Build instant messenger/chat plugin/addon for osclass script

Build real time instant messenger/chat for buyer/seller function ( plugin / add on ) for osclass script. Developer must know how to modify the OsClass Script so the real time instant messenger/chat for buyer and seller to communicate can be done ( remove / disable the contact publisher and leave your comment section area ) . include map area need to be disable. If buyer click the chat button buyer will have option to make offer for the seller item / seller can accept or reject the buyer with custom msg or can select msg option If the item listed sold there must have option for seller to mark as sold and seller and buyer can give feedback and rating each other. The real time instant chat function must be free form bugs and no delay in receive new msg or reply. In chat windows also must have function seller/buyer can upload image. ( please don't use any ready made chat function in the market its not stable and suitable ). I will be the new owner for all complete work and source code for this plugin / add on. Note: - The real time instant messenger/chat must be like what [login to view URL] do ( please try and testing how [login to view URL] instant messenger / chat seller and buyer make communication ) - MUST SEE before BID - Must have a document how to setup the plugin / add on correctly. - Make sure the code in good structure where other developer can follow and understand all the flow of the code - Make sure the chat function can be using with mobile browser ( smartphone or tablet mode ) without problem or bugs. - Must not effect with any new OsClass new version release. - The Plugin / Add on must not heavy in database and not use to much server resource Please bid if you really understand the task and can be done asap.