extention opencart -- 2

I have a ecommerce multi Seller/store on opencart platform. I am looking for a developer to create custom extention for my website. i'd like extention that when customer seach a product the extention calc distance from customer and seller ( meter or kilometer ) and show this info on each product scheda (example image in attachment). the extention wil permit to define filter ratio and permit to sort output search by distance ( min/Max). Location of customer will be ( gps coordinate gather from browser if customer use smartphone) or default location define in customer profile or custom location insert in specific filed before search. Other feature of extension is a buttom that permit to trasform output of list of product search in map with all product locator.