import { Injectable } from '@nestjs/common';
import { PrismaService } from '../prisma/prisma.service';
import { DbClient } from '../prisma/db-client';
import { AuditAction, AuditLog, Prisma } from '../../generated/prisma';

export interface RecordAuditLogInput {
  entityType: string;
  entityId: string;
  action: AuditAction;
  userId?: string;
  beforeData?: unknown;
  afterData?: unknown;
}

export interface AuditLogFilter {
  entityType?: string;
  entityId?: string;
}

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

  /**
   * With `tx` the entry commits or rolls back together with the change it
   * describes - no audited change without its entry, and no entry for a
   * change that never happened.
   */
  async record(
    input: RecordAuditLogInput,
    tx?: Prisma.TransactionClient,
  ): Promise<void> {
    const db: DbClient = tx ?? this.prisma;
    await db.auditLog.create({
      data: {
        entityType: input.entityType,
        entityId: input.entityId,
        action: input.action,
        userId: input.userId,
        beforeData: input.beforeData as Prisma.InputJsonValue,
        afterData: input.afterData as Prisma.InputJsonValue,
      },
    });
  }

  async findAll(filter: AuditLogFilter = {}): Promise<AuditLog[]> {
    return this.prisma.auditLog.findMany({
      where: { entityType: filter.entityType, entityId: filter.entityId },
      orderBy: { timestamp: 'desc' },
      take: 200,
    });
  }
}