/*!
 * Socket.IO - Listener
 * Copyright (c) 2010-2011 Guillermo Rauch <guillermo@learnboost.com>
 * MIT Licensed
 */

var EventEmitter = require('events').EventEmitter
  , util = require(process.binding('natives').util ? 'util' : 'sys')
  , clientVersion = require('./../../support/socket.io-client/lib/io').io.version
  , Client = require('./client')
  , merge = require('./utils').merge
  , url = require('url')
  , fs = require('fs')
  , transports = {};

/**
 * Supported transports.
 */

var transports = [
    'websocket'
  , 'flashsocket'
  , 'htmlfile'
  , 'xhr-multipart'
  , 'xhr-polling'
  , 'jsonp-polling'
];

/**
 * Expose `Listener`.
 */

module.exports = Listener;

/**
 * Initialize a `Listener` with the given `server` and `options`.
 *
 * @param {http.Server} server
 * @param {Object} options
 * @api private
 */

function Listener(server, options){
  var self = this;
  this.server = server;
  this.clients = this.clientsIndex = {};
  this._clientCount = 0;
  this._clientFiles = {};

  var defaults = {
      origins: '*:*'
    , resource: 'socket.io'
    , flashPolicyServer: true
    , transports: transports
    , transportOptions: {}
    , log: util.log
  };

  merge(this, merge(defaults, options || {}));
  this.log = this.log || function(){};

  
  var listeners = this.server.listeners('request');
  this.server.removeAllListeners('request');
  
  this.server.on('request', function(req, res){
    if (self.check(req, res)) return;
    for (var i = 0, len = listeners.length; i < len; i++){
      listeners[i].call(this, req, res);
    }
  });
  
  this.server.on('upgrade', function(req, socket, head){
    if (!self.check(req, socket, true, head)){
      socket.end();
      socket.destroy();
    }
  });
  
  this.transports.forEach(function(name) {
    if (!(name in transports))
      transports[name] = require('./transports/' + name);
    if ('init' in transports[name]) transports[name].init(self);
  });

  this.log('socket.io ready - accepting connections');
};

/**
 * Inherit from `EventEmitter.prototype`.
 */

Listener.prototype.__proto__ = EventEmitter.prototype;

/**
 * Broadcast `message` to all clients, omitting those specified
 * by the `except` argument.
 *
 * @param {String} message
 * @param {String|Number|Array} except
 * @return {Listener}
 * @api private
 */

Listener.prototype.broadcast = function(message, except){
  var keys = Object.keys(this.clients)
    , len = keys.length
    , key;

  for (var i = 0; i < len; ++i){
    key = keys[i];
    if (except) {
      if (Array.isArray(except) && ~except.indexOf(key)) continue;
      else if (key == except) continue;
    }
    this.clients[key].send(message);
  }

  return this;
};

Listener.prototype.check = function(req, res, httpUpgrade, head){
  var path = url.parse(req.url).pathname
    , parts
    , cn;

  if (path && 0 === path.indexOf('/' + this.resource)){
    parts = path.substr(2 + this.resource.length).split('/');
    if (this._serveClient(parts.join('/'), req, res)) return true;
    if (!(parts[0] in transports)) return false;
    if (parts[1]){
      cn = this.clients[parts[1]];
      if (cn){
        cn._onConnect(req, res);
      } else {
        req.connection.end();
        req.connection.destroy();
        this.log('Couldnt find client with session id "' + parts[1] + '"');
      }
    } else {
      this._onConnection(parts[0], req, res, httpUpgrade, head);
    }
    return true;
  }
  return false;
};

Listener.prototype._serveClient = function(file, req, res){
  var self = this
    , clientPaths = {
        'socket.io.js': 'socket.io.js',
        'lib/vendor/web-socket-js/WebSocketMain.swf': 'lib/vendor/web-socket-js/WebSocketMain.swf', // for compat with old clients
        'WebSocketMain.swf': 'lib/vendor/web-socket-js/WebSocketMain.swf'
      }
    , types = {
        swf: 'application/x-shockwave-flash',
        js: 'text/javascript'
      };
  
  function write(path){
    if (req.headers['if-none-match'] == clientVersion){
      res.writeHead(304);
      res.end();
    } else {
      res.writeHead(200, self._clientFiles[path].headers);
      res.end(self._clientFiles[path].content, self._clientFiles[path].encoding);
    }
  };
  
  var path = clientPaths[file];
  
  if (req.method == 'GET' && path !== undefined){
    if (path in this._clientFiles){
      write(path);
      return true;
    }
    
    fs.readFile(__dirname + '/../../support/socket.io-client/' + path, function(err, data){
      if (err){
        res.writeHead(404);
        res.end('404');
      } else {
        var ext = path.split('.').pop();
        self._clientFiles[path] = {
          headers: {
            'Content-Length': data.length,
            'Content-Type': types[ext],
            'ETag': clientVersion
          },
          content: data,
          encoding: ext == 'swf' ? 'binary' : 'utf8'
        };
        write(path);
      }
    });
    
    return true;
  }
  
  return false;
};

Listener.prototype._onClientConnect = function(client){
  this.clients[client.sessionId] = client;
  this.log('Client '+ client.sessionId +' connected');
  this.emit('clientConnect', client);
  this.emit('connection', client);
};

Listener.prototype._onClientMessage = function(data, client){
  this.emit('clientMessage', data, client);
};

Listener.prototype._onClientDisconnect = function(client){
  delete this.clients[client.sessionId];
  this.log('Client '+ client.sessionId +' disconnected');
  this.emit('clientDisconnect', client);
};

Listener.prototype._onConnection = function(transport, req, res, httpUpgrade, head){
  this.log('Initializing client with transport "'+ transport +'"');
  new transports[transport](this, req, res, this.transportOptions[transport], head);
};