asyncapi: 3.1.0
info:
  title: Galaxy Game Master Runtime Events Contract
  version: 1.0.0
  description: |
    Stable Redis Streams contract for runtime snapshot updates and game
    finish events published by `Game Master` toward `Game Lobby` on the
    `gm:lobby_events` stream.

    Two distinct message types share the channel and are discriminated
    by the `event_type` field on the payload:

    - `RuntimeSnapshotUpdate` (`event_type=runtime_snapshot_update`) is
      published whenever a turn was generated (success or failure), the
      runtime status transitioned, or the engine health summary changed
      in response to a `runtime:health_events` observation. Duplicates
      are suppressed when the summary did not change.
    - `GameFinished` (`event_type=game_finished`) is published once
      when the engine reports `finished:true` on a turn-generation
      response. The runtime stays in `status=finished` indefinitely;
      no further events are published for the game.

    Both payload schemas are closed (`additionalProperties: false`).
    Adding a field to either payload after this contract was frozen is
    a breaking change that requires a contract bump and a coordinated
    consumer update.

    Polymorphism: the AsyncAPI surface uses two messages on one channel
    and one `send` operation per message. The
    `runtime_health-asyncapi.yaml` style of a single message with
    `oneOf` details is not used here because the two payload shapes
    have no shared field set beyond the discriminator and the
    `game_id`. See `gamemaster/docs/stage06-contract-files.md`.
channels:
  lobbyEvents:
    address: gm:lobby_events
    messages:
      runtimeSnapshotUpdate:
        $ref: '#/components/messages/RuntimeSnapshotUpdate'
      gameFinished:
        $ref: '#/components/messages/GameFinished'
operations:
  publishRuntimeSnapshotUpdate:
    action: send
    summary: Publish a runtime snapshot update for Game Lobby.
    channel:
      $ref: '#/channels/lobbyEvents'
    messages:
      - $ref: '#/channels/lobbyEvents/messages/runtimeSnapshotUpdate'
  publishGameFinished:
    action: send
    summary: Publish a game finish event for Game Lobby.
    channel:
      $ref: '#/channels/lobbyEvents'
    messages:
      - $ref: '#/channels/lobbyEvents/messages/gameFinished'
components:
  messages:
    RuntimeSnapshotUpdate:
      name: RuntimeSnapshotUpdate
      title: Runtime snapshot update
      summary: Snapshot of one game's runtime state, published on transitions and health changes.
      payload:
        $ref: '#/components/schemas/RuntimeSnapshotUpdatePayload'
      examples:
        - name: runningTurnReady
          summary: Snapshot published after a successful turn generation.
          payload:
            event_type: runtime_snapshot_update
            game_id: game-123
            current_turn: 17
            runtime_status: running
            engine_health_summary: healthy
            player_turn_stats:
              - user_id: user-1
                planets: 4
                population: 12000
              - user_id: user-2
                planets: 3
                population: 9000
            occurred_at_ms: 1775121700000
    GameFinished:
      name: GameFinished
      title: Game finished
      summary: Terminal event published once when the engine reports finished:true on a turn-generation response.
      payload:
        $ref: '#/components/schemas/GameFinishedPayload'
      examples:
        - name: gameFinished
          summary: Game finished on turn 42; final per-player stats included.
          payload:
            event_type: game_finished
            game_id: game-123
            final_turn_number: 42
            runtime_status: finished
            player_turn_stats:
              - user_id: user-1
                planets: 6
                population: 25000
              - user_id: user-2
                planets: 0
                population: 0
            finished_at_ms: 1775130000000
  schemas:
    RuntimeStatus:
      type: string
      enum:
        - starting
        - running
        - generation_in_progress
        - generation_failed
        - stopped
        - engine_unreachable
        - finished
      description: Runtime status enum; identical to the value used in the internal REST contract.
    PlayerTurnStat:
      type: object
      additionalProperties: false
      required:
        - user_id
        - planets
        - population
      properties:
        user_id:
          type: string
          description: Platform user identifier of the player.
        planets:
          type: integer
          minimum: 0
          description: Number of planets controlled by the player at the snapshot turn.
        population:
          type: integer
          minimum: 0
          description: Total population controlled by the player at the snapshot turn.
    RuntimeSnapshotUpdatePayload:
      type: object
      additionalProperties: false
      required:
        - event_type
        - game_id
        - current_turn
        - runtime_status
        - engine_health_summary
        - player_turn_stats
        - occurred_at_ms
      properties:
        event_type:
          type: string
          const: runtime_snapshot_update
          description: Discriminator pinned to `runtime_snapshot_update`; consumers dispatch on this value.
        game_id:
          type: string
          description: Opaque stable game identifier.
        current_turn:
          type: integer
          minimum: 0
          description: Last completed turn number; zero when the snapshot reflects the pre-first-turn state.
        runtime_status:
          $ref: '#/components/schemas/RuntimeStatus'
        engine_health_summary:
          type: string
          description: Short text summary of engine health; empty until the first health observation.
        player_turn_stats:
          type: array
          items:
            $ref: '#/components/schemas/PlayerTurnStat'
          description: Per-player stats projection; empty before any turn has generated.
        occurred_at_ms:
          type: integer
          format: int64
          description: UTC Unix milliseconds when Game Master observed the underlying transition.
    GameFinishedPayload:
      type: object
      additionalProperties: false
      required:
        - event_type
        - game_id
        - final_turn_number
        - runtime_status
        - player_turn_stats
        - finished_at_ms
      properties:
        event_type:
          type: string
          const: game_finished
          description: Discriminator pinned to `game_finished`; consumers dispatch on this value.
        game_id:
          type: string
          description: Opaque stable game identifier.
        final_turn_number:
          type: integer
          minimum: 0
          description: Last turn number generated before the engine reported finished:true.
        runtime_status:
          $ref: '#/components/schemas/RuntimeStatus'
        player_turn_stats:
          type: array
          items:
            $ref: '#/components/schemas/PlayerTurnStat'
          description: Final per-player stats projection at the finish turn.
        finished_at_ms:
          type: integer
          format: int64
          description: UTC Unix milliseconds when Game Master persisted the finish transition.