# Mimic API — sprint 1 surface

This document covers the endpoints the frontend is expected to call in sprint 1.
Everything is JSON, every protected route relies on the Flask session cookie set
by `POST /api/v1/auth/login`. CORS is enabled only when `MIMIC_ENV=development`
and `MIMIC_CORS_ORIGINS` is set (the prod reverse proxy serves the SPA on the
same origin).

## Conventions

- **Base URL**: `/api/v1`.
- **Trailing slash**: routes accept the URL with **or without** a trailing
  slash. The app is configured with `strict_slashes=False`, so Werkzeug
  never issues a 308 redirect (which can drop the session cookie on some
  browsers). Use whichever form your client prefers; `docs/api.md` writes
  the no-slash form.
- **Auth transport**: Flask session cookie (`HttpOnly`, `SameSite=Lax`,
  `Secure` in production). The browser must send `credentials: "include"`
  on every request.
- **Content negotiation**: requests and responses use `application/json`.
- **Error envelope**: **every** failure returns the same shape, served by a
  global `HTTPException` handler:
  ```json
  { "error": "<snake_case_code>", "message": "<human>", "details": ... }
  ```
  `details` is only present for `422` (Pydantic per-field error list). Codes
  are stable identifiers; messages are human-readable but not localized.

| Status | `error` code | Use |
|--------|--------------|-----|
| 200 | — | OK |
| 201 | — | Resource created |
| 204 | — | OK, no body |
| 400 | `bad_request` | Malformed request (e.g. missing JSON body) |
| 401 | `not_authenticated` or `invalid_credentials` | Anonymous / bad creds |
| 403 | `forbidden` | Authenticated but missing permission |
| 404 | `not_found` | Resource not found (also tenant-scope denials, see below) |
| 405 | `method_not_allowed` | Method not allowed for that route |
| 415 | `unsupported_media_type` | Wrong `Content-Type` on a body |
| 422 | `validation_error` | Pydantic — see `details` |
| 429 | `rate_limited` | Reserved for future limiter |
| 500 | `internal_error` | Opaque — no leak |

### 422 `details` shape

`details` is the raw Pydantic `errors()` list — one entry per failed field:

```json
{
  "error": "validation_error",
  "message": "request failed",
  "details": [
    {
      "type": "missing",
      "loc": ["client_name"],
      "msg": "Field required",
      "input": { "description": "no client_name" }
    }
  ]
}
```

Use `details[i].loc` to map the error back to a form field.

### Tenant scope leak prevention (MA6 — F11)

RT operators only see engagements they are members of. Requests targeting an
engagement they don't belong to return **404**, never 403, so the existence of a
neighbouring engagement is not leaked between teams. RT leads see everything.

## Authentication

### `POST /api/v1/auth/login`

Body:
```json
{ "username": "alice@example.org", "password": "•••••" }
```

`username` maps to the `user.email` column server-side (kept "username" in the
HTTP contract so future identity sources can route through the same endpoint).

Success — `200`:
```json
{
  "user_id": "0c9e3a3a-7c8b-4d5e-9f10-1a2b3c4d5e6f",
  "username": "alice@example.org",
  "display_name": "Alice",
  "role": "rt_lead",
  "permissions": ["engagement.create", "engagement.read", "..."],
  "groups": ["rt_lead"]
}
```

Failures (all 401, uniform message — no enumeration leak between "unknown
user" and "wrong password"):
```json
{ "error": "invalid_credentials", "message": "invalid username or password" }
```

The endpoint runs a bcrypt round against a dummy hash when the user does not
exist, so request timing does not leak the username's existence either.

Side effects on success:
- A Flask session is established (cookie set, marked `permanent`).
- `user.last_login_at` is updated.
- An `auth.login` audit row is written.

### `POST /api/v1/auth/logout`

Requires an active session.

- `204 No Content` on success — cookie is cleared and an `auth.logout` audit
  entry is written.
- `401 not_authenticated` if there is no active session.

### `GET /api/v1/auth/me`

Returns the current principal in the same shape as `POST /login`. The frontend
calls this at boot to rehydrate the application state.

- `200` with the `CurrentUser` payload when authenticated.
- `401 not_authenticated` when there is no session cookie or the user has been
  disabled since login.

## Engagements

### `GET /api/v1/engagements`

Lists engagements visible to the caller (`engagement.read` permission).

- RT lead: all engagements.
- RT operator: only those for which a row in `engagement_member` ties the
  authenticated user to the engagement.

Response — `200`:
```json
[
  {
    "id": "•••",
    "client_name": "Demo Client",
    "description": null,
    "status": "draft",
    "c2_type": "mythic",
    "start_date": null,
    "end_date": null
  }
]
```

### `GET /api/v1/engagements<eid>`

Same payload shape as the list element. Returns 404 if the engagement does not
exist or the caller is not a member (MA6).

### `POST /api/v1/engagements`

Creates an engagement (`engagement.create` permission).

Body:
```json
{
  "client_name": "Demo Client",
  "description": "Internal Q3 drill",
  "c2_type": "mythic",
  "start_date": null,
  "end_date": null
}
```

- `201` with the created engagement.
- `422` on Pydantic validation failure (returns the per-field error list).
- `created_by_id` is set from the current session.
- An `engagement.create` audit row is written.

The RT lead currently does **not** get a per-engagement `engagement_member` row
on creation; they see every engagement via the `is_rt_lead()` short-circuit.
This will change in a future sprint when membership becomes the single scope
authority.

## Worked example

1. Create a local admin from the CLI:
   ```bash
   .venv/bin/mimic-cli user create --email alice@example.org --type rt_lead
   ```
2. `POST /api/v1/auth/login` with the credentials — receive the user payload
   plus the session cookie.
3. `POST /api/v1/engagements` with a body — receive the engagement.
4. `GET /api/v1/engagements` — see the new engagement in the list.
5. `POST /api/v1/auth/logout` — session cleared.