
}

function extendsClassNameMatch(match, name, index) {
	this.activeSelectors.forEach(function(selector) {
		if(!selector.extends)
			selector.extends = [];
		var extend = {
			name: name,
			start: index,
			length: match.length,
			from: null,
			fromType: null
		};
		selector.extends.push(extend);
		this.activeExtends.push(extend);
	}, this);
}

function extendsFromUrlMatch(match, request) {
	this.activeExtends.forEach(function(extend) {
		extend.from = request;
		extend.fromType = "url";
	});
}

function extendsFromMatch(match, request) {
	this.activeExtends.forEach(function(extend) {
		extend.from = loaderUtils.parseString(request);
		extend.fromType = "module";
	});
}

var parser = new Parser({
	// shared stuff
	comments: {
		"/\\*[\\s\\S]*?\\*/": true
	},
	strings: {
		'"([^\\\\"]|\\\\.)*"': true,
		"'([^\\\\']|\\\\.)*'": true
	},
	urls: {
		'(url\\s*\\()(\\s*"([^"]*)"\\s*)\\)': urlMatch,
		"(url\\s*\\()(\\s*'([^']*)'\\s*)\\)": urlMatch,
		"(url\\s*\\()(\\s*([^)]*)\\s*)\\)": urlMatch
	},
	scopedRules: {
		"(?:-[a-z]+-)?animation(?:-name)?:": ruleScopedMatch
	},

	// states
	source: [
		"comments",
		"strings",
		"urls",
		{
			// imports
			'@\\s*import\\s+"([^"]*)"\\s*([^;\\n]*);': importMatch,
			"@\\s*import\\s+'([^'']*)'\\s*([^;\\n]*);": importMatch,
			'@\\s*import\\s+url\\s*\\(\\s*"([^"]*)"\\s*\\)\\s*([^;\\n]*);': importMatch,
			"@\\s*import\\s+url\\s*\\(\\s*'([^']*)'\\s*\\)\\s*([^;\\n]*);": importMatch,
			"@\\s*import\\s+url\\s*\\(\\s*([^)]*)\\s*\\)\\s*([^;\\n]*);": importMatch,

			// charset
			"@charset": true,

			// namespace
			"@(?:-[a-z]+-)?namespace": true,

			// atrule
			"@(?:-[a-z]+-)?keyframes": "atruleScoped",
			"@": "atrule"
		},
		{
			// local
			"(\\s*):local\\(": localStart,
			"():local": enableLocal,
			"(\\s+):local\\s+": enableLocal,

			// global
			"(\\s*):global\\(": globalStart,
			"():global": enableGlobal,
			"(\\s+):global\\s+": enableGlobal,

			// class
			"(\\.)(-?[_a-zA-Z]+[_a-zA-Z0-9-]*)": selectorMatch,

			// id
			"(#)(-?[_a-zA-Z]+[_a-zA-Z0-9-]*)": selectorMatch,

			// inside
			"\\{": rulesStartMatch,

			",": nextSelectorMatch
		}
	],
	atruleScoped: [
		"comments",
		"strings",
		{
			// identifier
			":local\\(\\s*()([A-Za-z_\\-0-9]+)\\s*\\)": withMode("local", selectorMatch),
			":global\\(\\s*()([A-Za-z_\\-0-9]+)\\s*\\)": withMode("global", selectorMatch),
			"()([A-Za-z_\\-0-9]+)": selectorMatch,

			// local
			"():local": enableLocal,
			"(\\s+):local\\s+": enableLocal,

			// global
			"():global": enableGlobal,
			"(\\s+):global\\s+": enableGlobal,

			// back to normal source
			"\\{": "source"
		}
	],
	atrule: [
		"comments",
		"strings",
		{
			// back to normal source
			"\\{": "source"
		}
	],
	ruleScoped: [
		"comments",
		{
			// identifier
			":local\\(\\s*()([A-Za-z_\\-0-9]+)\\s*\\)": jump("ruleScopedInactive", withMode("local", selectorMatch)),
			":global\\(\\s*()([A-Za-z_\\-0-9]+)\\s*\\)": jump("ruleScopedInactive", withMode("global", selectorMatch)),
			"()([A-Za-z_\\-0-9]+)": jump("ruleScopedInactive", selectorMatch),

			// local
			"():local": enableLocal,
			"(\\s+):local\\s+": enableLocal,

			// global
			"():global": enableGlobal,
			"(\\s+):global\\s+": enableGlobal,

			// back to normal rule
			";": "rule",

			// back to normal source
			"\\}": rulesEndMatch
		}
	],
	ruleScopedInactive: [
		"comments",
		{
			// reactivate
			",": ruleScopedMatch,

			// back to normal rule
			";": "rule",

			// back to normal source
			"\\}": rulesEndMatch
		}
	],
	rule: [
		"comments",
		"strings",
		"urls",
		"scopedRules",
		{
			// back to normal source
			"\\}": rulesEndMatch
		}
	],
	firstRule: [
		"rule",
		{
			"extends\\s*:": extendsStartMatch,

			// whitespace
			"\\s+": true,

			// url
			".": "rule"
		}
	],
	extends: [
		"comments",
		{
			";\\s*": extendsEndMatch,

			// whitespace
			"\\s+": true,

			// from
			"from": "extendsFrom",

			// class name
			"([A-Za-z_\\-0-9]+)": extendsClassNameMatch,

			".+[;}]": errorMatch("expected class names or 'from'", "rule"),
			".": errorMatch("expected class names or 'from'", "rule")
		}
	],
	extendsFrom: [
		"comments",
		{
			";\\s*": extendsEndMatch,

			// whitespace
			"\\s+": true,

			// module
			'url\\s*\\(\\s*"([^"]*)"\\s*\\)': extendsFromUrlMatch,
			"url\\s*\\(\\s*'([^']*)'\\s*\\)": extendsFromUrlMatch,
			"url\\s*\\(\\s*([^)]*)\\s*\\)": extendsFromUrlMatch,
			'("(?:[^\\\\"]|\\\\.)*")': extendsFromMatch,
			"('(?:[^\\\\']|\\\\.)*')": extendsFromMatch,

			".+[;}]": errorMatch("expected module identifier (a string or 'url(...)'')", "rule"),
			".": errorMatch("expected module identifier (a string or 'url(...)'')", "rule")
		}
	],
	local: [
		"comments",
		"strings",
		{
			// class
			"(\\.)([A-Za-z_\\-0-9]+)": withMode("local", selectorMatch),

			// id
			"(#)([A-Za-z_\\-0-9]+)": withMode("local", selectorMatch),

			// brackets
			"\\(": innerBracketIn,
			"\\)": innerBracketOut
		}
	],
	global: [
		"comments",
		"strings",
		{
			// class
			"(\\.)([A-Za-z_\\-0-9]+)": withMode("global", selectorMatch),

			// id
			"(#)([A-Za-z_\\-0-9]+)": withMode("global", selectorMatch),

			// brackets
			"\\(": innerBracketIn,
			"\\)": innerBracketOut
		}
	]
});

module.exports = function parseSource(source) {
	var context = {
		source: source,
		imports: [],
		urls: [],
		selectors: [],
		remove: [],
		errors: [],
		activeSelectors: [],
		bracketStatus: 0,
		mode: null
	};
	return parser.parse("source", source, context);
};