Update index.html

index.html

@@ -401,10 +401,52 @@
         let pdfDocs = [];
         let currentPages = [];
         let zoomLevels = [];
+        let scrollPositions = [];
         let activeIndex = -1;
         let renderQueue = [];
         let isRendering = false;
 
+        // Load saved state from localStorage
+        function loadSavedState() {
+            try {
+                const savedState = localStorage.getItem('pdfViewerState');
+                if (savedState) {
+                    const state = JSON.parse(savedState);
+                    currentPages = state.currentPages || [];
+                    zoomLevels = state.zoomLevels || [];
+                    scrollPositions = state.scrollPositions || [];
+                    activeIndex = state.activeIndex || -1;
+                }
+            } catch (e) {
+                console.log('No saved state found');
+            }
+        }
+
+        // Save state to localStorage
+        function saveState() {
+            try {
+                const state = {
+                    currentPages,
+                    zoomLevels,
+                    scrollPositions,
+                    activeIndex,
+                    fileNames: pdfFiles.map(f => f.name)
+                };
+                localStorage.setItem('pdfViewerState', JSON.stringify(state));
+            } catch (e) {
+                console.error('Failed to save state:', e);
+            }
+        }
+
+        // Auto-save state periodically
+        setInterval(saveState, 2000);
+
+        // Save state before page unload
+        window.addEventListener('beforeunload', saveState);
+
+        // Load saved state on page load
+        loadSavedState();
+
         // File input
         fileInput.addEventListener('change', (e) => {
             handleFiles(e.target.files);
@@ -461,13 +503,24 @@
 
             newFiles.forEach((file, idx) => {
                 const fileIndex = startIndex + idx;
-                zoomLevels[fileIndex] = 1.5;
+                // Use saved zoom or default
+                if (!zoomLevels[fileIndex]) {
+                    zoomLevels[fileIndex] = 1.5;
+                }
+                if (!currentPages[fileIndex]) {
+                    currentPages[fileIndex] = 1;
+                }
+                if (!scrollPositions[fileIndex]) {
+                    scrollPositions[fileIndex] = 0;
+                }
                 addTab(file, fileIndex);
             });
 
             if (activeIndex === -1) {
                 switchTab(startIndex);
             }
+            
+            saveState();
         }
 
         function addTab(file, index) {
@@ -538,13 +591,24 @@
                 // Setup scroll tracking with throttle
                 let scrollTimeout;
                 viewerContainer.addEventListener('scroll', () => {
+                    // Save scroll position
+                    scrollPositions[index] = viewerContainer.scrollTop;
+                    
                     clearTimeout(scrollTimeout);
                     scrollTimeout = setTimeout(() => {
                         updateCurrentPage(index, viewerContainer);
                         renderVisiblePages(index, viewerContainer);
+                        saveState();
                     }, 100);
                 });
 
+                // Restore scroll position
+                if (scrollPositions[index]) {
+                    setTimeout(() => {
+                        viewerContainer.scrollTop = scrollPositions[index];
+                    }, 100);
+                }
+
                 // Initial render of visible pages
                 renderVisiblePages(index, viewerContainer);
 
@@ -632,6 +696,7 @@
 
             currentPages[index] = closestPage;
             currentPageEl.textContent = closestPage;
+            saveState();
         }
 
         function scrollToPrevPage() {
@@ -664,6 +729,8 @@
             zoomLevels[activeIndex] = Math.max(0.5, Math.min(3, zoomLevels[activeIndex] + delta));
             zoomLevelEl.textContent = Math.round(zoomLevels[activeIndex] * 100) + '%';
             
+            saveState();
+            
             // Re-render current PDF with new zoom
             const tabContent = contentContainer.querySelector(`.tab-content[data-index="${activeIndex}"]`);
             const file = pdfFiles[activeIndex];
@@ -674,6 +741,7 @@
                     const container = tabContent.querySelector('.pdf-viewer-container');
                     if (container) {
                         container.scrollTop = currentScroll * (zoomLevels[activeIndex] / (zoomLevels[activeIndex] - delta));
+                        scrollPositions[activeIndex] = container.scrollTop;
                     }
                 });
             }
@@ -708,6 +776,8 @@
                     setTimeout(() => renderVisiblePages(index, container), 100);
                 }
             }
+            
+            saveState();
         }
 
         function closeTab(index) {
@@ -715,6 +785,7 @@
             pdfDocs.splice(index, 1);
             currentPages.splice(index, 1);
             zoomLevels.splice(index, 1);
+            scrollPositions.splice(index, 1);
 
             const tab = tabsContainer.querySelector(`[data-index="${index}"]`);
             if (tab) tab.remove();
@@ -759,12 +830,15 @@
                         <p>Nhấn "Mở file" hoặc kéo thả file PDF vào đây</p>
                     </div>
                 `;
+                localStorage.removeItem('pdfViewerState');
             } else {
                 fileCountEl.textContent = `${pdfFiles.length} file`;
                 if (activeIndex >= pdfFiles.length || activeIndex === index) {
                     switchTab(Math.max(0, Math.min(index, pdfFiles.length - 1)));
                 }
             }
+            
+            saveState();
         }
 
         // Keyboard shortcuts