develop magento plugin

I need someone to develop a simple Magento plugin to add a new payment method to checkout. It should add a configuration tab in admin to add a api key. This api key will be used to call an api with the cart total, and then open a new browser tab with the link returned by the api. It should store this payment method as the payment method for the order with the status of "Pending". It should create a callback endpoint to be notified when the payment is done, and update the status to "Paid" It should create in admin a button in the order to check if the payment is done and update the status to "Paid". [login to view URL]