chore: import upstream snapshot with attribution

apps/sim/stores/undo-redo/code-store.ts

@@ -0,0 +1,151 @@
+import { create } from 'zustand'
+import { createJSONStorage, devtools, persist } from 'zustand/middleware'
+import { codeUndoRedoStorage } from '@/stores/undo-redo/code-storage'
+
+interface CodeUndoRedoEntry {
+  id: string
+  createdAt: number
+  workflowId: string
+  blockId: string
+  subBlockId: string
+  before: string
+  after: string
+}
+
+interface CodeUndoRedoStack {
+  undo: CodeUndoRedoEntry[]
+  redo: CodeUndoRedoEntry[]
+  lastUpdated?: number
+}
+
+interface CodeUndoRedoState {
+  stacks: Record<string, CodeUndoRedoStack>
+  capacity: number
+  push: (entry: CodeUndoRedoEntry) => void
+  undo: (workflowId: string, blockId: string, subBlockId: string) => CodeUndoRedoEntry | null
+  redo: (workflowId: string, blockId: string, subBlockId: string) => CodeUndoRedoEntry | null
+  clear: (workflowId: string, blockId: string, subBlockId: string) => void
+}
+
+const DEFAULT_CAPACITY = 500
+const MAX_STACKS = 50
+
+function getStackKey(workflowId: string, blockId: string, subBlockId: string): string {
+  return `${workflowId}:${blockId}:${subBlockId}`
+}
+
+const initialState = {
+  stacks: {} as Record<string, CodeUndoRedoStack>,
+  capacity: DEFAULT_CAPACITY,
+}
+
+export const useCodeUndoRedoStore = create<CodeUndoRedoState>()(
+  devtools(
+    persist(
+      (set, get) => ({
+        ...initialState,
+        push: (entry) => {
+          if (entry.before === entry.after) return
+
+          const state = get()
+          const key = getStackKey(entry.workflowId, entry.blockId, entry.subBlockId)
+          const currentStacks = { ...state.stacks }
+
+          const stackKeys = Object.keys(currentStacks)
+          if (stackKeys.length >= MAX_STACKS && !currentStacks[key]) {
+            let oldestKey: string | null = null
+            let oldestTime = Number.POSITIVE_INFINITY
+
+            for (const stackKey of stackKeys) {
+              const t = currentStacks[stackKey].lastUpdated ?? 0
+              if (t < oldestTime) {
+                oldestTime = t
+                oldestKey = stackKey
+              }
+            }
+
+            if (oldestKey) {
+              delete currentStacks[oldestKey]
+            }
+          }
+
+          const stack = currentStacks[key] || { undo: [], redo: [] }
+
+          const newUndo = [...stack.undo, entry]
+          if (newUndo.length > state.capacity) {
+            newUndo.shift()
+          }
+
+          currentStacks[key] = {
+            undo: newUndo,
+            redo: [],
+            lastUpdated: Date.now(),
+          }
+
+          set({ stacks: currentStacks })
+        },
+        undo: (workflowId, blockId, subBlockId) => {
+          const key = getStackKey(workflowId, blockId, subBlockId)
+          const state = get()
+          const stack = state.stacks[key]
+          if (!stack || stack.undo.length === 0) return null
+
+          const entry = stack.undo[stack.undo.length - 1]
+          const newUndo = stack.undo.slice(0, -1)
+          const newRedo = [...stack.redo, entry]
+
+          set({
+            stacks: {
+              ...state.stacks,
+              [key]: {
+                undo: newUndo,
+                redo: newRedo.slice(-state.capacity),
+                lastUpdated: Date.now(),
+              },
+            },
+          })
+
+          return entry
+        },
+        redo: (workflowId, blockId, subBlockId) => {
+          const key = getStackKey(workflowId, blockId, subBlockId)
+          const state = get()
+          const stack = state.stacks[key]
+          if (!stack || stack.redo.length === 0) return null
+
+          const entry = stack.redo[stack.redo.length - 1]
+          const newRedo = stack.redo.slice(0, -1)
+          const newUndo = [...stack.undo, entry]
+
+          set({
+            stacks: {
+              ...state.stacks,
+              [key]: {
+                undo: newUndo.slice(-state.capacity),
+                redo: newRedo,
+                lastUpdated: Date.now(),
+              },
+            },
+          })
+
+          return entry
+        },
+        clear: (workflowId, blockId, subBlockId) => {
+          const key = getStackKey(workflowId, blockId, subBlockId)
+          const state = get()
+          const { [key]: _, ...rest } = state.stacks
+          set({ stacks: rest })
+        },
+      }),
+      {
+        name: 'code-undo-redo-store',
+        storage: createJSONStorage(() => codeUndoRedoStorage),
+        partialize: (state) => ({
+          stacks: state.stacks,
+          capacity: state.capacity,
+        }),
+      }
+    ),
+    { name: 'code-undo-redo-store' }
+  )
+)