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 * Distributed under the BSD license:
 *
 * Copyright (c) 2010, Ajax.org B.V.
 * All rights reserved.
 * 
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 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
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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 Range = require("../range").Range;
var FoldLine = require("./fold_line").FoldLine;
var Fold = require("./fold").Fold;
var TokenIterator = require("../token_iterator").TokenIterator;

function Folding() {
    /*
     * Looks up a fold at a given row/column. Possible values for side:
     *   -1: ignore a fold if fold.start = row/column
     *   +1: ignore a fold if fold.end = row/column
     */
    this.getFoldAt = function(row, column, side) {
        var foldLine = this.getFoldLine(row);
        if (!foldLine)
            return null;

        var folds = foldLine.folds;
        for (var i = 0; i < folds.length; i++) {
            var fold = folds[i];
            if (fold.range.contains(row, column)) {
                if (side == 1 && fold.range.isEnd(row, column)) {
                    continue;
                } else if (side == -1 && fold.range.isStart(row, column)) {
                    continue;
                }
                return fold;
            }
        }
    };

    /*
     * Returns all folds in the given range. Note, that this will return folds
     *
     */
    this.getFoldsInRange = function(range) {
        range = range.clone();
        var start = range.start;
        var end = range.end;
        var foldLines = this.$foldData;
        var foundFolds = [];

        start.column += 1;
        end.column -= 1;

        for (var i = 0; i < foldLines.length; i++) {
            var cmp = foldLines[i].range.compareRange(range);
            if (cmp == 2) {
                // Range is before foldLine. No intersection. This means,
                // there might be other foldLines that intersect.
                continue;
            }
            else if (cmp == -2) {
                // Range is after foldLine. There can't be any other foldLines then,
                // so let's give up.
                break;
            }

            var folds = foldLines[i].folds;
            for (var j = 0; j < folds.length; j++) {
                var fold = folds[j];
                cmp = fold.range.compareRange(range);
                if (cmp == -2) {
                    break;
                } else if (cmp == 2) {
                    continue;
                } else
                // WTF-state: Can happen due to -1/+1 to start/end column.
                if (cmp == 42) {
                    break;
                }
                foundFolds.push(fold);
            }
        }
        return foundFolds;
    };
    
    /*
     * Returns all folds in the document
     */
    this.getAllFolds = function() {
        var folds = [];
        var foldLines = this.$foldData;
        
        function addFold(fold) {
            folds.push(fold);
            if (!fold.subFolds)
                return;
                
            for (var i = 0; i < fold.subFolds.length; i++)
                addFold(fold.subFolds[i]);
        }
        
        for (var i = 0; i < foldLines.length; i++)
            for (var j = 0; j < foldLines[i].folds.length; j++)
                addFold(foldLines[i].folds[j]);

        return folds;
    };

    /*
     * Returns the string between folds at the given position.
     * E.g.
     *  foo<fold>b|ar<fold>wolrd -> "bar"
     *  foo<fold>bar<fold>wol|rd -> "world"
     *  foo<fold>bar<fo|ld>wolrd -> <null>
     *
     * where | means the position of row/column
     *
     * The trim option determs if the return string should be trimed according
     * to the "side" passed with the trim value:
     *
     * E.g.
     *  foo<fold>b|ar<fold>wolrd -trim=-1> "b"
     *  foo<fold>bar<fold>wol|rd -trim=+1> "rld"
     *  fo|o<fold>bar<fold>wolrd -trim=00> "foo"
     */
    this.getFoldStringAt = function(row, column, trim, foldLine) {
        foldLine = foldLine || this.getFoldLine(row);
        if (!foldLine)
            return null;

        var lastFold = {
            end: { column: 0 }
        };
        // TODO: Refactor to use getNextFoldTo function.
        var str, fold;
        for (var i = 0; i < foldLine.folds.length; i++) {
            fold = foldLine.folds[i];
            var cmp = fold.range.compareEnd(row, column);
            if (cmp == -1) {
                str = this
                    .getLine(fold.start.row)
                    .substring(lastFold.end.column, fold.start.column);
                break;
            }
            else if (cmp === 0) {
                return null;
            }
            lastFold = fold;
        }
        if (!str)
            str = this.getLine(fold.start.row).substring(lastFold.end.column);

        if (trim == -1)
            return str.substring(0, column - lastFold.end.column);
        else if (trim == 1)
            return str.substring(column - lastFold.end.column);
        else
            return str;
    };

    this.getFoldLine = function(docRow, startFoldLine) {
        var foldData = this.$foldData;
        var i = 0;
        if (startFoldLine)
            i = foldData.indexOf(startFoldLine);
        if (i == -1)
            i = 0;
        for (i; i < foldData.length; i++) {
            var foldLine = foldData[i];
            if (foldLine.start.row <= docRow && foldLine.end.row >= docRow) {
                return foldLine;
            } else if (foldLine.end.row > docRow) {
                return null;
            }
        }
        return null;
    };

    // returns the fold which starts after or contains docRow
    this.getNextFoldLine = function(docRow, startFoldLine) {
        var foldData = this.$foldData;
        var i = 0;
        if (startFoldLine)
            i = foldData.indexOf(startFoldLine);
        if (i == -1)
            i = 0;
        for (i; i < foldData.length; i++) {
            var foldLine = foldData[i];
            if (foldLine.end.row >= docRow) {
                return foldLine;
            }
        }
        return null;
    };

    this.getFoldedRowCount = function(first, last) {
        var foldData = this.$foldData, rowCount = last-first+1;
        for (var i = 0; i < foldData.length; i++) {
            var foldLine = foldData[i],
                end = foldLine.end.row,
                start = foldLine.start.row;
            if (end >= last) {
                if(start < last) {
                    if(start >= first)
                        rowCount -= last-start;
                    else
                        rowCount = 0;//in one fold
                }
                break;
            } else if(end >= first){
                if (start >= first) //fold inside range
                    rowCount -=  end-start;
                else
                    rowCount -=  end-first+1;
            }
        }
        return rowCount;
    };

    this.$addFoldLine = function(foldLine) {
        this.$foldData.push(foldLine);
        this.$foldData.sort(function(a, b) {
            return a.start.row - b.start.row;
        });
        return foldLine;
    };

    /*
     * Adds a new fold.
     *
     * @returns
     *      The new created Fold object or an existing fold object in case the
     *      passed in range fits an existing fold exactly.
     */
    this.addFold = function(placeholder, range) {
        var foldData = this.$foldData;
        var added = false;
        var fold;
        
        if (placeholder instanceof Fold)
            fold = placeholder;
        else
            fold = new Fold(range, placeholder);

        this.$clipRangeToDocument(fold.range);

        var startRow = fold.start.row;
        var startColumn = fold.start.column;
        var endRow = fold.end.row;
        var endColumn = fold.end.column;

        // --- Some checking ---
        if (startRow == endRow && endColumn - startColumn < 2)
            throw "The range has to be at least 2 characters width";

        var startFold = this.getFoldAt(startRow, startColumn, 1);
        var endFold = this.getFoldAt(endRow, endColumn, -1);
        if (startFold && endFold == startFold)
            return startFold.addSubFold(fold);

        if (
            (startFold && !startFold.range.isStart(startRow, startColumn))
            || (endFold && !endFold.range.isEnd(endRow, endColumn))
        ) {
            throw "A fold can't intersect already existing fold" + fold.range + startFold.range;
        }

        // Check if there are folds in the range we create the new fold for.
        var folds = this.getFoldsInRange(fold.range);
        if (folds.length > 0) {
            // Remove the folds from fold data.
            this.removeFolds(folds);
            // Add the removed folds as subfolds on the new fold.
            fold.subFolds = folds;
        }

        for (var i = 0; i < foldData.length; i++) {
            var foldLine = foldData[i];
            if (endRow == foldLine.start.row) {
                foldLine.addFold(fold);
                added = true;
                break;
            }
            else if (startRow == foldLine.end.row) {
                foldLine.addFold(fold);
                added = true;
                if (!fold.sameRow) {
                    // Check if we might have to merge two FoldLines.
                    var foldLineNext = foldData[i + 1];
                    if (foldLineNext && foldLineNext.start.row == endRow) {
                        // We need to merge!
                        foldLine.merge(foldLineNext);
                        break;
                    }
                }
                break;
            }
            else if (endRow <= foldLine.start.row) {
                break;
            }
        }

        if (!added)
            foldLine = this.$addFoldLine(new FoldLine(this.$foldData, fold));

        if (this.$useWrapMode)
            this.$updateWrapData(foldLine.start.row, foldLine.start.row);
        else
            this.$updateRowLengthCache(foldLine.start.row, foldLine.start.row);

        // Notify that fold data has changed.
        this.$modified = true;
        this._emit("changeFold", { data: fold });

        return fold;
    };

    this.addFolds = function(folds) {
        folds.forEach(function(fold) {
            this.addFold(fold);
        }, this);
    };

    this.removeFold = function(fold) {
        var foldLine = fold.foldLine;
        var startRow = foldLine.start.row;
        var endRow = foldLine.end.row;

        var foldLines = this.$foldData;
        var folds = foldLine.folds;
        // Simple case where there is only one fold in the FoldLine such that
        // the entire fold line can get removed directly.
        if (folds.length == 1) {
            foldLines.splice(foldLines.indexOf(foldLine), 1);
        } else
        // If the fold is the last fold of the foldLine, just remove it.
        if (foldLine.range.isEnd(fold.end.row, fold.end.column)) {
            folds.pop();
            foldLine.end.row = folds[folds.length - 1].end.row;
            foldLine.end.column = folds[folds.length - 1].end.column;
        } else
        // If the fold is the first fold of the foldLine, just remove it.
        if (foldLine.range.isStart(fold.start.row, fold.start.column)) {
            folds.shift();
            foldLine.start.row = folds[0].start.row;
            foldLine.start.column = folds[0].start.column;
        } else
        // We know there are more then 2 folds and the fold is not at the edge.
        // This means, the fold is somewhere in between.
        //
        // If the fold is in one row, we just can remove it.
        if (fold.sameRow) {
            folds.splice(folds.indexOf(fold), 1);
        } else
        // The fold goes over more then one row. This means remvoing this fold
        // will cause the fold line to get splitted up. newFoldLine is the second part
        {
            var newFoldLine = foldLine.split(fold.start.row, fold.start.column);
            folds = newFoldLine.folds;
            folds.shift();
            newFoldLine.start.row = folds[0].start.row;
            newFoldLine.start.column = folds[0].start.column;
        }

        if (this.$useWrapMode)
            this.$updateWrapData(startRow, endRow);
        else
            this.$updateRowLengthCache(startRow, endRow);

        // Notify that fold data has changed.
        this.$modified = true;
        this._emit("changeFold", { data: fold });
    };

    this.removeFolds = function(folds) {
        // We need to clone the folds array passed in as it might be the folds
        // array of a fold line and as we call this.removeFold(fold), folds
        // are removed from folds and changes the current index.
        var cloneFolds = [];
        for (var i = 0; i < folds.length; i++) {
            cloneFolds.push(folds[i]);
        }

        cloneFolds.forEach(function(fold) {
            this.removeFold(fold);
        }, this);
        this.$modified = true;
    };

    this.expandFold = function(fold) {
        this.removeFold(fold);
        fold.subFolds.forEach(function(fold) {
            this.addFold(fold);
        }, this);
        fold.subFolds = [];
    };

    this.expandFolds = function(folds) {
        folds.forEach(function(fold) {
            this.expandFold(fold);
        }, this);
    };

    this.unfold = function(location, expandInner) {
        var range, folds;
        if (location == null)
            range = new Range(0, 0, this.getLength(), 0);
        else if (typeof location == "number")
            range = new Range(location, 0, location, this.getLine(location).length);
        else if ("row" in location)
            range = Range.fromPoints(location, location);
        else
            range = location;

        folds = this.getFoldsInRange(range);
        if (expandInner) {
            this.removeFolds(folds);
        } else {
            // TODO: might need to remove and add folds in one go instead of using
            // expandFolds several times.
            while (folds.length) {
                this.expandFolds(folds);
                folds = this.getFoldsInRange(range);
            }
        }
    };

    /*
     * Checks if a given documentRow is folded. This is true if there are some
     * folded parts such that some parts of the line is still visible.
     **/
    this.isRowFolded = function(docRow, startFoldRow) {
        return !!this.getFoldLine(docRow, startFoldRow);
    };

    this.getRowFoldEnd = function(docRow, startFoldRow) {
        var foldLine = this.getFoldLine(docRow, startFoldRow);
        return foldLine ? foldLine.end.row : docRow;
    };

    this.getFoldDisplayLine = function(foldLine, endRow, endColumn, startRow, startColumn) {
        if (startRow == null) {
            startRow = foldLine.start.row;
            startColumn = 0;
        }

        if (endRow == null) {
            endRow = foldLine.end.row;
            endColumn = this.getLine(endRow).length;
        }

        // Build the textline using the FoldLine walker.
        var doc = this.doc;
        var textLine = "";

        foldLine.walk(function(placeholder, row, column, lastColumn) {
            if (row < startRow) {
                return;
            } else if (row == startRow) {
                if (column < startColumn) {
                    return;
                }
                lastColumn = Math.max(startColumn, lastColumn);
            }
            if (placeholder != null) {
                textLine += placeholder;
            } else {
                textLine += doc.getLine(row).substring(lastColumn, column);
            }
        }.bind(this), endRow, endColumn);
        return textLine;
    };

    this.getDisplayLine = function(row, endColumn, startRow, startColumn) {
        var foldLine = this.getFoldLine(row);

        if (!foldLine) {
            var line;
            line = this.doc.getLine(row);
            return line.substring(startColumn || 0, endColumn || line.length);
        } else {
            return this.getFoldDisplayLine(
                foldLine, row, endColumn, startRow, startColumn);
        }
    };

    this.$cloneFoldData = function() {
        var fd = [];
        fd = this.$foldData.map(function(foldLine) {
            var folds = foldLine.folds.map(function(fold) {
                return fold.clone();
            });
            return new FoldLine(fd, folds);
        });

        return fd;
    };

    this.toggleFold = function(tryToUnfold) {
        var selection = this.selection;
        var range = selection.getRange();
        var fold;
        var bracketPos;

        if (range.isEmpty()) {
            var cursor = range.start;
            fold = this.getFoldAt(cursor.row, cursor.column);

            if (fold) {
                this.expandFold(fold);
                return;
            }
            else if (bracketPos = this.findMatchingBracket(cursor)) {
                if (range.comparePoint(bracketPos) == 1) {
                    range.end = bracketPos;
                } 
                else {
                    range.start = bracketPos;
                    range.start.column++;
                    range.end.column--;
                }
            }
            else if (bracketPos = this.findMatchingBracket({row: cursor.row, column: cursor.column + 1})) {
                if (range.comparePoint(bracketPos) == 1)
                    range.end = bracketPos;
                else
                    range.start = bracketPos;

                range.start.column++;
            }
            else {
                range = this.getCommentFoldRange(cursor.row, cursor.column) || range;
            }
        } else {
            var folds = this.getFoldsInRange(range);
            if (tryToUnfold && folds.length) {
                this.expandFolds(folds);
                return;
            } 
            else if (folds.length == 1 ) {
                fold = folds[0];
            }
        }

        if (!fold)
            fold = this.getFoldAt(range.start.row, range.start.column);

        if (fold && fold.range.toString() == range.toString()) {
            this.expandFold(fold);
            return;
        }

        var placeholder = "...";
        if (!range.isMultiLine()) {
            placeholder = this.getTextRange(range);
            if(placeholder.length < 4)
                return;
            placeholder = placeholder.trim().substring(0, 2) + "..";
        }

        this.addFold(placeholder, range);
    };

    this.getCommentFoldRange = function(row, column, dir) {
        var iterator = new TokenIterator(this, row, column);
        var token = iterator.getCurrentToken();
        if (token && /^comment|string/.test(token.type)) {
            var range = new Range();
            var re = new RegExp(token.type.replace(/\..*/, "\\."));
            if (dir != 1) {
                do {
                    token = iterator.stepBackward();
                } while(token && re.test(token.type));
                iterator.stepForward();
            }
            
            range.start.row = iterator.getCurrentTokenRow();
            range.start.column = iterator.getCurrentTokenColumn() + 2;

            iterator = new TokenIterator(this, row, column);
            
            if (dir != -1) {
                do {
                    token = iterator.stepForward();
                } while(token && re.test(token.type));
                token = iterator.stepBackward();
            } else
                token = iterator.getCurrentToken();

            range.end.row = iterator.getCurrentTokenRow();
            range.end.column = iterator.getCurrentTokenColumn() + token.value.length - 2;
            return range;
        }
    };

    this.foldAll = function(startRow, endRow) {
        var foldWidgets = this.foldWidgets;
        endRow = endRow || this.getLength();
        for (var row = startRow || 0; row < endRow; row++) {
            if (foldWidgets[row] == null)
                foldWidgets[row] = this.getFoldWidget(row);
            if (foldWidgets[row] != "start")
                continue;

            var range = this.getFoldWidgetRange(row);
            // sometimes range can be incompatible with existing fold
            // wouldn't it be better for addFold to return null istead of throwing?
            if (range && range.end.row <= endRow) try {
                this.addFold("...", range);
            } catch(e) {}
        }
    };
    
    this.$foldStyles = {
        "manual": 1,
        "markbegin": 1,
        "markbeginend": 1
    };
    this.$foldStyle = "markbegin";
    this.setFoldStyle = function(style) {
        if (!this.$foldStyles[style])
            throw new Error("invalid fold style: " + style + "[" + Object.keys(this.$foldStyles).join(", ") + "]");
        
        if (this.$foldStyle == style)
            return;

        this.$foldStyle = style;
        
        if (style == "manual")
            this.unfold();
        
        // reset folding
        var mode = this.$foldMode;
        this.$setFolding(null);
        this.$setFolding(mode);
    };

    // structured folding
    this.$setFolding = function(foldMode) {
        if (this.$foldMode == foldMode)
            return;
            
        this.$foldMode = foldMode;
        
        this.removeListener('change', this.$updateFoldWidgets);
        this._emit("changeAnnotation");
        
        if (!foldMode || this.$foldStyle == "manual") {
            this.foldWidgets = null;
            return;
        }
        
        this.foldWidgets = [];
        this.getFoldWidget = foldMode.getFoldWidget.bind(foldMode, this, this.$foldStyle);
        this.getFoldWidgetRange = foldMode.getFoldWidgetRange.bind(foldMode, this, this.$foldStyle);
        
        this.$updateFoldWidgets = this.updateFoldWidgets.bind(this);
        this.on('change', this.$updateFoldWidgets);
        
    };

    this.onFoldWidgetClick = function(row, e) {
        e = e.domEvent;
        var type = this.getFoldWidget(row);
        var line = this.getLine(row);
        var onlySubfolds = e.shiftKey;
        var addSubfolds = onlySubfolds || e.ctrlKey || e.altKey || e.metaKey;
        var fold;

        if (type == "end")
            fold = this.getFoldAt(row, 0, -1);
        else
            fold = this.getFoldAt(row, line.length, 1);

        if (fold) {
            if (addSubfolds)
                this.removeFold(fold);
            else
                this.expandFold(fold);
            return;
        }

        var range = this.getFoldWidgetRange(row);
        if (range) {
            // sometimes singleline folds can be missed by the code above
            if (!range.isMultiLine()) {
                fold = this.getFoldAt(range.start.row, range.start.column, 1);
                if (fold && range.isEqual(fold.range)) {
                    this.removeFold(fold);
                    return;
                }
            }
            
            if (!onlySubfolds)
                this.addFold("...", range);

            if (addSubfolds)
                this.foldAll(range.start.row + 1, range.end.row);
        } else {
            if (addSubfolds)
                this.foldAll(row + 1, this.getLength());
            (e.target || e.srcElement).className += " ace_invalid"
        }
    };
    
    this.updateFoldWidgets = function(e) {
        var delta = e.data;
        var range = delta.range;
        var firstRow = range.start.row;
        var len = range.end.row - firstRow;

        if (len === 0) {
            this.foldWidgets[firstRow] = null;
        } else if (delta.action == "removeText" || delta.action == "removeLines") {
            this.foldWidgets.splice(firstRow, len + 1, null);
        } else {
            var args = Array(len + 1);
            args.unshift(firstRow, 1);
            this.foldWidgets.splice.apply(this.foldWidgets, args);
        }
    };

}

exports.Folding = Folding;

});
