import { plainToInstance } from 'class-transformer';
import { IsNotEmpty, IsNumberString, IsOptional, IsString, validateSync } from 'class-validator';

class EnvironmentVariables {
  @IsOptional()
  @IsNumberString()
  PORT?: string;

  @IsOptional()
  @IsString()
  NODE_ENV?: string;

  @IsNotEmpty()
  @IsString()
  DB_URL!: string;

  @IsOptional()
  @IsString()
  REDIS_URL?: string;

  @IsNotEmpty()
  @IsString()
  JWT_SECRET!: string;

  @IsOptional()
  @IsString()
  JWT_ACCESS_TTL?: string;

  @IsOptional()
  @IsString()
  JWT_REFRESH_TTL?: string;

  @IsNotEmpty()
  @IsString()
  SMS_API_KEY!: string;

  @IsOptional()
  @IsNumberString()
  OTP_TTL_SECONDS?: string;
}

export function validateEnv(config: Record<string, unknown>) {
  const validatedConfig = plainToInstance(EnvironmentVariables, config, {
    enableImplicitConversion: true,
  });

  const errors = validateSync(validatedConfig, {
    skipMissingProperties: false,
  });

  if (errors.length > 0) {
    throw new Error(errors.toString());
  }

  return validatedConfig;
}