/**
 * POST /api/calendars - neuen Kalender erstellen (nur ADMIN).
 */
import { NextRequest, NextResponse } from 'next/server';
import { prisma } from '@/lib/db/client';
import { requireDbUser } from '@/lib/api/context';
import { createCalendarSchema } from '@/lib/validation';
import { errorResponse, forbiddenResponse } from '@/lib/api/responses';

export async function POST(request: NextRequest): Promise<NextResponse> {
  try {
    const user = await requireDbUser();
    if (user.role !== 'ADMIN') {
      return forbiddenResponse();
    }

    const body = createCalendarSchema.parse(await request.json());

    const calendar = await prisma.calendar.create({
      data: {
        ownerId: user.id,
        title: body.title,
        description: body.description ?? null,
        timezone: body.timezone,
      },
      select: { id: true, title: true, description: true, timezone: true },
    });

    return NextResponse.json({ calendar }, { status: 201 });
  } catch (error) {
    return errorResponse(error);
  }
}

/**
 * GET /api/calendars - Kalender des angemeldeten Benutzers.
 *
 * Admin: alle Kalender (Verwaltungsrolle, konsistent mit canManageCalendar
 * und den Server-Komponenten in Dashboard/Verwaltung). User: genau der
 * eine Kalender, in dem er Mitglied ist (plan.md Abschnitt 14: Dashboard).
 */
export async function GET(): Promise<NextResponse> {
  try {
    const user = await requireDbUser();

    if (user.role === 'ADMIN') {
      const calendars = await prisma.calendar.findMany({
        orderBy: { createdAt: 'desc' },
        select: {
          id: true,
          title: true,
          description: true,
          timezone: true,
          isActive: true,
          createdAt: true,
          _count: { select: { reservations: true, members: true } },
        },
      });
      return NextResponse.json({ calendars });
    }

    // User: genau ein Kalender (durch unique auf userId garantiert).
    const membership = await prisma.calendarMember.findUnique({
      where: { userId: user.id },
      include: {
        calendar: {
          select: {
            id: true,
            title: true,
            description: true,
            timezone: true,
            isActive: true,
            createdAt: true,
            _count: { select: { reservations: true, members: true } },
          },
        },
      },
    });

    return NextResponse.json({
      calendars: membership?.calendar ? [membership.calendar] : [],
    });
  } catch (error) {
    return errorResponse(error);
  }
}