// This is a simple app that demonstrates how to use the Backbone.js couch-connector.
// It is sort of a real time chat with private messages support.

$(function(){
  // Fill this with your database information.
  // `ddoc_name` is the name of your couchapp project.
  Backbone.couch_connector.config.db_name = "backbone-couchapp";
  Backbone.couch_connector.config.ddoc_name = "backbone_example";
  
  // If set to true, the connector will listen to the changes feed
  // and will provide your models with real time remote updates.
  // But in this case we enable the changes feed for each Collection on our own.
  Backbone.couch_connector.config.global_changes = false;
  
  // Enables Mustache.js-like templating.
  _.templateSettings = {
    interpolate : /\{\{(.+?)\}\}/g
  };
  
  var UserModel = Backbone.Model.extend({
    defaults : {
      name : "Anonymus"
    }
  });
  
  window.CurrentUser = new UserModel();
  
  // The model for a message is kinda simple.
  // We only need a name, a text and a date.
  var MessageModel = Backbone.Model.extend({
    initialize : function(){
      if(!this.get("date")){
        this.set({"date": new Date().getTime()});
      }
    }
  });
  
  // Now let's define a new Collection of Messages
  var MessagesList = Backbone.Collection.extend({
    db : {
      view : "messages",
      changes : true,
      // If you don't know what filters are in CouchDB, then read it up here:
      // <a href="http://guide.couchdb.org/draft/notifications.html#filters">http://guide.couchdb.org/draft/notifications.html#filters</a>
      // Look up how the filter works in `chat_example/filters/private_messages.js`.
      // IMPORTANT: see `filters/messages.js` to see how to retrieve remove events
      filter : Backbone.couch_connector.config.ddoc_name + "/messages"
    },
    // The couchdb-connector is capable of mapping the url scheme
    // proposed by the authors of Backbone to documents in your database,
    // so that you don't have to change existing apps when you switch the sync-strategy
    url : "/messages",
    model : MessageModel,
    // The messages should be ordered by date
    comparator : function(comment){
      return comment.get("date");
    }
  });
  
  var Messages = new MessagesList();

  var PrivateMessage = MessageModel.extend({
  });
  
  // Private messages get an own collection because they need a filter
  var PrivateMessageList = Backbone.Collection.extend({
    db : {
      view : "none__",
      changes : false,
      // The filter avoids that private messages appear in the public stream.
      filter : Backbone.couch_connector.config.ddoc_name + "/private_messages"
    },
    
    url : "/private_messages",
    
    model : PrivateMessage
  });
  
  var PrivateMessages = new PrivateMessageList();

  // Displays the current user's name and the message input field.
  var InputView = Backbone.View.extend({
    el : $('#input'),
    
    regex : /@(\w+)/,
    
    events : {
      "click #send" : "onSubmit",
      "keypress #message" : "keypress"
    },
    
    initialize : function(){
      _.bindAll(this, "onSubmit", "nameChanged", "keypress");
      CurrentUser.bind("change:name", this.nameChanged);
    },
    
    onSubmit : function(){
      var message = $("#message").val();
      // Sanitize messages a bit before we send them to the server.
      message = message.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/"/g, '&quot;');
      if(message.length > 0){
        var executed = this.regex.exec(message);
        // Do a regex check to see if it is a private message
        if(executed != null)
          PrivateMessages.create({
            "from" : CurrentUser.get("name"),
            "to" : executed[1],
            "message" : message.replace(executed[0], "")
          });
        else
          Messages.create({
            "from" : CurrentUser.get("name"),
            "message" : message
          });
      }
      $("#message").val("");
    },
    
    nameChanged : function(){
      $('#name').text(CurrentUser.get('name'));
    },
    
    keypress : function(ev){
      // Send message on ENTER
      if(ev.keyCode == 13)
        this.onSubmit();
    },
    
    fillAndFocus : function(text){
      $('#message').val(text).focus();
    }
  });
  
  // Represents a message entry
  var EntryView = Backbone.View.extend({
    tagName : "li",
    
    template : _.template($("#entry-template").html()),
    
    events : {
      "click .delete" : "delete_me"
    },
    
    // If there's a change in our model, rerender it
    initialize : function(){
      _.bindAll(this, 'render', 'delete_me', 'delete_row');
      this.model.bind('change', this.render);
      this.model.bind('remove', this.delete_row);
    },
    
    render : function(){ 
      var content = this.model.toJSON();
      $(this.el).html(this.template(content));
      return this;
    },
    
    delete_me : function(){
      if(CurrentUser.get('name') == this.model.get('from')){
        this.model.destroy();
        this.delete_row(); 
      }else{
        alert("You can only delete your own messages!");
      }
    },
    
    delete_row : function(){
      $(this.el).remove();
    }
  });
  
  // A private message
  var PrivateEntryView = EntryView.extend({
    className : "private",
    template : _.template($("#private-entry-template").html())
  });
  
  // The view for the chat messages
  var MessagesList = Backbone.View.extend({
    el: $("#messages"),
  
    initialize : function(){
      _.bindAll(this, 'reseted', 'addRow', 'addPrivateRow');
    
      Messages.bind("reset", this.reseted);
      Messages.bind("add", this.addRow);
      PrivateMessages.bind("add", this.addPrivateRow);
    },
  
    // Adds an entry row 
    addRow : function(comment){
      var view = new EntryView({model: comment});
      var rendered = view.render().el;
      this.el.append(rendered);
    },
  
    addPrivateRow : function(private_message){
      var view = new PrivateEntryView({model: private_message});
      var rendered = view.render().el;
      this.el.append(rendered);
    },
  
    // Renders all comments into the table
    reseted : function(){
      // reset the table
      this.el.html("");
      if(Messages.length > 0){
        // add each element
        Messages.each(this.addRow);
      }
    }
  });

  
  var UserSession = Backbone.Model.extend({
  });

  var UserListCollection = Backbone.Collection.extend({
    db : {
      changes : true
    },
    url : "/user_list",
    model : UserSession
  });

  var UserList = new UserListCollection();

  var UserListEntry = Backbone.View.extend({
    tagName : "li",
    className : "user",
  
    initialize : function(){
      _.bindAll(this, 'remove_me');
      
      // When the session gets destroyed, the row will be destroyed too
      this.model.bind("remove", this.remove_me)
    },
  
    render : function(){
      this.el = $(this.el);
      this.el.html("");
      this.el.unbind();
      this.el.text(this.model.get("name"));
      // Insert "@username" into the input field
      var temp = "@" + this.model.get("name") + " ";
      this.el.click(function(){
        Input.fillAndFocus(temp);
      });
      return this.el;
    },
  
    remove_me : function(){
      that = this;
      this.el.fadeOut(function(){
        that.el.remove();
      })
    }
  });
  
  // The list where all usernames are displayed
  var UserListView = Backbone.View.extend({
    el : $('#userlist'),
  
    initialize : function(){
      _.bindAll(this, 'reseted', 'addRow');
      
      // The view listens to the realtime updates of the couchdb changes feed
      UserList.bind("add", this.addRow);
      UserList.bind("reset", this.reseted);
    },
  
    addRow : function(model){
      this.el.append(new UserListEntry({model:model}).render());
    },
  
    reseted : function(){
      UserList.each(this.addRow);
    }
  });

  // The App router initializes the app by calling `UserList.fetch()`
  var App = Backbone.Router.extend({
    initialize : function(){
      UserList.fetch();
    }
  });

  // The current session will be stored in here
  var CurrentSession = null;

  var Input = new InputView();
  
  // Booststrap app after delay to avoid continuous activity spinner 
  _.delay(function(){
    
    // Destroy the current session on unload
    $(window).unload(function(){
      $.ajaxSetup({
        async : false
      });
      if(CurrentSession != null)
        CurrentSession.destroy();
    });
    
    // Includes the couchlogin
    // check it out here: <a href="https://github.com/couchapp/couchdb-login-jquery">https://github.com/couchapp/couchdb-login-jquery</a>
    $('#login').couchLogin({
      loggedIn : function(user){
        CurrentUser.set(user);
        PrivateMessages.listen_to_changes();
        // Only add a User if it's not already in the list
        if(!UserList.detect(function(user){return user.get("name") == CurrentUser.get("name");})){
          CurrentSession = UserList.create({
            "name" : CurrentUser.get("name"),
            "logged_in_at" : new Date().getTime()
          });
        }
      },
      loggedOut : function(){
        PrivateMessages.stop_changes();
        CurrentUser.set(new UserModel().toJSON());
        CurrentUser.trigger("change:name");
        if(CurrentSession != null)
          CurrentSession.destroy();
      }
    });
    
    // Bootstrapping
    new MessagesList();
    new UserListView();
    new App();

  }, 100);
});