/** @fileOverview Module for internal BEM helpers */
/** @requires BEM */

(function(BEM, $, undefined) {

/**
 * Separator for modifiers and their values
 * @const
 * @type String
 */
var MOD_DELIM = '_',

/**
 * Separator between names of a block and a nested element
 * @const
 * @type String
 */
    ELEM_DELIM = '__',

/**
 * Pattern for acceptable element and modifier names
 * @const
 * @type String
 */
    NAME_PATTERN = '[a-zA-Z0-9-]+';

function buildModPostfix(modName, modVal, buffer) {

    buffer.push(MOD_DELIM, modName, MOD_DELIM, modVal);

}

function buildBlockClass(name, modName, modVal, buffer) {

    buffer.push(name);
    modVal && buildModPostfix(modName, modVal, buffer);

}

function buildElemClass(block, name, modName, modVal, buffer) {

    buildBlockClass(block, undefined, undefined, buffer);
    buffer.push(ELEM_DELIM, name);
    modVal && buildModPostfix(modName, modVal, buffer);

}

BEM.INTERNAL = {

    NAME_PATTERN : NAME_PATTERN,

    MOD_DELIM : MOD_DELIM,
    ELEM_DELIM : ELEM_DELIM,

    buildModPostfix : function(modName, modVal, buffer) {

        var res = buffer || [];
        buildModPostfix(modName, modVal, res);
        return buffer? res : res.join('');

    },

    /**
     * Builds the class of a block or element with a modifier
     * @private
     * @param {String} block Block name
     * @param {String} [elem] Element name
     * @param {String} [modName] Modifier name
     * @param {String} [modVal] Modifier value
     * @param {Array} [buffer] Buffer
     * @returns {String|Array} Class or buffer string (depending on whether the buffer parameter is present)
     */
    buildClass : function(block, elem, modName, modVal, buffer) {

        var typeOf = typeof modName;
        if(typeOf == 'string') {
            if(typeof modVal != 'string') {
                buffer = modVal;
                modVal = modName;
                modName = elem;
                elem = undefined;
            }
        } else if(typeOf != 'undefined') {
            buffer = modName;
            modName = undefined;
        } else if(elem && typeof elem != 'string') {
            buffer = elem;
            elem = undefined;
        }

        if(!(elem || modName || buffer)) { // оптимизация для самого простого случая
            return block;
        }

        var res = buffer || [];

        elem?
            buildElemClass(block, elem, modName, modVal, res) :
            buildBlockClass(block, modName, modVal, res);

        return buffer? res : res.join('');

    },

    /**
     * Builds full classes for a buffer or element with modifiers
     * @private
     * @param {String} block Block name
     * @param {String} [elem] Element name
     * @param {Object} [mods] Modifiers
     * @param {Array} [buffer] Buffer
     * @returns {String|Array} Class or buffer string (depending on whether the buffer parameter is present)
     */
    buildClasses : function(block, elem, mods, buffer) {

        if(elem && typeof elem != 'string') {
            buffer = mods;
            mods = elem;
            elem = undefined;
        }

        var res = buffer || [];

        elem?
            buildElemClass(block, elem, undefined, undefined, res) :
            buildBlockClass(block, undefined, undefined, res);

        mods && $.each(mods, function(modName, modVal) {
            if(modVal) {
                res.push(' ');
                elem?
                    buildElemClass(block, elem, modName, modVal, res) :
                    buildBlockClass(block, modName, modVal, res);
            }
        });

        return buffer? res : res.join('');

        /*var typeOf = typeof elem;
        if(typeOf != 'string' && typeOf != 'undefined') {
            buffer = mods;
            mods = elem;
            elem = undefined;
        }
        if($.isArray(mods)) {
            buffer = mods;
            mods = undefined;
        }

        var res = buffer || [];
        buildClasses(block, elem, mods, res);
        return buffer? res : res.join('');*/

    }

}

})(BEM, jQuery);