feat: add tag usage pie chart component and statistics utility for enhanced session tracking

Author: murdercode

src/index.html

@@ -254,6 +254,22 @@ <h3>Focus Weekly Summary</h3>
             </div>
           </div>
 
+          <!-- Tag Usage Pie Chart -->
+          <div class="tag-usage-card">
+            <h3>Tag Usage This Week</h3>
+            <div class="tag-chart-container">
+              <div class="tag-pie-chart" id="tag-pie-chart">
+                <div class="pie-chart-placeholder">
+                  <i class="ri-pie-chart-line"></i>
+                  <span>No data available</span>
+                </div>
+              </div>
+              <div class="tag-legend" id="tag-legend">
+                <!-- Legend items will be populated by JavaScript -->
+              </div>
+            </div>
+          </div>
+
           <!-- Weekly Sessions Chart -->
           <div class="weekly-chart-card">
             <h3>This Week's Sessions</h3>

src/managers/navigation-manager.js

@@ -1,12 +1,14 @@
 // Navigation Manager for Sidebar
 import { TimeUtils } from '../utils/common-utils.js';
+import { TagStatistics } from '../utils/tag-statistics.js';
 
 export class NavigationManager {
     constructor() {
         this.currentView = 'timer';
         this.initialized = false;
         this.currentTooltip = null; // Track current tooltip for proper cleanup
         this.tooltipTimeout = null; // Track timeout for debounced tooltip removal
+        this.tagStatistics = new TagStatistics(); // Initialize tag statistics utility
 
         // Apply timer-active class on initial load since default view is timer
         document.body.classList.add('timer-active');
@@ -84,6 +86,7 @@ export class NavigationManager {
             await this.updateFocusSummary();
             await this.updateWeeklySessionsChart();
             this.updateDailyChart();
+            await this.updateTagUsageChart(); // Update tag usage pie chart
             await this.updateSelectedDayDetails();
             await this.initSessionsTable(); // Initialize sessions table when viewing calendar
         } else if (view === 'settings') {

src/styles/statistics.css

@@ -136,4 +136,173 @@
 .focus-metric .metric-change.negative {
   color: var(--focus-color) !important;
   background: color-mix(in srgb, var(--focus-color) 10%, transparent) !important;
+}
+
+/* Tag Usage Pie Chart Styles */
+.tag-usage-card {
+  background: white;
+  border-radius: 12px;
+  padding: 24px;
+  margin-bottom: 24px;
+  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.05);
+  border: 1px solid #e5e7eb;
+}
+
+.tag-usage-card h3 {
+  margin: 0 0 20px 0;
+  color: #374151;
+  font-size: 1.1rem;
+  font-weight: 600;
+}
+
+.tag-chart-container {
+  display: flex;
+  align-items: center;
+  gap: 24px;
+  min-height: 200px;
+}
+
+.tag-pie-chart {
+  position: relative;
+  width: 200px;
+  height: 200px;
+  border-radius: 50%;
+  flex-shrink: 0;
+}
+
+.pie-chart-placeholder {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  width: 100%;
+  height: 100%;
+  color: #9ca3af;
+  border: 2px dashed #d1d5db;
+  border-radius: 50%;
+}
+
+.pie-chart-placeholder i {
+  font-size: 48px;
+  margin-bottom: 8px;
+}
+
+.pie-chart-placeholder span {
+  font-size: 14px;
+  text-align: center;
+}
+
+.tag-legend {
+  flex: 1;
+  display: flex;
+  flex-direction: column;
+  gap: 12px;
+}
+
+.tag-legend-item {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+}
+
+.tag-legend-color {
+  width: 16px;
+  height: 16px;
+  border-radius: 4px;
+  flex-shrink: 0;
+}
+
+.tag-legend-info {
+  flex: 1;
+}
+
+.tag-legend-name {
+  font-weight: 500;
+  color: #374151;
+  font-size: 14px;
+}
+
+.tag-legend-stats {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  margin-top: 2px;
+}
+
+.tag-legend-time {
+  color: #6b7280;
+  font-size: 13px;
+}
+
+.tag-legend-percent {
+  color: #9ca3af;
+  font-size: 12px;
+  font-weight: 500;
+}
+
+/* Pie chart segments */
+.pie-segment {
+  position: absolute;
+  width: 100%;
+  height: 100%;
+  border-radius: 50%;
+  clip-path: polygon(50% 50%, 50% 0%, 100% 0%, 100% 100%, 0% 100%, 0% 0%, 50% 0%);
+}
+
+/* Dark theme styles for tag usage chart */
+[data-theme="dark"] .tag-usage-card {
+  background: #1e293b;
+  border-color: #334155;
+  color: #f1f5f9;
+}
+
+[data-theme="dark"] .tag-usage-card h3 {
+  color: #f1f5f9;
+}
+
+[data-theme="dark"] .pie-chart-placeholder {
+  color: #64748b;
+  border-color: #475569;
+}
+
+[data-theme="dark"] .tag-legend-name {
+  color: #f1f5f9;
+}
+
+[data-theme="dark"] .tag-legend-time {
+  color: #94a3b8;
+}
+
+[data-theme="dark"] .tag-legend-percent {
+  color: #64748b;
+}
+
+/* Auto theme dark styles for tag usage chart */
+@media (prefers-color-scheme: dark) {
+  [data-theme="auto"] .tag-usage-card {
+    background: #1e293b;
+    border-color: #334155;
+    color: #f1f5f9;
+  }
+
+  [data-theme="auto"] .tag-usage-card h3 {
+    color: #f1f5f9;
+  }
+
+  [data-theme="auto"] .pie-chart-placeholder {
+    color: #64748b;
+    border-color: #475569;
+  }
+
+  [data-theme="auto"] .tag-legend-name {
+    color: #f1f5f9;
+  }
+
+  [data-theme="auto"] .tag-legend-time {
+    color: #94a3b8;
+  }
+
+  [data-theme="auto"] .tag-legend-percent {
+    color: #64748b;
+  }
 }