Click 2 Call Button

Hi, I am looking to make a plugin for wordpress that allows a click to call button to be easily added to a site. Essentially the UI will need to allow the user to enter their secret key, their contact number, their opening hours and allow colour cusomisation. On the website there will need to be a button that when clicked, launches a lightbox which asks for the customers name and telephone number. There needs to be an 'IF' sequence that checks if the opening hours are in time, it will need to display a 'We'll call you back when the call centre is open' message or something along them lines. When they press call this will need to send a request to my server which will in turn make a call to the user and the customer. Would also like to have this coded as a web app that can be used on my own website to allow customers to generate the html code to place on their website. Attached are a couple of images of conceptual design. Thanks.