import { Injectable, NotFoundException } from "@nestjs/common";
import QR from "qrcode";
import { PrismaService } from "../../prisma/prisma.service";

@Injectable()
export class QrcodeService {
  constructor(private readonly prisma: PrismaService) {}

  findAll(tenantId: string) {
    return this.prisma.qRCode.findMany({
      where: { tenantId },
      orderBy: { createdAt: "desc" },
      include: {
        registration: { include: { attendee: true, event: true } }
      }
    });
  }

  async createForRegistration(tenantId: string, registrationId: string) {
    const registration = await this.prisma.registration.findFirst({
      where: { id: registrationId, tenantId },
      include: { attendee: true, event: true }
    });
    if (!registration) throw new NotFoundException("Registration not found");

    const payload = {
      code: registration.code,
      eventId: registration.eventId,
      tenantId: registration.tenantId,
      registrationId: registration.id
    };

    const qrCode = await this.prisma.qRCode.upsert({
      where: { registrationId: registration.id },
      create: {
        tenantId,
        registrationId: registration.id,
        code: registration.code,
        payload
      },
      update: {
        code: registration.code,
        payload,
        status: "active"
      },
      include: { registration: { include: { attendee: true, event: true } } }
    });

    const dataUrl = await QR.toDataURL(JSON.stringify(payload), { errorCorrectionLevel: "M", margin: 1, width: 320 });
    return { qrCode, dataUrl };
  }
}