phoenix-api-gen

# Phoenix API Generator

## Workflow

### From OpenAPI YAML

1. Parse the OpenAPI spec — extract paths, schemas, request/response bodies.
2. Map each schema to an Ecto schema + migration.
3. Map each path to a controller action; group by resource context.
4. Generate auth plugs from `securitySchemes`.
5. Generate ExUnit tests covering happy path + validation errors.

### From Natural Language

1. Extract resources, fields, types, and relationships from the description.
2. Infer context boundaries (group related resources).
3. Generate schemas, migrations, controllers, views, router, and tests.
4. Ask the user to confirm before writing files.

## File Generation Order

1. Migrations (timestamps prefix: `YYYYMMDDHHMMSS`)
2. Ecto schemas + changesets
3. Context modules (CRUD functions)
4. Controllers + FallbackController
5. JSON renderers (Phoenix 1.7+ `*JSON` modules, or `*View` for older)
6. Router scope + pipelines
7. Auth plugs
8. Tests + factories

## Phoenix Conventions

See [references/phoenix-conventions.md](references/phoenix-conventions.md) for project structure, naming, context patterns.

Key rules:
- One context per bounded domain (e.g., `Accounts`, `Billing`, `Notifications`).
- Context is the public API — controllers never call Repo directly.
- Schemas live under contexts: `MyApp.Accounts.User`.
- Controllers delegate to contexts; return `{:ok, resource}` or `{:error, changeset}`.
- Use `FallbackController` with `action_fallback/1` to handle error tuples.

## Ecto Patterns

See [references/ecto-patterns.md](references/ecto-patterns.md) for schema, changeset, migration details.

Key rules:
- Always use `timestamps(type: :utc_datetime_usec)`.
- Binary IDs: `@primary_key {:id, :binary_id, autogenerate: true}` + `@foreign_key_type :binary_id`.
- Separate `create_changeset/2` and `update_changeset/2` when create/update fields differ.
- Validate required fields, formats, and constraints in changesets — not in controllers.

## Multi-Tenancy

Add `tenant_id :bina...