After last week's Cargo System I started planning out the shop system, with the image above being the design ultimately decided on. I made it through the prototyping phase but haven't implemented actual functionality yet. Started a daily exercise routine to offset the sedentary programming time both at work and at home and that's been a disruption I've had to start getting used to. Lots of jump roping, sit-ups, and weight lifting so hopefully that is helpful in some way and eventually feeds back into programming energy.
I started off with the shop screen, here you can see it in the "I want to buy mode" which shows the cargo contents of the other ship and lets you initiate transactions based on that list. Clicking "I want to sell" will eventually swap out the list with the contents of your own cargo and change the "Buy for X each" to "Sell for X each". Clicking this button takes you to the transaction screen.
This transaction screen will allow you to select how many of the item you wish to buy or sell given the constraints of your/their cargo hold and how much money you or the npc have.

Now that this UI is layed out I am hoping in the next week to get it functional so trade can start happening. 💳