"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.commentBlock = function(session, row) {
        var re = /\S/;
        var line = session.getLine(row);
        var startLevel = line.search(re);
        if (startLevel == -1 || line[startLevel] != "#")
            return;

        var startColumn = line.length;
        var maxRow = session.getLength();
        var startRow = row;
        var endRow = row;

        while (++row < maxRow) {
            line = session.getLine(row);
            var level = line.search(re);

            if (level == -1)
                continue;

            if (line[level] != "#")
                break;

            endRow = row;
        }

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

    this.getFoldWidgetRange = function(session, foldStyle, row) {
        var range = this.indentationBlock(session, row);
        if (range)
            return range;

        range = this.commentBlock(session, row);
        if (range)
            return range;
    };

    // must return "" if there's no fold, to enable caching
    this.getFoldWidget = function(session, foldStyle, row) {
        var line = session.getLine(row);
        var indent = line.search(/\S/);
        var next = session.getLine(row + 1);
        var prev = session.getLine(row - 1);
        var prevIndent = prev.search(/\S/);
        var nextIndent = next.search(/\S/);

        if (indent == -1) {
            session.foldWidgets[row - 1] = prevIndent!= -1 && prevIndent < nextIndent ? "start" : "";
            return "";
        }

        // documentation comments
        if (prevIndent == -1) {
            if (indent == nextIndent && line[indent] == "#" && next[indent] == "#") {
                session.foldWidgets[row - 1] = "";
                session.foldWidgets[row + 1] = "";
                return "start";
            }
        } else if (prevIndent == indent && line[indent] == "#" && prev[indent] == "#") {
            if (session.getLine(row - 2).search(/\S/) == -1) {
                session.foldWidgets[row - 1] = "start";
                session.foldWidgets[row + 1] = "";
                return "";
            }
        }

        if (prevIndent!= -1 && prevIndent < indent)
            session.foldWidgets[row - 1] = "start";
        else
            session.foldWidgets[row - 1] = "";

        if (indent < nextIndent)
            return "start";
        else
            return "";
    };

}).call(FoldMode.prototype);
