perf(frontend): architect transient react progress state with zustand

src/App.tsx

@@ -8,6 +8,7 @@ import { PropertiesModal } from "./components/PropertiesModal";
 import { DeleteConfirmationModal } from "./components/DeleteConfirmationModal";
 import { listenEvent as listen, invokeCommand as invoke } from "./ipc";
 import { useDownloadStore, MAIN_QUEUE_ID } from './store/useDownloadStore';
+import { initDownloadListener } from './store/downloadStore';
 import { useSettingsStore } from "./store/useSettingsStore";
 import { isPermissionGranted, requestPermission, sendNotification } from '@tauri-apps/plugin-notification';
 import SchedulerView from "./components/SchedulerView";
@@ -204,20 +205,7 @@ function App() {
   }, [theme]);
 
   useEffect(() => {
-    const unlistenProgress = listen('download-progress', (event: any) => {
-      const { id, fraction, speed, eta, size } = event.payload;
-      const state = useDownloadStore.getState();
-      const current = state.downloads.find(d => d.id === id);
-      
-      const updates: any = { fraction, speed, eta };
-      if (size) updates.size = size;
-      
-      if (current && current.status === 'queued') {
-        updates.status = 'downloading';
-      }
-      
-      updateDownload(id, updates);
-    });
+    initDownloadListener();
 
     const unlistenComplete = listen('download-complete', (event) => {
       updateDownload(event.payload, { status: 'completed', fraction: 1.0, speed: '-', eta: '-' });
@@ -255,7 +243,6 @@ function App() {
 
     return () => {
       invoke('set_extension_frontend_ready', { ready: false }).catch(() => {});
-      unlistenProgress.then(f => f());
       unlistenComplete.then(f => f());
       unlistenFailed.then(f => f());
       unlistenExtension.then(f => f());

src/components/DownloadItem.tsx

@@ -0,0 +1,146 @@
+import React, { useEffect, useRef } from 'react';
+import { useDownloadStore } from '../store/useDownloadStore';
+import { useDownloadProgressStore } from '../store/downloadStore';
+import { Play, Pause, MoreVertical } from 'lucide-react';
+import type { DownloadItem as DownloadItemType } from '../bindings/DownloadItem';
+
+interface DownloadItemProps {
+  downloadId: string;
+  index: number;
+  tableGridTemplate: string;
+  setContextMenu: (menu: { x: number; y: number; id: string }) => void;
+  handlePause: (id: string) => void;
+  handleResume: (item: DownloadItemType) => void;
+  getCategoryIcon: (category: string) => React.ReactNode;
+}
+
+export const DownloadItem = React.memo<DownloadItemProps>(({
+  downloadId,
+  index,
+  tableGridTemplate,
+  setContextMenu,
+  handlePause,
+  handleResume,
+  getCategoryIcon,
+}) => {
+  const download = useDownloadStore(state => state.downloads.find(d => d.id === downloadId));
+
+  const progressBarRef = useRef<HTMLDivElement>(null);
+  const statusTextRef = useRef<HTMLSpanElement>(null);
+  const speedTextRef = useRef<HTMLSpanElement>(null);
+  const etaTextRef = useRef<HTMLSpanElement>(null);
+
+  useEffect(() => {
+    // We only need transient updates while it's actively downloading
+    if (!download || download.status !== 'downloading') return;
+
+    const unsubscribe = useDownloadProgressStore.subscribe((state) => {
+      const progress = state.progressMap[downloadId];
+      if (!progress) return;
+
+      if (progressBarRef.current) {
+        progressBarRef.current.style.width = `${progress.fraction * 100}%`;
+      }
+      if (statusTextRef.current) {
+        statusTextRef.current.innerText = `${(progress.fraction * 100).toFixed(0)}%`;
+      }
+      if (speedTextRef.current) {
+        speedTextRef.current.innerText = progress.speed;
+      }
+      if (etaTextRef.current) {
+        etaTextRef.current.innerText = progress.eta;
+      }
+    });
+
+    return () => unsubscribe();
+  }, [downloadId, download?.status]);
+
+  if (!download) return null;
+
+  return (
+    <div
+      className={`download-row group cursor-default relative ${index % 2 !== 0 ? 'striped' : ''}`}
+      style={{ gridTemplateColumns: tableGridTemplate }}
+      onContextMenu={(e) => {
+        e.preventDefault();
+        setContextMenu({ x: e.clientX, y: e.clientY, id: download.id });
+      }}
+    >
+      <div className="download-file-cell">
+        <span className="shrink-0 text-text-muted">
+          {getCategoryIcon(download.category)}
+        </span>
+        <span className="download-file-name">
+          {download.fileName}
+        </span>
+      </div>
+      
+      <div>
+        <span className="tabular-nums">
+          {download.size && download.size !== '-' ? download.size : 'Unknown'}
+        </span>
+      </div>
+      
+      <div className="download-status-cell">
+        {download.status === 'completed' ? (
+          <span className="download-status download-status-completed">Completed</span>
+        ) : (
+          <>
+            <div className="download-progress-track">
+              <div
+                ref={progressBarRef}
+                className={`download-progress-fill ${download.status === 'paused' ? 'paused' : ''}`}
+                style={{ width: `${(download.fraction || 0) * 100}%` }}
+              />
+            </div>
+            <span 
+              ref={statusTextRef}
+              className={`download-status ${download.status === 'paused' ? 'download-status-paused' : download.status === 'failed' ? 'download-status-failed' : download.status === 'downloading' ? 'download-status-downloading' : ''}`}
+            >
+              {download.status === 'downloading'
+                ? `${((download.fraction || 0) * 100).toFixed(0)}%`
+                : download.status.charAt(0).toUpperCase() + download.status.slice(1)}
+            </span>
+          </>
+        )}
+      </div>
+      
+      <div>
+        <span ref={speedTextRef} className="tabular-nums">{download.status === 'downloading' ? download.speed : '-'}</span>
+      </div>
+      
+      <div>
+        <span ref={etaTextRef} className="tabular-nums">{download.status === 'downloading' ? download.eta : '-'}</span>
+      </div>
+      
+      <div className="download-cell-right">
+        <span className="truncate group-hover:hidden tabular-nums ml-auto">
+          {download.dateAdded ? new Date(download.dateAdded).toLocaleDateString() : '-'}
+        </span>
+        
+        <div className="hidden group-hover:flex items-center justify-end gap-0.5 w-full ml-auto">
+          {download.status === 'downloading' && (
+            <button onClick={() => handlePause(download.id)} className="app-icon-button h-7 w-7" title="Pause">
+              <Pause size={14} fill="currentColor" />
+            </button>
+          )}
+          {download.status === 'paused' && (
+            <button onClick={() => handleResume(download)} className="app-icon-button h-7 w-7" title="Resume">
+              <Play size={14} fill="currentColor" />
+            </button>
+          )}
+          <button
+            onClick={(e) => {
+               e.stopPropagation();
+               setContextMenu({ x: e.clientX, y: e.clientY, id: download.id });
+            }}
+            className="app-icon-button h-7 w-7"
+            title="Options"
+          >
+            <MoreVertical size={14} />
+          </button>
+        </div>
+      </div>
+    </div>
+  );
+});

src/components/DownloadTable.tsx

@@ -2,7 +2,8 @@ import React, { useState, useEffect } from 'react';
 import { useDownloadStore, DownloadItem } from '../store/useDownloadStore';
 import { useSettingsStore } from '../store/useSettingsStore';
 import { SidebarFilter } from './Sidebar';
-import { Play, Pause, Plus, FileText, Image as ImageIcon, Music, Film, Box, Archive, FileQuestion, MoreVertical, PanelLeft, ArrowDownCircle, Command } from 'lucide-react';
+import { Play, Pause, Plus, FileText, Image as ImageIcon, Music, Film, Box, Archive, FileQuestion, PanelLeft, ArrowDownCircle, Command } from 'lucide-react';
+import { DownloadItem as DownloadItemComponent } from './DownloadItem';
 import { invokeCommand as invoke } from '../ipc';
 import { homeDir } from '@tauri-apps/api/path';
 
@@ -210,87 +211,16 @@ export const DownloadTable: React.FC<DownloadTableProps> = ({ filter }) => {
             <div className="download-table-body">
             <div className="h-full overflow-auto flex flex-col">
               {filteredDownloads.map((d, index) => (
-                <div
+                <DownloadItemComponent
                   key={d.id}
-                  className={`download-row group cursor-default relative ${index % 2 !== 0 ? 'striped' : ''}`}
-                  style={{ gridTemplateColumns: tableGridTemplate }}
-                  onContextMenu={(e) => {
-                    e.preventDefault();
-                    setContextMenu({ x: e.clientX, y: e.clientY, id: d.id });
-                  }}
-                >
-                  <div className="download-file-cell">
-                    <span className="shrink-0 text-text-muted">
-                      {getCategoryIcon(d.category)}
-                    </span>
-                    <span className="download-file-name">
-                      {d.fileName}
-                    </span>
-                  </div>
-                  
-                  <div>
-                    <span className="tabular-nums">
-                      {d.size && d.size !== '-' ? d.size : 'Unknown'}
-                    </span>
-                  </div>
-                  
-                  <div className="download-status-cell">
-                    {d.status === 'completed' ? (
-                      <span className="download-status download-status-completed">Completed</span>
-                    ) : (
-                      <>
-                        <div className="download-progress-track">
-                          <div
-                            className={`download-progress-fill ${d.status === 'paused' ? 'paused' : ''}`}
-                            style={{ width: `${(d.fraction || 0) * 100}%` }}
-                          />
-                        </div>
-                        <span className={`download-status ${d.status === 'paused' ? 'download-status-paused' : d.status === 'failed' ? 'download-status-failed' : d.status === 'downloading' ? 'download-status-downloading' : ''}`}>
-                          {d.status === 'downloading'
-                            ? `${((d.fraction || 0) * 100).toFixed(0)}%`
-                            : d.status.charAt(0).toUpperCase() + d.status.slice(1)}
-                        </span>
-                      </>
-                    )}
-                  </div>
-                  
-                  <div>
-                    <span className="tabular-nums">{d.status === 'downloading' ? d.speed : '-'}</span>
-                  </div>
-                  
-                  <div>
-                    <span className="tabular-nums">{d.status === 'downloading' ? d.eta : '-'}</span>
-                  </div>
-                  
-                  <div className="download-cell-right">
-                    <span className="truncate group-hover:hidden tabular-nums ml-auto">
-                      {d.dateAdded ? new Date(d.dateAdded).toLocaleDateString() : '-'}
-                    </span>
-                    
-                    <div className="hidden group-hover:flex items-center justify-end gap-0.5 w-full ml-auto">
-                      {d.status === 'downloading' && (
-                        <button onClick={() => handlePause(d.id)} className="app-icon-button h-7 w-7" title="Pause">
-                          <Pause size={14} fill="currentColor" />
-                        </button>
-                      )}
-                      {d.status === 'paused' && (
-                        <button onClick={() => handleResume(d)} className="app-icon-button h-7 w-7" title="Resume">
-                          <Play size={14} fill="currentColor" />
-                        </button>
-                      )}
-                      <button
-                        onClick={(e) => {
-                           e.stopPropagation();
-                           setContextMenu({ x: e.clientX, y: e.clientY, id: d.id });
-                        }}
-                        className="app-icon-button h-7 w-7"
-                        title="Options"
-                      >
-                        <MoreVertical size={14} />
-                      </button>
-                    </div>
-                  </div>
-                </div>
+                  downloadId={d.id}
+                  index={index}
+                  tableGridTemplate={tableGridTemplate}
+                  setContextMenu={setContextMenu}
+                  handlePause={handlePause}
+                  handleResume={handleResume}
+                  getCategoryIcon={getCategoryIcon}
+                />
               ))}
               {Array.from({ length: Math.max(0, 50 - filteredDownloads.length) }).map((_, i) => {
                 const globalIndex = filteredDownloads.length + i;

src/store/downloadStore.ts

@@ -0,0 +1,41 @@
+import { create } from 'zustand';
+import { listen, UnlistenFn } from '@tauri-apps/api/event';
+import type { DownloadProgressEvent } from '../bindings/DownloadProgressEvent';
+
+interface DownloadProgressState {
+  progressMap: Record<string, DownloadProgressEvent>;
+  updateDownloadProgress: (id: string, payload: DownloadProgressEvent) => void;
+}
+
+import { useDownloadStore } from './useDownloadStore';
+
+export const useDownloadProgressStore = create<DownloadProgressState>((set) => ({
+  progressMap: {},
+  updateDownloadProgress: (id, payload) =>
+    set((state) => ({
+      progressMap: {
+        ...state.progressMap,
+        [id]: payload,
+      },
+    })),
+}));
+
+let unlistenProgress: UnlistenFn | null = null;
+
+export async function initDownloadListener() {
+  if (unlistenProgress) return;
+  unlistenProgress = await listen<DownloadProgressEvent>('download-progress', (event) => {
+    const payload = event.payload;
+    useDownloadProgressStore.getState().updateDownloadProgress(payload.id, payload);
+
+    const mainStore = useDownloadStore.getState();
+    const current = mainStore.downloads.find(d => d.id === payload.id);
+    if (current && current.status === 'queued') {
+      const updates: any = { status: 'downloading' };
+      if (payload.size && current.size !== payload.size) updates.size = payload.size;
+      mainStore.updateDownload(payload.id, updates);
+    } else if (current && payload.size && current.size !== payload.size) {
+      mainStore.updateDownload(payload.id, { size: payload.size });
+    }
+  });
+}