Add non-blocking filter, search direction/start line, and tab state preservation

- Make filter non-blocking: yield to event loop every 50ms with progress
  updates, add cancellation support, pre-compile regex patterns once
- Add search direction (top-to-bottom / bottom-to-top) and start line
  options via gear popup, with "Search from here" in context menu
- Preserve analysis results, filter state, and highlights across tab
  switches so content and sidebar state are not lost

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: ozgesolidkey

src/main/index.ts

@@ -1388,12 +1388,17 @@ function compileAdvancedFilter(config: AdvancedFilterConfig): CompiledMatcher {
   return (text: string, level: string) => compiledGroups.every(fn => fn(text, level));
 }
 
+// Cancellation signal for filter
+let filterSignal = { cancelled: false };
+
 ipcMain.handle('apply-filter', async (_, config: FilterConfig) => {
   const handler = getFileHandler();
   if (!handler || !currentFilePath) {
     return { success: false, error: 'No file open' };
   }
 
+  filterSignal = { cancelled: false };
+
   try {
     const totalLines = handler.getTotalLines();
     const matchingLines: Set<number> = new Set();
@@ -1417,26 +1422,43 @@ ipcMain.handle('apply-filter', async (_, config: FilterConfig) => {
     // Pattern matching helper respecting matchCase and exactMatch options
     const caseSensitive = config.matchCase || false;
     const exactMatch = config.exactMatch || false;
-    const matchPattern = (text: string, pattern: string): boolean => {
+
+    // Pre-compile regex patterns once for performance (avoid re-creating RegExp per line)
+    type CompiledPattern = { regex: RegExp } | { literal: string; lowerLiteral: string };
+    const compilePattern = (pattern: string): CompiledPattern => {
       if (exactMatch) {
-        // Literal substring match
-        return caseSensitive
-          ? text.includes(pattern)
-          : text.toLowerCase().includes(pattern.toLowerCase());
+        return { literal: pattern, lowerLiteral: pattern.toLowerCase() };
       }
-      // Regex match with fallback to substring
       try {
-        return new RegExp(pattern, caseSensitive ? '' : 'i').test(text);
+        return { regex: new RegExp(pattern, caseSensitive ? '' : 'i') };
       } catch {
-        return caseSensitive
-          ? text.includes(pattern)
-          : text.toLowerCase().includes(pattern.toLowerCase());
+        return { literal: pattern, lowerLiteral: pattern.toLowerCase() };
+      }
+    };
+
+    const compiledIncludePatterns = config.includePatterns.map(compilePattern);
+    const compiledExcludePatterns = config.excludePatterns.map(compilePattern);
+
+    const matchCompiled = (text: string, compiled: CompiledPattern): boolean => {
+      if ('regex' in compiled) {
+        return compiled.regex.test(text);
       }
+      return caseSensitive
+        ? text.includes(compiled.literal)
+        : text.toLowerCase().includes(compiled.lowerLiteral);
     };
 
     // Process in batches for performance
     const batchSize = 10000;
+    let processedLines = 0;
+    let lastProgressUpdate = Date.now();
+
     for (let start = 0; start < totalLines; start += batchSize) {
+      // Check for cancellation
+      if (filterSignal.cancelled) {
+        return { success: false, error: 'Cancelled' };
+      }
+
       const count = Math.min(batchSize, totalLines - start);
       const lines = handler.getLines(start, count);
 
@@ -1456,13 +1478,13 @@ ipcMain.handle('apply-filter', async (_, config: FilterConfig) => {
           }
 
           // Include patterns (OR logic)
-          if (matches && config.includePatterns.length > 0) {
-            matches = config.includePatterns.some(pattern => matchPattern(line.text, pattern));
+          if (matches && compiledIncludePatterns.length > 0) {
+            matches = compiledIncludePatterns.some(cp => matchCompiled(line.text, cp));
           }
 
           // Track exclude matches separately (exact lines only)
           if (hasBasicExclude) {
-            const excluded = config.excludePatterns.some(pattern => matchPattern(line.text, pattern));
+            const excluded = compiledExcludePatterns.some(cp => matchCompiled(line.text, cp));
             if (excluded) {
               excludeLines.add(line.lineNumber);
             }
@@ -1473,6 +1495,17 @@ ipcMain.handle('apply-filter', async (_, config: FilterConfig) => {
           matchingLines.add(line.lineNumber);
         }
       }
+
+      processedLines += count;
+
+      // Yield to event loop and send progress every 50ms to keep UI responsive
+      const now = Date.now();
+      if (now - lastProgressUpdate > 50) {
+        await yieldToEventLoop();
+        const progress = Math.round((processedLines / totalLines) * 100);
+        mainWindow?.webContents.send('filter-progress', { percent: Math.min(progress, 99) });
+        lastProgressUpdate = Date.now();
+      }
     }
 
     // Add context lines around include matches (before exclude removal)
@@ -1508,6 +1541,11 @@ ipcMain.handle('apply-filter', async (_, config: FilterConfig) => {
   }
 });
 
+ipcMain.handle('cancel-filter', async () => {
+  filterSignal.cancelled = true;
+  return { success: true };
+});
+
 ipcMain.handle('clear-filter', async () => {
   if (currentFilePath) {
     filterState.delete(currentFilePath);

src/preload/index.ts

@@ -166,6 +166,15 @@ const api = {
   applyFilter: (config: any): Promise<{ success: boolean; stats?: { filteredLines: number }; error?: string }> =>
     ipcRenderer.invoke('apply-filter', config),
 
+  cancelFilter: (): Promise<{ success: boolean }> =>
+    ipcRenderer.invoke('cancel-filter'),
+
+  onFilterProgress: (callback: (data: { percent: number }) => void): (() => void) => {
+    const handler = (_: any, data: { percent: number }) => callback(data);
+    ipcRenderer.on('filter-progress', handler);
+    return () => ipcRenderer.removeListener('filter-progress', handler);
+  },
+
   clearFilter: (): Promise<{ success: boolean }> =>
     ipcRenderer.invoke('clear-filter'),
 

src/renderer/index.html

@@ -43,6 +43,19 @@
             <input type="checkbox" id="search-whole-word"> Whole Word
           </label>
           <button id="btn-search" class="toolbar-btn" title="Search">Search</button>
+          <div class="search-options-wrapper">
+            <button id="btn-search-options" class="toolbar-btn small" title="Search options">&#9881;</button>
+            <div id="search-options-popup" class="search-options-popup hidden">
+              <div class="search-option-row">
+                <label class="search-option-label">Direction</label>
+                <button id="search-direction" class="toolbar-btn small search-direction-btn" title="Toggle search direction">&#8595; Top to Bottom</button>
+              </div>
+              <div class="search-option-row">
+                <label class="search-option-label" for="search-start-line">Start from line</label>
+                <input type="number" id="search-start-line" class="search-start-line-input" placeholder="1" min="1">
+              </div>
+            </div>
+          </div>
           <button id="btn-prev-result" class="toolbar-btn small" title="Previous result" disabled>&lt;</button>
           <span id="search-result-count" class="result-count"></span>
           <span id="search-engine-badge" class="search-engine-badge" title="Search engine"></span>