// @ts-nocheck
"use strict";

var Range = require("../range").Range;
var FoldLine = require("./fold_line").FoldLine;
var Fold = require("./fold").Fold;
var TokenIterator = require("../token_iterator").TokenIterator;
var MouseEvent = require("../mouse/mouse_event").MouseEvent;

/**
 * @typedef {import("../edit_session").EditSession & import("../../ace-internal").Ace.Folding} IFolding
 * @typedef {import("../../ace-internal").Ace.Delta } Delta
 */

/**
 * @this {IFolding}
 * @type {IFolding}
 */
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
     * @param {number} row
     * @param {number} column
     * @param {number} [side]
     * @return {Fold}
     **/
    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 range = folds[i].range;
            if (range.contains(row, column)) {
                if (side == 1 && range.isEnd(row, column) && !range.isEmpty()) {
                    continue;
                } else if (side == -1 && range.isStart(row, column) && !range.isEmpty()) {
                    continue;
                }
                return folds[i];
            }
        }
    };

    /**
     * Returns all folds in the given range. Note, that this will return folds
     * @param {Range| Delta} range
     * @returns {Fold[]}
     **/
    this.getFoldsInRange = function(range) {
        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);
            }
        }
        start.column -= 1;
        end.column += 1;

        return foundFolds;
    };

    /**
     * 
     * @param {Range[]|Range}ranges
     * @returns {Fold[]}
     */
    this.getFoldsInRangeList = function(ranges) {
        if (Array.isArray(ranges)) {
            /**@type {Fold[]} */
            var folds = [];
            ranges.forEach(function(range) {
                folds = folds.concat(this.getFoldsInRange(range));
            }, this);
        } else {
            var folds = this.getFoldsInRange(ranges);
        }
        return folds;
    };
    
    /**
     * Returns all folds in the document
     * @returns {Fold[]}
     */
    this.getAllFolds = function() {
        var folds = [];
        var foldLines = this.$foldData;
        
        for (var i = 0; i < foldLines.length; i++)
            for (var j = 0; j < foldLines[i].folds.length; j++)
                folds.push(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"
     *  @param {number} row
     *  @param {number} column
     *  @param {number} [trim]
     *  @param {FoldLine} [foldLine]
     *  @returns {string | null}
     */
    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;
    };

    /**
     * 
     * @param {number} docRow
     * @param {FoldLine} [startFoldLine]
     * @returns {null|FoldLine}
     */
    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
     * @param {number} docRow
     * @param {FoldLine} [startFoldLine]
     * @returns {null|FoldLine}
     */
    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;
    };

    /**
     * 
     * @param {number} first
     * @param {number} last
     * @return {number}
     */
    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;
    };

    /**
     * 
     * @param {FoldLine}foldLine
     * @return {FoldLine}
     */
    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.
     *
     * @param {Fold|string} placeholder
     * @param {Range} [range]
     * @returns {Fold}
     *      The new created Fold object or an existing fold object in case the
     *      passed in range fits an existing fold exactly.
     * @this {IFolding}
     */
    this.addFold = function(placeholder, range) {
        var foldData = this.$foldData;
        var added = false;
        /**@type {Fold}*/
        var fold;
        
        if (placeholder instanceof Fold)
            fold = placeholder;
        else {
            fold = new Fold(range, placeholder);
            // @ts-ignore
            fold.collapseChildren = range.collapseChildren;
        }
        this.$clipRangeToDocument(fold.range);

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

        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))
            this.removeFold(startFold);
        
        if (endFold && !endFold.range.isEnd(endRow, endColumn))
            this.removeFold(endFold);
        
        // 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.
            if (!fold.collapseChildren) {
                folds.forEach(function(subFold) {
                    fold.addSubFold(subFold);
                });
            }
        }

        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._signal("changeFold", { data: fold, action: "add" });

        return fold;
    };

    /**
     * @param {Fold[]} folds
     */
    this.addFolds = function(folds) {
        folds.forEach(function(fold) {
            this.addFold(fold);
        }, this);
    };

    /**
     * 
     * @param {Fold} fold
     */
    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.$updating) {
            if (this.$useWrapMode)
                this.$updateWrapData(startRow, endRow);
            else
                this.$updateRowLengthCache(startRow, endRow);
        }
        
        // Notify that fold data has changed.
        this.$modified = true;
        this._signal("changeFold", { data: fold, action: "remove" });
    };

    /**
     * 
     * @param {Fold[]} folds
     */
    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;
    };

    /**
     * @param {Fold} fold
     */
    this.expandFold = function(fold) {
        this.removeFold(fold);
        fold.subFolds.forEach(function(subFold) {
            fold.restoreRange(subFold);
            this.addFold(subFold);
        }, this);
        if (fold.collapseChildren > 0) {
            this.foldAll(fold.start.row+1, fold.end.row, fold.collapseChildren-1);
        }
        fold.subFolds = [];
    };

    /**
     * @param {Fold[]}folds
     */
    this.expandFolds = function(folds) {
        folds.forEach(function(fold) {
            this.expandFold(fold);
        }, this);
    };

    /**
     * 
     * @param {number|null|import("../../ace-internal").Ace.Point|Range|Range[]} [location]
     * @param {boolean} [expandInner]
     * @return {Fold[]| undefined}
     */
    this.unfold = function(location, expandInner) {
        var range, folds;
        if (location == null) {
            range = new Range(0, 0, this.getLength(), 0);
            if (expandInner == null) expandInner = true;
        } 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 if (Array.isArray(location)) {
            folds = [];
            location.forEach(function(range) {
                folds = folds.concat(this.unfold(range));
            }, this);
            return folds;
        } else {
            range = location;
        }
        
        folds = this.getFoldsInRangeList(range);
        var outermostFolds = folds;
        // if range itself is in a fold, expand that fold instead of removing, 
        // to not accidentally remove sibling folds
        while (
            folds.length == 1
            && Range.comparePoints(folds[0].start, range.start) < 0 
            && Range.comparePoints(folds[0].end, range.end) > 0
        ) {
            this.expandFolds(folds);
            folds = this.getFoldsInRangeList(range);
        }
        
        if (expandInner != false) {
            this.removeFolds(folds);
        } else {
            this.expandFolds(folds);
        }
        if (outermostFolds.length)
            return outermostFolds;
    };

    /**
     * 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.
     * @param {number} docRow
     * @param {FoldLine} [startFoldRow]
     * @returns {boolean}
     **/
    this.isRowFolded = function(docRow, startFoldRow) {
        return !!this.getFoldLine(docRow, startFoldRow);
    };

    /**
     * 
     * @param {number} docRow
     * @param {FoldLine} [startFoldRow]
     * @return {number}
     */
    this.getRowFoldEnd = function(docRow, startFoldRow) {
        var foldLine = this.getFoldLine(docRow, startFoldRow);
        return foldLine ? foldLine.end.row : docRow;
    };

    /**
     * 
     * @param {number} docRow
     * @param {FoldLine} [startFoldRow]
     * @returns {number}
     */
    this.getRowFoldStart = function(docRow, startFoldRow) {
        var foldLine = this.getFoldLine(docRow, startFoldRow);
        return foldLine ? foldLine.start.row : docRow;
    };

    /**
     * 
     * @param {FoldLine} foldLine
     * @param {number | null} [endRow]
     * @param {number | null} [endColumn]
     * @param {number | null} [startRow]
     * @param {number | null} [startColumn]
     * @return {string}
     */
    this.getFoldDisplayLine = function(foldLine, endRow, endColumn, startRow, startColumn) {
        if (startRow == null)
            startRow = foldLine.start.row;
        if (startColumn == null)
            startColumn = 0;
        if (endRow == null)
            endRow = foldLine.end.row;
        if (endColumn == null)
            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;
            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);
            }
        }, endRow, endColumn);
        return textLine;
    };

    /**
     * 
     * @param {number} row
     * @param {number | null} endColumn
     * @param {number | null} startRow
     * @param {number | null} startColumn
     * @return {string}
     */
    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);
        }
    };

    /**
     * @return {FoldLine[]}
     */
    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;
    };

    /**
     * @param {boolean} [tryToUnfold]
     */
    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 (tryToUnfold) {
                var foldLine = this.getFoldLine(cursor.row);
                if (foldLine)
                    this.expandFolds(foldLine.folds);
                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);
    };

    /**
     * 
     * @param {number} row
     * @param {number} column
     * @param {number} [dir]
     * @return {Range | undefined}
     */
    this.getCommentFoldRange = function(row, column, dir) {
        var iterator = new TokenIterator(this, row, column);
        var token = iterator.getCurrentToken();
        var type = token && token.type;
        if (token && /^comment|string/.test(type)) {
            type = type.match(/comment|string/)[0];
            if (type == "comment")
                type += "|doc-start|\\.doc";
            var re = new RegExp(type);
            var range = new Range();
            if (dir != 1) {
                do {
                    token = iterator.stepBackward();
                } while (token && re.test(token.type));
                token = iterator.stepForward();
            }
            
            range.start.row = iterator.getCurrentTokenRow();
            range.start.column = iterator.getCurrentTokenColumn() + token.value.length;

            iterator = new TokenIterator(this, row, column);
            var initState = this.getState(iterator.$row);
            
            if (dir != -1) {
                var lastRow = -1;
                do {
                    token = iterator.stepForward();
                    if (lastRow == -1) {
                        var state = this.getState(iterator.$row);
                        if (initState.toString() !== state.toString())
                            lastRow = iterator.$row;
                    } else if (iterator.$row > lastRow) {
                        break;
                    }
                } while (token && re.test(token.type));
                token = iterator.stepBackward();
            } else
                token = iterator.getCurrentToken();

            range.end.row = iterator.getCurrentTokenRow();
            range.end.column = iterator.getCurrentTokenColumn();
            if (range.start.row == range.end.row && range.start.column > range.end.column)
                return;
            return range;
        }
    };

    /**
     * 
     * @param {number | null} [startRow]
     * @param {number | null} [endRow]
     * @param {number | null} [depth]
     * @param {Function} [test]
     */
    this.foldAll = function(startRow, endRow, depth, test) {
        if (depth == undefined)
            depth = 100000; // JSON.stringify doesn't hanle Infinity
        var foldWidgets = this.foldWidgets;
        if (!foldWidgets)
            return; // mode doesn't support folding
        endRow = endRow || this.getLength();
        startRow = startRow || 0;
        for (var row = startRow; row < endRow; row++) {
            if (foldWidgets[row] == null)
                foldWidgets[row] = this.getFoldWidget(row);
            if (foldWidgets[row] != "start")
                continue;
            
            if (test && !test(row)) continue;

            var range = this.getFoldWidgetRange(row);
            if (range && range.isMultiLine()
                && range.end.row <= endRow
                && range.start.row >= startRow
            ) {
                row = range.end.row;
                range.collapseChildren = depth;
                // addFold can change the range
                this.addFold("...", range);
            }
        }
    };

    /**
     * 
     * @param {number} level
     */
    this.foldToLevel = function(level) {
        this.foldAll();
        while (level-- > 0)
            this.unfold(null, false);
    };

    /**
     *
     */
    this.foldAllComments = function() {
        var session = this;
        this.foldAll(null, null, null, function(row) {
            var tokens = session.getTokens(row);
            for (var i = 0; i < tokens.length; i++) {
                var token = tokens[i];
                if (token.type == "text" && /^\s+$/.test(token.value))
                    continue;
                if (/comment/.test(token.type))
                    return true;
                return false;
            }
        });
    };
    
    // structured folding
    this.$foldStyles = {
        "manual": 1,
        "markbegin": 1,
        "markbeginend": 1
    };
    this.$foldStyle = "markbegin";
    
    /**
     * @param {string} style
     */
    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);
    };

    /**
     * @param {import("../../ace-internal").Ace.FoldMode} foldMode
     */
    this.$setFolding = function(foldMode) {
        if (this.$foldMode == foldMode)
            return;


        this.$foldMode = foldMode;
        
        this.off('change', this.$updateFoldWidgets);
        this.off('tokenizerUpdate', this.$tokenizerUpdateFoldWidgets);
        this._signal("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.$updateFoldWidgets = this.updateFoldWidgets.bind(this);
        this.$tokenizerUpdateFoldWidgets = this.tokenizerUpdateFoldWidgets.bind(this);
        this.on('change', this.$updateFoldWidgets);
        this.on('tokenizerUpdate', this.$tokenizerUpdateFoldWidgets);
    };
    /**
     * @param {number} row
     * @param {boolean} [ignoreCurrent]
     * @return {{range?: Range, firstRange?: Range}}
     */
    this.getParentFoldRangeData = function (row, ignoreCurrent) {
        var fw = this.foldWidgets;
        if (!fw || (ignoreCurrent && fw[row]))
            return {};

        var i = row - 1, firstRange;
        while (i >= 0) {
            var c = fw[i];
            if (c == null)
                c = fw[i] = this.getFoldWidget(i);

            if (c == "start") {
                var range = this.getFoldWidgetRange(i);
                if (!firstRange)
                    firstRange = range;
                if (range && range.end.row >= row)
                    break;
            }
            i--;
        }

        return {
            range: i !== -1 && range,
            firstRange: firstRange
        };
    };

    /**
     * 
     * @param {number} row
     * @param {any} e
     */
    this.onFoldWidgetClick = function(row, e) {
        if (e instanceof MouseEvent)
            e = e.domEvent;

        var options = {
            children: e.shiftKey,
            all: e.ctrlKey || e.metaKey,
            siblings: e.altKey
        };
        
        var range = this.$toggleFoldWidget(row, options);
        if (!range) {
            var el = (e.target || e.srcElement);
            if (el && /ace_fold-widget/.test(el.className))
                el.className += " ace_invalid";
        }
    };

    /**
     * 
     * @param {number} row
     * @param options
     * @return {Fold|*}
     */
    this.$toggleFoldWidget = function(row, options) {
        if (!this.getFoldWidget)
            return;
        var type = this.getFoldWidget(row);
        var line = this.getLine(row);

        var dir = type === "end" ? -1 : 1;
        var fold = this.getFoldAt(row, dir === -1 ? 0 : line.length, dir);

        if (fold) {
            if (options.children || options.all)
                this.removeFold(fold);
            else
                this.expandFold(fold);
            return fold;
        }

        var range = this.getFoldWidgetRange(row, true);
        // sometimes singleline folds can be missed by the code above
        if (range && !range.isMultiLine()) {
            fold = this.getFoldAt(range.start.row, range.start.column, 1);
            if (fold && range.isEqual(fold.range)) {
                this.removeFold(fold);
                return fold;
            }
        }
        
        if (options.siblings) {
            var data = this.getParentFoldRangeData(row);
            if (data.range) {
                var startRow = data.range.start.row + 1;
                var endRow = data.range.end.row;
            }
            this.foldAll(startRow, endRow, options.all ? 10000 : 0);
        } else if (options.children) {
            endRow = range ? range.end.row : this.getLength();
            this.foldAll(row + 1, endRow, options.all ? 10000 : 0);
        } else if (range) {
            if (options.all) 
                range.collapseChildren = 10000;
            this.addFold("...", range);
        }
        
        return range;
    };
    
    /**
     * 
     * @param {boolean} [toggleParent]
     */
    this.toggleFoldWidget = function(toggleParent) {
        var row = this.selection.getCursor().row;
        row = this.getRowFoldStart(row);
        var range = this.$toggleFoldWidget(row, {});
        
        if (range)
            return;
        // handle toggleParent
        var data = this.getParentFoldRangeData(row, true);
        range = data.range || data.firstRange;
        
        if (range) {
            row = range.start.row;
            var fold = this.getFoldAt(row, this.getLine(row).length, 1);

            if (fold) {
                this.removeFold(fold);
            } else {
                this.addFold("...", range);
            }
        }
    };

    /**
     * @param {Delta} delta
     */
    this.updateFoldWidgets = function(delta) {
        var firstRow = delta.start.row;
        var len = delta.end.row - firstRow;

        if (len === 0) {
            this.foldWidgets[firstRow] = null;
        } else if (delta.action == 'remove') {
            this.foldWidgets.splice(firstRow, len + 1, null);
        } else {
            var args = Array(len + 1);
            args.unshift(firstRow, 1);
            this.foldWidgets.splice.apply(this.foldWidgets, args);
        }
    };
    /**
     * @param e
     */
    this.tokenizerUpdateFoldWidgets = function(e) {
        var rows = e.data;
        if (rows.first != rows.last) {
            if (this.foldWidgets.length > rows.first)
                this.foldWidgets.splice(rows.first, this.foldWidgets.length);
        }
    };
}

exports.Folding = Folding;
