import { ApiPropertyOptional } from '@nestjs/swagger';
import { IsNotEmpty, IsOptional, IsString, MaxLength } from 'class-validator';

/**
 * Edit a built train's display identity: its name and its fixed import/export
 * run numbers. Composition (yard, locomotives, wagons) has its own endpoints.
 * Omitted fields keep their current value; an empty trainName clears the name.
 */
export class UpdateTrainDetailsDto {
  @ApiPropertyOptional({ description: 'Display name; empty string clears it' })
  @IsOptional()
  @IsString()
  @MaxLength(100)
  trainName?: string;

  @ApiPropertyOptional({ description: 'Fixed IMPORT (even) run number' })
  @IsOptional()
  @IsString()
  @IsNotEmpty()
  @MaxLength(20)
  importTrainNumber?: string;

  @ApiPropertyOptional({ description: 'Fixed EXPORT (odd) run number' })
  @IsOptional()
  @IsString()
  @IsNotEmpty()
  @MaxLength(20)
  exportTrainNumber?: string;
}