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 *       notice, this list of conditions and the following disclaimer.
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 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
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define(function(require, exports, module) {
"use strict";

var oop = require("../../lib/oop");
var BaseFoldMode = require("./fold_mode").FoldMode;
var Range = require("../../range").Range;
var TokenIterator = require("../../token_iterator").TokenIterator;


var FoldMode = exports.FoldMode = function() {};

oop.inherits(FoldMode, BaseFoldMode);

(function() {

    this.foldingStartMarker = /\b(function|then|do|repeat)\b|{\s*$|(\[=*\[)/;
    this.foldingStopMarker = /\bend\b|^\s*}|\]=*\]/;

    this.getFoldWidget = function(session, foldStyle, row) {
        var line = session.getLine(row);
        var isStart = this.foldingStartMarker.test(line);
        var isEnd = this.foldingStopMarker.test(line);

        if (isStart && !isEnd) {
            var match = line.match(this.foldingStartMarker);
            if (match[1] == "then" && /\belseif\b/.test(line))
                return;
            if (match[1]) {
                if (session.getTokenAt(row, match.index + 1).type === "keyword")
                    return "start";
            } else if (match[2]) {
                var type = session.bgTokenizer.getState(row) || "";
                if (type.indexOf("comment") != -1 || type.indexOf("string") != -1)
                    return "start";
            } else {
                return "start";
            }
        }
        if (foldStyle != "markbeginend" || !isEnd || isStart && isEnd)
            return "";

        var match = line.match(this.foldingStopMarker);
        if (match[0] === "end") {
            if (session.getTokenAt(row, match.index + 1).type === "keyword")
                return "end";
        } else if (match[0][0] === "]") {
            var type = session.bgTokenizer.getState(row - 1) || "";
            if (type.indexOf("comment") != -1 || type.indexOf("string") != -1)
                return "end";
        } else
            return "end";
    };

    this.getFoldWidgetRange = function(session, foldStyle, row) {
        var line = session.doc.getLine(row);
        var match = this.foldingStartMarker.exec(line);
        if (match) {
            if (match[1])
                return this.luaBlock(session, row, match.index + 1);

            if (match[2])
                return session.getCommentFoldRange(row, match.index + 1);

            return this.openingBracketBlock(session, "{", row, match.index);
        }

        var match = this.foldingStopMarker.exec(line);
        if (match) {
            if (match[0] === "end") {
                if (session.getTokenAt(row, match.index + 1).type === "keyword")
                    return this.luaBlock(session, row, match.index + 1);
            }

            if (match[0][0] === "]")
                return session.getCommentFoldRange(row, match.index + 1);

            return this.closingBracketBlock(session, "}", row, match.index + match[0].length);
        }
    };

    this.luaBlock = function(session, row, column) {
        var stream = new TokenIterator(session, row, column);
        var indentKeywords = {
            "function": 1,
            "do": 1,
            "then": 1,
            "elseif": -1,
            "end": -1,
            "repeat": 1,
            "until": -1,
        };

        var token = stream.getCurrentToken();
        if (!token || token.type != "keyword")
            return;

        var val = token.value;
        var stack = [val];
        var dir = indentKeywords[val];

        if (!dir)
            return;

        var startColumn = dir === -1 ? stream.getCurrentTokenColumn() : session.getLine(row).length;
        var startRow = row;

        stream.step = dir === -1 ? stream.stepBackward : stream.stepForward;
        while(token = stream.step()) {
            if (token.type !== "keyword")
                continue;
            var level = dir * indentKeywords[token.value];

            if (level > 0) {
                stack.unshift(token.value);
            } else if (level <= 0) {
                stack.shift();
                if (!stack.length && token.value != "elseif")
                    break;
                if (level === 0)
                    stack.unshift(token.value);
            }
        }

        var row = stream.getCurrentTokenRow();
        if (dir === -1)
            return new Range(row, session.getLine(row).length, startRow, startColumn);
        else
            return new Range(startRow, startColumn, row, stream.getCurrentTokenColumn());
    };

}).call(FoldMode.prototype);

});
