amcgee/remjs

var express = require('express');
var _ = require('lodash');
var bodyParser = require('body-parser');
var REMResource = require('./resource');
var BPromise = require('bluebird');

var authentication = require('./plugins/authentication');

var REM = function(options) {
    if ( !options.version ) {
        throw new Error("REM version is required.");
    }
    if ( !options.engine ) {
        throw new Error("REM engine is required.");
    }

    this.options = _.clone(options);

    this.connected = false;
};

REM.prototype.connect = function(callback) {
    var connectFunction = BPromise.delay.bind(null, 1);
    if ( this.options.engine.connect ) {
        connectFunction = this.options.engine.connect.bind(this.options.engine);
    }

    return connectFunction()
    .catch(function(e) {
        throw new Error( "Failed to connect to the database engine.  Error: " + e );
    })
    .bind(this)
    .then(function() {
        this.resources = _.mapValues( _.extend({}, this.options.resources), function( resource_options, resource_name ) {
            resource_options = _.extend({
                engine: this.options.engine,
                permissions: (this.options.authentication? ( this.options.permissions || {} ) : null )
            }, resource_options );
            return new REMResource( resource_name, resource_options );
        }.bind(this) );

        this.createRouter();
        this.connected = true;
    })
    .return(this)
    .nodeify(callback);
};

REM.prototype.createRouter = function() {
    var router = express.Router();

    router.use( function(req, res, next) {
        req.rem = {};
        res.set( 'X-Powered-By', 'Express/REM.js' );
        next();
    } );

    router.use( bodyParser.json() );
    router.use( function( err, req, res, next ) {
        if ( err ) { // TODO: Make sure it's actually a JSON error?
            console.log( "Invalid JSON." );
            res.status(400).send("Invalid JSON.");
        } else {
            next();
        }
    } );

    if ( this.options.authentication ) {
        this.authentication = authentication(this.resources, this.options);
        router.use( this.authentication.router() );
    }

    router.get( '/_version', function( req, res ) {
        res.status(200).send(this.options.version);
    }.bind(this));
    router.get( '/_help', function( req, res ) {
        res.status(200).send(_.keys(this.resources));
    }.bind(this));

    _.forEach( this.resources, function( resource, resource_name ) {
        router.use( "/" + resource_name, resource.router );
    } );

    this.router = router;
};

module.exports = REM;