Write PHP + jQuery or Ajax instant chat plugin

Write PHP + jQuery or Ajax instant chat plugin for osclass script. ( [login to view URL] ) - This plugin for seller and buyer to communicate instant about the product listing - When buyer want to start conversation there must have option chat now , make offer ( where buyer can add amount offer or negotiation price ) seller can accept the offer or reject the offer. - when buyer want to start conversation there have a selected msg where them can pick to make them easy start the conversation example . ( Hi - still available , interested in this , do you have more picture , do you deliver , do you COD. ( Admin can add more text from dashboard) - when the deal is confirm seller can mark the listing item already booking or sold - admin can see the conversation between seller and buyer for record and future information when the have something wrong with the seller and buyer deal Code must be clear and easy to understand for other developer to handle Please understand the task before bid I will own all source code and complete work and I need guarantee about the bugs free code. Must have documentation about installation or setup Payment will be made after project complete if not agree please don't bid thanks