Write some Software

We have a multi-site magento webstore with Country based IP-redirect. A Canadian store as well as USA store. We will be adding more country specific stores in the future. Currently we are shipping from a single warehouse(MAIN) in usa. We want to add two more warehouses (H and PH) that we will be shipping products from. Both warehouses combined will have approximately 15,000 unique skus. We need to import the products into magento seamlessly every 2-3 hours from a specific FTP location. We need to be able to specify which products/categories to be enabled manually and automatically. The entire product database should be updated once a month or when required manually but the stock status should be updated every 2-3 hours. Warehouse H and PH may stock the same sku, the script should always go with warehouse PH and if PH is of stock it should go with H. The csv file will also have image source locations on the web which the script should fetch and update to product. Prices need to be set as well such as MSRP price or MSRP -10% or MSRP+5% etc. There will be product with discounts indicated with a percentage on the csv file, these products should be pushed to homepage or featured, when the discount is over they shall become regular items again only browse-able through the category listing. Once customer orders are placed it should automatically create an order csv file at a specific time every single day which then can be uploaded to a specific ftp location for each warehouse to process its orders. This file must be in a specific .txt format and unique to each warehouse When the warehouse processes orders they will post the txt file back onto the ftp location with tracking number, we need to then import those tracking numbers and update order and mark shipped.