Clone of app ''Whatsapp'' but also add voice call support (for Android)

"Whatsapp" clone Want to have made a clone of whatsapp application so it works for Android (at first ) but be able to later be ported to Iphone wasily. Once installed program must stay on/active at all times. App must scan all phone numbers in contact list and see if they are also users. App must also routinely scan contact list for any NEW contacts that has been added since it was installed and add any new such cotnacts. **app must somehow ALSO be able to "see" other whatsapp users and somehow be able to chat with these users (chat only) even though this app is a different app.** For now then app should just be programmed for android but must be easy to convert into iphone. The layout/GUI must be 100% identical to Whatsapp (Will change layout later). Bid also includes the software that is needed to make users see each other including installation. (P2P) Write what relevant experience you have. Also, write what experience you have with VOIP protcols. Write why you are the right coder for this project.