fix(push): stop web push from posting to arbitrary endpoints

server/supabase/functions/send-push/dispatch-response.ts

@@ -0,0 +1,74 @@
+// server/supabase/functions/send-push/dispatch-response.ts
+// Pure presenter: turns a processed push dispatch into the HTTP body/status.
+//
+// Provider transport codes (webpush_send_timeout, fcm_send_failed, …) and
+// their distinct HTTP statuses describe what happened on the function's own
+// network. Echoing them to an end-user caller turns the dispatch endpoint into
+// a reachability oracle, so user callers only ever see one generic failure.
+// Trusted system callers (service role, drain worker) keep the detailed code
+// for operations.
+
+export type DispatchAudience = 'user' | 'system'
+
+export interface DispatchOutcome {
+  status: 'pending' | 'processing' | 'succeeded' | 'partial' | 'failed'
+  complete: boolean
+  attempted: number
+  delivered: number
+  stale: number
+  retryableFailed: number
+  permanentFailed: number
+  nextRetryAt: string | null
+  transientError: string | null
+  transientStatus: number | null
+}
+
+export interface DispatchResponse {
+  body: Record<string, unknown>
+  status: number
+}
+
+export const DELIVERY_FAILURE_CODE = 'push_delivery_failed'
+const DELIVERY_FAILURE_STATUS = 502
+
+export function presentDispatchOutcome(
+  audience: DispatchAudience,
+  eventType: string,
+  resourceId: string,
+  outcome: DispatchOutcome,
+): DispatchResponse {
+  const body: Record<string, unknown> = {
+    event_type: eventType,
+    resource_id: resourceId,
+    duplicate: false,
+    status: outcome.status,
+    complete: outcome.complete,
+    attempted: outcome.attempted,
+    sent: outcome.delivered,
+    stale_removed: outcome.stale,
+    retryable_failed: outcome.retryableFailed,
+    permanent_failed: outcome.permanentFailed,
+    next_retry_at: outcome.nextRetryAt,
+  }
+  const failed = outcome.status === 'partial' || outcome.status === 'failed'
+
+  if (outcome.transientError) {
+    if (audience === 'user') {
+      return {
+        body: { error: DELIVERY_FAILURE_CODE, ...body },
+        status: DELIVERY_FAILURE_STATUS,
+      }
+    }
+    return {
+      body: { error: outcome.transientError, ...body },
+      status: outcome.transientStatus ?? DELIVERY_FAILURE_STATUS,
+    }
+  }
+  if (failed) {
+    return {
+      body: { error: DELIVERY_FAILURE_CODE, ...body },
+      status: DELIVERY_FAILURE_STATUS,
+    }
+  }
+  return { body, status: outcome.complete ? 200 : 202 }
+}