From 8a3a843dc4b0e43dad5ba4eb38dd76b6c3d966ac Mon Sep 17 00:00:00 2001
From: Tim Goyer <tim.goyer@alliancebernstein.com>
Date: Mon, 9 Sep 2024 11:37:00 -0500
Subject: [PATCH] Add data history hook

---
 lib/useDataHistory/useDataHistory.ts | 67 ++++++++++++++++++++++++++++
 package.json                         |  2 +-
 2 files changed, 68 insertions(+), 1 deletion(-)
 create mode 100644 lib/useDataHistory/useDataHistory.ts

diff --git a/lib/useDataHistory/useDataHistory.ts b/lib/useDataHistory/useDataHistory.ts
new file mode 100644
index 0000000..6a5d08f
--- /dev/null
+++ b/lib/useDataHistory/useDataHistory.ts
@@ -0,0 +1,67 @@
+import { useReducer } from 'react';
+
+interface State<T> {
+  past: T[];
+  data: T;
+  future: T[];
+}
+
+interface Action<T> {
+  type: string;
+  value?: T;
+}
+
+const ACTION_TYPES = {
+  CHANGE: 'CHANGE',
+  UNDO: 'UNDO',
+  REDO: 'REDO',
+} as const;
+
+const getDefaultState = <T>(value: T): State<T> => ({ past: [], data: value, future: [] });
+
+const reducer = <T>(state: State<T>, action: Action<T>): State<T> => {
+  const { past, data, future } = state;
+  switch (action.type) {
+    case ACTION_TYPES.CHANGE:
+      return {
+        past: [...past, data],
+        data: action.value as T,
+        future: [],
+      };
+    case ACTION_TYPES.UNDO:
+      if (past.length === 0) return state;
+      return {
+        past: past.slice(0, -1),
+        data: past[past.length - 1],
+        future: [data, ...future],
+      };
+    case ACTION_TYPES.REDO:
+      if (future.length === 0) return state;
+      return {
+        past: [...past, data],
+        data: future[0],
+        future: future.slice(1),
+      };
+    default:
+      return state;
+  }
+};
+
+export function useHistory<T>(initialValue: T) {
+  const [state, dispatch] = useReducer(reducer, getDefaultState(initialValue));
+  const { past, data, future } = state;
+
+  const redo = () => {
+    dispatch({ type: ACTION_TYPES.REDO });
+  };
+
+  const set = (value: T) => {
+    dispatch({ type: ACTION_TYPES.CHANGE, value });
+  };
+
+  const undo = () => {
+    dispatch({ type: ACTION_TYPES.UNDO });
+  };
+
+  return { data, history: { past, future }, actions: { redo, set, undo } };
+}
diff --git a/package.json b/package.json
index 7f0e781..f39e4b3 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "@spiffdog/spiffy-hooks",
   "private": false,
-  "version": "0.0.6-3",
+  "version": "0.0.6-4",
   "description": "",
   "type": "module",
   "main": "dist/index.cjs.js",