Build a Purchase Order management in PHP

What I need is a basic Purchase Order Management system. I have an online shop where I can generate a PDF of a purchase order for my providers when the stock is getting low. As of today, we send them an email with the PDF, then reply to the email saying if it is ok, then they send little by little docs needed for the importation, and after a while another email with the final commercial invoice. It is A LOT of email exchange, and it is extremely messy! What I need is: My employees (I can create as many as I want) go 1- An admin panel where I can create providers and employees, eventually get out some stats of delays, times of responses etc... 2- Create departments to which I can assign employees (like this they don't see the POs of other departments) 3- Access for the employees to the list of the POs of their department 4- One employee assigned per PO and of course on provider assigned on the other end per PO 5- Employees can upload the PDF file which generates an automatic email to the provider selected with extra information entered before submitting the form (Date of deadline for production of the order for example) 6- When the provider received the automatic email, he connects to the platform with the account we created for him from the backend, and he has access to the history of all the past POs, and the current ones. 7- Each new PO is set to an automatic "Pending" status while the provider reviews the information, quantities, delays requested etc... If there is a problem, he should be able to add a comment or a note which will be saved in the POs page, and a notification by email sent to the employee assigned to the PO. They can communicate back and forth like that, it would be kind of like a ticket system. 8- Once the provider wants to validated the PO is accepted, he clicks on a button "Confirm" which sets the status to this PO. From that point on, it means production will start. 8a- The provider should also be able to set "Pending payment" and "Pending partial payment" (each provider has different agreements with us) and once the payment done, "Payment received" or "Partial Payment received". 9- From the moment the production starts, the provider needs to be able to upload documents to us so we can organize the importation. There should be the possibility to create the upload requirements (they might change from a year to the next) in backend, and the provider would have to upload them one by one in defined upload zones, and be able to update them in case of needs of changes. 10- Production is over, and merchandise ready to be sent, the provider must change the status to "Ready to go", this way we can send our transporters to pick up the order. 11- Once the goods picked up, the provider changes a last time the status to "Shipped". 12- When we received it, we lock the PO by setting the status "Received" or if any problem "Received with issue" and add a note or message that explains the issue to the provider. Basically it is a series of back and forth communication with automatic emails everytime there is a new note, new document or new status update. This way we can archive and centralize all our communications on a particular Purchase Order with our providers. We just want a basic PHP script with MySQL database that we would install as a subfolder in our company Portal.