/*!
 * socket.io-node
 * Copyright(c) 2011 LearnBoost <dev@learnboost.com>
 * MIT Licensed
 */

/**
 * Module dependencies.
 */

var crypto = require( 'crypto' )
	, Store = require( '../store' )
	, assert = require( 'assert' );

/**
 * Exports the constructor.
 */

exports = module.exports = Redis;
Redis.Client = Client;

/**
 * Redis store.
 * Options:
 *     - nodeId (fn) gets an id that uniquely identifies this node
 *     - redis (fn) redis constructor, defaults to redis
 *     - redisPub (object) options to pass to the pub redis client
 *     - redisSub (object) options to pass to the sub redis client
 *     - redisClient (object) options to pass to the general redis client
 *     - pack (fn) custom packing, defaults to JSON or msgpack if installed
 *     - unpack (fn) custom packing, defaults to JSON or msgpack if installed
 *
 * @api public
 */

function Redis( opts ) {
	opts = opts || {};

	// node id to uniquely identify this node
	var nodeId = opts.nodeId || function () {
		// by default, we generate a random id
		return Math.abs( Math.random() * Math.random() * Date.now() | 0 );
	};

	this.nodeId = nodeId();

	// packing / unpacking mechanism
	if ( opts.pack ) {
		this.pack = opts.pack;
		this.unpack = opts.unpack;
	} else {
		try {
			var msgpack = require( 'msgpack' );
			this.pack = msgpack.pack;
			this.unpack = msgpack.unpack;
		} catch ( e ) {
			this.pack = JSON.stringify;
			this.unpack = JSON.parse;
		}
	}

	var redis = opts.redis || require( 'redis' )
		, RedisClient = redis.RedisClient;

	// initialize a pubsub client and a regular client
	if ( opts.redisPub instanceof RedisClient ) {
		this.pub = opts.redisPub;
	} else {
		opts.redisPub || (opts.redisPub = {});
		this.pub = redis.createClient( opts.redisPub.port, opts.redisPub.host, opts.redisPub );
	}
	if ( opts.redisSub instanceof RedisClient ) {
		this.sub = opts.redisSub;
	} else {
		opts.redisSub || (opts.redisSub = {});
		this.sub = redis.createClient( opts.redisSub.port, opts.redisSub.host, opts.redisSub );
	}
	if ( opts.redisClient instanceof RedisClient ) {
		this.cmd = opts.redisClient;
	} else {
		opts.redisClient || (opts.redisClient = {});
		this.cmd = redis.createClient( opts.redisClient.port, opts.redisClient.host, opts.redisClient );
	}

	Store.call( this, opts );

	this.sub.setMaxListeners( 0 );
	this.setMaxListeners( 0 );
}
;

/**
 * Inherits from Store.
 */

Redis.prototype.__proto__ = Store.prototype;

/**
 * Publishes a message.
 *
 * @api private
 */

Redis.prototype.publish = function ( name ) {
	var args = Array.prototype.slice.call( arguments, 1 );
	this.pub.publish( name, this.pack( { nodeId : this.nodeId, args : args } ) );
	this.emit.apply( this, ['publish', name].concat( args ) );
};

/**
 * Subscribes to a channel
 *
 * @api private
 */

Redis.prototype.subscribe = function ( name, consumer, fn ) {
	this.sub.subscribe( name );

	if ( consumer || fn ) {
		var self = this;

		self.sub.on( 'subscribe', function subscribe( ch ) {
			if ( name == ch ) {
				function message( ch, msg ) {
					if ( name == ch ) {
						msg = self.unpack( msg );

						// we check that the message consumed wasnt emitted by this node
						if ( self.nodeId != msg.nodeId ) {
							consumer.apply( null, msg.args );
						}
					}
				}

				;

				self.sub.on( 'message', message );

				self.on( 'unsubscribe', function unsubscribe( ch ) {
					if ( name == ch ) {
						self.sub.removeListener( 'message', message );
						self.removeListener( 'unsubscribe', unsubscribe );
					}
				} );

				self.sub.removeListener( 'subscribe', subscribe );

				fn && fn();
			}
		} );
	}

	this.emit( 'subscribe', name, consumer, fn );
};

/**
 * Unsubscribes
 *
 * @api private
 */

Redis.prototype.unsubscribe = function ( name, fn ) {
	this.sub.unsubscribe( name );

	if ( fn ) {
		var client = this.sub;

		client.on( 'unsubscribe', function unsubscribe( ch ) {
			if ( name == ch ) {
				fn();
				client.removeListener( 'unsubscribe', unsubscribe );
			}
		} );
	}

	this.emit( 'unsubscribe', name, fn );
};

/**
 * Destroys the store
 *
 * @api public
 */

Redis.prototype.destroy = function () {
	Store.prototype.destroy.call( this );

	this.pub.end();
	this.sub.end();
	this.cmd.end();
};

/**
 * Client constructor
 *
 * @api private
 */

function Client( store, id ) {
	Store.Client.call( this, store, id );
}
;

/**
 * Inherits from Store.Client
 */

Client.prototype.__proto__ = Store.Client;

/**
 * Redis hash get
 *
 * @api private
 */

Client.prototype.get = function ( key, fn ) {
	this.store.cmd.hget( this.id, key, fn );
	return this;
};

/**
 * Redis hash set
 *
 * @api private
 */

Client.prototype.set = function ( key, value, fn ) {
	this.store.cmd.hset( this.id, key, value, fn );
	return this;
};

/**
 * Redis hash del
 *
 * @api private
 */

Client.prototype.del = function ( key, fn ) {
	this.store.cmd.hdel( this.id, key, fn );
	return this;
};

/**
 * Redis hash has
 *
 * @api private
 */

Client.prototype.has = function ( key, fn ) {
	this.store.cmd.hexists( this.id, key, function ( err, has ) {
		if ( err ) {
			return fn( err );
		}
		fn( null, !!has );
	} );
	return this;
};

/**
 * Destroys client
 *
 * @param {Number} number of seconds to expire data
 * @api private
 */

Client.prototype.destroy = function ( expiration ) {
	if ( 'number' != typeof expiration ) {
		this.store.cmd.del( this.id );
	} else {
		this.store.cmd.expire( this.id, expiration );
	}

	return this;
};