import { CallHandler, ExecutionContext, HttpException, Injectable, Logger, NestInterceptor } from '@nestjs/common';
import { Observable, tap } from 'rxjs';

/** One line per request, failed ones included: 4xx as a warning, 5xx as an error. */
@Injectable()
export class LoggingInterceptor implements NestInterceptor {
  private readonly logger = new Logger('HTTP');

  intercept(context: ExecutionContext, next: CallHandler): Observable<unknown> {
    const http = context.switchToHttp();
    const request = http.getRequest();
    const start = Date.now();
    const line = (status: number) => {
      const actor = request.user?.id ?? request.device?.id ?? 'anonymous';
      const venueId = request.user?.venueId ?? request.device?.venueId ?? '-';
      return `${request.method} ${request.url} ${status} | actor=${actor} venue=${venueId} | ${Date.now() - start}ms`;
    };
    return next.handle().pipe(
      tap({
        next: () => this.logger.log(line(http.getResponse().statusCode)),
        error: (error: unknown) => {
          const status = error instanceof HttpException ? error.getStatus() : 500;
          if (status >= 500) this.logger.error(line(status));
          else this.logger.warn(line(status));
        },
      }),
    );
  }
}