feat: add group waitlist functionality

- Introduced GroupWaitlistEntry model in Prisma schema to manage waitlisted users for groups.
- Implemented API route to add users to the group waitlist with validation.
- Enhanced attendee creation logic to handle group capacity and waitlisting scenarios.
- Added new problem builders for handling waitlist-related errors.
- Updated frontend to support waitlist interactions, including modals for capacity warnings.
- Created tests for waitlist functionality, ensuring proper handling of full groups and existing waitlist entries.

apps/backend/src/modules/attendees/features/create/use-case.ts

@@ -1,12 +1,22 @@
 import type { PrismaClient } from '@generated/prisma/client';
-import type { AttendeeDto, CreateAttendee, ProblemDetails, Result } from '@gruperly/shared';
+import type { CreateAttendee, CreateAttendeeResult, ProblemDetails, Result } from '@gruperly/shared';
 import { err, ok } from '@gruperly/shared';
-import { conflictProblem, noGroupAccessProblem, notFoundResourceProblem } from '@/http/problem-builders';
+import {
+  alreadyWaitlistedProblem,
+  capacityReachedProblem,
+  conflictProblem,
+  noGroupAccessProblem,
+  notFoundResourceProblem,
+} from '@/http/problem-builders';
 import prisma from '@/lib/prisma';
 import { type AttendeeRecord, normalizePhone, toAttendeeDto } from '../../lib/helpers';
 
 type CreateAttendeeDeps = {
-  db?: Pick<PrismaClient, 'group' | 'attendee'>;
+  db?: Pick<PrismaClient, 'group' | 'attendee' | 'groupWaitlistEntry'>;
+};
+
+type CreateAttendeeOptions = {
+  allowOverflow?: boolean;
 };
 
 export class CreateAttendeeUseCase {
@@ -16,7 +26,8 @@ export class CreateAttendeeUseCase {
     groupId: string,
     userId: string,
     payload: CreateAttendee,
-  ): Promise<Result<AttendeeDto, ProblemDetails>> {
+    options: CreateAttendeeOptions = {},
+  ): Promise<Result<CreateAttendeeResult, ProblemDetails>> {
     const db = this.deps.db ?? prisma;
 
     const group = await db.group.findUnique({
@@ -57,6 +68,42 @@ export class CreateAttendeeUseCase {
     }
 
     const fullName = `${payload.firstName.trim()} ${payload.lastName.trim()}`.trim();
+
+    if (group.capacity !== null) {
+      const currentCount = await db.attendee.count({ where: { groupId } });
+
+      if (currentCount >= group.capacity) {
+        if (isOwner && !options.allowOverflow) {
+          return err(capacityReachedProblem(group.capacity));
+        }
+
+        if (!isOwner) {
+          const existingWaitlistEntry = await db.groupWaitlistEntry.findFirst({
+            where: { groupId, phone },
+          });
+
+          if (existingWaitlistEntry) {
+            return err(alreadyWaitlistedProblem());
+          }
+
+          await db.groupWaitlistEntry.create({
+            data: {
+              groupId,
+              fullName,
+              phone,
+              email: payload.email?.trim() || null,
+              notes: payload.notes?.trim() || null,
+            },
+          });
+
+          return ok({
+            outcome: 'waitlisted',
+            message: `${fullName} fue agregado a la lista de espera del grupo.`,
+          });
+        }
+      }
+    }
+
     const attendee = await db.attendee.create({
       data: {
         groupId,
@@ -67,6 +114,9 @@ export class CreateAttendeeUseCase {
       },
     });
 
-    return ok(toAttendeeDto(attendee as unknown as AttendeeRecord));
+    return ok({
+      outcome: 'created',
+      attendee: toAttendeeDto(attendee as unknown as AttendeeRecord),
+    });
   }
-}
+}