/*jshint expr:true, onevar:false */

/**
Provides the `Selection` class, which normalizes text selection functionality
across browsers.

@module gallery-sm-selection
@main gallery-sm-selection
**/

/**
Normalizes text selection functionality across browsers.

@class Selection
@constructor
**/

var doc = Y.config.doc,
    win = Y.config.win,

    isHTML5 = !!(win && win.getSelection);

var Selection = isHTML5 ? function () {
    this._selection = win.getSelection();
} : function () {
    this._selection = doc.selection;
};

Selection.prototype = {
    // -- Public Methods -------------------------------------------------------

    anchorNode: isHTML5 ? function () {
        return this._selection.anchorNode;
    } : function () {
        throw new Error('Not yet implemented.');
    },

    // anchorOffset: function () {},

    // collapse (toStart/toEnd)
    // containsNode
    // deleteFromDocument
    // extend

    // focusNode: function () {},

    // focusOffset: function () {},

    // isCollapsed: function () {},

    // modify

    rangeCount: isHTML5 ? function () {
        return this._selection.rangeCount;
    } : function () {
        throw new Error('Not yet implemented.');
    },

    /**
    Returns the `Range` instance at the specified _index_, or the first range in
    this selection if no index is specified. If no ranges are selected, returns
    `null`.

    @method range
    @param {Number} [index=0] Range index.
    @return {Range} Range instance at the specified _index_, or the first range
        in this selection if no index is specified. If no ranges are selected,
        returns `null`.
    **/
    range: isHTML5 ? function (index) {
        return this.rangeCount() ?
            new Y.Range(this._selection.getRangeAt(index || 0)) : null;
    } : function () {
        throw new Error('Not yet implemented.');
    },

    /**
    Returns an array containing all the ranges in this selection.

    @method ranges
    @return {Range[]} Array containing all the ranges in this selection.
    **/
    ranges: function () {
        var ranges = [];

        for (var i = 0, len = this.rangeCount(); i < len; i++) {
            ranges.push(this.range(i));
        }

        return ranges;
    },

    /**
    Selects the specified _range_.

    By default, this will result in only this range being selected. If
    `options.multi` is truthy, then the _range_ will be added to the current
    selection without first unselecting any other selected ranges.

    @method select
    @param {Range} range Range to select.
    @param {Object} [options] Options.
        @param {Boolean} [options.multi=false] If `true`, the specified _range_
            will be added to the current list of selected ranges instead of
            replacing the current selection.
    @chainable
    **/
    select: isHTML5 ? function (range, options) {
        if (!options || !options.multi) {
            this.unselect();
        }

        this._selection.addRange(range._range);
        return this;
    } : function () {
        throw new Error('Not yet implemented.');
    },

    /**
    Removes the specified _range_ from this selection, or unselects all ranges
    if no _range_ is specified.

    @method unselect
    @param {Range} [range] Range to unselect.
    @chainable
    **/
    unselect: isHTML5 ? function (range) {
        if (range) {
            this._selection.removeRange(range._range);
        } else {
            this._selection.removeAllRanges();
        }

        return this;
    } : function () {
        throw new Error('Not yet implemented.');
    },

    // selectAllChildren
    // selectionLanguageChange?

    /**
    Returns a string representation of the combined text content of all the
    ranges in this selection.

    @method toString
    @return {String} String representation of the combined text content of all
        the ranges in this selection.
    **/
    toString: function () {
        var ranges = this.ranges(),
            string = '';

        for (var i = 0, len = ranges.length; i < len; i++) {
            string += ranges[i].toString();
        }

        return string;
    }
};

Y.Selection = Selection;