feat: search, filter and act on items from the library pages

app/lib/database/database.dart

@@ -162,26 +162,72 @@ class MewsDatabase extends _$MewsDatabase {
     return (await query.getSingle()).read(total) ?? 0;
   }
 
-  /// The most recent external visits, newest first.
-  Future<List<HistoryItem>> recentVisits({int limit = 50}) async {
-    final query = (select(historyItems)
-          ..orderBy([
-            (r) => OrderingTerm.desc(r.visitedAt),
-            (r) => OrderingTerm.desc(r.id),
-          ])
-          ..limit(limit));
-    return query.get();
+  /// The most recently visited pages, newest first, one row per address so a
+  /// page visited often is not listed over and over. [query] narrows by title
+  /// or address.
+  Future<List<VisitedPage>> recentPages({String? query, int limit = 200}) async {
+    // Group on the highest row id rather than the latest timestamp: visits
+    // recorded within the same clock tick share a timestamp, and sqlite then
+    // picks any one of their rows for the plain columns below. Ids always
+    // climb, so the newest visit is the one with the largest id.
+    final lastVisit = historyItems.id.max();
+    final statement = selectOnly(historyItems)
+      ..addColumns([
+        historyItems.url,
+        historyItems.title,
+        historyItems.visitedAt,
+        lastVisit,
+      ])
+      ..groupBy([historyItems.url])
+      ..orderBy([OrderingTerm.desc(lastVisit)])
+      ..limit(limit);
+    final filter = _search([historyItems.url, historyItems.title], query);
+    if (filter != null) statement.where(filter);
+
+    return (await statement.get()).map((row) {
+      return VisitedPage(
+        // Selecting a plain column alongside max() gives the value from the
+        // row that matched it, so these describe the latest visit.
+        url: row.read(historyItems.url)!,
+        title: row.read(historyItems.title),
+        visitedAt: row.read(historyItems.visitedAt)!,
+      );
+    }).toList();
   }
 
-  /// Bookmarks in the order they were added, newest first.
-  Future<List<Bookmark>> bookmarksByDate() async {
-    final query = (select(bookmarks)
+  /// Removes every visit to one page.
+  Future<void> forgetPage(String url) =>
+      (delete(historyItems)..where((r) => r.url.equals(url))).go();
+
+  Future<void> clearHistory() => delete(historyItems).go();
+
+  /// Narrows a list to rows where any of [columns] contains [query]. Returns
+  /// null when there is nothing to search for, so the caller adds no clause.
+  Expression<bool>? _search(
+      List<GeneratedColumn<String>> columns, String? query) {
+    final needle = query?.trim();
+    if (needle == null || needle.isEmpty) return null;
+    // The reader is typing text, not a pattern, so LIKE's wildcards are
+    // escaped and matched literally.
+    final pattern =
+        '%${needle.replaceAll('\\', '\\\\').replaceAll('%', '\\%').replaceAll('_', '\\_')}%';
+    return columns
+        .map((column) => column.like(pattern, escapeChar: '\\'))
+        .reduce((a, b) => a | b);
+  }
+
+  /// Bookmarks in the order they were added, newest first. [query] narrows by
+  /// title or address.
+  Future<List<Bookmark>> bookmarksByDate({String? query}) async {
+    final statement = (select(bookmarks)
           ..orderBy([
             (r) => OrderingTerm.desc(r.createdAt),
             // Tiebreak bookmarks added within the same clock tick.
             (r) => OrderingTerm.asc(r.url),
           ]));
-    return query.get();
+    final filter = _search([bookmarks.url, bookmarks.title], query);
+    if (filter != null) statement.where((_) => filter);
+    return statement.get();
   }
 
   // Bookmarks -----------------------------------------------------------
@@ -214,13 +260,16 @@ class MewsDatabase extends _$MewsDatabase {
         await _removeTagsOf(TagKind.subscription, url);
       });
 
-  Future<List<Subscription>> allSubscriptions() async {
-    final query = (select(subscriptions)
+  /// Subscribed sites, newest first. [query] narrows by title or address.
+  Future<List<Subscription>> allSubscriptions({String? query}) async {
+    final statement = (select(subscriptions)
           ..orderBy([
             (r) => OrderingTerm.desc(r.createdAt),
             (r) => OrderingTerm.asc(r.url),
           ]));
-    return query.get();
+    final filter = _search([subscriptions.url, subscriptions.title], query);
+    if (filter != null) statement.where((_) => filter);
+    return statement.get();
   }
 
   /// Records that a site was checked, whether or not anything was found.
@@ -432,6 +481,19 @@ enum EntrySort {
   };
 }
 
+/// One page the reader visited, collapsed to its latest visit.
+class VisitedPage {
+  const VisitedPage({
+    required this.url,
+    required this.title,
+    required this.visitedAt,
+  });
+
+  final String url;
+  final String? title;
+  final DateTime visitedAt;
+}
+
 /// One post together with the site that published it.
 class RiverEntry {
   const RiverEntry({