An online store update with a customized inventory management module

The Fish Club Project Plan 1. Background a. we currently run an e-commerce website at fishclub.com.my. We would like to revamp our website. And as you may know, inventory management is very important for us. Therefore we would like to add in an inventory management function, which is rather customised, where we can track the stock-in activities - where we track the in-flow of the stocks, and also the costs for each stock (documentation will be provided) 2. Overall requirements a. Wordpress 4.5 and above b. CentOS 7 with Cpanel, installed on DigitalOcean (hosting will be provided) c. Setup of dev site and production (potentially setting up on a different site / server, then later migrate to our main one) d. Dual language - English and Mandarin (contents will be provided) 3. Front-end descriptions & functionalities a. Main Shop page i. Please follow [login to view URL] or [login to view URL] b. Shop Page i. Ability to filter by attributes, page needs to be in AJAX for better customer experience ii. Only selected attributes will be on the shop page c. Product page i. Please follow [login to view URL] or [login to view URL], but need to be able to have product variation (for example, different sizes of fish) ii. Please also study our current website [login to view URL] d. Checkout i. ability to select delivery slot based on admin’s settings (for example, Wed/Fri/Sun for State 1, Thu for State 2) 4. Back-end descriptions & functionalities a. Typical WooCommerce functionalities b. Invoices i. Automatically generate invoices upon ordering, with ability to update invoices based on changes to orders ii. Ability to email out invoices upon ordering, or updating c. Inventory i. There should be a general stock adjustment form, for the admin to also adjust the existing stock. So overall there should be a few forms for inventory management purpose: stock purchase added to inventory, stock out (for example, the order fulfilment from customers), general stock edit, stock write-off etc., ideally we can just have a dynamic seeder table for all the purposes, if it makes sense ii. Stock-in are tracked by batches, everyday admin will put in a ‘stock-in’ form, documentation and suggested database structure will be provided, the stock-in will track date, invoice number (invoice from our suppliers, not invoices to customers) iii. Stock-in should also allow tracking by supplier, and stock-in costs, therefore allow us to understand our cost of the SKU since our cost of goods always fluctuate iv. Ideally done in AJAX to give the admin real-time update on the stock level as he / she keys in the changes d. Customer Management i. Registration via FB & Google ii. Notification for customer registration e. Orders i. filter by delivery date selected by customer ii. Ability to create manual order, or make changes to existing orders iii. Ability to track payments, to track whether payment has been received, or any balance to be collected via cash-on-delivery  iv. Notification to admin email on all orders f. Product Management i. Ability to create product, tag attributes for easy customer search ii. Ability to create product bundles g. Reporting i. daily sales summary ii. Tracking of product repeat-purchase rate iii. monthly summary for purchases, by invoices, by supplier, and cost price (documentation will be provided)  h. Others i. smtp server operations should be coded such that it will not impact page loading timing