import { Injectable } from '@nestjs/common';
import { DELETED_USER_DISPLAY_NAME } from '@dorfteich/shared';
import { PinoLogger } from 'nestjs-pino';

import { PrismaService } from '../prisma/prisma.service';

/**
 * GDPR account deletion (issue #59, security.md §Privacy). Rather than
 * hard-deleting the user row — which would orphan or cascade authored content —
 * this scrubs the personal data, drops the login credentials, and trashes the
 * personal pond. The (kept) row is what `created_by`/authorship references, so
 * shared content the user authored simply shows as "Deleted user".
 */
@Injectable()
export class PseudonymizationService {
  constructor(
    private readonly prisma: PrismaService,
    private readonly logger: PinoLogger,
  ) {
    this.logger.setContext(PseudonymizationService.name);
  }

  async pseudonymize(userId: string): Promise<void> {
    const marker = `deleted-${userId}`;
    await this.prisma.$transaction(async (tx) => {
      // Remove every login path (password + any linked identities).
      await tx.userIdentity.deleteMany({ where: { userId } });
      await tx.session.deleteMany({ where: { userId } });
      await tx.user.update({
        where: { id: userId },
        data: {
          username: marker,
          email: `${marker}@deleted.invalid`,
          displayName: DELETED_USER_DISPLAY_NAME,
          status: 'DISABLED',
          isSiteAdmin: false,
          emailVerifiedAt: null,
        },
      });
      // The personal pond follows the trash path (security.md §Privacy).
      await tx.pond.updateMany({
        where: { ownerId: userId, type: 'PERSONAL', deletedAt: null },
        data: { deletedAt: new Date(), deletedBy: userId },
      });
    });
    this.logger.info({ userId }, 'audit: user pseudonymized (account deleted)');
  }
}