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<!-- markdownlint-disable MD024 -->
# Capability Spec Delta: api-plugin-notifications (wire-notification-channels)
**Package**: `@suaveplan/api-plugin-notifications`
**Status**: PROPOSED
> Every requirement below carries a `**Verified by:**` line at authoring time.
## ADDED Requirements
### Requirement: NotificationDispatcher orchestrator
The package SHALL export a `NotificationDispatcher` class that
resolves `@suaveplan/notification-channel`'s `DeliveryChannel`
instances by the dispatcher-facing channel name and exposes a
`dispatch(input: DispatchInput): Promise<DispatchResult>` surface.
The dispatcher SHALL fan a single input out to one of the registered
delivery channels (defaulting to the configured `defaultChannel`),
record an OTel counter increment per dispatch
(`notificationsDispatchedTotal` on success,
`notificationsDispatchFailedTotal` on failure), and forward a
`delivery:sent` or `delivery:bounced` event through the configured
`DeliveryEventStore` (when one is supplied). Channel selection
failures SHALL surface as
`NotificationsPluginError(DISPATCH_CHANNEL_UNAVAILABLE)`. Underlying
transport failures returned by the router as a `failed` status SHALL
surface as `NotificationsPluginError(DISPATCH_FAILED)` carrying the
router error as `cause`. Per-dispatch idempotency SHALL be applied
through an injected `DispatcherIdempotencyAdapter` whose default
implementation (`NoopIdempotencyAdapter`) is the identity.
**Verified by:** `src/dispatcher/notification-dispatcher/notification-dispatcher.test.ts::"dispatch routes to the default channel"`, `src/dispatcher/notification-dispatcher/notification-dispatcher.test.ts::"dispatch routes to an explicit channel"`, `src/dispatcher/notification-dispatcher/notification-dispatcher.test.ts::"dispatch raises DISPATCH_CHANNEL_UNAVAILABLE for an unknown channel"`, `src/dispatcher/notification-dispatcher/notification-dispatcher.test.ts::"dispatch raises DISPATCH_FAILED when the channel returns failed"`, `src/dispatcher/notification-dispatcher/notification-dispatcher.test.ts::"dispatch records delivery:sent through the configured store"`, `src/dispatcher/notification-dispatcher/notification-dispatcher.test.ts::"dispatch records delivery:bounced when the channel fails"`, `src/dispatcher/notification-dispatcher/notification-dispatcher.test.ts::"dispatch emits notificationsDispatchedTotal on success"`, `src/dispatcher/notification-dispatcher/notification-dispatcher.test.ts::"dispatch emits notificationsDispatchFailedTotal on failure"`.
#### Scenario: dispatch routes to the default channel when channel is unspecified
- **WHEN** `dispatcher.dispatch({ recipient, body })` is called and `defaultChannel === "apn"`
- **THEN** the registered APN `DeliveryChannel` receives `send(notification)` and the result `channel === "apn"`
#### Scenario: dispatch routes to an explicit channel when provided
- **WHEN** `dispatcher.dispatch({ recipient, body, channel: "email" })` is called against a dispatcher with both `apn` and `email` channels registered
- **THEN** only the email channel receives `send`, and the result `channel === "email"`
#### Scenario: unknown channel raises DISPATCH_CHANNEL_UNAVAILABLE
- **WHEN** `dispatcher.dispatch({ channel: "sms", … })` is called and no `sms` channel is registered
- **THEN** the call rejects with `NotificationsPluginError(DISPATCH_CHANNEL_UNAVAILABLE)`
#### Scenario: channel-returned failure raises DISPATCH_FAILED
- **WHEN** the underlying channel's `send` returns `{ success: false, error: "transport failed" }`
- **THEN** `dispatch` rejects with `NotificationsPluginError(DISPATCH_FAILED)` whose `context.channelError === "transport failed"`
#### Scenario: delivery-tracking sees a delivery:sent event on success
- **WHEN** `dispatch` succeeds and a `DeliveryEventStore` is configured
- **THEN** the store records a `DeliveryEvent` with `eventType === "sent"`, the dispatcher's tenantId, and `messageId === dispatchResult.id`
#### Scenario: delivery-tracking sees a delivery:bounced event on failure
- **WHEN** `dispatch` fails through a channel failure and a `DeliveryEventStore` is configured
- **THEN** the store records a `DeliveryEvent` with `eventType === "bounced"`
#### Scenario: idempotency adapter dedupes repeated dispatches
- **WHEN** the dispatcher is configured with an adapter that caches by key and `dispatch` is invoked twice with the same key
- **THEN** the underlying channel's `send` is called only once
---
### Requirement: ApnDeliveryChannel adapter
The package SHALL export an `ApnDeliveryChannel` class implementing
`@suaveplan/notification-channel`'s `DeliveryChannel` interface
against the in-package `ApnService`. The channel SHALL be registered
under `name === "apn"` and SHALL accept the device token via
`Notification.metadata.deviceToken` (string) or
`Notification.metadata.deviceTokens` (string array, for fan-out).
Missing-token inputs SHALL return
`{ success: false, error: "deviceToken metadata required" }`. APN
per-device failures SHALL fold into a single `DeliveryResult` whose
`success` reflects whether at least one delivery succeeded.
**Verified by:** `src/channels/apn-channel/apn-channel.test.ts::"sends through ApnService for a single deviceToken"`, `src/channels/apn-channel/apn-channel.test.ts::"fans out to multiple deviceTokens via metadata.deviceTokens"`, `src/channels/apn-channel/apn-channel.test.ts::"returns success false when deviceToken metadata is missing"`, `src/channels/apn-channel/apn-channel.test.ts::"folds APN per-device failures into the DeliveryResult"`, `src/channels/apn-channel/apn-channel.test.ts::"reports canSend true only for push channel notifications"`.
#### Scenario: single deviceToken in metadata
- **WHEN** `apnChannel.send({ channel: "push", metadata: { deviceToken: "tok" }, body: "hi", … })` is called
- **THEN** `ApnService.sendNotification` is invoked with `payload.deviceToken === "tok"` and the returned `DeliveryResult.success === true`
#### Scenario: deviceTokens array fans out
- **WHEN** `apnChannel.send({ channel: "push", metadata: { deviceTokens: ["a","b"] }, body: "hi", … })` is called
- **THEN** `ApnService.sendBulkNotifications` is invoked with the two-element array and the returned `DeliveryResult.success === true`
#### Scenario: missing deviceToken metadata
- **WHEN** `apnChannel.send` is called with no `deviceToken` and no `deviceTokens`
- **THEN** the call resolves with `{ success: false, channel: "apn", error: "deviceToken metadata required" }`
#### Scenario: APN per-device failure surfaces as DeliveryResult.error
- **WHEN** the underlying `ApnService.sendNotification` returns `{ sent: 0, failed: 1, errors: [{ error: "Unregistered" }] }`
- **THEN** `apnChannel.send` resolves with `success: false` and `error: "Unregistered"`
#### Scenario: canSend gates on channel
- **WHEN** `apnChannel.canSend(notification)` is called
- **THEN** the result is `true` iff `notification.channel === "push"`
---
### Requirement: EmailDeliveryChannel adapter
The package SHALL export an `EmailDeliveryChannel` class implementing
`@suaveplan/notification-channel`'s `DeliveryChannel` interface
against `@suaveplan/emailer`'s `EmailService`. The channel SHALL be
registered under `name === "email"` and SHALL map
`Notification.recipient` → `EmailMessage.to`, `Notification.subject`
→ `EmailMessage.subject` (defaulting to the configured
`defaultSubject` when missing), `Notification.body` →
`EmailMessage.text` (or `html` when `metadata.html === true`).
Transport failures returned by `EmailService.send` SHALL surface as
`{ success: false, error: <error message> }`. The channel SHALL throw
`NotificationsPluginError(EMAIL_SERVICE_UNAVAILABLE)` at construction
when `emailService` is `null`.
**Verified by:** `src/channels/email-channel/email-channel.test.ts::"sends through EmailService with subject + text"`, `src/channels/email-channel/email-channel.test.ts::"falls back to defaultSubject when notification has no subject"`, `src/channels/email-channel/email-channel.test.ts::"sends HTML body when metadata.html is true"`, `src/channels/email-channel/email-channel.test.ts::"folds transport failure into DeliveryResult.error"`, `src/channels/email-channel/email-channel.test.ts::"throws EMAIL_SERVICE_UNAVAILABLE when constructed with null service"`, `src/channels/email-channel/email-channel.test.ts::"canSend gates on channel === email"`.
#### Scenario: success path with explicit subject
- **WHEN** `emailChannel.send({ channel: "email", recipient: "x@y.z", subject: "S", body: "B", … })` is called
- **THEN** `EmailService.send` receives `{ to: "x@y.z", subject: "S", text: "B" }` and the channel returns `{ success: true, channel: "email" }`
#### Scenario: default subject fallback
- **WHEN** the notification has no `subject` and the channel was constructed with `defaultSubject: "Notification"`
- **THEN** `EmailService.send` receives `subject: "Notification"`
#### Scenario: HTML body via metadata
- **WHEN** `emailChannel.send({ channel: "email", metadata: { html: true }, body: "<p>x</p>", … })` is called
- **THEN** `EmailService.send` receives `{ html: "<p>x</p>" }` instead of `text`
#### Scenario: transport failure
- **WHEN** the underlying `EmailService.send` returns `{ success: false, error: new Error("smtp dead"), … }`
- **THEN** the channel returns `{ success: false, error: "smtp dead" }`
#### Scenario: null service refused at construction
- **WHEN** `new EmailDeliveryChannel({ emailService: null, … })` is invoked
- **THEN** the constructor throws `NotificationsPluginError(EMAIL_SERVICE_UNAVAILABLE)`
#### Scenario: canSend gating
- **WHEN** `emailChannel.canSend({ channel: "email", … })` versus `{ channel: "push", … }`
- **THEN** the first returns `true`, the second returns `false`
---
### Requirement: DispatcherIdempotencyAdapter contract
The package SHALL export a `DispatcherIdempotencyAdapter` interface
exposing exactly one method
`execute<T>(key: string, fn: () => Promise<T>): Promise<T>` and a
default `NoopIdempotencyAdapter` class that simply calls `fn()`.
Callers SHALL be able to plug `@suaveplan/idempotency`'s
`IdempotencyGuard` (whose `execute(key, fn, opts?)` signature is
structurally compatible) without the package importing the guard at
runtime. The dispatcher SHALL call `adapter.execute(key, () =>
underlyingDispatch())` when a `key` is derivable from the input,
short-circuiting duplicate dispatches with the adapter's cached
return value.
**Verified by:** `src/dispatcher/idempotency-adapter/idempotency-adapter.test.ts::"NoopIdempotencyAdapter calls fn exactly once"`, `src/dispatcher/idempotency-adapter/idempotency-adapter.test.ts::"a caching adapter dedupes repeated executions"`, `src/dispatcher/notification-dispatcher/notification-dispatcher.test.ts::"idempotency adapter dedupes repeated dispatches"`.
#### Scenario: noop adapter is the identity
- **WHEN** `new NoopIdempotencyAdapter().execute("k", fn)` is invoked
- **THEN** `fn()` is called exactly once and its result is returned
#### Scenario: caching adapter dedupes
- **WHEN** the same `key` is passed twice and the adapter caches by key
- **THEN** the underlying `fn` is invoked only once and both calls return the same result
---
### Requirement: Dispatch input/result schemas
The package SHALL export `DispatchInputSchema` and
`DispatchResultSchema` (Zod) plus matching `DispatchInput` /
`DispatchResult` types. `DispatchInputSchema` SHALL accept
`recipient` (non-empty string), `body` (non-empty string), optional
`channel` (one of the `notification-channel` channel literals),
optional `subject`, optional `metadata` (record),
optional `priority`, and an optional `idempotencyKey`. Invalid input
SHALL produce
`NotificationsPluginError(DISPATCH_INPUT_INVALID)` carrying the
`ZodError` as `cause`.
**Verified by:** `src/schemas/dispatch-schemas.test.ts::"DispatchInputSchema rejects empty recipient"`, `src/schemas/dispatch-schemas.test.ts::"DispatchInputSchema rejects empty body"`, `src/schemas/dispatch-schemas.test.ts::"DispatchInputSchema accepts a minimal payload"`, `src/schemas/dispatch-schemas.test.ts::"DispatchInputSchema accepts idempotencyKey"`, `src/schemas/dispatch-schemas.test.ts::"DispatchResultSchema accepts canonical shape"`.
#### Scenario: empty recipient rejected
- **WHEN** `DispatchInputSchema.safeParse({ recipient: "", body: "x" })` is invoked
- **THEN** the result `success === false`
#### Scenario: minimal payload accepted
- **WHEN** `DispatchInputSchema.safeParse({ recipient: "u", body: "b" })` is invoked
- **THEN** the result `success === true`
---
### Requirement: New error codes wired into production paths
The registry SHALL gain four codes — `DISPATCH_FAILED`,
`DISPATCH_CHANNEL_UNAVAILABLE`, `DISPATCH_INPUT_INVALID`,
`EMAIL_SERVICE_UNAVAILABLE` — and every one SHALL be thrown from at
least one production source under `src/`. The
`error-codes.test.ts` reachability scan SHALL include the four new
codes.
**Verified by:** `src/error-codes/error-codes.test.ts::"every code reachable from src"`.
#### Scenario: registry exposes the four new codes
- **WHEN** `Object.values(NOTIFICATIONS_PLUGIN_CODES)` is inspected
- **THEN** the array contains `NOTIFICATIONS_PLUGIN.DISPATCH_FAILED`, `NOTIFICATIONS_PLUGIN.DISPATCH_CHANNEL_UNAVAILABLE`, `NOTIFICATIONS_PLUGIN.DISPATCH_INPUT_INVALID`, and `NOTIFICATIONS_PLUGIN.EMAIL_SERVICE_UNAVAILABLE`
#### Scenario: every new code reachable from src
- **WHEN** the spec-conformance scan concatenates every non-test `.ts` under `src/`
- **THEN** the concatenation contains `NOTIFICATIONS_PLUGIN_CODES.DISPATCH_FAILED`, `…DISPATCH_CHANNEL_UNAVAILABLE`, `…DISPATCH_INPUT_INVALID`, and `…EMAIL_SERVICE_UNAVAILABLE`
---
### Requirement: New OTel counters
`getNotificationsInstruments()` SHALL expose two additional counters:
`notificationsDispatchedTotal` (incremented by `NotificationDispatcher`
on a successful dispatch, with `channel` attribute) and
`notificationsDispatchFailedTotal` (incremented on a failed dispatch,
with `channel` + `reason` attributes). Both SHALL be observable
through an `InMemoryMetricExporter` in the OTel test.
**Verified by:** `src/otel/instruments.test.ts::"exposes dispatcher counters"`, `src/otel/instruments.test.ts::"dispatcher counters emit on flush"`.
#### Scenario: instrument bundle exposes the two new counters
- **WHEN** `getNotificationsInstruments()` is called
- **THEN** the returned object has `notificationsDispatchedTotal` and `notificationsDispatchFailedTotal` properties
#### Scenario: counters appear in the exporter snapshot
- **WHEN** both counters are incremented and `flushTestMetrics()` is called
- **THEN** the exporter snapshot includes both metric names
---
### Requirement: Service-registry augmentation for dispatcher + email
The package SHALL extend the existing `ServiceRegistry` module
augmentation with two optional slots:
`notificationDispatcher` (`NotificationDispatcher`) and
`emailService` (`EmailService` from `@suaveplan/emailer`). The slots
SHALL only be populated when the plugin's `enableDispatcher` option
is `true` (dispatcher) or when the host injects an `EmailService`
(email).
**Verified by:** `src/api-plugin-notifications.spec-conformance.test.ts::"registry slots include dispatcher and emailService"`, `src/plugin/plugin.test.ts::"onInit registers notificationDispatcher when enableDispatcher is on"`.
#### Scenario: dispatcher slot populated when enabled
- **WHEN** `onInit` runs with `enableDispatcher: true`
- **THEN** `ctx.getService("notificationDispatcher")` resolves to a `NotificationDispatcher` instance
#### Scenario: emailService slot populated when injected
- **WHEN** the host calls `createNotificationsPlugin({ services: { emailService } })` and `onInit` runs
- **THEN** `ctx.getService("emailService")` resolves to the same `EmailService` instance
## MODIFIED Requirements
### Requirement: Plugin factory and lifecycle
The package SHALL export `createNotificationsPlugin(options?:
NotificationsPluginConfigInput & { services?: { emailService?: EmailService } })`
returning a `PluginDescriptor<NotificationsPluginConfig>` that mounts
both the `/notifications` and `/push` route groups against
`@suaveplan/api`. The factory SHALL Zod-validate input via
`NotificationsPluginOptionsSchema` and throw
`NotificationsPluginError(INVALID_CONFIG)` carrying the `ZodError`
as `cause` on invalid input. `onInit` SHALL register
`notificationRepository`, `deviceTokenRepository`, and (when
`enablePush`) `apnService` in the host's `ServiceRegistry`. When the
caller supplies `services.emailService`, `onInit` SHALL register it
under the `emailService` slot. When the config has `enableDispatcher:
true`, `onInit` SHALL construct a `NotificationDispatcher` wired with
every available channel (`apn` if `apnService` is registered, `email`
if `emailService` is registered) and register it under
`notificationDispatcher`; the dispatcher SHALL refuse to construct
when zero channels are available
(`NotificationsPluginError(DISPATCH_CHANNEL_UNAVAILABLE)`).
`onReady` SHALL mount both route trees and refuse to double-mount.
`onClose` SHALL shut down the APN transport (if any), null the
dispatcher reference, and clear runtime state.
**Verified by:** `src/plugin/plugin.test.ts`, `src/schemas/options.test.ts`, `src/api-plugin-notifications.spec-conformance.test.ts`.
#### Scenario: valid options produce a descriptor
- **WHEN** `createNotificationsPlugin({ basePath: "/v1/notifications" })` is called
- **THEN** the descriptor has `name === "notifications"`, `dependencies === ["database"]`, and `defaults.basePath === "/v1/notifications"`
#### Scenario: invalid options fail fast
- **WHEN** `createNotificationsPlugin({ basePath: "" } as never)` is called
- **THEN** the call throws `NotificationsPluginError` with `code === NOTIFICATIONS_PLUGIN_CODES.INVALID_CONFIG`
#### Scenario: onInit registers repositories
- **WHEN** `onInit(ctx)` runs with a real `db` service in the registry
- **THEN** `ctx.getService("notificationRepository")` and `ctx.getService("deviceTokenRepository")` resolve to non-null instances
#### Scenario: onInit fails without database service
- **WHEN** `onInit(ctx)` runs with no `db` service registered
- **THEN** it throws `NotificationsPluginError(SERVICE_NOT_AVAILABLE)`
#### Scenario: onInit registers APN when enabled
- **WHEN** `onInit(ctx)` runs with `enablePush === true` and a valid `apn` config
- **THEN** `ctx.getService("apnService")` resolves to an `ApnService` instance whose `isInitialized()` returns `true`
#### Scenario: onInit fails when enablePush without apn
- **WHEN** `onInit(ctx)` runs with `enablePush === true` and `apn === undefined`
- **THEN** it throws `NotificationsPluginError(APN_CONFIG_MISSING)`
#### Scenario: onInit registers notificationDispatcher when enableDispatcher is on
- **WHEN** `onInit(ctx)` runs with `enableDispatcher: true`, `enablePush: true`, and a valid APN config
- **THEN** `ctx.getService("notificationDispatcher")` resolves to a `NotificationDispatcher` whose `dispatch({ channel: "apn", … })` succeeds
#### Scenario: onInit refuses dispatcher with zero channels
- **WHEN** `onInit(ctx)` runs with `enableDispatcher: true`, `enablePush: false`, and no `emailService` injected
- **THEN** it throws `NotificationsPluginError(DISPATCH_CHANNEL_UNAVAILABLE)`
#### Scenario: onReady mounts both route trees
- **WHEN** `onReady(ctx)` runs after `onInit`
- **THEN** `ctx.getService("app").routes` contains entries whose `path` begins with the configured `basePath` AND with the configured `pushBasePath`
#### Scenario: onReady refuses to double-mount
- **WHEN** `onReady(ctx)` is invoked twice against the same app instance
- **THEN** the second call throws `NotificationsPluginError(ROUTE_PREFIX_COLLISION)`
#### Scenario: onClose clears repositories AND dispatcher
- **WHEN** `onClose()` is invoked after a successful boot with `enableDispatcher: true`
- **THEN** the dispatcher reference is nulled and subsequent `onReady` invocations against a fresh app raise `SERVICE_NOT_AVAILABLE`