module.exports = {
    userId: null,
    imageGroupList: function() {
        return {
            'secion': 'secion',
            'user': 'user',
            'admin': 'admin',
            'player': 'player'
        }
    },
    imageGroup: null,
    decodeBase64Image: function(dataString, imageGroup, userId) {
        this.userId = userId;
        this.imageGroup = imageGroup;
        if (this.userId == null && this.userId == null) {
            return new Error('Invalid input');
        }
        var matches = dataString.match(/^data:([A-Za-z-+\/]+);base64,(.+)$/),
            response = {};

        if (matches.length !== 3) {
            return new Error('Invalid input');
        }

        response.type = matches[1];
        response.data = new Buffer(matches[2], 'base64');
        var data = this.imageNameData(dataString);
        var imageName = 'storage/' + this.imageGroup + '/' + data;
        require("fs").writeFile(imageName, response.data, function(err) {
            return new Error('Invalid input');
        });
        // return imageName;
        return {
            path: imageName,
            name: data
        };
    },

    imageNameData: function(data) {
        var imageName = this.userId + '_' + this.imageGroup + '_' + Math.random();
        if (data.indexOf('image/jpeg') > -1) {
            return imageName + '.jpeg';
        }
        if (data.indexOf('image/png') > -1) {
            return imageName + '.png';
        }
        if (data.indexOf('image/gif') > -1) {
            return imageName + '.gif';
        }
    },

    getImage: function(host, image) {
        if (image == null) {
            return '';
        }
        return host + image;
    },

    imagePath: function(containor, name) {
        return containor + '/' + name;
    }


}




-----------------------

use of this lib  in main api
-----------------------

imageProcessing = require('./node_image_save_from_base_64');
imageProcessing.decodeBase64Image(BASE_64_OF_IMAGE, GROUP_NAMELIKE_SECTION, USER_ID_TO_CHECK_AND_IMAGE_NAME_CREATION);