Actually implement mod code into server

common/inventory.ts

@@ -49,7 +49,7 @@ export class ContainerSlot {
 	#item_stack: ItemStack | undefined;
 
 	has_item() {
-		return this.#item_stack !== undefined;
+		return this.get_item() !== undefined;
 	}
 
 	set_item(item_stack: ItemStack | undefined) {
@@ -60,11 +60,15 @@ export class ContainerSlot {
 	}
 
 	get_item() {
+		// scripts can count a stack down to nothing, it's gone then
+		if (this.#item_stack && this.#item_stack.amount <= 0) {
+			this.#item_stack = undefined;
+		}
 		return this.#item_stack;
 	}
 
 	get type_id() {
-		return this.#item_stack?.type_id;
+		return this.get_item()?.type_id;
 	}
 
 	set amount(new_amount: number) {
@@ -77,11 +81,11 @@ export class ContainerSlot {
 	}
 
 	get amount(): number | undefined {
-		return this.#item_stack?.amount;
+		return this.get_item()?.amount;
 	}
 
 	get max_amount() {
-		return this.#item_stack?.max_amount;
+		return this.get_item()?.max_amount;
 	}
 }
 

common/mod_api/server.ts

@@ -12,6 +12,7 @@ export interface ServerContext {
 	world: ServerWorld;
 	players: PlayerList;
 	containers: ContainerApi;
+	items: ItemApi;
 	recipes: RecipeApi;
 	ui: ServerUi;
 	net: ServerNet;
@@ -123,6 +124,8 @@ export interface ServerWorld {
 	get_state(x: number, y: number, z: number, name: string): number | undefined;
 	set_state(x: number, y: number, z: number, name: string, value: number): boolean;
 	get_block_data<T>(x: number, y: number, z: number): T | undefined;
+	// pops an item out of the block at x y z, like a broken block's drops
+	drop_item(x: number, y: number, z: number, item: ItemStack): void;
 	is_loaded(x: number, z: number): boolean;
 	readonly seed: string;
 }
@@ -177,6 +180,12 @@ export interface ContainerApi {
 	delete(id: string): void;
 }
 
+export interface ItemApi {
+	exists(id: Id): boolean;
+	// how many fit in one slot
+	max_stack(id: Id): number;
+}
+
 export interface RecipeApi {
 	furnace_result(input: Id): { output: ItemStack; cook_time: number } | undefined;
 	fuel_value(item: Id): number; // burn time in ticks, 0 if it isn't fuel
@@ -214,20 +223,39 @@ export type FormResult<T> = ({ canceled: true } & Partial<T>) | ({ canceled: fal
 export type SlotFilter = "smeltable" | "fuel" | ((item: ItemStack) => boolean);
 
 export interface ContainerScreenOptions {
-	title: string;
 	container: Container;
-	// x and y in slot units
-	layout: { slot: number; x: number; y: number; filter?: SlotFilter; output_only?: boolean }[];
-	player_inventory?: boolean;
-	bars?: { id: string; x: number; y: number; texture: Id }[];
-	labels?: { x: number; y: number; property: string }[];
+	// x and y in slot units, below the player's inventory. can be fractional
+	layout: {
+		slot: number;
+		x: number;
+		y: number;
+		// what can be put in, checked on the server
+		filter?: SlotFilter;
+		// can only be taken from, all at once, like the furnace result
+		output_only?: boolean;
+	}[];
+	// height of the screen's area in slots, fits the layout and bars when not set
+	rows?: number;
+	// progress bars, filled with the property value divided by the property max
+	bars?: {
+		x: number;
+		y: number;
+		value: string;
+		max: string;
+		direction: "up" | "right";
+		empty_texture: Id;
+		full_texture: Id;
+	}[];
 }
 
 export interface ScreenHandle<Props = unknown> {
 	readonly player: Player;
+	readonly open: boolean;
+	// numbers the bars show, synced to the player when they change
 	set_property(id: string, value: number): void;
 	update(props: Props): void; // custom screens only
 	close(): void;
+	// when it closes for any reason: the player closed it, left, opened another screen, or it was closed
 	on_close(fn: () => void): void;
 }