Add Subgraphs (#3905)

Co-authored-by: github-actions <github-actions@github.com>

src/stores/subgraphNavigationStore.ts

@@ -0,0 +1,87 @@
+import type { Subgraph } from '@comfyorg/litegraph'
+import { defineStore } from 'pinia'
+import { computed, shallowReactive, shallowRef, watch } from 'vue'
+
+import { app } from '@/scripts/app'
+import { isNonNullish } from '@/utils/typeGuardUtil'
+
+import { useWorkflowStore } from './workflowStore'
+
+/**
+ * Stores the current subgraph navigation state; a stack representing subgraph
+ * navigation history from the root graph to the subgraph that is currently
+ * open.
+ */
+export const useSubgraphNavigationStore = defineStore(
+  'subgraphNavigation',
+  () => {
+    const workflowStore = useWorkflowStore()
+
+    /** The currently opened subgraph. */
+    const activeSubgraph = shallowRef<Subgraph>()
+
+    /** The stack of subgraph IDs from the root graph to the currently opened subgraph. */
+    const idStack = shallowReactive<string[]>([])
+
+    /**
+     * A stack representing subgraph navigation history from the root graph to
+     * the current opened subgraph.
+     */
+    const navigationStack = computed(() =>
+      idStack.map((id) => app.graph.subgraphs.get(id)).filter(isNonNullish)
+    )
+
+    /**
+     * Restore the navigation stack from a list of subgraph IDs.
+     * @param subgraphIds The list of subgraph IDs to restore the navigation stack from.
+     * @see exportState
+     */
+    const restoreState = (subgraphIds: string[]) => {
+      idStack.length = 0
+      for (const id of subgraphIds) idStack.push(id)
+    }
+
+    /**
+     * Export the navigation stack as a list of subgraph IDs.
+     * @returns The list of subgraph IDs, ending with the currently active subgraph.
+     * @see restoreState
+     */
+    const exportState = () => [...idStack]
+
+    // Reset on workflow change
+    watch(
+      () => workflowStore.activeWorkflow,
+      () => (idStack.length = 0)
+    )
+
+    // Update navigation stack when opened subgraph changes
+    watch(
+      () => workflowStore.activeSubgraph,
+      (subgraph) => {
+        // Navigated back to the root graph
+        if (!subgraph) {
+          idStack.length = 0
+          return
+        }
+
+        const index = idStack.lastIndexOf(subgraph.id)
+        const lastIndex = idStack.length - 1
+
+        if (index === -1) {
+          // Opened a new subgraph
+          idStack.push(subgraph.id)
+        } else if (index !== lastIndex) {
+          // Navigated to a different subgraph
+          idStack.splice(index + 1, lastIndex - index)
+        }
+      }
+    )
+
+    return {
+      activeSubgraph,
+      navigationStack,
+      restoreState,
+      exportState
+    }
+  }
+)