From 7a6fae8f6c7c4b83e64e9b79146f5dc9980d082c Mon Sep 17 00:00:00 2001
From: barkstone2 <barkstone2@gmail.com>
Date: Sun, 8 Feb 2026 21:59:45 +0900
Subject: [PATCH] feat: add draggable left sidebar resizing

---
 .../components/WorkspaceLeafResizeHandle.tsx  |  9 ++---
 .../src/containers/WorkspaceContainer.tsx     | 34 ++++++++++++++++++-
 .../containers/WorkspaceSplitContainer.tsx    | 25 ++++++++++----
 3 files changed, 57 insertions(+), 11 deletions(-)

diff --git a/react-app-internal/src/components/WorkspaceLeafResizeHandle.tsx b/react-app-internal/src/components/WorkspaceLeafResizeHandle.tsx
index 537729d..409e9fa 100644
--- a/react-app-internal/src/components/WorkspaceLeafResizeHandle.tsx
+++ b/react-app-internal/src/components/WorkspaceLeafResizeHandle.tsx
@@ -1,10 +1,11 @@
-import {CSSProperties} from "react";
+import {CSSProperties, MouseEvent} from "react";
 
 interface WorkspaceLeafResizeHandleProps {
     style?: CSSProperties;
+    onMouseDown?: (event: MouseEvent<HTMLHRElement>) => void;
 }
-export function WorkspaceLeafResizeHandle({style}: WorkspaceLeafResizeHandleProps) {
+export function WorkspaceLeafResizeHandle({style, onMouseDown}: WorkspaceLeafResizeHandleProps) {
     return (
-        <hr className="workspace-leaf-resize-handle" style={style}/>
+        <hr className="workspace-leaf-resize-handle" style={style} onMouseDown={onMouseDown}/>
     )
-}
\ No newline at end of file
+}
diff --git a/react-app-internal/src/containers/WorkspaceContainer.tsx b/react-app-internal/src/containers/WorkspaceContainer.tsx
index c6b67d4..f1d46e8 100644
--- a/react-app-internal/src/containers/WorkspaceContainer.tsx
+++ b/react-app-internal/src/containers/WorkspaceContainer.tsx
@@ -1,4 +1,4 @@
-import {ReactNode, useEffect, useState} from "react";
+import {MouseEvent as ReactMouseEvent, ReactNode, useCallback, useEffect, useState} from "react";
 import {WorkspaceSplitContainer} from "./WorkspaceSplitContainer";
 import TreeContainer from "../components/TreeContainer";
 import {WorkspaceTabs} from "../components/tab-header/WorkspaceTabs";
@@ -33,6 +33,9 @@ export function resolveTocHeaders(
 
 const leftSideDockOpenedClassName = 'is-left-sidedock-open';
 const rightSideDockOpenedClassName = 'is-right-sidedock-open';
+const defaultLeftSideDockWidth = 300;
+const minLeftSideDockWidth = 220;
+const maxLeftSideDockWidth = 560;
 
 export function WorkspaceContainer({children}: {children: ReactNode}) {
     const {'*': filePath } = useParams();
@@ -54,6 +57,7 @@ export function WorkspaceContainer({children}: {children: ReactNode}) {
 
     const [isLeftSideDockOpened, setIsLeftSideDockOpened] = useState(!isMobile);
     const [isRightSideDockOpened, setIsRightSideDockOpened] = useState(!isMobile);
+    const [leftSideDockWidth, setLeftSideDockWidth] = useState(defaultLeftSideDockWidth);
 
     useEffect(() => {
         setIsLeftSideDockOpened(!isMobile)
@@ -69,11 +73,39 @@ export function WorkspaceContainer({children}: {children: ReactNode}) {
         workspaceClassName += ' ' + rightSideDockOpenedClassName;
     }
 
+    const handleLeftSidebarResizeMouseDown = useCallback((event: ReactMouseEvent<HTMLHRElement>) => {
+        if (isMobile || !isLeftSideDockOpened) {
+            return;
+        }
+
+        event.preventDefault();
+        const startX = event.clientX;
+        const startWidth = leftSideDockWidth;
+
+        const handleMouseMove = (moveEvent: MouseEvent) => {
+            const nextWidth = Math.min(
+                maxLeftSideDockWidth,
+                Math.max(minLeftSideDockWidth, startWidth + (moveEvent.clientX - startX)),
+            );
+            setLeftSideDockWidth(nextWidth);
+        };
+
+        const handleMouseUp = () => {
+            window.removeEventListener('mousemove', handleMouseMove);
+            window.removeEventListener('mouseup', handleMouseUp);
+        };
+
+        window.addEventListener('mousemove', handleMouseMove);
+        window.addEventListener('mouseup', handleMouseUp);
+    }, [isLeftSideDockOpened, isMobile, leftSideDockWidth]);
+
     return (
         <div className={workspaceClassName}>
             <WorkspaceSplitContainer modOrientation={'mod-horizontal'}
                                      isSideDock={true}
                                      isSideDockCollapse={!isLeftSideDockOpened}
+                                     width={leftSideDockWidth}
+                                     onResizeMouseDown={handleLeftSidebarResizeMouseDown}
                                      modSplitDirection={'mod-left-split'}>
                 <WorkspaceTabs spaceDirection={'mod-top-left-space'}>
                     <WorkspaceTabHeaderContainer
diff --git a/react-app-internal/src/containers/WorkspaceSplitContainer.tsx b/react-app-internal/src/containers/WorkspaceSplitContainer.tsx
index 70f5438..b2b2ab5 100644
--- a/react-app-internal/src/containers/WorkspaceSplitContainer.tsx
+++ b/react-app-internal/src/containers/WorkspaceSplitContainer.tsx
@@ -1,24 +1,37 @@
 import {WorkspaceLeafResizeHandle} from "../components/WorkspaceLeafResizeHandle";
-import {CSSProperties} from "react";
+import {CSSProperties, MouseEvent, ReactNode} from "react";
 
 interface WorkspaceSplitContainerProps {
     modOrientation: "mod-vertical" | "mod-horizontal";
     isSideDock: boolean;
     modSplitDirection?: "mod-left-split" | "mod-right-split";
     isSideDockCollapse?: boolean;
-    children?: React.ReactNode;
+    width?: number;
+    onResizeMouseDown?: (event: MouseEvent<HTMLHRElement>) => void;
+    children?: ReactNode;
 }
 
-export function WorkspaceSplitContainer({modOrientation, isSideDock, modSplitDirection, isSideDockCollapse, children}: WorkspaceSplitContainerProps) {
+export function WorkspaceSplitContainer({
+    modOrientation,
+    isSideDock,
+    modSplitDirection,
+    isSideDockCollapse,
+    width,
+    onResizeMouseDown,
+    children,
+}: WorkspaceSplitContainerProps) {
     const collapsedClass = isSideDockCollapse && "is-sidedock-collapsed";
-    let styles: CSSProperties = isSideDock ? {width: '300px'} : {}
+    let styles: CSSProperties = isSideDock ? {width: `${width ?? 300}px`} : {}
     styles = isSideDockCollapse ? {width: 0, display: 'none'} : styles;
     return (
         <div
             className={`workspace-split ${modOrientation} ${isSideDock ? 'mod-sidedock' : 'mod-root'} ${modSplitDirection} ${collapsedClass}`}
             style={styles}>
-            <WorkspaceLeafResizeHandle style={(isSideDock && !isSideDockCollapse) ? {opacity: 1} : {opacity: 0}}/>
+            <WorkspaceLeafResizeHandle
+                style={(isSideDock && !isSideDockCollapse) ? {opacity: 1} : {opacity: 0}}
+                onMouseDown={onResizeMouseDown}
+            />
             {children}
         </div>
     )
-}
\ No newline at end of file
+}