Add subgraph skeleton classes (#997)

Allows downstream consumers to use subgraph types ahead of impl.

src/subgraph/SubgraphSlotBase.ts

@@ -0,0 +1,64 @@
+import type { SubgraphIONodeBase } from "./SubgraphIONodeBase"
+import type { Point, ReadOnlyRect, Rect } from "@/interfaces"
+import type { LinkId } from "@/LLink"
+import type { Serialisable, SubgraphIO } from "@/types/serialisation"
+
+import { LiteGraph } from "@/litegraph"
+import { SlotBase } from "@/node/SlotBase"
+import { createUuidv4, type UUID } from "@/utils/uuid"
+
+/** Shared base class for the slots used on Subgraph . */
+export abstract class SubgraphSlot extends SlotBase implements SubgraphIO, Serialisable<SubgraphIO> {
+  static get defaultHeight() {
+    return LiteGraph.NODE_SLOT_HEIGHT
+  }
+
+  readonly #pos: Point = new Float32Array(2)
+
+  readonly id: UUID
+  readonly parent: SubgraphIONodeBase
+  override type: string
+
+  readonly linkIds: LinkId[] = []
+
+  readonly boundingRect: Rect = [0, 0, 0, SubgraphSlot.defaultHeight]
+
+  override get pos() {
+    return this.#pos
+  }
+
+  override set pos(value) {
+    if (!value || value.length < 2) return
+
+    this.#pos[0] = value[0]
+    this.#pos[1] = value[1]
+  }
+
+  /** Whether this slot is connected to another slot. */
+  override get isConnected() {
+    return this.linkIds.length > 0
+  }
+
+  /** The display name of this slot. */
+  get displayName() {
+    return this.label ?? this.localized_name ?? this.name
+  }
+
+  abstract get labelPos(): Point
+
+  constructor(slot: SubgraphIO, parent: SubgraphIONodeBase) {
+    super(slot.name, slot.type, slot.boundingRect)
+
+    Object.assign(this, slot)
+    this.id = slot.id ?? createUuidv4()
+    this.type = slot.type
+    this.parent = parent
+  }
+
+  abstract arrange(rect: ReadOnlyRect): void
+
+  asSerialisable(): SubgraphIO {
+    const { id, name, type, linkIds, localized_name, label, dir, shape, color_off, color_on, pos, boundingRect } = this
+    return { id, name, type, linkIds, localized_name, label, dir, shape, color_off, color_on, pos, boundingRect }
+  }
+}