Codeigniter Project: Make a module which allows registered users to exchange private messages

Greetings! Here is a list of features that i would have in my project, the current website is Full migration to Codeigniter, bootstrap, and JQuery programming skills. 1) Private messages are available for registered users only. 2) Private messages have to be grouped into conversations (aims or branches) by the sender 3) There should be an adjustable url for private messages of each username, opening existing conversation or creating a new one. If user did not sent any message this conversation will not save. 4) Conversations with a new messages should be marked visually (till the user did not open the conversation) 5) New messages should be marked in conversation (till the user did not read those messages) 6) Conversations should be sorted by date of the latest message (conversations with new messages on top) 7) Conversations shows with time and date of the latest message, text of the message + there should be a place for user’s avatar pic (48x48px) 8) Messages in conversation should be sorted by date (new messages on top) 9) Message is plain text. Only urls should appears like links in a message text. 10) There should be smileys in messages (less than 30). 11) This widget is supposed to display new messages in to the website interface 12) Make a widget to choose a language of content. General conditions: i) Make a single module. Use as less other modules interactions as you can. ii) It has to be a cross-platform and cross-browser solution iii )It supposed to work with high load website so if your scripts needs many data access, use caching.