feat(core,app,android): sort, fold and shelve the Android library

Bring the phase 2 library to Android. Search, sorting and franchise folding
move from the desktop app into pstr_core::browse, so both clients find,
fold and order the same titles the same way.

The bridge gains AndroidEngine::arrangement, which returns the grid's tiles
and up to three shelves as keys into the library's titles. Each TitleRecord
now carries its display name, wide art, format, season, studios, directors,
tags, airing state and franchise. The library bar has a sort menu with the
franchise toggle, folded tiles show a +N badge, and shelves sit above the
grid. The title page shows the same facts, tags and franchise row as the
desktop. Settings -> Appearance gains Title names.

The default title name is now English, which is what Android always showed.
A folded franchise now sorts by its lead's displayed name rather than by its
alphabetically first member.

crates/pstr-core/src/browse.rs

@@ -0,0 +1,395 @@
+//! Finding and ordering titles: what both library grids show, and in what
+//! order.
+//!
+//! Here rather than in a front end so the desktop and Android agree: the same
+//! search finds the same titles, a franchise folds into the same tile, and
+//! "Newest" means the same thing on both.
+
+use std::collections::{HashMap, HashSet};
+
+use crate::library::{Library, Title, sort_name};
+use crate::metadata::{MetadataRecord, TitleNames};
+
+/// What order a grid is in.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub enum Sort {
+    /// By the name shown, ignoring a leading article.
+    #[default]
+    Name,
+    /// Most recently played first.
+    Recent,
+    /// Most recently given a new file first.
+    Added,
+    /// Newest first by when it aired, undated last.
+    Release,
+    /// Best rated first, unrated last.
+    Rating,
+    /// Most followed at the provider first.
+    Popularity,
+}
+
+impl Sort {
+    pub const ALL: [Self; 6] = [
+        Self::Name,
+        Self::Recent,
+        Self::Added,
+        Self::Release,
+        Self::Rating,
+        Self::Popularity,
+    ];
+
+    pub fn label(self) -> &'static str {
+        match self {
+            Self::Name => "A – Z",
+            Self::Recent => "Recently watched",
+            Self::Added => "Recently added",
+            Self::Release => "Newest",
+            Self::Rating => "Highest rated",
+            Self::Popularity => "Most popular",
+        }
+    }
+}
+
+/// The name to show for `title`: the provider's, in the form the viewer
+/// picked, else the share's.
+pub fn display_name<'a>(
+    title: &'a Title,
+    metadata: &'a HashMap<String, MetadataRecord>,
+    names: TitleNames,
+) -> &'a str {
+    metadata
+        .get(&title.key)
+        .and_then(|record| record.metadata.as_ref())
+        .and_then(|found| found.display_name(names))
+        .unwrap_or(&title.name)
+}
+
+/// The titles `query` finds, in library order.
+///
+/// By the share's name and every filename under it — a release group, an
+/// episode name — and by every name the provider gave: a folder called
+/// `Sousou no Frieren` is found by typing "Frieren: Beyond".
+pub fn search<'a>(
+    library: &'a Library,
+    metadata: &HashMap<String, MetadataRecord>,
+    query: &str,
+) -> Vec<&'a Title> {
+    let needle = query.trim().to_lowercase();
+    let by_files: HashSet<*const Title> = library
+        .search(query)
+        .into_iter()
+        .map(|title| title as *const Title)
+        .collect();
+    library
+        .titles
+        .iter()
+        .filter(|title| {
+            by_files.contains(&(*title as *const Title))
+                || metadata
+                    .get(&title.key)
+                    .and_then(|record| record.metadata.as_ref())
+                    .is_some_and(|found| {
+                        std::iter::once(found.name.as_str())
+                            .chain(found.original_name.as_deref())
+                            .chain(
+                                found
+                                    .details
+                                    .as_ref()
+                                    .and_then(|details| details.romaji.as_deref()),
+                            )
+                            .any(|name| name.to_lowercase().contains(&needle))
+                    })
+        })
+        .collect()
+}
+
+/// How to order a grid.
+#[derive(Debug, Clone, Copy)]
+pub struct Order<'a> {
+    pub sort: Sort,
+    /// One tile per franchise rather than one per title.
+    pub grouped: bool,
+    pub names: TitleNames,
+    pub metadata: &'a HashMap<String, MetadataRecord>,
+    /// When each title last gained a file, by key — see
+    /// [`Library::added_at`].
+    pub added: &'a HashMap<String, i64>,
+}
+
+/// One tile: the title drawn, and every title it stands for — itself
+/// included, in release order — as indices into what was arranged.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Tile {
+    pub lead: usize,
+    pub members: Vec<usize>,
+}
+
+/// `titles` as tiles, in `order`.
+///
+/// Every sort is stable over the name order, so ties — and the undated,
+/// unrated and unplayed — keep their alphabetical order.
+pub fn arrange<'t>(titles: &[&'t Title], order: Order<'_>) -> Vec<Tile> {
+    let metadata = order.metadata;
+    let found = |title: &Title| {
+        metadata
+            .get(&title.key)
+            .and_then(|record| record.metadata.as_ref())
+    };
+
+    let mut by_name: Vec<usize> = (0..titles.len()).collect();
+    by_name
+        .sort_by_cached_key(|&index| sort_name(display_name(titles[index], metadata, order.names)));
+    let sorted: Vec<&Title> = by_name.iter().map(|&index| titles[index]).collect();
+
+    let mut tiles: Vec<Tile> = if order.grouped {
+        crate::franchise::group(&sorted, metadata)
+            .into_iter()
+            .map(|franchise| Tile {
+                lead: by_name[franchise.lead(&sorted)],
+                members: franchise
+                    .members
+                    .iter()
+                    .map(|&member| by_name[member])
+                    .collect(),
+            })
+            .collect()
+    } else {
+        by_name
+            .iter()
+            .map(|&index| Tile {
+                lead: index,
+                members: vec![index],
+            })
+            .collect()
+    };
+
+    // A folded franchise files under the name on its tile — the lead's — and
+    // not under whichever member sorted first: "Made in Abyss" belongs at M
+    // even when its film is called "Dawn of the Deep Soul".
+    tiles.sort_by_cached_key(|tile| {
+        sort_name(display_name(titles[tile.lead], metadata, order.names))
+    });
+
+    let members = |tile: &Tile| -> Vec<&'t Title> {
+        tile.members.iter().map(|&index| titles[index]).collect()
+    };
+    match order.sort {
+        Sort::Name => {}
+        Sort::Recent => tiles.sort_by_key(|tile| {
+            std::cmp::Reverse(members(tile).iter().map(|title| title.last_played()).max())
+        }),
+        Sort::Added => tiles.sort_by_key(|tile| {
+            std::cmp::Reverse(
+                members(tile)
+                    .iter()
+                    .filter_map(|title| order.added.get(&title.key))
+                    .max()
+                    .copied(),
+            )
+        }),
+        Sort::Release => tiles.sort_by_cached_key(|tile| {
+            std::cmp::Reverse(
+                members(tile)
+                    .iter()
+                    .map(|title| crate::franchise::release_key(title, metadata))
+                    // `~` is how the key says "undated"; it sorts last here
+                    // rather than first.
+                    .filter(|key| key != "~")
+                    .max(),
+            )
+        }),
+        Sort::Rating => tiles.sort_by_key(|tile| {
+            std::cmp::Reverse(
+                found(titles[tile.lead])
+                    .and_then(|found| found.rating)
+                    .map(|rating| (rating * 100.0) as i64),
+            )
+        }),
+        Sort::Popularity => tiles.sort_by_key(|tile| {
+            std::cmp::Reverse(
+                found(titles[tile.lead])
+                    .and_then(|found| found.details.as_ref())
+                    .and_then(|details| details.popularity),
+            )
+        }),
+    }
+    tiles
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::library::TitleKind;
+    use crate::metadata::{ProviderId, TitleDetails, TitleMetadata};
+
+    fn title(key: &str, name: &str, kind: TitleKind) -> Title {
+        Title {
+            key: key.into(),
+            name: name.into(),
+            year: None,
+            kind,
+            seasons: Vec::new(),
+            share_ids: Vec::new(),
+        }
+    }
+
+    fn matched(
+        key: &str,
+        id: &str,
+        english: &str,
+        start: &str,
+        rating: f32,
+        related: &[&str],
+    ) -> (String, MetadataRecord) {
+        (
+            key.into(),
+            MetadataRecord {
+                title_key: key.into(),
+                provider: ProviderId::AniList,
+                metadata: Some(TitleMetadata {
+                    provider: ProviderId::AniList,
+                    remote_id: id.into(),
+                    name: english.into(),
+                    original_name: None,
+                    overview: None,
+                    year: None,
+                    kind: TitleKind::Series,
+                    poster_url: None,
+                    backdrop_url: None,
+                    rating: Some(rating),
+                    genres: Vec::new(),
+                    episodes: None,
+                    url: None,
+                    details: Some(TitleDetails {
+                        romaji: Some(key.into()),
+                        start_date: Some(start.into()),
+                        related: related.iter().map(|id| id.to_string()).collect(),
+                        ..TitleDetails::default()
+                    }),
+                }),
+                fetched_at: 0,
+                manual: false,
+            },
+        )
+    }
+
+    fn fixture() -> (Vec<Title>, HashMap<String, MetadataRecord>) {
+        let titles = vec![
+            title("abyss film", "Made in Abyss Dawn", TitleKind::Film),
+            title("made in abyss", "Made in Abyss", TitleKind::Series),
+            title("sousou no frieren", "Sousou no Frieren", TitleKind::Series),
+        ];
+        let metadata = HashMap::from([
+            matched(
+                "abyss film",
+                "2",
+                "Dawn of the Deep Soul",
+                "2020-01-17",
+                8.5,
+                &["1"],
+            ),
+            matched(
+                "made in abyss",
+                "1",
+                "Made in Abyss",
+                "2017-07-07",
+                8.4,
+                &["2"],
+            ),
+            matched(
+                "sousou no frieren",
+                "3",
+                "Frieren: Beyond Journey's End",
+                "2023-09-29",
+                9.1,
+                &[],
+            ),
+        ]);
+        (titles, metadata)
+    }
+
+    fn keys(tiles: &[Tile], titles: &[&Title]) -> Vec<String> {
+        tiles
+            .iter()
+            .map(|tile| titles[tile.lead].key.clone())
+            .collect()
+    }
+
+    #[test]
+    fn a_franchise_folds_into_its_series_and_sorts_by_the_name_shown() {
+        let (owned, metadata) = fixture();
+        let titles: Vec<&Title> = owned.iter().collect();
+        let added = HashMap::new();
+        let order = Order {
+            sort: Sort::Name,
+            grouped: true,
+            names: TitleNames::English,
+            metadata: &metadata,
+            added: &added,
+        };
+        let tiles = arrange(&titles, order);
+        // "Frieren" before "Made in Abyss" in English; the film is folded.
+        assert_eq!(
+            keys(&tiles, &titles),
+            vec!["sousou no frieren", "made in abyss"]
+        );
+        assert_eq!(tiles[1].members, vec![1, 0]);
+
+        let tiles = arrange(
+            &titles,
+            Order {
+                names: TitleNames::Library,
+                grouped: false,
+                ..order
+            },
+        );
+        assert_eq!(
+            keys(&tiles, &titles),
+            vec!["made in abyss", "abyss film", "sousou no frieren"]
+        );
+    }
+
+    #[test]
+    fn newest_and_best_rated_read_the_provider_and_put_the_unknown_last() {
+        let (mut owned, metadata) = fixture();
+        owned.push(title(
+            "game of thrones",
+            "Game of Thrones",
+            TitleKind::Series,
+        ));
+        let titles: Vec<&Title> = owned.iter().collect();
+        let added = HashMap::new();
+        let order = Order {
+            sort: Sort::Release,
+            grouped: true,
+            names: TitleNames::Library,
+            metadata: &metadata,
+            added: &added,
+        };
+        // The Made in Abyss franchise dates from its newest part, 2020.
+        assert_eq!(
+            keys(&arrange(&titles, order), &titles),
+            vec!["sousou no frieren", "made in abyss", "game of thrones"]
+        );
+        let order = Order {
+            sort: Sort::Rating,
+            ..order
+        };
+        assert_eq!(
+            keys(&arrange(&titles, order), &titles)
+                .last()
+                .map(String::as_str),
+            Some("game of thrones")
+        );
+    }
+
+    #[test]
+    fn search_finds_a_title_by_any_name_the_provider_gave_it() {
+        let (owned, metadata) = fixture();
+        let library = Library { titles: owned };
+        let found = search(&library, &metadata, "beyond journey");
+        assert_eq!(found.len(), 1);
+        assert_eq!(found[0].key, "sousou no frieren");
+        assert_eq!(search(&library, &metadata, "").len(), 3);
+    }
+}

crates/pstr-core/src/lib.rs

@@ -6,6 +6,7 @@
 #![forbid(unsafe_code)]
 
 pub mod appearance;
+pub mod browse;
 pub mod catalog;
 pub mod chapters;
 pub mod config;

crates/pstr-core/src/metadata.rs

@@ -240,11 +240,13 @@ impl TitleMetadata {
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Default, Serialize, Deserialize)]
 #[serde(rename_all = "kebab-case")]
 pub enum TitleNames {
-    /// The folder's — what the share calls it. The default, because it is the
-    /// one name that is there whether or not anything matched.
-    #[default]
+    /// The folder's — what the share calls it.
     Library,
-    /// The provider's English title, where it has one.
+    /// The provider's English title, where it has one. The default, because
+    /// it is what Android always showed, and a folder name is whatever an
+    /// uploader typed — `Kaijuu 8-gou`, `Fate Stay Night - Heaven s Feel -
+    /// THE MOVIE I presage flower`.
+    #[default]
     English,
     /// The provider's romaji title.
     Romaji,