import { z } from 'zod';

/**
 * Helper to parse boolean from string
 */
const booleanString = z
  .string()
  .optional()
  .default('false')
  .transform((val) => val === 'true');

/**
 * Environment variables schema validation using Zod
 */
export const envSchema = z.object({
  // Environment
  NODE_ENV: z
    .enum(['development', 'production', 'test'])
    .default('development'),
  PORT: z.coerce.number().default(3000),

  // Database
  DATABASE_URL: z.string().url(),

  // JWT
  JWT_SECRET: z.string().min(32),
  JWT_ACCESS_EXPIRATION: z.string().default('15m'),
  JWT_REFRESH_EXPIRATION: z.string().default('7d'),

  // Redis
  REDIS_HOST: z.string().default('localhost'),
  REDIS_PORT: z.coerce.number().default(6379),
  REDIS_PASSWORD: z.string().optional(),

  // i18n
  DEFAULT_LANGUAGE: z.string().default('en'),
  FALLBACK_LANGUAGE: z.string().default('en'),

  // Optional Features
  ENABLE_MAIL: booleanString,
  ENABLE_S3: booleanString,
  ENABLE_WEBSOCKET: booleanString,
  ENABLE_MULTI_TENANCY: booleanString,

  // Mail (Optional)
  MAIL_HOST: z.string().optional(),
  MAIL_PORT: z.coerce.number().optional(),
  MAIL_USER: z.string().optional(),
  MAIL_PASSWORD: z.string().optional(),
  MAIL_FROM: z.string().optional(),

  // S3 (Optional)
  S3_ENDPOINT: z.string().optional(),
  S3_ACCESS_KEY: z.string().optional(),
  S3_SECRET_KEY: z.string().optional(),
  S3_BUCKET: z.string().optional(),
  S3_REGION: z.string().optional(),

  // Throttle
  THROTTLE_TTL: z.coerce.number().default(60000),
  THROTTLE_LIMIT: z.coerce.number().default(100),
});

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

/**
 * Validate environment variables
 */
export function validateEnv(config: Record<string, unknown>): EnvConfig {
  const result = envSchema.safeParse(config);

  if (!result.success) {
    const errors = result.error.issues.map(
      (err) => `${err.path.join('.')}: ${err.message}`,
    );
    throw new Error(`Environment validation failed:\n${errors.join('\n')}`);
  }

  return result.data;
}