feat: check every subscription in the background and add the posts page

app/lib/application/pages/hub_page.dart

@@ -1,6 +1,7 @@
 import '../../database/database.dart';
 import '../../l10n/strings.dart';
 import '../../mews/document.dart';
+import '../controllers/subscriptions_controller.dart';
 import 'mews_urls.dart';
 import 'page_blocks.dart';
 
@@ -10,11 +11,13 @@ import 'page_blocks.dart';
 Future<MewsPage> buildHubPage(
   Uri url, {
   required MewsDatabase db,
+  required SubscriptionsController subscriptions,
   required Strings strings,
 }) async {
   final bookmarks = await db.countBookmarks();
   final sites = await db.countSubscriptions();
   final visits = await db.countHistory();
+  final unread = await db.unreadCount();
 
   return internalPage(
     url: url,
@@ -22,6 +25,14 @@ Future<MewsPage> buildHubPage(
     body: [
       HeadingBlock(1, [MewsText(strings.t('hub-title'))]),
       itemList([
+        itemRow(
+          href: MewsUrls.posts,
+          label: strings.t('nav-posts'),
+          note: countText(strings, unread,
+              none: 'count-unread-none',
+              one: 'count-unread-one',
+              many: 'count-unread-many'),
+        ),
         itemRow(
           href: MewsUrls.bookmarks,
           label: strings.t('nav-bookmarks'),
@@ -48,6 +59,14 @@ Future<MewsPage> buildHubPage(
         ),
         itemRow(href: MewsUrls.settings, label: strings.t('nav-settings')),
       ]),
+      ParagraphBlock([
+        if (subscriptions.refreshing.value)
+          MewsEmphasis(EmphasisStyle.emphasis,
+              [MewsText(strings.t('posts-checking'))])
+        else
+          MewsLink(MewsUrls.action('refresh-subscriptions'),
+              [MewsText(strings.t('action-refresh'))]),
+      ]),
     ],
   );
 }

app/lib/application/pages/mews_urls.dart

@@ -13,6 +13,7 @@ abstract final class MewsUrls {
   static const scheme = 'mews';
 
   static const hub = 'mews:hub';
+  static const posts = 'mews:posts';
   static const bookmarks = 'mews:bookmarks';
   static const subscriptions = 'mews:subscriptions';
   static const history = 'mews:history';

app/lib/application/pages/page_blocks.dart

@@ -11,9 +11,14 @@ import 'mews_urls.dart';
 /// constant here rather than a message.
 const actionSeparator = '  ';
 
-/// One choice in a group of mutually exclusive values.
+/// A link with its label: a choice in a group, or an action on a row. For an
+/// action [current] is always false.
 typedef Choice = ({String href, String label, bool current});
 
+/// An action link on a row.
+Choice action(String href, String label) =>
+    (href: href, label: label, current: false);
+
 /// One entry in the strip of internal pages.
 typedef NavItem = ({String url, String labelId});
 
@@ -21,6 +26,7 @@ typedef NavItem = ({String url, String labelId});
 /// never shifts under the reader.
 const navItems = <NavItem>[
   (url: MewsUrls.hub, labelId: 'nav-hub'),
+  (url: MewsUrls.posts, labelId: 'nav-posts'),
   (url: MewsUrls.bookmarks, labelId: 'nav-bookmarks'),
   (url: MewsUrls.subscriptions, labelId: 'nav-subscriptions'),
   (url: MewsUrls.history, labelId: 'nav-history'),
@@ -61,18 +67,59 @@ MewsListItem itemRow({
   required String label,
   String? date,
   String? note,
+  bool strong = false,
+  List<Choice> actions = const [],
 }) {
+  final text = date == null ? label : '$date $label';
   return MewsListItem([
     ParagraphBlock([
-      MewsLink(href, [MewsText(date == null ? label : '$date $label')]),
+      MewsLink(href, [
+        if (strong)
+          MewsEmphasis(EmphasisStyle.strong, [MewsText(text)])
+        else
+          MewsText(text),
+      ]),
       if (note != null) ...[
         const MewsLineBreak(),
         MewsEmphasis(EmphasisStyle.emphasis, [MewsText(note)]),
       ],
+      if (actions.isNotEmpty) ...[
+        const MewsLineBreak(),
+        ..._separated(
+            [for (final action in actions) MewsLink(action.href, [MewsText(action.label)])]),
+      ],
     ]),
   ]);
 }
 
+/// Joins runs with the separator between them, never around them.
+List<MewsInline> _separated(List<MewsInline> runs) {
+  final out = <MewsInline>[];
+  for (final run in runs) {
+    if (out.isNotEmpty) out.add(const MewsText(actionSeparator));
+    out.add(run);
+  }
+  return out;
+}
+
+/// A group of mutually exclusive values on one line, for a short group that
+/// would waste a list. The chosen value is plain text, the rest are links.
+List<MewsBlock> choiceLine({required String label, required List<Choice> options}) {
+  return [
+    ParagraphBlock([
+      MewsEmphasis(EmphasisStyle.emphasis, [MewsText(label)]),
+      const MewsText(actionSeparator),
+      ..._separated([
+        for (final option in options)
+          if (option.current)
+            MewsEmphasis(EmphasisStyle.strong, [MewsText(option.label)])
+          else
+            MewsLink(option.href, [MewsText(option.label)]),
+      ]),
+    ]),
+  ];
+}
+
 /// A group of mutually exclusive values: the current one plain, the rest links.
 ListBlock choiceRow(List<Choice> options) {
   return ListBlock(

app/lib/application/pages/posts_page.dart

@@ -0,0 +1,104 @@
+import '../../database/database.dart';
+import '../../l10n/strings.dart';
+import '../../mews/document.dart';
+import 'mews_urls.dart';
+import 'page_blocks.dart';
+
+/// Every post from every subscribed site in one list (spec 6.1), newest first
+/// unless the reader orders it otherwise. Unread posts stand out, and opening
+/// one marks it read.
+Future<MewsPage> buildPostsPage(
+  Uri url, {
+  required MewsDatabase db,
+  required Strings strings,
+  required bool refreshing,
+}) async {
+  final sort = EntrySort.parse(url.queryParameters['sort']);
+  final unreadOnly = url.queryParameters['show'] == 'unread';
+  final entries =
+      await db.riverEntries(sort: sort, unreadOnly: unreadOnly);
+  final unread = await db.unreadCount();
+  final title = strings.t('posts-title');
+
+  return internalPage(
+    url: url,
+    title: title,
+    body: [
+      ...chrome(title: title, current: url, strings: strings),
+      ParagraphBlock([
+        MewsEmphasis(EmphasisStyle.emphasis, [
+          MewsText(countText(strings, unread,
+              none: 'count-unread-none',
+              one: 'count-unread-one',
+              many: 'count-unread-many')),
+        ]),
+        const MewsText(actionSeparator),
+        if (refreshing)
+          MewsEmphasis(EmphasisStyle.emphasis,
+              [MewsText(strings.t('posts-checking'))])
+        else
+          MewsLink(MewsUrls.action('refresh-subscriptions'),
+              [MewsText(strings.t('action-refresh'))]),
+      ]),
+      ...choiceLine(
+        label: strings.t('posts-sort-label'),
+        options: [
+          for (final option in const [
+            (EntrySort.date, 'posts-sort-date'),
+            (EntrySort.source, 'posts-sort-source'),
+            (EntrySort.unread, 'posts-sort-unread'),
+          ])
+            (
+              href: MewsUrls.page(url, {'sort': option.$1.name}),
+              label: strings.t(option.$2),
+              current: option.$1 == sort,
+            ),
+        ],
+      ),
+      ...choiceLine(
+        label: strings.t('posts-show-label'),
+        options: [
+          (
+            href: MewsUrls.page(url, {'show': null}),
+            label: strings.t('posts-show-all'),
+            current: !unreadOnly,
+          ),
+          (
+            href: MewsUrls.page(url, {'show': 'unread'}),
+            label: strings.t('posts-show-unread'),
+            current: unreadOnly,
+          ),
+        ],
+      ),
+      const RuleBlock(),
+      if (entries.isEmpty)
+        ParagraphBlock([
+          MewsText(strings
+              .t(unreadOnly ? 'posts-none-unread' : 'posts-empty')),
+        ])
+      else
+        itemList([
+          for (final entry in entries)
+            itemRow(
+              href: entry.url,
+              label: entry.title,
+              date: dayText(entry.date),
+              note: entry.siteName,
+              strong: entry.unread,
+              actions: [
+                if (entry.unread)
+                  action(
+                      MewsUrls.action('mark-read',
+                          {'site': entry.siteUrl, 'url': entry.url}),
+                      strings.t('posts-mark-read'))
+                else
+                  action(
+                      MewsUrls.action('mark-unread',
+                          {'site': entry.siteUrl, 'url': entry.url}),
+                      strings.t('posts-mark-unread')),
+              ],
+            ),
+        ]),
+    ],
+  );
+}