feat(app,android,ios): search across episodes and people

A search now also finds, with posters and descriptions on, the directors
and studios and the genres whose names hold it, as chips that open their
page, and the episodes whose provider names hold it, which play from the
result (pstr_core::discover::find). The titles it found follow under
their own heading.

The last eight searches are kept in recent-searches.json on this device
only (pstr_core::recent), written only when a search led somewhere, and
offered under the empty search box with a way to clear them. The bridge
exposes search_extras, recent_searches, remember_search and
forget_searches.

On Android and iOS the library's titles are now the whole library
whatever is searched for; the grid narrows through the arrangement, as
it already did. A title opened from an episode result can then always be
shown, and History and Downloads no longer shrink to the search.

ios/ProtonStream/UI/LibraryView.swift

@@ -59,6 +59,8 @@ struct LibraryView: View {
     let onTitle: (TitleRecord) -> Void
     var onAddShare: () -> Void = {}
     var onOpenSettings: () -> Void = {}
+    /// Open every title sharing a genre, studio or director a search named.
+    var onBrowse: (BrowseFacet) -> Void = { _ in }
 
     // What a long press opened a menu for: a title, or a Continue watching card.
     @State private var menuFor: TitleRecord?
@@ -178,8 +180,13 @@ struct LibraryView: View {
     @ViewBuilder private func content(_ resumable: [Resumable], featured: [TitleRecord]) -> some View {
         if model.loading {
             LibrarySkeleton()
-        } else if model.titles.isEmpty && !model.query.trimmingCharacters(in: .whitespaces).isEmpty {
-            EmptyState("Nothing matches", "No title in the library is called “\(model.query.trimmingCharacters(in: .whitespaces))”.")
+        } else if searching && model.query.trimmingCharacters(in: .whitespaces).isEmpty && !model.recentSearches.isEmpty {
+            // Empty and with the field open: the last few searches.
+            recentSearches
+        } else if !model.query.trimmingCharacters(in: .whitespaces).isEmpty,
+                  model.arrangement?.tiles.isEmpty == true,
+                  model.searchExtras?.isEmpty ?? true {
+            EmptyState("Nothing matches", "Nothing in the library is called “\(model.query.trimmingCharacters(in: .whitespaces))”.")
         } else if model.titles.isEmpty, let activity = model.activity {
             // A share just added: say it is being looked through, rather than
             // offer to add the one that is already filling the page.
@@ -284,6 +291,14 @@ struct LibraryView: View {
                         Text("All titles").textStyle(.titleMedium).foregroundStyle(scheme.onSurface).padding(.top, 8)
                     }
                 }
+                // What the search found besides titles, above the titles it
+                // found.
+                if !browsing, let extras = model.searchExtras {
+                    searchExtras(extras, byKey: byKey)
+                    if !tiles.isEmpty && !extras.isEmpty {
+                        Text("Titles").textStyle(.titleMedium).foregroundStyle(scheme.onSurface)
+                    }
+                }
                 if browsing {
                     ScrollView(.horizontal, showsIndicators: false) {
                         HStack(spacing: 8) {
@@ -316,6 +331,71 @@ struct LibraryView: View {
         .scrollDismissesKeyboard(.immediately)
     }
 
+    /// The people, studios and genres a search named as chips, then the
+    /// episodes it found by name. Android's `facetChips` and its episode rows.
+    @ViewBuilder private func searchExtras(_ extras: SearchExtrasRecord, byKey: [String: TitleRecord]) -> some View {
+        ForEach([("People and studios", extras.people), ("Genres", extras.genres)], id: \.0) { heading, facets in
+            if !facets.isEmpty {
+                VStack(alignment: .leading, spacing: 8) {
+                    Text(heading).textStyle(.titleMedium).foregroundStyle(scheme.onSurface)
+                    FlowLayout(spacing: 6) {
+                        ForEach(facets, id: \.facet.label) { found in
+                            GenreChip(text: "\(found.facet.label) · \(found.count)") { onBrowse(found.facet) }
+                        }
+                    }
+                }
+            }
+        }
+        if !extras.episodes.isEmpty {
+            VStack(alignment: .leading, spacing: 4) {
+                Text("Episodes").textStyle(.titleMedium).foregroundStyle(scheme.onSurface)
+                ForEach(extras.episodes, id: \.linkId) { hit in
+                    if let title = byKey[hit.titleKey],
+                       let index = title.playlist.firstIndex(where: { $0.linkId == hit.linkId }) {
+                        Button { onResume(title, index) } label: {
+                            HStack(spacing: 12) {
+                                Image(systemName: "play.fill").foregroundStyle(scheme.onSurfaceVariant)
+                                VStack(alignment: .leading, spacing: 2) {
+                                    Text(hit.name).textStyle(.bodyLarge).foregroundStyle(scheme.onSurface).lineLimit(1)
+                                    Text("\(title.displayName) · \(hit.label)")
+                                        .textStyle(.bodySmall).foregroundStyle(scheme.onSurfaceVariant).lineLimit(1)
+                                }
+                                Spacer(minLength: 0)
+                            }
+                            .padding(.vertical, 8)
+                            .contentShape(Rectangle())
+                        }
+                        .buttonStyle(.plain)
+                        .accessibilityHint("Play")
+                    }
+                }
+            }
+        }
+    }
+
+    /// The last few searches, under an empty search field.
+    private var recentSearches: some View {
+        ScrollView {
+            VStack(alignment: .leading, spacing: 0) {
+                Text("Recent searches").textStyle(.titleMedium).foregroundStyle(scheme.onSurface).padding(.vertical, 8)
+                ForEach(model.recentSearches, id: \.self) { query in
+                    Button { model.search(query) } label: {
+                        Label(query, systemImage: "clock.arrow.circlepath")
+                            .textStyle(.bodyLarge)
+                            .foregroundStyle(scheme.onSurface)
+                            .frame(maxWidth: .infinity, minHeight: 48, alignment: .leading)
+                            .contentShape(Rectangle())
+                    }
+                    .buttonStyle(.plain)
+                }
+                Button("Clear recent searches") { model.forgetSearches() }
+                    .buttonStyle(.quiet)
+                    .padding(.top, 8)
+            }
+            .padding(.horizontal, 16)
+        }
+    }
+
     private func longPressed(_ open: () -> Void) {
         UIImpactFeedbackGenerator(style: .medium).impactOccurred()
         open()
@@ -846,3 +926,8 @@ extension BrowseFacet {
         }
     }
 }
+
+extension SearchExtrasRecord {
+    /// Whether a search found nothing besides titles.
+    var isEmpty: Bool { episodes.isEmpty && people.isEmpty && genres.isEmpty }
+}