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

    var Range = require("../range").Range;
    var RangeList = require("../range_list").RangeList;
    var oop = require("../lib/oop")
    /*
     * Simple fold-data struct.
     **/
    var Fold = exports.Fold = function (range, placeholder) {
        this.foldLine = null;
        this.placeholder = placeholder;
        this.range = range;
        this.start = range.start;
        this.end = range.end;

        this.sameRow = range.start.row == range.end.row;
        this.subFolds = this.ranges = [];
    };

    oop.inherits(Fold, RangeList);

    (function () {

        this.toString = function () {
            return '"' + this.placeholder + '" ' + this.range.toString();
        };

        this.setFoldLine = function (foldLine) {
            this.foldLine = foldLine;
            this.subFolds.forEach(function (fold) {
                fold.setFoldLine(foldLine);
            });
        };

        this.clone = function () {
            var range = this.range.clone();
            var fold = new Fold(range, this.placeholder);
            this.subFolds.forEach(function (subFold) {
                fold.subFolds.push(subFold.clone());
            });
            fold.collapseChildren = this.collapseChildren;
            return fold;
        };

        this.addSubFold = function (fold) {
            if (this.range.isEqual(fold))
                return;

            if (!this.range.containsRange(fold))
                throw new Error("A fold can't intersect already existing fold" + fold.range + this.range);

            // transform fold to local coordinates
            consumeRange(fold, this.start);

            var row = fold.start.row, column = fold.start.column;
            for (var i = 0, cmp = -1; i < this.subFolds.length; i++) {
                cmp = this.subFolds[i].range.compare(row, column);
                if (cmp != 1)
                    break;
            }
            var afterStart = this.subFolds[i];

            if (cmp == 0)
                return afterStart.addSubFold(fold);

            // cmp == -1
            var row = fold.range.end.row, column = fold.range.end.column;
            for (var j = i, cmp = -1; j < this.subFolds.length; j++) {
                cmp = this.subFolds[j].range.compare(row, column);
                if (cmp != 1)
                    break;
            }
            var afterEnd = this.subFolds[j];

            if (cmp == 0)
                throw new Error("A fold can't intersect already existing fold" + fold.range + this.range);

            var consumedFolds = this.subFolds.splice(i, j - i, fold);
            fold.setFoldLine(this.foldLine);

            return fold;
        };

        this.restoreRange = function (range) {
            return restoreRange(range, this.start);
        };

    }).call(Fold.prototype);

    function consumePoint(point, anchor) {
        point.row -= anchor.row;
        if (point.row == 0)
            point.column -= anchor.column;
    }

    function consumeRange(range, anchor) {
        consumePoint(range.start, anchor);
        consumePoint(range.end, anchor);
    }

    function restorePoint(point, anchor) {
        if (point.row == 0)
            point.column += anchor.column;
        point.row += anchor.row;
    }

    function restoreRange(range, anchor) {
        restorePoint(range.start, anchor);
        restorePoint(range.end, anchor);
    }

});
