// Prisma schema for portal-bff.
//
// `multiSchema` preview is enabled because per ADR-0013 the audit log
// lives in its own `audit` schema with role-based append-only access
// (audit_owner / audit_writer / audit_reader / audit_archiver). The
// public schema holds the regular business data; only audit.events
// lives in audit.

generator client {
  provider        = "prisma-client-js"
  previewFeatures = ["multiSchema"]
}

datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
  schemas  = ["public", "audit"]
}

// ============================================================
// Audit log (per ADR-0013)
// ============================================================
//
// Append-only by Postgres role grants — the schema, roles, and
// default privileges are provisioned by infra/local/init/postgres/
// 01-init.sql in dev and the equivalent production manifest. The
// migration that creates this table re-applies the grants
// explicitly and ALTERs the table owner to `audit_owner` so the
// runtime role contract holds even when the migration runs as a
// privileged migrator account.
//
// At runtime, the BFF wraps every INSERT into this table in a
// transaction that begins with `SET LOCAL ROLE audit_writer`, so
// even a compromised BFF connection cannot UPDATE / TRUNCATE /
// DELETE — those grants are not on `audit_writer`.

enum AuditAudience {
  workforce
  customer

  @@schema("audit")
}

enum AuditOutcome {
  success
  failure
  denied

  @@schema("audit")
}

// ============================================================
// User directory (per ADR-0020 §"v1 scope — User list")
// ============================================================
//
// Persistent ledger of every identity that has signed in to either
// portal-shell or portal-admin. Upserted at sign-in by
// `UserDirectoryService.recordSignIn` (called from
// `SessionEstablisher.establish`), read by the future
// `GET /api/admin/users` endpoint per ADR-0020 §"User list
// (read-only)".
//
// **Not the source of truth for identity.** Entra ID is. This table
// is a cache the BFF maintains so the admin UI can list "everyone
// who's ever signed in" without re-querying the directory at
// every render. Per-tenant `oid` is the join key on the audit side
// (combined with the salted hash) — never the BFF's primary actor
// identifier elsewhere.
//
// **No PII redaction on read.** Per ADR-0013 the audit module
// hashes the actor id to defend against an audit-log dump leaking
// who-did-what. This table is the *deliberate* PII storage: an
// admin browsing the user list explicitly wants display names and
// usernames. The trust boundary is the admin role gate
// (ADR-0020 §"Auth — `admin` role claim").

model User {
  // Entra `oid` — stable per-user identifier inside the tenant.
  // Used as the natural primary key. Per-tenant uniqueness is
  // sufficient: the dual-audience design (ADR-0008) currently
  // assumes single workforce tenant; cross-tenant collisions
  // become a separate ADR when we onboard the second one.
  oid          String   @id
  tid          String
  audience     String
  username     String
  displayName  String   @map("display_name")
  // `first_seen_at` is set once at first sign-in and never
  // updated thereafter. Lets the admin list "users since
  // <date>" without joining anything.
  firstSeenAt  DateTime @default(now()) @map("first_seen_at") @db.Timestamptz(6)
  // `last_seen_at` is set every time the upsert fires (one upsert
  // per sign-in), so "most recently active" can be computed
  // without scanning audit.events.
  lastSeenAt   DateTime @default(now()) @map("last_seen_at") @db.Timestamptz(6)

  @@map("users")
  @@schema("public")
  @@index([lastSeenAt(sort: Desc)])
  @@index([username])
}

model AuditEvent {
  id          String        @id @default(uuid()) @db.Uuid
  createdAt   DateTime      @default(now()) @map("created_at") @db.Timestamptz(6)
  eventType   String        @map("event_type")
  audience    AuditAudience
  // Salted hash (LOG_USER_ID_SALT) of the actor's stable id. NULL
  // when the actor is unauthenticated (e.g. failed login attempt
  // before resolving an identity). The same salt is used by the
  // BFF Pino logger so audit and app logs cross-correlate on this
  // field.
  actorIdHash String?       @map("actor_id_hash")
  // W3C trace id (32 hex chars) of the request that produced the
  // event. Cross-correlates with traces in Jaeger and with Pino
  // log lines that carry the same `trace_id` field. NULL only if
  // the event was emitted outside any inbound request (e.g. a
  // future cron job).
  traceId     String?       @map("trace_id")
  // Free-form identifier of what the event is *about* — typically
  // a domain entity URI like `user:42` or `dossier:xyz`. NULL when
  // the event is system-wide and has no clear subject.
  subject     String?
  outcome     AuditOutcome
  // Event-specific structured detail. Redaction of PII is the
  // caller's responsibility; the BFF Pino redact list is the
  // reference allow-/deny-list.
  payload     Json?

  @@map("events")
  @@schema("audit")
  @@index([createdAt])
  @@index([eventType])
  @@index([traceId])
}
