Promises are good qualities

var Promise = require("bluebird");
var bcrypt = Promise.promisifyAll(require('bcrypt-nodejs'));
var config = require(global.base + 'config.json');
var gcloud = Promise.promisifyAll(require('gcloud')({
  projectId: config.app.projectId,
  keyFilename: config.app.keyFilename
}));
var bunyan = require('bunyan');

var log = bunyan.createLogger({name: 'main'});
var dataset = Promise.promisifyAll(gcloud.datastore.dataset({namespace: 'users'}));

module.exports.getUser = function(id){
    return new Promise(function(resolve) {
        //we must have a callback here because google is no fun and will not let us pass resolve
        dataset.get(dataset.key(['User', id]), function(err, entity){
            if(err)
                throw err;
            resolve(entity)
        });
    });
}

module.exports.register = function(data){
    return new Promise(function(resolve) {
        log.info("registering user");

        var key = dataset.key(['User', data.email]);

        //we must have a callback here because google is no fun and will not let us pass resolve
        dataset.save({ key: key, data: data }, function(err){
            if(err)
                throw err;
        });
    });
}

module.exports.reqRegister = function(req, res){
    return new Promise(function initialChecks(resolve){
        log.info("register request");
        var email = req.body.email;
        var password = req.body.password;
        var tos = req.body.tos != '0';

        if(!tos){
            throw 'Must accept TOS';
        }

        if(email == null || password == null){
            throw 'Must fill entire form';
        }

        if(false){
            throw 'Must enter valid email';
        }

        if(password.length < 6){
            throw 'Password must be 6 characters long';
        }

        if(password.length > 256 || email.length > 256){
            throw 'Email and password may not exceed 256 characters';
        }
        log.info("passed basic checks");
        resolve(email);
    })
    .then(module.exports.getUser)
    .then(function userExistsCheck( entity){
        if(entity != null){
            throw req.body.email + ' is in use';
        }
        log.info("user does not exist");
        return req.body.password;
    })
    .then(function jsonify(password){
        log.info("jsonifying");
        return {
            email : req.body.email,
            password : bcrypt.hashSync(password)
        };
    })
    .then(module.exports.register)
    .then(function success(){
        log.info("Success!");

        //login user here
    })
    .catch(function error(err){
        log.error(err);

        var data = {
            error: err
        }

        res.json(data);
    });
}