feat(auto): play a local-music folder's subfolders recursively too

totalPistas counted only DIRECT audio children, so "Reproducir carpeta"/
"Aleatorio" were hidden for a folder that contains only subfolders, and
playing a folder queued only its direct tracks.

Add a bounded recursive walk (pistasRecursivas) that collects every track
beneath a folder, depth-first, sorted by name at each level. Bounded on
two independent axes to keep a single tap's native SAF round-trips and
in-memory list size predictable on a deep or wide library:
- depth: 4 levels below the tapped folder (profundidadMaximaRecursivaLocal)
- count: 500 tracks total (limitePistasRecursivasLocal)

The folder-play/shuffle actions are now offered whenever the recursive
count is > 0, and "Reproducir carpeta"/"Aleatorio" queue everything found,
not just direct children.
This commit is contained in:
2026-07-31 00:43:20 +02:00
parent eea8ec31e6
commit 6822432a51
2 changed files with 569 additions and 27 deletions
+161 -24
View File
@@ -447,6 +447,12 @@ class ConstructorArbolAuto {
int tamano = _maxItemsCarpetaLocal,
@visibleForTesting
MediaItem Function(NodoLocal, Map<String, MetadatosPista>)? construirItem,
// Item 2 (recursive folder play): optional so every pre-existing call
// site/test that has no need for the recursive gate keeps working
// unchanged. Only used on page 0, and only when [nodos] has zero
// DIRECT tracks (a direct track already makes the gate cheaply true
// without it) — see the `hayContenidoReproducible` computation below.
FuenteMusicaLocalAuto? fuente,
}) async {
final construir = construirItem ?? _itemLocal;
final ordenados = [...nodos]..sort(compararNodoLocalParaNavegacion);
@@ -462,14 +468,26 @@ class ConstructorArbolAuto {
}
if (pagina == 0) {
final totalPistas = nodos.where((n) => !n.esDirectorio).length;
// Item 2: a folder plays everything beneath it, recursively -- so
// the play actions must be offered whenever the RECURSIVE count is
// > 0, not just the direct count. `totalPistas > 0` short-circuits
// the bounded recursive walk entirely for the common case (a direct
// track already answers the question); only a folder with ZERO
// direct tracks but at least one subfolder pays the recursive-check
// cost, and only up to [profundidadMaximaRecursivaLocal] levels.
final hayContenidoReproducible =
totalPistas > 0 ||
(fuente != null &&
await _haySubcarpetaConPistas(nodos, fuente: fuente));
final prepend = <MediaItem>[
// Folder-play actions (Design ADR-5, Phase 3): prepended BEFORE
// the sort/bucket nav entries, guarded the same shape as
// ofreceOrdenCalidad(totalPistas > 0) — present iff the folder has
// at least one direct audio child, absent for a folder with only
// subfolders (Spec "Folder has no tracks").
if (totalPistas > 0) _itemReproducirCarpeta(documentIdPadre),
if (totalPistas > 0) _itemReproducirAleatorio(documentIdPadre),
// Folder-play actions (Design ADR-5, Phase 3; recursive gate item
// 2): prepended BEFORE the sort/bucket nav entries, present iff
// the folder has at least one playable track anywhere beneath it
// (direct or nested), absent for a folder that is genuinely empty
// even recursively (Spec "Folder has no tracks").
if (hayContenidoReproducible) _itemReproducirCarpeta(documentIdPadre),
if (hayContenidoReproducible)
_itemReproducirAleatorio(documentIdPadre),
if (ofreceOrdenCalidad(totalPistas))
_itemModoOrdenCalidad(documentIdPadre),
if (ofreceBuckets(totalPistas))
@@ -481,6 +499,32 @@ class ConstructorArbolAuto {
return items;
}
/// Whether at least one subfolder within [nodos] recursively contains a
/// playable track (Design "recursive folder play, gate", item 2): called
/// ONLY when the folder has zero DIRECT tracks (the caller already
/// checked that cheaply) — descends into each direct subfolder via
/// [pistasRecursivas] with `limite: 1`, stopping at the very first
/// match so a folder with an early hit costs as little as possible.
/// [nodos] is assumed already resolved by the caller (its own
/// `fuente.hijos(...)` result), so this folder's own children are never
/// re-fetched.
Future<bool> _haySubcarpetaConPistas(
List<NodoLocal> nodos, {
required FuenteMusicaLocalAuto fuente,
}) async {
for (final nodo in nodos) {
if (!nodo.esDirectorio) continue;
final encontradas = await pistasRecursivas(
nodo.documentId,
fuente: fuente,
profundidadMaxima: profundidadMaximaRecursivaLocal - 1,
limite: 1,
);
if (encontradas.isNotEmpty) return true;
}
return false;
}
/// Whether the "Ordenar por calidad" mode entry should be offered for a
/// folder with [totalPistas] audio files (Design ADR-3): present for
/// `0 < totalPistas <= 150`, omitted otherwise (empty folder or above the
@@ -946,17 +990,115 @@ List<NodoLocal> mezclarFisherYates(List<NodoLocal> nodos, Random rng) {
List<NodoLocal> pistasEnOrdenAleatorio(List<NodoLocal> nodos, Random rng) =>
mezclarFisherYates(pistasEnOrdenNombre(nodos), rng);
/// Maximum recursion depth for "play folder recursively" (Design "recursive
/// folder play, cost bound", item 2): SAF directory listing is a native
/// round-trip PER folder, so unbounded recursion could turn a single tap
/// into dozens of channel calls for a pathologically deep tree. 4 levels
/// below the tapped folder covers virtually every real music-library
/// layout (even `Artist/Album/Disc/track.mp3` is only 3 levels deep) while
/// keeping a worst-case tree's native-call count bounded. A subfolder
/// beyond this depth is simply never explored — its tracks are not
/// collected, exactly like content beyond the browse tree's own page cap
/// is never listed.
const profundidadMaximaRecursivaLocal = 4;
/// Maximum number of tracks collected by a recursive folder walk (Design
/// "recursive folder play, cost bound", item 2): a folder-play/shuffle
/// queue beyond a few hundred tracks has no practical benefit, and an
/// unbounded collection risks an extremely long queue AND an extremely
/// long recursive walk over a huge library. 500 is an order of magnitude
/// above the existing quality-sort cap
/// ([ConstructorArbolAuto._maxPistasParaOrdenCalidad], 150) — generous for
/// a "play everything" action, while still bounded.
const limitePistasRecursivasLocal = 500;
/// Recursively collects every audio-file [NodoLocal] reachable from
/// [documentId] (Design "recursive folder play", item 2): [documentId]'s
/// own direct audio children, plus — for every direct subfolder — that
/// subfolder's own recursive result. Walked depth-first, sorted by
/// [NodoLocal.nombre] at each level (the SAME comparator the sequential/
/// shuffle play actions already used pre-recursion), so the collected
/// order is deterministic and reproducible under a fixed shuffle seed.
///
/// Bounded on two independent axes so a pathological tree (very deep, or
/// very wide-and-deep) can never turn a single tap into an unbounded
/// number of native SAF round-trips or an unbounded in-memory list:
/// - [profundidadMaxima] caps how many folder levels BELOW [documentId]
/// are ever descended into (`0` = only [documentId]'s own direct
/// children, no descent at all).
/// - [limite] caps the TOTAL number of tracks collected across the whole
/// walk; collection stops (mid-folder if needed) the instant this many
/// have been gathered.
///
/// Never throws: a [fuente.hijos] failure on any one subfolder (revoked
/// permission, a race with the OS SAF layer) is swallowed for that
/// subfolder only — sibling folders already queued for traversal are
/// still visited — mirroring this file's existing no-throw contract
/// (Design "no-op on empty/unresolvable folder").
Future<List<NodoLocal>> pistasRecursivas(
String documentId, {
required FuenteMusicaLocalAuto fuente,
int profundidadMaxima = profundidadMaximaRecursivaLocal,
int limite = limitePistasRecursivasLocal,
}) async {
final resultado = <NodoLocal>[];
await _recolectarPistasRecursivas(
documentId,
fuente: fuente,
profundidadRestante: profundidadMaxima,
limite: limite,
resultado: resultado,
);
return resultado;
}
Future<void> _recolectarPistasRecursivas(
String documentId, {
required FuenteMusicaLocalAuto fuente,
required int profundidadRestante,
required int limite,
required List<NodoLocal> resultado,
}) async {
if (resultado.length >= limite) return;
final List<NodoLocal> hijos;
try {
hijos = await fuente.hijos(documentId);
} catch (_) {
return;
}
final ordenados = [...hijos]..sort((a, b) => a.nombre.compareTo(b.nombre));
for (final nodo in ordenados) {
if (resultado.length >= limite) return;
if (nodo.esDirectorio) {
if (profundidadRestante <= 0) continue;
await _recolectarPistasRecursivas(
nodo.documentId,
fuente: fuente,
profundidadRestante: profundidadRestante - 1,
limite: limite,
resultado: resultado,
);
} else {
resultado.add(nodo);
}
}
}
/// Orchestrates a "Reproducir carpeta"/"Reproducir aleatorio" tap (Design
/// "Data Flow", ADR-5/ADR-6, Phase 3 task 4.2): resolves whichever of the
/// two action prefixes matches [id] (ignoring [aleatorio] for the STRIP —
/// the prefix itself is authoritative), fetches [fuente]'s direct children
/// for that folder, filters to audio files, orders them ([aleatorio] picks
/// shuffled vs name order), and hands the resulting list to [iniciarCola].
/// "Data Flow", ADR-5/ADR-6, Phase 3 task 4.2; recursive collection item
/// 2): resolves whichever of the two action prefixes matches [id]
/// (ignoring [aleatorio] for the STRIP — the prefix itself is
/// authoritative), RECURSIVELY collects every track beneath that folder
/// via [pistasRecursivas] (direct children AND every nested subfolder, up
/// to its depth/count bounds), orders them ([aleatorio] picks shuffled vs
/// the recursive walk's own name-sorted order), and hands the resulting
/// list to [iniciarCola].
///
/// A no-op (never calls [iniciarCola]) when: [id] matches neither action
/// prefix; [fuente.hijos] throws or returns only directories (an
/// unresolvable/empty folder — Design "no-op on empty/unresolvable
/// folder").
/// prefix; the folder (or everything beneath it, within the recursion
/// bounds) is unresolvable/empty (Design "no-op on empty/unresolvable
/// folder") — [pistasRecursivas] never throws, so this never propagates an
/// exception either.
Future<void> reproducirCarpetaLocal(
String id, {
required bool aleatorio,
@@ -974,16 +1116,10 @@ Future<void> reproducirCarpetaLocal(
return;
}
final List<NodoLocal> nodos;
try {
nodos = await fuente.hijos(documentId);
} catch (_) {
return;
}
final recolectadas = await pistasRecursivas(documentId, fuente: fuente);
final pistas = aleatorio
? pistasEnOrdenAleatorio(nodos, rng ?? Random())
: pistasEnOrdenNombre(nodos);
? mezclarFisherYates(recolectadas, rng ?? Random())
: recolectadas;
if (pistas.isEmpty) return;
await iniciarCola(pistas);
@@ -1129,6 +1265,7 @@ Future<List<MediaItem>?> hijosMusicaLocal(
documentIdPadre: documentId,
pagina: pagina,
metadatosDe: (ids) => _metadatosDeConCache(ids, fuente: fuente),
fuente: fuente,
);
} catch (_) {
return const [];