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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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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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 = /^(?:[=-]+\s*$|#{1,6} |`{3})/;

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

            if (line[0] == "`") {
                if (session.bgTokenizer.getState(row) == "start")
                    return "end";
                return "start";
            }

            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;

            if (line[0] == "`") {
                if (session.bgTokenizer.getState(row) !== "start") {
                    while (++row < maxRow) {
                        line = session.getLine(row);
                        if (line[0] == "`" & line.substring(0, 3) == "```")
                            break;
                    }
                    return new Range(startRow, startColumn, row, 0);
                } else {
                    while (row-- > 0) {
                        line = session.getLine(row);
                        if (line[0] == "`" & line.substring(0, 3) == "```")
                            break;
                    }
                    return new Range(row, line.length, startRow, 0);
                }
            }

            var token;

            function isHeading(row) {
                token = session.getTokens(row)[0];
                return token && token.type.lastIndexOf(heading, 0) === 0;
            }

            var heading = "markup.heading";

            function getLevel() {
                var ch = token.value[0];
                if (ch == "=") return 6;
                if (ch == "-") return 5;
                return 7 - token.value.search(/[^#]/);
            }

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

                endRow = row - (!token || ["=", "-"].indexOf(token.value[0]) == -1 ? 1 : 2);

                if (endRow > startRow) {
                    while (endRow > startRow && /^\s*$/.test(session.getLine(endRow)))
                        endRow--;
                }

                if (endRow > startRow) {
                    var endColumn = session.getLine(endRow).length;
                    return new Range(startRow, startColumn, endRow, endColumn);
                }
            }
        };

    }).call(FoldMode.prototype);

});
