import { z } from 'zod';

const envSchema = z.object({
  DATABASE_URL: z
    .string()
    .regex(
      /^postgres(ql)?:\/\//,
      'DATABASE_URL must be a PostgreSQL connection string',
    ),
  PORT: z.preprocess(
    (value) => (value === undefined || value === '' ? 3000 : value),
    z.coerce.number().int().positive(),
  ),
});

export type AppConfig = z.infer<typeof envSchema>;

export function validateEnv(config: Record<string, unknown>): AppConfig {
  const result = envSchema.safeParse({
    DATABASE_URL: config.DATABASE_URL,
    PORT: config.PORT,
  });
  if (!result.success) {
    const details = result.error.issues
      .map((issue) => `${issue.path.join('.') || 'env'}: ${issue.message}`)
      .join('\n');
    throw new Error(`Environment validation failed:\n${details}`);
  }
  return result.data;
}