Implementation of Trade

TL;DR:

• Trading intrinsic property of connector-connected grids, not a block
• Set buy/sell orders with pricing for item stacks in cargo, allow automatic trading for both player and NPC (similar system for non-stack fluids and energy)
• Trade UI for manual trading if other grid has buy/sell orders set, like NPC stations
• NPC stations have all items for sale, and will buy any item by default. NPC have infinite or regenerating money as default.
• Stores of money to facilitate trade (character pocket, block wallet, stack of coin)
• Stacks remember price, so UI can show profit without manual notekeeping
• Trade UI shows relative pricing in some form, to help with decisionmaking
• Trade contracts for extra income for buying or selling specific items

Youre docked at another ship/station. Your cargos are within reach of their cargos. Connectors are connected.

How does it work from there?

My system has no trade block. Its an intrinsic property of grids that are connected.

If you want non-grid trading, directly to character inventory, I suppose that needs a trade block. But I would start by implementing grid-to-grid trading and then making the decision if a trade block is even necessary.

I propose the following User Interface:

First, make Limit Orders

1. Mark items for sale by right clicking a Stack in cargo. Set price.
2. Mark items for purchase in separate menu by selecting item type. Set price. This could be a "shadow stack", a stack of 0, which gets filled as the item is bought.

Those are for your own items. The other ship will have their own selections for above.

Second, Open Trade UI.

Select which grid you are trading with.

Trade UI lists all of their items for sale. Trade UI lists all of your items, whether theyre for sale or not. (You can sell your own items even if you have not set a price explicitly - youll just sell them at the other grids set purchase price instead of your own price).

You can then Buy any item they have for sale. You can also Sell any item they have an order for to buy. For example if theyre buying Gold for 100 money, you can sell them gold. If they dont have a Buy order for gold, you cannot sell them gold!

AI grids should have buy orders for all item types unless there is a reason not to. So you can sell anything to AI. Pricing could be Fixed (predetermined values for items) or Dynamic (dependent on supply/demand). Either will work.

AI grids should start with items to sell. Again, fixed or dynamic price. AI grids should produce items over time to simulate a living economy, or have infinite supply. Either will work.

But dont stop there!

To make smart trades, you need to be able to keep track of profit!

Any bought stack should remember what it was bought for. How much money you paid for it. This memory will reset if the stack is modified (split, used for production, added more items to).

A smart trader will keep their stacks untouched, so they remember price.

Why?

So when you go sell that stack, the Trade UI will show profit if sold. No need for manual notekeeping!

You can see the purchase price of a stack by mousing over it, or maybe in the corner of the stack icon.

Since you also marked your own items for sale by price, any other player can buy them simply by docking and paying the price. Additionally any AI ship can buy them simply by docking and paying the price - no further action needed from you beside setting the price beforehand.

Lets go even further!

When in Trade UI, game should show relative price for all items. Are they priced above or below market? To simplify things, I would allow player to select any NPC station in drop down list, and see prices relative to that market. This can later be updated to something that takes player grids into account. So trading wouldnt be blind. Need information to make good decisions!

But wait, what about money? Money would be in three places:

1. Player Character
2. Wallet Block
3. Stack of coin in Cargo

When buying / selling, money moves between the two grids. Where it goes, maybe a simple drop down list. Do you want money in your pocket, your wallet block, or just throw it in cargo?

AI should have infinite or constantly regenerating money. Or just a lot of it.

To add gameplay, have trade contracts! Sell N ore to station A. Buy N ore from station B and sell it wherever you wish.

Non-stack items like fuel, water, oxygen, electricity would have their own section in UI, but work by the same principles.

Have further ideas for trading Quality of Life? Comment!