import { Injectable, OnApplicationShutdown } from '@nestjs/common';
import { PinoLogger } from 'nestjs-pino';

type LogLevel = 'debug' | 'error' | 'info' | 'warn';
type LogContext = Record<string, boolean | number | string | undefined>;

const allowedFields = new Set([
  'asOf',
  'attempts',
  'brokerageAccountId',
  'channelState',
  'clientRequestId',
  'code',
  'count',
  'durationMs',
  'environment',
  'errorName',
  'errorStack',
  'found',
  'grpcCode',
  'headersReceived',
  'invalidFields',
  'method',
  'networkMs',
  'operation',
  'queueWaitMs',
  'requestId',
  'route',
  'service',
  'status',
  'trackingId',
  'userId',
]);

@Injectable()
export class StructuredLogger implements OnApplicationShutdown {
  constructor(private readonly pino: PinoLogger) {}

  info(message: string, context?: LogContext): void {
    this.write('info', message, context);
  }

  event(level: LogLevel, message: string, context?: LogContext): void {
    this.write(level, message, context);
  }

  onApplicationShutdown(): void {
    this.info('application.stopped');
  }

  private write(
    level: LogLevel,
    message: string,
    context: LogContext = {},
  ): void {
    // eslint-disable-next-line security/detect-object-injection -- The log level is restricted to the internal LogLevel union.
    this.pino[level](
      this.safeContext(context),
      message,
    );
  }

  private safeContext(context: LogContext): LogContext {
    return Object.fromEntries(
      Object.entries(context).filter(
        ([key, value]) => allowedFields.has(key) && value !== undefined,
      ),
    );
  }
}