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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
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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 FoldMode = exports.FoldMode = function () {
    };
    oop.inherits(FoldMode, BaseFoldMode);

    (function () {
        this.foldingStartMarker = /^(?:\|={10,}|[\.\/=\-~^+]{4,}\s*$|={1,5} )/;
        this.singleLineHeadingRe = /^={1,5}(?=\s+\S)/;

        this.getFoldWidget = function (session, foldStyle, row) {
            var line = session.getLine(row);
            if (!this.foldingStartMarker.test(line))
                return ""

            if (line[0] == "=") {
                if (this.singleLineHeadingRe.test(line))
                    return "start";
                if (session.getLine(row - 1).length != session.getLine(row).length)
                    return "";
                return "start";
            }
            if (session.bgTokenizer.getState(row) == "dissallowDelimitedBlock")
                return "end";
            return "start";
        };

        this.getFoldWidgetRange = function (session, foldStyle, row) {
            var line = session.getLine(row);
            var startColumn = line.length;
            var maxRow = session.getLength();
            var startRow = row;
            var endRow = row;
            if (!line.match(this.foldingStartMarker))
                return;

            var token;

            function getTokenType(row) {
                token = session.getTokens(row)[0];
                return token && token.type;
            }

            var levels = ["=", "-", "~", "^", "+"];
            var heading = "markup.heading";
            var singleLineHeadingRe = this.singleLineHeadingRe;

            function getLevel() {
                var match = token.value.match(singleLineHeadingRe);
                if (match)
                    return match[0].length;
                var level = levels.indexOf(token.value[0]) + 1;
                if (level == 1) {
                    if (session.getLine(row - 1).length != session.getLine(row).length)
                        return Infinity;
                }
                return level;
            }

            if (getTokenType(row) == heading) {
                var startHeadingLevel = getLevel();
                while (++row < maxRow) {
                    if (getTokenType(row) != heading)
                        continue;
                    var level = getLevel();
                    if (level <= startHeadingLevel)
                        break;
                }

                var isSingleLineHeading = token && token.value.match(this.singleLineHeadingRe);
                endRow = isSingleLineHeading ? row - 1 : row - 2;

                if (endRow > startRow) {
                    while (endRow > startRow && (!getTokenType(endRow) || token.value[0] == "["))
                        endRow--;
                }

                if (endRow > startRow) {
                    var endColumn = session.getLine(endRow).length;
                    return new Range(startRow, startColumn, endRow, endColumn);
                }
            } else {
                var state = session.bgTokenizer.getState(row);
                if (state == "dissallowDelimitedBlock") {
                    while (row-- > 0) {
                        if (session.bgTokenizer.getState(row).lastIndexOf("Block") == -1)
                            break;
                    }
                    endRow = row + 1;
                    if (endRow < startRow) {
                        var endColumn = session.getLine(row).length;
                        return new Range(endRow, 5, startRow, startColumn - 5);
                    }
                } else {
                    while (++row < maxRow) {
                        if (session.bgTokenizer.getState(row) == "dissallowDelimitedBlock")
                            break;
                    }
                    endRow = row;
                    if (endRow > startRow) {
                        var endColumn = session.getLine(row).length;
                        return new Range(startRow, 5, endRow, endColumn - 5);
                    }
                }
            }
        };

    }).call(FoldMode.prototype);

});
