gold_land_server/src/config/env.validation.ts

import { plainToInstance } from 'class-transformer'
import { IsIn, IsInt, IsOptional, IsString, Min, validateSync } from 'class-validator'

export class EnvironmentVariables {
  @IsIn(['development', 'production', 'test'])
  NODE_ENV!: 'development' | 'production' | 'test'

  @IsInt()
  @Min(1)
  PORT!: number

  @IsString()
  HOST!: string

  @IsString()
  CORS_ORIGIN!: string

  @IsOptional()
  @IsString()
  DB_PATH?: string

  @IsOptional()
  @IsString()
  JWT_SECRET?: string
}

export function validateEnv(config: Record<string, unknown>): EnvironmentVariables {
  const nodeEnv = (config.NODE_ENV as string | undefined) ?? 'development'
  const jwtSecret = config.JWT_SECRET as string | undefined

  if (nodeEnv === 'production' && (!jwtSecret || jwtSecret.trim().length === 0)) {
    throw new Error('JWT_SECRET is required when NODE_ENV=production')
  }

  if (nodeEnv !== 'production' && !jwtSecret) {
    console.warn(
      '[config] JWT_SECRET is not set — using development fallback. Do not use in production.',
    )
  }

  const normalized = {
    NODE_ENV: nodeEnv,
    PORT: Number(config.PORT ?? 3001),
    HOST: (config.HOST as string | undefined) ?? '0.0.0.0',
    CORS_ORIGIN: (config.CORS_ORIGIN as string | undefined) ?? 'http://localhost:5173',
    DB_PATH: config.DB_PATH as string | undefined,
    JWT_SECRET: jwtSecret ?? 'gold-land-dev-secret-change-in-production',
  }

  const validated = plainToInstance(EnvironmentVariables, normalized, {
    enableImplicitConversion: true,
  })

  const errors = validateSync(validated, { skipMissingProperties: false })
  if (errors.length > 0) {
    throw new Error(errors.toString())
  }

  return validated
}