Build Application for a Company which can be accessed through Iphone, Andriod and Website

We are into construction contracting business I want an application for our company which can be accessed by various employees of the company through different platforms. (iphone, Andriod and website). There will be users accounts and different menu screens based on their designations. It will not include accounting aspects. Process related to procurement(purchase), leave applications, GPS based attendance, project reporting(progress reporting by project managers), divisional progress reporting, group chat, various reports etc. will be controlled through it. Cloud based centralized database. I will share organization process chart. I am having application chart which I want to develop. Expecting full proof project without any bugs. Need experienced professional only. Developer should provide full code and details of final developed application on various platform. Training material of application for employees will be required. Project execution 30 days.