Game platform field: free-text → enum (single value per entry) #26

Motivation

Game.Platform is currently a free-text string?. That's bad for filtering, search, normalisation, and IGDB enrichment (which surfaces a canonical platform name we then drop on the floor as a free-text string). Replace it with a curated enum, one platform per entry — multi-platform copies are modelled as separate entries (see "Why one-per-entry" below).

Proposed enum

public enum GamePlatform
{
    Other = 0,
    Pc, Mac, Linux, Mobile,

    // Xbox
    XboxOriginal, Xbox360, XboxOne, XboxSeriesXS,

    // PlayStation
    PS1, PS2, PS3, PS4, PS5, Vita, PSP,

    // Nintendo
    Nes, Snes, N64, GameCube, Wii, WiiU, Switch, Switch2,
    GameBoy, GameBoyColor, GameBoyAdvance, Ds, Ds3,

    // Sega + retro / PC handheld
    Genesis, Saturn, Dreamcast,
    SteamDeck,
}

Display labels live in a GAME_PLATFORMS array on the client (label / value), same shape as the existing MUSIC_FORMATS / MOVIE_FORMAT_FLAGS.

Why one-per-entry (and not a multi-platform field)

A collection tracker tracks releases, which is also IGDB's model. Each release has its own per-platform attributes that don't generalise across platforms:

• Format (Disc / Digital), digital store, barcode
• Condition, purchase price / date, location
• Completion status, hours played, last played
• Status (Owned / Wishlist / OnOrder / Sold) — "owned on PS5, wishlist on Switch" works trivially with two entries
• Year + developer can differ per release (e.g. Halo 3 on 360 vs MCC on Series X)

A multi-platform field forces every per-copy field into nested arrays / sub-records, which complicates the schema, every form, and every endpoint. Separate entries keeps the model flat and matches how barcode scanning + IGDB lookup feed data in (one release per scan).

A "duplicate to another platform" button on the edit page covers the convenience case (see follow-up below).

Implementation

Backend

• Collectify.Domain.Enums.GamePlatform (new file).
• Game.Platform becomes GamePlatform (non-nullable; Other is the safe default for unknown).
• EF migration: rename existing Platform to PlatformLegacy (string), add new Platform (int), backfill via case-insensitive match against the enum's display labels (e.g. "PS5" → PS5, "Switch" → Switch, otherwise → Other and the original string is preserved in PlatformLegacy for one release so users can fix manually).
• IGDB mapping: when IgdbGameProvider.Map extracts the first IGDB platform name, lookup-table it onto GamePlatform. Leave Other for unmapped values.
• Endpoint tests: roundtrip the enum as a string via JsonStringEnumConverter (already configured globally).

Frontend

• services/types.ts — add GAME_PLATFORMS: { value: GamePlatform; label: string }[] and the GamePlatform union type.
• GameForm — swap the <Input> for a <Select> driven by GAME_PLATFORMS.
• GamesList / list cards — render the label for the stored enum value.
• IGDB lookup importLookup — use the new platform mapping so picked / scanned games land on a canonical enum.

Migration safety

• Migration is one-way (string → int with a legacy column kept until a follow-up PR drops it).
• Document any unmapped values surface as Other; the legacy column lets users see what they'd typed.

Out of scope (follow-ups)

• "Duplicate to another platform" button on the edit page — pre-fills a new GameForm with the same metadata (title, developer, igdbId, cover, …) and a different Platform. Issue to be filed once this lands.
• Drop the PlatformLegacy column once the user has had a chance to clean up unmapped values.
• Multi-platform display badge ("also owned on PS5 / Switch") on the detail page — needs the search/filter index work in Search / filter list pages by per-type attributes #25 to know which entries share an igdbId.

Verification

• Server tests: endpoint roundtrips the enum, migration backfills sample inputs deterministically.
• Manual: existing free-text platforms still display, can be re-saved with a real enum value, IGDB-scanned games land on the right platform.
• Client tests: form submits the right enum value; list card renders the label.