Add visual month navigator with mini donut chart previews

Replace dropdown selector with a visual navigator featuring:
- Left/right arrow buttons for month navigation
- Clickable month buttons with mini donut chart previews
- Russian month labels (e.g., "Январь'25")
- Responsive layout for mobile screens
- Arrows disable at navigation boundaries

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

app.js

@@ -871,6 +871,80 @@ function loadTinyColor() {
     });
 }
 
+// Global state for month navigation
+let availableMonths = [];
+let currentMonthIndex = 0;
+let monthDataCache = {}; // Cache for month data previews
+
+// Predefined colors for categories (same as in transformToSunburst)
+const categoryColors = [
+    '#5470c6', '#91cc75', '#fac858', '#ee6666', '#73c0de',
+    '#2d8041', '#fc8452', '#7b4d90', '#ea7ccc', '#4cae72',
+    '#d56358', '#82b1ff', '#f19143', '#addf84', '#6f7787'
+];
+
+// Fixed order for categories
+const categoryOrder = [
+    'Квартира', 'Еда', 'Технологии', 'Развлечения', 'Семьи',
+    'Здоровье', 'Логистика', 'Расходники', 'Красота'
+];
+
+// Generate conic-gradient CSS for a month's category breakdown
+function generateMonthPreviewGradient(data) {
+    // Group by category and sum amounts
+    const categoryTotals = {};
+    let total = 0;
+
+    data.forEach(item => {
+        const category = item.category || '';
+        const amount = Math.abs(parseFloat(item.amount_rub));
+        if (!isNaN(amount) && category) {
+            categoryTotals[category] = (categoryTotals[category] || 0) + amount;
+            total += amount;
+        }
+    });
+
+    if (total === 0) return 'conic-gradient(#eee 0deg 360deg)';
+
+    // Sort categories by predefined order
+    const sortedCategories = Object.keys(categoryTotals).sort((a, b) => {
+        const indexA = categoryOrder.indexOf(a);
+        const indexB = categoryOrder.indexOf(b);
+        if (indexA !== -1 && indexB !== -1) return indexA - indexB;
+        if (indexA !== -1) return -1;
+        if (indexB !== -1) return 1;
+        return categoryTotals[b] - categoryTotals[a];
+    });
+
+    // Build conic-gradient
+    const gradientStops = [];
+    let currentAngle = 0;
+
+    sortedCategories.forEach((category, index) => {
+        const percentage = categoryTotals[category] / total;
+        const angle = percentage * 360;
+        const colorIndex = categoryOrder.indexOf(category);
+        const color = colorIndex !== -1 ? categoryColors[colorIndex] : categoryColors[index % categoryColors.length];
+
+        gradientStops.push(`${color} ${currentAngle}deg ${currentAngle + angle}deg`);
+        currentAngle += angle;
+    });
+
+    return `conic-gradient(${gradientStops.join(', ')})`;
+}
+
+// Format month for display: "2025-01" -> "Январь'25"
+function formatMonthLabel(dateStr) {
+    const [year, month] = dateStr.split('-');
+    const shortYear = year.slice(-2);
+    const russianMonths = [
+        'Январь', 'Февраль', 'Март', 'Апрель', 'Май', 'Июнь',
+        'Июль', 'Август', 'Сентябрь', 'Октябрь', 'Ноябрь', 'Декабрь'
+    ];
+    const monthName = russianMonths[parseInt(month) - 1];
+    return `${monthName}'${shortYear}`;
+}
+
 // Load all available month files
 async function loadAvailableMonths() {
     // Load TinyColor first
@@ -878,39 +952,92 @@ async function loadAvailableMonths() {
 
     // Fetch available months from server
     const response = await fetch('/api/months');
-    const months = await response.json();
+    availableMonths = await response.json();
 
-    if (months.length === 0) {
+    if (availableMonths.length === 0) {
         console.error('No month data files found');
         return;
     }
 
     const select = document.getElementById('month-select');
+    const monthList = document.getElementById('month-list');
 
     // Clear existing options
     select.innerHTML = '';
+    monthList.innerHTML = '';
 
-    months.forEach(month => {
+    // Populate hidden select (for compatibility with renderChart)
+    availableMonths.forEach(month => {
         const option = document.createElement('option');
         option.value = month;
         option.textContent = month;
         select.appendChild(option);
     });
 
-    // Load the most recent month by default
+    // Load data for all months and create buttons with previews
-    const latestMonth = months[months.length - 1];
+    await Promise.all(availableMonths.map(async (month, index) => {
-    
-    // Set the select value to match BEFORE loading data
-    select.value = latestMonth;
-    
-    // Now load the data for the selected month
-    const data = await parseCSV(`altcats-${latestMonth}.csv`);
-    renderChart(data);
-    
-    // Add event listener for month selection
-    select.addEventListener('change', async (e) => {
-        const month = e.target.value;
         const data = await parseCSV(`altcats-${month}.csv`);
+        monthDataCache[month] = data;
+    }));
+
+    // Create month buttons with previews
+    availableMonths.forEach((month, index) => {
+        const btn = document.createElement('button');
+        btn.className = 'month-btn';
+        btn.dataset.month = month;
+        btn.dataset.index = index;
+
+        // Create preview circle
+        const preview = document.createElement('div');
+        preview.className = 'month-preview';
+        preview.style.background = generateMonthPreviewGradient(monthDataCache[month]);
+
+        // Create label
+        const label = document.createElement('span');
+        label.className = 'month-label';
+        label.textContent = formatMonthLabel(month);
+
+        btn.appendChild(preview);
+        btn.appendChild(label);
+        btn.addEventListener('click', () => selectMonth(index));
+        monthList.appendChild(btn);
+    });
+
+    // Load the most recent month by default
+    currentMonthIndex = availableMonths.length - 1;
+    await selectMonth(currentMonthIndex);
+
+    // Set up arrow button handlers
+    document.getElementById('prev-month').addEventListener('click', () => {
+        if (currentMonthIndex > 0) {
+            selectMonth(currentMonthIndex - 1);
+        }
+    });
+
+    document.getElementById('next-month').addEventListener('click', () => {
+        if (currentMonthIndex < availableMonths.length - 1) {
+            selectMonth(currentMonthIndex + 1);
+        }
+    });
+}
+
+// Select and load a specific month
+async function selectMonth(index) {
+    currentMonthIndex = index;
+    const month = availableMonths[index];
+
+    // Update hidden select for compatibility
+    const select = document.getElementById('month-select');
+    select.value = month;
+
+    // Update month button active states
+    updateMonthNavigator();
+
+    // Load and render data
+    const data = await parseCSV(`altcats-${month}.csv`);
+
+    // Check if chart already has data (for animation)
+    if (option && option.series && option.series.data) {
         const sunburstData = transformToSunburst(data);
 
         // Update only the series data and preserve layout
@@ -918,9 +1045,9 @@ async function loadAvailableMonths() {
         const newData = sunburstData.data;
 
         // Map old values to new data to preserve positions
-        newData.forEach((newItem, index) => {
+        newData.forEach((newItem, idx) => {
-            if (oldData[index]) {
+            if (oldData[idx]) {
-                newItem.layoutId = oldData[index].name; // Use name as layout identifier
+                newItem.layoutId = oldData[idx].name;
             }
         });
 
@@ -938,7 +1065,8 @@ async function loadAvailableMonths() {
                 layoutAnimation: true,
                 animationDuration: 500,
                 animationEasing: 'cubicInOut'
-            }]
+            }],
+            graphic: option.graphic
         }, {
             lazyUpdate: false,
             silent: false
@@ -946,7 +1074,36 @@ async function loadAvailableMonths() {
 
         // Update hover events
         setupHoverEvents(sunburstData);
+    } else {
+        // Initial render
+        renderChart(data);
+    }
+
+    // Scroll selected month button into view
+    const activeBtn = document.querySelector('.month-btn.active');
+    if (activeBtn) {
+        activeBtn.scrollIntoView({ behavior: 'smooth', inline: 'center', block: 'nearest' });
+    }
+}
+
+// Update month navigator UI state
+function updateMonthNavigator() {
+    // Update button active states
+    const buttons = document.querySelectorAll('.month-btn');
+    buttons.forEach((btn, index) => {
+        if (index === currentMonthIndex) {
+            btn.classList.add('active');
+        } else {
+            btn.classList.remove('active');
+        }
     });
+
+    // Update arrow disabled states
+    const prevBtn = document.getElementById('prev-month');
+    const nextBtn = document.getElementById('next-month');
+
+    prevBtn.disabled = currentMonthIndex === 0;
+    nextBtn.disabled = currentMonthIndex === availableMonths.length - 1;
 }
 
 // Initialize the visualization

index.html

@@ -12,10 +12,12 @@
     <div class="container">
         <div class="header">
             <h1>Семейные траты за месяц</h1>
-            <div class="month-selector">
+            <div class="month-navigator">
-                <label for="month-select">Месяц:</label>
+                <button class="nav-arrow nav-prev" id="prev-month">&#8249;</button>
-                <select id="month-select"></select>
+                <div class="month-list" id="month-list"></div>
+                <button class="nav-arrow nav-next" id="next-month">&#8250;</button>
             </div>
+            <select id="month-select" style="display: none;"></select>
         </div>
         <div class="content-wrapper">
             <div id="chart-container"></div>

styles.css

@@ -23,16 +23,108 @@ body {
     margin-bottom: 20px;
 }
 
-.month-selector {
+/* Month Navigator */
+.month-navigator {
     display: flex;
     align-items: center;
-    gap: 10px;
+    gap: 8px;
+    max-width: 60%;
 }
 
-#month-select {
+.nav-arrow {
-    padding: 8px;
+    width: 36px;
-    border-radius: 4px;
+    height: 36px;
     border: 1px solid #ddd;
+    border-radius: 4px;
+    background-color: white;
+    font-size: 24px;
+    line-height: 1;
+    cursor: pointer;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    transition: background-color 0.2s, border-color 0.2s;
+    flex-shrink: 0;
+}
+
+.nav-arrow:hover:not(:disabled) {
+    background-color: #f0f0f0;
+    border-color: #999;
+}
+
+.nav-arrow:disabled {
+    opacity: 0.4;
+    cursor: not-allowed;
+}
+
+.month-list {
+    display: flex;
+    gap: 6px;
+    overflow-x: auto;
+    scrollbar-width: none;
+    -ms-overflow-style: none;
+}
+
+.month-list::-webkit-scrollbar {
+    display: none;
+}
+
+.month-btn {
+    padding: 8px 12px;
+    border: 1px solid #ddd;
+    border-radius: 4px;
+    background-color: white;
+    font-size: 14px;
+    cursor: pointer;
+    white-space: nowrap;
+    transition: background-color 0.2s, border-color 0.2s, color 0.2s;
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    gap: 6px;
+}
+
+.month-btn:hover {
+    background-color: #f0f0f0;
+    border-color: #999;
+}
+
+.month-btn.active {
+    background-color: #5470c6;
+    border-color: #5470c6;
+    color: white;
+}
+
+.month-preview {
+    width: 40px;
+    height: 40px;
+    border-radius: 50%;
+    border: 1px solid #eee;
+    position: relative;
+}
+
+.month-preview::after {
+    content: '';
+    position: absolute;
+    top: 50%;
+    left: 50%;
+    transform: translate(-50%, -50%);
+    width: 35%;
+    height: 35%;
+    background: white;
+    border-radius: 50%;
+}
+
+.month-btn.active .month-preview {
+    border-color: rgba(255, 255, 255, 0.3);
+}
+
+.month-btn.active .month-preview::after {
+    background: #5470c6;
+}
+
+.month-label {
+    font-size: 12px;
 }
 
 .content-wrapper {
@@ -163,6 +255,17 @@ body {
 
 
 @media (max-width: 850px) {
+    .header {
+        flex-direction: column;
+        align-items: flex-start;
+        gap: 15px;
+    }
+
+    .month-navigator {
+        max-width: 100%;
+        width: 100%;
+    }
+
     .content-wrapper {
         flex-direction: column;
     }
@@ -187,3 +290,25 @@ body {
     }
 }
 
+@media (max-width: 500px) {
+    .month-btn {
+        padding: 6px 8px;
+        font-size: 12px;
+    }
+
+    .month-preview {
+        width: 32px;
+        height: 32px;
+    }
+
+    .month-label {
+        font-size: 10px;
+    }
+
+    .nav-arrow {
+        width: 30px;
+        height: 30px;
+        font-size: 20px;
+    }
+}
+