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define(function (require, exports, module) {
    "use strict";

    var oop = require("../../lib/oop");
    var Range = require("../../range").Range;
    var BaseFoldMode = require("./cstyle").FoldMode;

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

    oop.inherits(FoldMode, BaseFoldMode);

    (function () {
        /**
         * Inheriting cstyle folding because it handles the region comment folding
         * and special block comment folding appropriately.
         *
         * Cstyle's getCommentRegionBlock() contains the sql comment characters '--' for end region block.
         */

        this.foldingStartMarker = /(\bCASE\b|\bBEGIN\b)|^\s*(\/\*)/i;
        // this.foldingStopMarker = /(\bEND\b)|^[\s\*]*(\*\/)/i;
        this.startRegionRe = /^\s*(\/\*|--)#?region\b/;

        this.getFoldWidgetRange = function (session, foldStyle, row, forceMultiline) {
            var line = session.getLine(row);

            if (this.startRegionRe.test(line)) return this.getCommentRegionBlock(session, line, row);

            var match = line.match(this.foldingStartMarker);
            if (match) {
                var i = match.index;
                if (match[1]) return this.getBeginEndBlock(session, row, i, match[1]);

                var range = session.getCommentFoldRange(row, i + match[0].length, 1);
                if (range && !range.isMultiLine()) {
                    if (forceMultiline) {
                        range = this.getSectionRange(session, row);
                    }
                    else if (foldStyle != "all") range = null;
                }

                return range;
            }

            if (foldStyle === "markbegin") return;
            //TODO: add support for end folding markers
            return;
        };

        /**
         * @returns {range} folding block for sequence that starts with 'CASE' or 'BEGIN' and ends with 'END'
         * @param {string} matchSequence - the sequence of charaters that started the fold widget, which should remain visible when the fold widget is folded
         */
        this.getBeginEndBlock = function (session, row, column, matchSequence) {
            var start = {
                row: row,
                column: column + matchSequence.length
            };
            var maxRow = session.getLength();
            var line;

            var depth = 1;
            var re = /(\bCASE\b|\bBEGIN\b)|(\bEND\b)/i;
            while (++row < maxRow) {
                line = session.getLine(row);
                var m = re.exec(line);
                if (!m) continue;
                if (m[1]) depth++;
                else depth--;

                if (!depth) break;
            }
            var endRow = row;
            if (endRow > start.row) {
                return new Range(start.row, start.column, endRow, line.length);
            }
        };

    }).call(FoldMode.prototype);

});
