"use strict";

var modes = require("../config").$modes;

var oop = require("../lib/oop");
var lang = require("../lib/lang");
var TextHighlightRules = require("./text_highlight_rules").TextHighlightRules;
var HtmlHighlightRules = require("./html_highlight_rules").HtmlHighlightRules;

var escaped = function(ch) {
    return "(?:[^" + lang.escapeRegExp(ch) + "\\\\]|\\\\.)*";
};

var MarkdownHighlightRules = function() {
    HtmlHighlightRules.call(this);
    // regexp must not have capturing parentheses
    // regexps are ordered -> the first match is used
    var codeBlockStartRule = {
        token : "support.function",
        regex : /^\s*(```+[^`]*|~~~+[^~]*)$/,
        onMatch: function(value, state, stack, line) {
            var m = value.match(/^(\s*)([`~]+)(.*)/);
            var language = /[\w-]+|$/.exec(m[3])[0];
            // TODO lazy-load modes
            if (!modes[language])
                language = "";
            stack.unshift("githubblock", [], [m[1], m[2], language], state);
            return this.token;
        },
        next  : "githubblock"
    };
    var codeBlockRules = [{
        token : "support.function",
        regex : ".*",
        onMatch: function(value, state, stack, line) {
            var embedState = stack[1];
            var indent = stack[2][0];
            var endMarker = stack[2][1];
            var language = stack[2][2];
            
            var m = /^(\s*)(`+|~+)\s*$/.exec(value);
            if (
                m && m[1].length < indent.length + 3
                && m[2].length >= endMarker.length && m[2][0] == endMarker[0]
            ) {
                stack.splice(0, 3);
                this.next = stack.shift();
                return this.token;
            }
            this.next = "";
            if (language && modes[language]) {
                var data = modes[language].getTokenizer().getLineTokens(value, embedState.slice(0));
                stack[1] = data.state;
                return data.tokens;
            }
            return this.token;
        }
    }];

    this.$rules["start"].unshift({
        token : "empty_line",
        regex : '^$',
        next: "allowBlock"
    }, { // h1
        token: "markup.heading.1",
        regex: "^=+(?=\\s*$)"
    }, { // h2
        token: "markup.heading.2",
        regex: "^\\-+(?=\\s*$)"
    }, {
        token : function(value) {
            return "markup.heading." + value.length;
        },
        regex : /^#{1,6}(?=\s|$)/,
        next : "header"
    },
    codeBlockStartRule,
    { // block quote
        token : "string.blockquote",
        regex : "^\\s*>\\s*(?:[*+-]|\\d+\\.)?\\s+",
        next  : "blockquote"
    }, { // HR * - _
        token : "constant",
        regex : "^ {0,3}(?:(?:\\* ?){3,}|(?:\\- ?){3,}|(?:\\_ ?){3,})\\s*$",
        next: "allowBlock"
    }, { // list
        token : "markup.list",
        regex : "^\\s{0,3}(?:[*+-]|\\d+\\.)\\s+",
        next  : "listblock-start"
    }, {
        include : "basic"
    });

    this.addRules({
        "basic" : [{
            token : "constant.language.escape",
            regex : /\\[\\`*_{}\[\]()#+\-.!]/
        }, { // code span `
            token : "support.function",
            regex : "(`+)(.*?[^`])(\\1)"
        }, { // reference
            token : ["text", "constant", "text", "url", "string", "text"],
            regex : "^([ ]{0,3}\\[)([^\\]]+)(\\]:\\s*)([^ ]+)(\\s*(?:[\"][^\"]+[\"])?(\\s*))$"
        }, { // link by reference
            token : ["text", "string", "text", "constant", "text"],
            regex : "(\\[)(" + escaped("]") + ")(\\]\\s*\\[)("+ escaped("]") + ")(\\])"
        }, { // link by url
            token : ["text", "string", "text", "markup.underline", "string", "text"],
            regex : "(\\!?\\[)(" +                                        // [
                    escaped("]") +                                    // link text or alt text
                    ")(\\]\\()"+                                      // ](
                    '((?:[^\\)\\s\\\\]|\\\\.|\\s(?=[^"]))*)' +        // href or image
                    '(\\s*"' +  escaped('"') + '"\\s*)?' +            // "title"
                    "(\\))"                                           // )
        }, { // strong ** __
            token : "string.strong",
            regex : "([*]{2}|[_]{2}(?=\\S))(.*?\\S[*_]*)(\\1)"
        }, { // emphasis * _
            token : "string.emphasis",
            regex : "([*]|[_](?=\\S))(.*?\\S[*_]*)(\\1)"
        }, { //
            token : ["text", "url", "text"],
            regex : "(<)("+
                      "(?:https?|ftp|dict):[^'\">\\s]+"+
                      "|"+
                      "(?:mailto:)?[-.\\w]+\\@[-a-z0-9]+(?:\\.[-a-z0-9]+)*\\.[a-z]+"+
                    ")(>)"
        }],

        // code block
        "allowBlock": [
            {token : "support.function", regex : "^ {4}.+", next : "allowBlock"},
            {token : "empty_line", regex : '^$', next: "allowBlock"},
            {token : "empty", regex : "", next : "start"}
        ],

        "header" : [{
            regex: "$",
            next : "start"
        }, {
            include: "basic"
        }, {
            defaultToken : "heading"
        } ],

        "listblock-start" : [{
            token : "support.variable",
            regex : /(?:\[[ x]\])?/,
            next  : "listblock"
        }],

        "listblock" : [ { // Lists only escape on completely blank lines.
            token : "empty_line",
            regex : "^$",
            next  : "start"
        }, { // list
            token : "markup.list",
            regex : "^\\s{0,3}(?:[*+-]|\\d+\\.)\\s+",
            next  : "listblock-start"
        }, {
            include : "basic", noEscape: true
        },
        codeBlockStartRule,
        {
            defaultToken : "list" //do not use markup.list to allow stling leading `*` differntly
        } ],

        "blockquote" : [ { // Blockquotes only escape on blank lines.
            token : "empty_line",
            regex : "^\\s*$",
            next  : "start"
        }, { // block quote
            token : "string.blockquote",
            regex : "^\\s*>\\s*(?:[*+-]|\\d+\\.)?\\s+",
            next  : "blockquote"
        }, {
            include : "basic", noEscape: true
        }, {
            defaultToken : "string.blockquote"
        } ],

        "githubblock" : codeBlockRules
    });

    this.normalizeRules();
};
oop.inherits(MarkdownHighlightRules, TextHighlightRules);

exports.MarkdownHighlightRules = MarkdownHighlightRules;
