# Backend (Go + Gin)

REST API that serves the schedule/time endpoints and current episode control. Built in Go, containerized with a multi-stage Dockerfile.

## Prerequisites
- Go 1.22+
- PostgreSQL reachable (uses env-driven DSN pieces)
- `golang-migrate` not required locally (migrations shipped in repo)

## Env
The server builds its DSN from:
- `PGHOST`, `POSTGRES_PORT`, `POSTGRES_USER`, `POSTGRES_PASSWORD`, `POSTGRES_DB`, `PGSSLMODE`
- `ADDR` (listen address, default `:8082`)
- `GIN_MODE` (e.g., `release`)
- Auth (optional):
  - `AUTH_ENABLED` (default `false`)
  - `FIREBASE_PROJECT_ID`
  - `FIREBASE_CREDENTIALS_JSON` (raw JSON or base64-encoded service account JSON) or `FIREBASE_CREDENTIALS_FILE` (path to JSON)

## Commands
```bash
# Run locally (expects Postgres per env)
go run ./cmd/server

# Fetch one dアニメ episode to stdout
go run ./cmd/danime-episode <partId>

# Run migrations
go run ./cmd/migrate

# Tests
go test ./...

# Swagger create docs
swag init -g cmd/server/main.go -o ./docs
```

## Docker build (used by compose)
```bash
docker build -t watchparty-backend .
```
Compose uses the same image for `api` and the one-off `migrate` job.

## Endpoints (key)
- `GET /api/v1/time` — server time for client clock sync
- `GET /api/v1/current` — current schedule item
- `POST /api/v1/current` — set current episode (expects `{ id, start_time? }`)
- `GET /api/v1/shows` — list of episodes
- `POST /api/v1/shows` — create a new episode (expects `{ ep_num, ep_title, season_name, start_time, playback_length }`)
- `GET /api/v1/danime?part_id=...` — scrape dアニメ episode metadata (returns `{ ep_num, ep_title, season_name, playback_length }`)
- `POST /api/v1/oauth/firebase` — verify a Firebase ID token and echo back UID/email
- `DELETE /api/v1/shows?id=...` — delete a show (guarded by Firebase auth when `AUTH_ENABLED=true`)
- `GET /healthz` — health check

### Auth examples
```bash
# Verify Firebase ID token (AUTH_ENABLED=true)
curl -X POST http://localhost:8082/api/v1/oauth/firebase \
  -H "Content-Type: application/json" \
  -d '{"id_token":"<firebase-id-token>"}'

# Delete a show with auth
curl -X DELETE "http://localhost:8082/api/v1/shows?id=123" \
  -H "Authorization: Bearer <firebase-id-token>"
```