Add browser caching

src/pages/index.astro

@@ -156,11 +156,44 @@ const REPO_FILTER = import.meta.env.PUBLIC_REPO_FILTER || '';
 			}
 
 			async function fetchTimes() {
-				var since = getSinceDate();
+				var cached = loadCachedEntries();
+				var since;
+				if (cached && cached.length > 0) {
+					var latest = cached.reduce(function(max, e) {
+						return e.created > max ? e.created : max;
+					}, cached[0].created);
+					var d = new Date(latest);
+					d.setSeconds(d.getSeconds() - 1);
+					since = d.toISOString();
+					console.log('[fetch] latest cached entry: ' + latest + ', fetching since: ' + since);
+				} else {
+					since = getSinceDate();
+					console.log('[fetch] no cache, fetching full 12 months since: ' + since);
+				}
 				var url = API_BASE + '/user/times?access_token=' + TOKEN + '&since=' + since;
 				var resp = await fetch(url);
 				if (!resp.ok) throw new Error('API error: ' + resp.status);
-				return resp.json();
+				var newEntries = await resp.json();
+				console.log('[fetch] received ' + newEntries.length + ' entries from API');
+				if (cached && cached.length > 0) {
+					var before = cached.length;
+					var existingIds = {};
+					for (var i = 0; i < cached.length; i++) {
+						if (cached[i].id) existingIds[cached[i].id] = true;
+					}
+					for (var i = 0; i < newEntries.length; i++) {
+						if (!newEntries[i].id || !existingIds[newEntries[i].id]) {
+							cached.push(newEntries[i]);
+						}
+					}
+					console.log('[fetch] merged: ' + cached.length + ' total (' + (cached.length - before) + ' new)');
+					saveCachedEntries(cached);
+					return cached;
+				} else {
+					console.log('[fetch] storing ' + newEntries.length + ' entries as fresh cache');
+					saveCachedEntries(newEntries);
+					return newEntries;
+				}
 			}
 
 			function getTodayStart() {
@@ -180,6 +213,33 @@ const REPO_FILTER = import.meta.env.PUBLIC_REPO_FILTER || '';
 				return Date.UTC(now.getFullYear(), now.getMonth(), 1);
 			}
 
+			const CACHE_KEY = 'timeTrackingEntries';
+
+			function loadCachedEntries() {
+				try {
+					var raw = localStorage.getItem(CACHE_KEY);
+					if (raw) {
+						var entries = JSON.parse(raw);
+						console.log('[cache] loaded ' + entries.length + ' entries from localStorage');
+						return entries;
+					}
+					console.log('[cache] no cached data found');
+					return null;
+				} catch(e) {
+					console.log('[cache] load error:', e);
+					return null;
+				}
+			}
+
+			function saveCachedEntries(entries) {
+				try {
+					localStorage.setItem(CACHE_KEY, JSON.stringify(entries));
+					console.log('[cache] saved ' + entries.length + ' entries to localStorage');
+				} catch(e) {
+					console.log('[cache] save error:', e);
+				}
+			}
+
 			function getSinceDate() {
 				var now = new Date();
 				var d = new Date(Date.UTC(now.getFullYear(), now.getMonth(), 1));
@@ -421,7 +481,15 @@ const REPO_FILTER = import.meta.env.PUBLIC_REPO_FILTER || '';
 					document.getElementById('loading').style.display = 'none';
 					document.getElementById('dashboard').style.display = 'block';
 				} catch (err) {
-					console.error(err);
+					console.error('[fetch] API error:', err);
+					var cached = loadCachedEntries();
+					if (cached && cached.length > 0) {
+						console.log('[app] falling back to ' + cached.length + ' cached entries');
+						renderCharts(cached);
+						document.getElementById('loading').style.display = 'none';
+						document.getElementById('dashboard').style.display = 'block';
+						return;
+					}
 					showError(err.message || 'Failed to fetch data');
 				}
 			}