added some function for choose date

static/js/app.js

@@ -2,6 +2,7 @@
 let selectedFile = null;
 let projects = {};
 let lastEvents = [];
+let previewData = [];
 
 // DOM Elements
 const uploadZone = document.getElementById('uploadZone');
@@ -203,18 +204,105 @@ function setFile(file) {
     fileSize.textContent = formatFileSize(file.size);
     
     updateSubmitButton();
+    generatePreview(file);
+}
+
+async function generatePreview(file) {
+    const formData = new FormData();
+    formData.append('file', file);
+    
+    showLoading(true);
+    try {
+        const response = await fetch('/preview-time', {
+            method: 'POST',
+            body: formData
+        });
+        const data = await response.json();
+        
+        if (!response.ok) {
+            throw new Error(data.detail || `HTTP ${response.status}`);
+        }
+        
+        renderPreview(data);
+    } catch (error) {
+        console.error('Preview error:', error);
+        showToast('Failed to generate preview: ' + error.message, 'error');
+        document.getElementById('previewContainer').style.display = 'none';
+    } finally {
+        showLoading(false);
+    }
+}
+
+function renderPreview(data) {
+    previewData = data.map(item => ({...item, selected: true}));
+    const container = document.getElementById('previewContainer');
+    container.style.display = 'block';
+    
+    updatePreviewTable();
+    
+    document.getElementById('selectAllPreview').onchange = (e) => {
+        const checked = e.target.checked;
+        previewData.forEach(item => item.selected = checked);
+        updatePreviewTable();
+    };
+}
+
+// Ensure togglePreviewItem is available globally for inline onclick handlers
+window.togglePreviewItem = function(index) {
+    previewData[index].selected = !previewData[index].selected;
+    
+    // Update "select all" checkbox state
+    const allSelected = previewData.every(item => item.selected);
+    const noneSelected = previewData.every(item => !item.selected);
+    const selectAllCheckbox = document.getElementById('selectAllPreview');
+    selectAllCheckbox.checked = allSelected;
+    selectAllCheckbox.indeterminate = !allSelected && !noneSelected;
+    
+    updatePreviewTable();
+};
+
+function updatePreviewTable() {
+    const tbody = document.getElementById('previewTableBody');
+    tbody.innerHTML = '';
+    let totalHours = 0;
+    let selectedCount = 0;
+    
+    previewData.forEach((item, index) => {
+        if (item.selected) {
+            totalHours += item.hours;
+            selectedCount++;
+        }
+        
+        const tr = document.createElement('tr');
+        if (!item.selected) tr.classList.add('excluded');
+        
+        tr.innerHTML = `
+            <td><input type="checkbox" ${item.selected ? 'checked' : ''} onclick="event.stopPropagation(); togglePreviewItem(${index})"></td>
+            <td>${item.date}</td>
+            <td>${item.hours.toFixed(2)}</td>
+        `;
+        
+        tr.onclick = () => togglePreviewItem(index);
+        tbody.appendChild(tr);
+    });
+    
+    document.getElementById('previewTotalHours').textContent = totalHours.toFixed(2);
+    updateSubmitButton();
 }
 
 function removeFile() {
     selectedFile = null;
+    previewData = [];
     fileInput.value = '';
     uploadZone.style.display = 'block';
     filePreview.style.display = 'none';
+    document.getElementById('previewContainer').style.display = 'none';
     updateSubmitButton();
 }
 
 function updateSubmitButton() {
-    submitBtn.disabled = !(selectedFile && projectSelect.value);
+    const hasSelectedDates = previewData.length === 0 || previewData.some(item => item.selected);
+    submitBtn.disabled = !(selectedFile && projectSelect.value && hasSelectedDates);
 }
 
 function setDefaultDateRange() {
@@ -238,10 +326,16 @@ async function handleSubmit() {
     
     const projectName = projectSelect.value;
     
+    const excludedDates = previewData
+        .filter(item => !item.selected)
+        .map(item => item.date)
+        .join(',');
+    
     showLoading(true);
     
     try {
-        const response = await fetch(`/report-time?project_name=${encodeURIComponent(projectName)}`, {
+        const url = `/report-time?project_name=${encodeURIComponent(projectName)}&excluded_dates=${encodeURIComponent(excludedDates)}`;
+        const response = await fetch(url, {
             method: 'POST',
             body: formData
         });