pluriwave/openspec/changes/archive/2026-07-19-android-auto-favorite-groups/proposal.md

Proposal: Android Auto Favorite Groups

Intent

The Android Auto browse tree exposes only 3 flat folders (Favoritos, Todas, Mis Emisoras), making stations hard to find while driving. The user asked for favorites grouped by category. This is NOT a new feature: favorite groups already exist end-to-end (GrupoFavoritos model, SQLite grupos_favoritos CRUD, Emisora.grupoFavoritosId, EstadoRadio.gruposFavoritos, and the phone UI _GrupoFavoritosPanel). The only gap is that this categorization was never pushed into the Auto-facing data source. Success = the same grouping the phone already shows becomes reachable in the car, driver-distraction-safe.

Scope

In Scope

• Extend FuenteEmisorasAuto / actualizarSnapshot() with a grupos parameter so favorite groups and their member stations reach the Auto data source.
• Wire EstadoRadio to push gruposFavoritos into _fuenteAuto on snapshot updates.
• Extend ConstructorArbolAuto to render favorite groups as sub-folders reachable from the existing Favoritos folder, with a new grupo:<id> media-id scheme.
• Keep Todas and Mis Emisoras unchanged (conservative reorg).
• Flag the empty-group and folder-count car-UX decisions for sdd-design to resolve.

Out of Scope

• Automatic grouping by pais/idioma/codec (explore Approach 2).
• EQ-from-car (separate android-auto-eq-presets change — deliver AFTER this).
• Any change to group CRUD, phone UI, or the SQLite schema.
• Android for Cars App Library / custom templates.

Capabilities

New Capabilities

• None.

Modified Capabilities

• android-auto-media: browse tree gains favorite-group sub-folders under Favoritos and a grupo:<id> browsable media-id. NOTE: this spec is mid-archive by a concurrent process — sdd-spec must confirm its final location before writing the delta.

Approach

Follow explore Investigation 1, Approach 1 (data-model reuse, not new categorization). Add grupos() + a grupos snapshot field to the Auto data source, mirroring the existing favoritos/misEmisoras/todas seams. ConstructorArbolAuto.raiz() keeps 3 root folders; hijos(idFavoritos) returns group sub-folders; hijos(grupo:<id>) returns that group's stations (reusing the existing sort + 50-item cap). Playable leaves stay emisora:<uuid>. Direct mirror of pantalla_favoritos.dart parity.

Affected Areas

Area	Impact	Description
lib/servicios/navegacion_auto.dart	Modified	FuenteEmisorasAuto interface + ConstructorArbolAuto tree/media-ids
lib/estado/estado_radio.dart	Modified	Push gruposFavoritos into Auto snapshot
lib/modelos/grupo_favoritos.dart, lib/servicios/servicio_favoritos.dart	Read-only reuse	Existing group data/CRUD

Risks

Risk	Likelihood	Mitigation
Shared-file merge conflict with android-auto-eq-presets	Med	Deliver this change FIRST, sequentially
Path collision with mid-archive android-auto-media specs	Med	Do not touch those paths; sdd-spec confirms spec location
Driver distraction from too many / empty group folders	Med	Defer empty-group + folder-count decision to sdd-design
Browse depth increases (root -> group -> stations)	Low	Keep root flat; only Favoritos gains one level

Rollback Plan

Additive change. Revert the grupos parameter, the EstadoRadio snapshot wiring, and the ConstructorArbolAuto group-folder branch. The pre-existing 3-folder tree is restored; group data in SQLite and phone UI are untouched.

Dependencies

• None external. Depends only on already-shipped group data model (parent android-auto-media change).

Success Criteria

• actualizarSnapshot() accepts and stores favorite groups.
• Auto browse tree shows one sub-folder per surfaced group under Favoritos.
• Selecting a group folder lists its member stations; selecting a station plays it.
• Todas and Mis Emisoras behavior unchanged.
• Empty-group and folder-count UX resolved as explicit design decisions.