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var ready = function () {

    /**
     * When the send message link on our home page is clicked
     * send an ajax request to our rails app with the sender_id and
     * recipient_id
     */

    $('.start-conversation').click(function (e) {
        e.preventDefault();

        var sender_id = $(this).data('sid');
        var recipient_id = $(this).data('rip');

        $.post("/conversations", { sender_id: sender_id, recipient_id: recipient_id }, function (data) {
            chatBox.chatWith(data.conversation_id);
        });
    });

    /**
     * Used to minimize the chatbox
     */

    $(document).on('click', '.toggleChatBox', function (e) {
        e.preventDefault();

        var id = $(this).data('cid');
        chatBox.toggleChatBoxGrowth(id);
    });

    /**
     * Used to close the chatbox
     */

    $(document).on('click', '.closeChat', function (e) {
        e.preventDefault();

        var id = $(this).data('cid');
        chatBox.close(id);
    });


    /**
     * Listen on keypress' in our chat textarea and call the
     * chatInputKey in chat.js for inspection
     */

    $(document).on('keydown', '.chatboxtextarea', function (event) {

        var id = $(this).data('cid');
        chatBox.checkInputKey(event, $(this), id);
    });

    /**
     * When a conversation link is clicked show up the respective
     * conversation chatbox
     */

    $('a.conversation').click(function (e) {
        e.preventDefault();

        var conversation_id = $(this).data('cid');
        chatBox.chatWith(conversation_id);
    });


}

$(document).ready(ready);
$(document).on("page:load", ready);

class User < ActiveRecord::Base

  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable

  has_many :conversations, :foreign_key => :sender_id
end

<% @users.each_with_index do |user, index| %>
    <tr>
      <td><%= index +=1 %></td>
      <td><%= user.name %></td>
      <td>
        <%= link_to "Send Message", "#", class: "btn btn-success btn-xs start-conversation",
                    "data-sid" => current_user.id, "data-rip" => user.id %>
      </td>
    </tr>
<% end %>

<div class="chatboxhead">
  <div class="chatboxtitle">
    <i class="fa fa-comments"></i>

    <h1><%= @reciever.name %> </h1>
  </div>
  <div class="chatboxoptions">
    <%= link_to "<i class='fa  fa-minus'></i> ".html_safe, "#", class: "toggleChatBox", "data-cid" => @conversation.id %>
    &nbsp;&nbsp;
    <%= link_to "<i class='fa  fa-times'></i> ".html_safe, "#", class: "closeChat", "data-cid" => @conversation.id %>
  </div>
  <br clear="all"/>
</div>
<div class="chatboxcontent">
  <% if @messages.any? %>
      <%= render @messages %>
  <% end %>
</div>
<div class="chatboxinput">
  <%= form_for([@conversation, @message], :remote => true, :html => {id: "conversation_form_#{@conversation.id}"}) do |f| %>
      <%= f.text_area :body, class: "chatboxtextarea", "data-cid" => @conversation.id %>
  <% end %>
</div>

<%= subscribe_to conversation_path(@conversation) %>

Rails.application.routes.draw do

  devise_for :users

  authenticated :user do
    root 'users#index'
  end

  unauthenticated :user do
    devise_scope :user do
      get "/" => "devise/sessions#new"
    end
  end

  resources :conversations do
    resources :messages
  end
end

<meta content='<%= user_signed_in? ? current_user.id : "" %>' name='user-id'/>

module MessagesHelper
  def self_or_other(message)
    message.user == current_user ? "self" : "other"
  end

  def message_interlocutor(message)
    message.user == message.conversation.sender ? message.conversation.sender : message.conversation.recipient
  end
end

class MessagesController < ApplicationController
  before_filter :authenticate_user!

  def create
    @conversation = Conversation.find(params[:conversation_id])
    @message = @conversation.messages.build(message_params)
    @message.user_id = current_user.id
    @message.save!

    @path = conversation_path(@conversation)
  end

  private

  def message_params
    params.require(:message).permit(:body)
  end
end

class Message < ActiveRecord::Base
  belongs_to :conversation
  belongs_to :user

  validates_presence_of :body, :conversation_id, :user_id
end

class CreateConversations < ActiveRecord::Migration
  def change
    create_table :conversations do |t|
      t.integer :sender_id
      t.integer :recipient_id

      t.timestamps
    end
    
    add_index :conversations, :sender_id
    add_index :conversations, :recipient_id
  end
end

<% publish_to @path do %>
    var id = "<%= @conversation.id %>";
    var chatbox = $("#chatbox_" + id + " .chatboxcontent");
    var sender_id = "<%= @message.user.id %>";
    var reciever_id = $('meta[name=user-id]').attr("content");

    chatbox.append("<%= j render( partial: @message ) %>");
    chatbox.scrollTop(chatbox[0].scrollHeight);

    if(sender_id != reciever_id){
    	chatBox.chatWith(id);
        chatbox.children().last().removeClass("self").addClass("other");        
    	chatbox.scrollTop(chatbox[0].scrollHeight);
        chatBox.notify();
    }
<% end %>

class ConversationsController < ApplicationController
  before_filter :authenticate_user!

  layout false

  def create
    if Conversation.between(params[:sender_id],params[:recipient_id]).present?
      @conversation = Conversation.between(params[:sender_id],params[:recipient_id]).first
    else
      @conversation = Conversation.create!(conversation_params)
    end

    render json: { conversation_id: @conversation.id }
  end

  def show
    @conversation = Conversation.find(params[:id])
    @reciever = interlocutor(@conversation)
    @messages = @conversation.messages
    @message = Message.new
  end

  private
  def conversation_params
    params.permit(:sender_id, :recipient_id)
  end

  def interlocutor(conversation)
    current_user == conversation.recipient ? conversation.sender : conversation.recipient
  end
end

class Conversation < ActiveRecord::Base
  belongs_to :sender, :foreign_key => :sender_id, class_name: 'User'
  belongs_to :recipient, :foreign_key => :recipient_id, class_name: 'User'

  has_many :messages, dependent: :destroy

  validates_uniqueness_of :sender_id, :scope => :recipient_id

  scope :involving, -> (user) do
    where("conversations.sender_id =? OR conversations.recipient_id =?",user.id,user.id)
  end

  scope :between, -> (sender_id,recipient_id) do
    where("(conversations.sender_id = ? AND conversations.recipient_id =?) OR (conversations.sender_id = ? AND conversations.recipient_id =?)", sender_id,recipient_id, recipient_id, sender_id)
  end
end

/**
 * Chat logic
 *
 * Most of the js functionality is inspired from anatgarg.com
 * jQuery tag Module from the tutorial
 * http://anantgarg.com/2009/05/13/gmail-facebook-style-jquery-chat/
 *
 */


var chatboxFocus = new Array();
var chatBoxes = new Array();

var ready = function () {

    chatBox = {

        /**
         * creates an inline chatbox on the page by calling the
         * createChatBox function passing along the unique conversation_id
         * 
         * @param conversation_id
         */

        chatWith: function (conversation_id) {

            chatBox.createChatBox(conversation_id);
            $("#chatbox_" + conversation_id + " .chatboxtextarea").focus();
        },

        /**
         * closes the chatbox by essentially hiding it from the page
         * 
         * @param conversation_id
         */

        close: function (conversation_id) {
            $('#chatbox_' + conversation_id).css('display', 'none');
            chatBox.restructure();
        },

        /**
         * Plays a notification sound when a new chat message arrives
         */

        notify: function () {
            var audioplayer = $('#chatAudio')[0];
            audioplayer.play();
        },

        /**
         * Handles 'smart layouts' of the chatboxes. Like when new chatboxes are
         * added or removed from the view, it restructures them so that they appear
         * neatly aligned on the page
         */

        restructure: function () {
            align = 0;
            for (x in chatBoxes) {
                chatbox_id = chatBoxes[x];

                if ($("#chatbox_" + chatbox_id).css('display') != 'none') {
                    if (align == 0) {
                        $("#chatbox_" + chatbox_id).css('right', '20px');
                    } else {
                        width = (align) * (280 + 7) + 20;
                        $("#chatbox_" + chatbox_id).css('right', width + 'px');
                    }
                    align++;
                }
            }

        },

        /**
         * Takes in two parameters. It is responsible for fetching the specific conversation's
         * html page and appending it to the body of our home page e.g if conversation_id = 1
         *
         * $.get("conversations/1, function(data){
         *    // rest of the logic here
         * }, "html")
         *
         * @param conversation_id
         * @param minimizeChatBox
         */

        createChatBox: function (conversation_id, minimizeChatBox) {
            if ($("#chatbox_" + conversation_id).length > 0) {
                if ($("#chatbox_" + conversation_id).css('display') == 'none') {
                    $("#chatbox_" + conversation_id).css('display', 'block');
                    chatBox.restructure();
                }
                $("#chatbox_" + conversation_id + " .chatboxtextarea").focus();
                return;
            }

            $("body").append('<div id="chatbox_' + conversation_id + '" class="chatbox"></div>')

            $.get("conversations/" + conversation_id, function (data) {
                $('#chatbox_' + conversation_id).html(data);
                $("#chatbox_" + conversation_id + " .chatboxcontent").scrollTop($("#chatbox_" + conversation_id + " .chatboxcontent")[0].scrollHeight);
            }, "html");

            $("#chatbox_" + conversation_id).css('bottom', '0px');

            chatBoxeslength = 0;

            for (x in chatBoxes) {
                if ($("#chatbox_" + chatBoxes[x]).css('display') != 'none') {
                    chatBoxeslength++;
                }
            }

            if (chatBoxeslength == 0) {
                $("#chatbox_" + conversation_id).css('right', '20px');
            } else {
                width = (chatBoxeslength) * (280 + 7) + 20;
                $("#chatbox_" + conversation_id).css('right', width + 'px');
            }

            chatBoxes.push(conversation_id);

            if (minimizeChatBox == 1) {
                minimizedChatBoxes = new Array();

                if ($.cookie('chatbox_minimized')) {
                    minimizedChatBoxes = $.cookie('chatbox_minimized').split(/\|/);
                }
                minimize = 0;
                for (j = 0; j < minimizedChatBoxes.length; j++) {
                    if (minimizedChatBoxes[j] == conversation_id) {
                        minimize = 1;
                    }
                }

                if (minimize == 1) {
                    $('#chatbox_' + conversation_id + ' .chatboxcontent').css('display', 'none');
                    $('#chatbox_' + conversation_id + ' .chatboxinput').css('display', 'none');
                }
            }

            chatboxFocus[conversation_id] = false;

            $("#chatbox_" + conversation_id + " .chatboxtextarea").blur(function () {
                chatboxFocus[conversation_id] = false;
                $("#chatbox_" + conversation_id + " .chatboxtextarea").removeClass('chatboxtextareaselected');
            }).focus(function () {
                chatboxFocus[conversation_id] = true;
                $('#chatbox_' + conversation_id + ' .chatboxhead').removeClass('chatboxblink');
                $("#chatbox_" + conversation_id + " .chatboxtextarea").addClass('chatboxtextareaselected');
            });

            $("#chatbox_" + conversation_id).click(function () {
                if ($('#chatbox_' + conversation_id + ' .chatboxcontent').css('display') != 'none') {
                    $("#chatbox_" + conversation_id + " .chatboxtextarea").focus();
                }
            });

            $("#chatbox_" + conversation_id).show();

        },

        /**
         * Responsible for listening to the keypresses when chatting. If the Enter button is pressed,
         * we submit our conversation form to our rails app
         *
         * @param event
         * @param chatboxtextarea
         * @param conversation_id
         */

        checkInputKey: function (event, chatboxtextarea, conversation_id) {
            if (event.keyCode == 13 && event.shiftKey == 0) {
                event.preventDefault();

                message = chatboxtextarea.val();
                message = message.replace(/^\s+|\s+$/g, "");

                if (message != '') {
                    $('#conversation_form_' + conversation_id).submit();
                    $(chatboxtextarea).val('');
                    $(chatboxtextarea).focus();
                    $(chatboxtextarea).css('height', '44px');
                }
            }

            var adjustedHeight = chatboxtextarea.clientHeight;
            var maxHeight = 94;

            if (maxHeight > adjustedHeight) {
                adjustedHeight = Math.max(chatboxtextarea.scrollHeight, adjustedHeight);
                if (maxHeight)
                    adjustedHeight = Math.min(maxHeight, adjustedHeight);
                if (adjustedHeight > chatboxtextarea.clientHeight)
                    $(chatboxtextarea).css('height', adjustedHeight + 8 + 'px');
            } else {
                $(chatboxtextarea).css('overflow', 'auto');
            }

        },

        /**
         * Responsible for handling minimize and maximize of the chatbox
         *
         * @param conversation_id
         */

        toggleChatBoxGrowth: function (conversation_id) {
            if ($('#chatbox_' + conversation_id + ' .chatboxcontent').css('display') == 'none') {

                var minimizedChatBoxes = new Array();

                if ($.cookie('chatbox_minimized')) {
                    minimizedChatBoxes = $.cookie('chatbox_minimized').split(/\|/);
                }

                var newCookie = '';

                for (i = 0; i < minimizedChatBoxes.length; i++) {
                    if (minimizedChatBoxes[i] != conversation_id) {
                        newCookie += conversation_id + '|';
                    }
                }

                newCookie = newCookie.slice(0, -1)


                $.cookie('chatbox_minimized', newCookie);
                $('#chatbox_' + conversation_id + ' .chatboxcontent').css('display', 'block');
                $('#chatbox_' + conversation_id + ' .chatboxinput').css('display', 'block');
                $("#chatbox_" + conversation_id + " .chatboxcontent").scrollTop($("#chatbox_" + conversation_id + " .chatboxcontent")[0].scrollHeight);
            } else {

                var newCookie = conversation_id;

                if ($.cookie('chatbox_minimized')) {
                    newCookie += '|' + $.cookie('chatbox_minimized');
                }


                $.cookie('chatbox_minimized', newCookie);
                $('#chatbox_' + conversation_id + ' .chatboxcontent').css('display', 'none');
                $('#chatbox_' + conversation_id + ' .chatboxinput').css('display', 'none');
            }

        }



    }


    /**
     * Cookie plugin
     *
     * Copyright (c) 2006 Klaus Hartl (stilbuero.de)
     * Dual licensed under the MIT and GPL licenses:
     * http://www.opensource.org/licenses/mit-license.php
     * http://www.gnu.org/licenses/gpl.html
     *
     */

    jQuery.cookie = function (name, value, options) {
        if (typeof value != 'undefined') { // name and value given, set cookie
            options = options || {};
            if (value === null) {
                value = '';
                options.expires = -1;
            }
            var expires = '';
            if (options.expires && (typeof options.expires == 'number' || options.expires.toUTCString)) {
                var date;
                if (typeof options.expires == 'number') {
                    date = new Date();
                    date.setTime(date.getTime() + (options.expires * 24 * 60 * 60 * 1000));
                } else {
                    date = options.expires;
                }
                expires = '; expires=' + date.toUTCString(); // use expires attribute, max-age is not supported by IE
            }
            // CAUTION: Needed to parenthesize options.path and options.domain
            // in the following expressions, otherwise they evaluate to undefined
            // in the packed version for some reason...
            var path = options.path ? '; path=' + (options.path) : '';
            var domain = options.domain ? '; domain=' + (options.domain) : '';
            var secure = options.secure ? '; secure' : '';
            document.cookie = [name, '=', encodeURIComponent(value), expires, path, domain, secure].join('');
        } else { // only name given, get cookie
            var cookieValue = null;
            if (document.cookie && document.cookie != '') {
                var cookies = document.cookie.split(';');
                for (var i = 0; i < cookies.length; i++) {
                    var cookie = jQuery.trim(cookies[i]);
                    // Does this cookie string begin with the name we want?
                    if (cookie.substring(0, name.length + 1) == (name + '=')) {
                        cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
                        break;
                    }
                }
            }
            return cookieValue;
        }
    };


}

$(document).ready(ready);
$(document).on("page:load", ready);

/**
 * GMAIL Like chat css
 * CREDITS: http://css-tricks.com/replicating-google-hangouts-chat/
 *
 */

.chatbox {
    position: fixed;
    position: expression("absolute");
    width: 280px;
    display: none;
}

.chatboxhead {
    background: #666;
    color: white;
    padding: 0.5rem;
    overflow: hidden;

    border-right: 1px solid rgba(85, 85, 85, 0.87);
    border-left: 1px solid rgba(85, 85, 85, 0.87);
}

.chatboxhead h1 {
    display: inline;
    font-size: 17px;
    font-weight: 700;
}

.chatboxblink {
    background-color: #176689;
    border-right: 1px solid #176689;
    border-left: 1px solid #176689;
}

.chatboxcontent {
    font-family: arial, sans-serif;
    height: 280px;
    width: 280px;
    overflow-y: auto;
    padding: 7px;
    border-left: 1px solid #cccccc;
    border-right: 1px solid #cccccc;
    border-bottom: 1px solid #eeeeee;
    background: #e5e5e5;
    line-height: 1.3em;
    list-style: none;
}

.chatboxcontent li {
    padding: 0.5rem;
    overflow: hidden;
    display: flex;
}

.chatboxcontent .avatar {
    width: 40px;
    position: relative;
}

.chatboxcontent .avatar img {
    display: block;
    width: 100%;
}

.other .avatar:after {
    content: "";
    position: absolute;
    top: 0;
    right: 0;
    width: 0;
    height: 0;
    border: 5px solid white;
    border-left-color: transparent;
    border-bottom-color: transparent;
}

.self {
    justify-content: flex-end;
    align-items: flex-end;
}

.self .chatboxmessagecontent {
    order: 1;
    border-bottom-right-radius: 0;
}

.self .avatar {
    order: 2;
}

.self .avatar:after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 0;
    border: 5px solid white;
    border-right-color: transparent;
    border-top-color: transparent;
    box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.2);
}

.chatboxmessagecontent {
    background: white;
    padding: 10px;
    border-radius: 2px;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

.chatboxmessagecontent p {
    font-size: 12px;
    margin: 0 0 0.2rem 0;
    -ms-word-break: break-all;

    /* Non standard for webkit */
    word-break: break-word;

    -webkit-hyphens: auto;
    -moz-hyphens: auto;
    hyphens: auto;
}

.chatboxmessagecontent time {
    font-size: 9px;
    color: #ccc;
}

.chatboxinput {
    padding: 5px;
    background-color: #ffffff;
    border-left: 1px solid #cccccc;
    border-right: 1px solid #cccccc;
    border-bottom: 1px solid #cccccc;
}

.chatboxtextarea {
    width: 262px;
    height: 44px;
    padding: 3px 0pt 3px 3px;
    border: 1px solid #eeeeee;
    margin: 1px;
    overflow: hidden;
    resize: none !important;
}

.chatboxtextareaselected {
    border: 2px solid #878787;
    margin: 0;
}

.chatboxmessage {
    margin-left: 1em;
}

.chatboxinfo {
    margin-left: -1em;
    color: #666666;

}

.chatboxoptions {
    float: right;
}

.chatboxoptions a {
    text-decoration: none;
    color: white;
    font-weight: bold;
}

.chatboxtitle {
    float: left;
}

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <meta name="description" content="">
  <meta name="author" content="">
  <meta content='<%= user_signed_in? ? current_user.id : "" %>' name='user-id'/>

  <title>Chatty</title>
  <%= stylesheet_link_tag    'application', media: 'all', 'data-turbolinks-track' => true %>
  <%= stylesheet_link_tag '//maxcdn.bootstrapcdn.com/font-awesome/4.1.0/css/font-awesome.min.css' %>
  <%= javascript_include_tag 'application', 'data-turbolinks-track' => true %>
  <%= csrf_meta_tags %>

  <!-- shiv here -->

</head>

<body>

<%= render 'layouts/nav' %>

<div class="container">
  <!-- flash messages here -->
  <%= yield %>
</div>
<audio id="chatAudio"><source src="/sounds/notification.mp3" type="audio/mpeg"></audio>
</body>

</html>

<li class="<%=  self_or_other(message) %>">
  <div class="avatar">
    <img src="http://placehold.it/50x50" />
  </div>
  <div class="chatboxmessagecontent">
    <p><%= message.body %></p>
    <time datetime="<%= message.created_at %>" title="<%= message.created_at.strftime("%d %b  %Y at %I:%M%p") %>">
      <%= message_interlocutor(message).name %> • <%= message.created_at.strftime("%H:%M %p") %>
    </time>
  </div>
</li>