Feed filter implementation

vue/src/composables/useFeeds.js

@@ -1,11 +1,37 @@
-import { ref, nextTick } from 'vue';
+import { ref, computed, nextTick } from 'vue';
 import axios from 'axios';
 import { Readability } from '@mozilla/readability';
 
 // Module-level state — declared outside useFeeds() so every caller shares the
 // same singleton refs (a Pinia-free "store" for the feed list and its UI state).
 const showMessage = ref(false)
+// `allItems` is the full flattened+sorted stream from the last fetch (the
+// master); `feeds` is the currently displayed projection of it (all items, or a
+// single feed when a filter is active). Every view/observer consumer operates on
+// `feeds` — the filter layer only ever swaps what `feeds` points at, so none of
+// the index-based observer / currentIndex logic has to know a filter exists.
+const allItems = ref([]);
 const feeds = ref([]);
+const feedFilter = ref(null) // selected feedTitle, or null = all feeds (not persisted)
+// Distinct feed titles present in the loaded (unread) items — the filter options.
+// The active filter is always kept in the list even once its feed runs out of
+// unread items, so the <select> never binds to a value that isn't an option
+// (it just shows "All caught up") and the feed stays re-selectable.
+const feedTitles = computed(() => {
+  const titles = new Set(allItems.value.map(i => i.feedTitle))
+  if (feedFilter.value) titles.add(feedFilter.value)
+  return [...titles].sort((a, b) => a.localeCompare(b))
+})
+// The header badge count: unread items in the selected feed when a filter is
+// active, otherwise the global unread total. Derived from the master (allItems)
+// rather than the displayed `feeds` so article view's read-but-still-shown
+// items are excluded and the count matches the filter regardless of view.
+const unreadCount = computed(() => {
+  const items = feedFilter.value
+    ? allItems.value.filter(i => i.feedTitle === feedFilter.value)
+    : allItems.value
+  return items.filter(i => !i.read).length
+})
 const message = ref('')
 const showModal = ref(false)
 const viewMode = ref('list') // 'list' | 'article' — toggled from the hamburger menu
@@ -176,6 +202,30 @@ async function markRead(id) {
   }
 }
 
+// Projects the master list onto `feeds` through the active filter. A filtered
+// feed with no remaining unread items projects to an empty list ("All caught
+// up") while staying selected — see feedTitles.
+function applyFilter() {
+  feeds.value = feedFilter.value
+    ? allItems.value.filter(i => i.feedTitle === feedFilter.value)
+    : allItems.value.slice()
+}
+
+// Changes the active feed filter and re-projects. Mirrors toggleLayout's
+// observer/scroll-safe pattern: disconnect first, scroll to top, then re-point
+// the observer at the new .observe nodes after Vue has re-rendered. Works in
+// article view too — there are no .observe nodes there so the setup is a no-op,
+// and resetting currentIndex keeps paging valid against the new list.
+async function setFeedFilter(title) {
+  disconnectObserver()
+  window.scrollTo(0, 0)
+  feedFilter.value = title // null for "All feeds"
+  currentIndex.value = 0
+  applyFilter()
+  await nextTick()
+  setupIntersectionObserver()
+}
+
 const fetchData = async () => {
   const user_id = localStorage.getItem("user-id")
   try {
@@ -187,7 +237,8 @@ const fetchData = async () => {
     // timestamps are zero-padded "YYYY-MM-DD HH:MM:SS" strings, so a plain
     // lexicographic comparison sorts them chronologically.
     items.sort((a, b) => b.timestamp.localeCompare(a.timestamp));
-    feeds.value = items;
+    allItems.value = items;
+    applyFilter();
     await nextTick();
     setupIntersectionObserver();
   } catch (error) {
@@ -262,6 +313,8 @@ function handleIntersection(entries, topbarHeight = 0) {
   markProgrammaticScroll()
   const readIds = new Set(readFeeds.map(feed => feed.id))
   feeds.value = feeds.value.filter(feed => !readIds.has(feed.id))
+  // Mirror into the master so cleared filters don't resurrect read articles.
+  allItems.value = allItems.value.filter(feed => !readIds.has(feed.id))
 
   for (const feed of readFeeds) {
     markRead(feed.id)
@@ -302,7 +355,11 @@ async function markAllRead() {
   if (!window.confirm('Mark all articles as read?')) return
 
   const ids = feeds.value.map(feed => feed.id)
+  const readIds = new Set(ids)
   feeds.value = []
+  // markAllRead operates on the visible subset (only the filtered feed, if one
+  // is active) — drop exactly those from the master too.
+  allItems.value = allItems.value.filter(feed => !readIds.has(feed.id))
   currentIndex.value = 0
   // markRead swallows its own errors, so Promise.all can't reject here.
   await Promise.all(ids.map(id => markRead(id)))
@@ -325,6 +382,8 @@ async function leaveArticleView() {
   // in place so currentIndex stayed valid — drop them now so they don't keep
   // showing up in the list view.
   feeds.value = feeds.value.filter(feed => !feed.read)
+  // Shared references — the paged-past objects carry .read on the master too.
+  allItems.value = allItems.value.filter(feed => !feed.read)
   currentIndex.value = 0
   viewMode.value = 'list'
   // The v-if on the list container tears down and recreates all .observe DOM
@@ -382,6 +441,11 @@ function prevArticle() {
 export function useFeeds() {
   return {
     feeds,
+    allItems,
+    feedFilter,
+    feedTitles,
+    unreadCount,
+    setFeedFilter,
     showMessage,
     message,
     showModal,