import { Injectable } from '@nestjs/common';
import { Prisma } from '@prisma/client';
import { PinoLogger } from 'nestjs-pino';

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

export interface AuditEvent {
  /** Stable dot-namespaced id, e.g. `grant.created` — the UI translates it. */
  action: string;
  /** The acting user; null/undefined for anonymous events. */
  actorId?: string | null;
  targetType?: string;
  targetId?: string;
  /** Small, structured context — never secrets, tokens, or page content. */
  details?: Record<string, unknown>;
}

/**
 * The persistent audit trail (issue #86, security.md §Logging): auth events
 * and admin actions land as queryable rows for the Site-Admin viewer AND as
 * the established `audit: …` stdout line. Content activity (pages, files,
 * exports, labels) intentionally stays log-only — the trail answers "who
 * changed access/configuration", not "who edited what".
 *
 * Recording must never break the audited operation: failures are logged and
 * swallowed (the stdout line still fired, so nothing is silently lost).
 */
@Injectable()
export class AuditService {
  constructor(
    private readonly prisma: PrismaService,
    private readonly logger: PinoLogger,
  ) {
    this.logger.setContext(AuditService.name);
  }

  async record(event: AuditEvent): Promise<void> {
    const { action, actorId, targetType, targetId, details } = event;
    this.logger.info(
      { actor: actorId ?? null, targetType, targetId, ...details },
      `audit: ${action}`,
    );
    try {
      await this.prisma.auditEntry.create({
        data: {
          action,
          actorId: actorId ?? null,
          targetType,
          targetId,
          details: details ? (details as Prisma.InputJsonObject) : undefined,
        },
      });
    } catch (error) {
      this.logger.error({ action, err: error }, 'audit entry could not be persisted');
    }
  }
}