# API Changes (Not Yet Reflected in `backend/openapi/openapi.json`)

This document lists additive API changes currently implemented in the Go backend.

## Summary

Existing endpoints remain compatible.

Added capabilities:

1. Position board persistence for live/admin ordering.
2. Stage session control (`start`/`end`) for event flow.
3. Stage history retrieval.
4. New state fields (`positionBoards`, `current_stage`, `last_stage`).

## 1) Position Board Endpoint

- Method: `PUT`
- Path: `/api/admin/positions/:board`
- Auth: admin bearer token (`Authorization: Bearer <token>`)

### Supported `:board` values

- `preliminary`
- `final`
- `prelim_tiebreak`
- `final_tiebreak`

### Request body

```json
{
  "slots": [
    { "playerId": 12, "groupKey": "A", "position": 1 },
    { "playerId": 15, "groupKey": "A", "position": 2 },
    { "playerId": 20, "groupKey": "B", "position": 1 }
  ]
}
```

Fields:

- `playerId` (integer, required)
- `groupKey` (string, required)
- `position` (integer > 0, required)

Notes:

- The request replaces all saved slots for the target board.
- For `preliminary`, `players.group_code` is synchronized from `groupKey`.
- Special value `UNASSIGNED` maps to empty player group.

### Response

- `200 OK` with full updated admin state payload.

## 2) Stage Session Control Endpoints

### Start stage

- Method: `POST`
- Path: `/api/admin/stage/start`
- Auth: admin bearer token

Request body:

```json
{
  "phase": "preliminary",
  "group": "A",
  "round": 2
}
```

Rules:

- `phase` must be one of:
  - `preliminary`
  - `prelim_tiebreak`
  - `final`
  - `final_tiebreak`
- `group` validation depends on phase:
  - `preliminary`: group code string (or `UNASSIGNED`)
  - `final`: `"1"` or `"2"`
  - tie-break phases: positive numeric string
- `round` normalization:
  - `preliminary`: `1..3`
  - `final`: `1..2`
  - tie-break phases: always `1`
- If another stage is active (started, not ended), API returns `409`.

Response:

- `200 OK` with full updated admin state payload.

### End stage

- Method: `POST`
- Path: `/api/admin/stage/end`
- Auth: admin bearer token

Rules:

- Ends the currently active stage by setting `ended_at`.
- If no active stage exists, API returns `400`.

Response:

- `200 OK` with full updated admin state payload.

## 3) Stage History Endpoint

- Method: `GET`
- Path: `/api/admin/stage/history`
- Auth: admin bearer token

Response:

```json
{
  "items": [
    {
      "id": 1,
      "phase": "preliminary",
      "group": "A",
      "round": 2,
      "startedAt": "2026-04-30T08:27:13Z",
      "endedAt": "2026-04-30T08:28:01Z"
    }
  ]
}
```

## 4) New State Fields

Both endpoints now include these fields:

- `GET /api/state`
- `GET /api/admin/state`

```json
{
  "positionBoards": {
    "preliminary": {
      "12": { "groupKey": "A", "position": 1 }
    },
    "final": {
      "12": { "groupKey": "1", "position": 3 }
    },
    "prelim_tiebreak": {},
    "final_tiebreak": {}
  },
  "current_stage": {
    "id": 7,
    "phase": "preliminary",
    "group": "A",
    "round": 2,
    "startedAt": "2026-04-30T09:00:00Z"
  },
  "last_stage": {
    "id": 6,
    "phase": "final",
    "group": "1",
    "round": 1,
    "startedAt": "2026-04-30T08:45:00Z",
    "endedAt": "2026-04-30T08:55:00Z"
  }
}
```

Notes:

- `positionBoards` keys are player IDs as strings.
- `current_stage` is `null` when no stage is active.
- `last_stage` is `null` when no stage session has ever started.
- `last_stage` is the most recently started session (ended or still active).

## Compatibility Impact

- Additive only; existing consumers remain functional.
- Consumers can ignore unknown fields safely.
- Consumers needing control/monitoring can use new stage endpoints and fields.