From 61179bb7c77fe7e96588f41c8c0cc6ff8d02b0ba Mon Sep 17 00:00:00 2001
From: "Alinson S. Xavier" <git@axavier.org>
Date: Thu, 13 Nov 2025 08:54:38 -0600
Subject: [PATCH] web: add redo

---
 .../components/CaseBuilder/CaseBuilder.tsx    | 21 ++++++++++++++++++-
 .../src/components/CaseBuilder/Header.tsx     | 12 ++++++++++-
 .../Buttons/SiteHeaderButton.module.css       | 10 +++++++--
 .../Common/Buttons/SiteHeaderButton.tsx       |  6 +++++-
 4 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/web/frontend/src/components/CaseBuilder/CaseBuilder.tsx b/web/frontend/src/components/CaseBuilder/CaseBuilder.tsx
index 7b34c1c..6150010 100644
--- a/web/frontend/src/components/CaseBuilder/CaseBuilder.tsx
+++ b/web/frontend/src/components/CaseBuilder/CaseBuilder.tsx
@@ -44,11 +44,13 @@ const CaseBuilder = () => {
     return processedScenario!!;
   });
   const [undoStack, setUndoStack] = useState<UnitCommitmentScenario[]>([]);
+  const [redoStack, setRedoStack] = useState<UnitCommitmentScenario[]>([]);
   const [toastMessage, setToastMessage] = useState<string>("");
 
   const setAndSaveScenario = (
     newScenario: UnitCommitmentScenario,
     updateUndoStack = true,
+    clearRedoStack = true,
   ) => {
     if (updateUndoStack) {
       const newUndoStack = [...undoStack, scenario];
@@ -57,6 +59,9 @@ const CaseBuilder = () => {
       }
       setUndoStack(newUndoStack);
     }
+    if (clearRedoStack) {
+      setRedoStack([]);
+    }
     setScenario(newScenario);
     localStorage.setItem("scenario", JSON.stringify(newScenario));
   };
@@ -90,8 +95,19 @@ const CaseBuilder = () => {
 
   const onUndo = () => {
     if (undoStack.length === 0) return;
+    const newRedoStack = [...redoStack, scenario];
+    if (newRedoStack.length > 25) {
+      newRedoStack.splice(0, newRedoStack.length - 25);
+    }
+    setRedoStack(newRedoStack);
     setUndoStack(undoStack.slice(0, -1));
-    setAndSaveScenario(undoStack[undoStack.length - 1]!, false);
+    setAndSaveScenario(undoStack[undoStack.length - 1]!, false, false);
+  };
+
+  const onRedo = () => {
+    if (redoStack.length === 0) return;
+    setRedoStack(redoStack.slice(0, -1));
+    setAndSaveScenario(redoStack[redoStack.length - 1]!, true, false);
   };
 
   const onSolve = async () => {
@@ -128,7 +144,10 @@ const CaseBuilder = () => {
         onSave={onSave}
         onLoad={onLoad}
         onUndo={onUndo}
+        onRedo={onRedo}
         onSolve={onSolve}
+        canUndo={undoStack.length > 0}
+        canRedo={redoStack.length > 0}
       />
       <div className="content">
         <Parameters
diff --git a/web/frontend/src/components/CaseBuilder/Header.tsx b/web/frontend/src/components/CaseBuilder/Header.tsx
index 925cc8f..b454bdc 100644
--- a/web/frontend/src/components/CaseBuilder/Header.tsx
+++ b/web/frontend/src/components/CaseBuilder/Header.tsx
@@ -9,14 +9,17 @@ import SiteHeaderButton from "../Common/Buttons/SiteHeaderButton";
 import { useRef } from "react";
 import FileUploadElement from "../Common/Buttons/FileUploadElement";
 import { UnitCommitmentScenario } from "../../core/Data/types";
-import { faDownload, faGear, faRotateLeft, faTrash, faUpload } from "@fortawesome/free-solid-svg-icons";
+import { faDownload, faGear, faRotateLeft, faRotateRight, faTrash, faUpload } from "@fortawesome/free-solid-svg-icons";
 
 interface HeaderProps {
   onClear: () => void;
   onSave: () => void;
   onUndo: () => void;
+  onRedo: () => void;
   onLoad: (data: UnitCommitmentScenario) => void;
   onSolve: () => void;
+  canUndo: boolean;
+  canRedo: boolean;
 }
 
 function Header(props: HeaderProps) {
@@ -44,6 +47,13 @@ function Header(props: HeaderProps) {
             title="Undo"
             icon={faRotateLeft}
             onClick={props.onUndo}
+            disabled={!props.canUndo}
+          />
+          <SiteHeaderButton
+            title="Redo"
+            icon={faRotateRight}
+            onClick={props.onRedo}
+            disabled={!props.canRedo}
           />
           <SiteHeaderButton
             title="Clear"
diff --git a/web/frontend/src/components/Common/Buttons/SiteHeaderButton.module.css b/web/frontend/src/components/Common/Buttons/SiteHeaderButton.module.css
index 04d69d9..a751354 100644
--- a/web/frontend/src/components/Common/Buttons/SiteHeaderButton.module.css
+++ b/web/frontend/src/components/Common/Buttons/SiteHeaderButton.module.css
@@ -5,8 +5,8 @@
  */
 
 .SiteHeaderButton {
-  padding: 6px 20px;
-  margin: 0 0 0 0px;
+  padding: 6px 16px;
+  margin: 0 0 0 0;
   line-height: 24px;
   border: var(--box-border);
   box-shadow: var(--box-shadow);
@@ -59,3 +59,9 @@
 .primary:active {
   background: color-mix(in hsl, #000, var(--primary) 90%);
 }
+
+.disabled {
+  color: var(--contrast-20);
+  cursor: not-allowed;
+  pointer-events: none;
+}
diff --git a/web/frontend/src/components/Common/Buttons/SiteHeaderButton.tsx b/web/frontend/src/components/Common/Buttons/SiteHeaderButton.tsx
index e805bb3..34fc1c9 100644
--- a/web/frontend/src/components/Common/Buttons/SiteHeaderButton.tsx
+++ b/web/frontend/src/components/Common/Buttons/SiteHeaderButton.tsx
@@ -13,19 +13,23 @@ function SiteHeaderButton({
   icon,
   onClick,
   variant = "light",
+  disabled = false,
 }: {
   title: string;
   icon: IconDefinition;
   onClick?: () => void;
   variant?: "light" | "primary";
+  disabled?: boolean;
 }) {
   const variantClass = variant === "primary" ? styles.primary : styles.light;
+  const disabledClass = disabled ? styles.disabled : "";
 
   return (
     <button
-      className={`${styles.SiteHeaderButton} ${variantClass}`}
+      className={`${styles.SiteHeaderButton} ${variantClass} ${disabledClass}`}
       title={title}
       onClick={onClick}
+      disabled={disabled}
     >
       <FontAwesomeIcon icon={icon} />
     </button>