import dotenv from 'dotenv';

dotenv.config();

function required(name: string): string {
  const value = process.env[name];
  if (!value) {
    throw new Error(`Missing required environment variable: ${name}`);
  }
  return value;
}

function optional(name: string, defaultValue: string): string {
  return process.env[name] || defaultValue;
}

function optionalInt(name: string, defaultValue: number): number {
  const value = process.env[name];
  if (!value) return defaultValue;
  const parsed = parseInt(value, 10);
  return isNaN(parsed) ? defaultValue : parsed;
}

export const config = {
  telegram: {
    botToken: required('TELEGRAM_BOT_TOKEN'),
  },
  api: {
    baseUrl: optional('API_BASE_URL', 'http://localhost:3000'),
  },
  frontend: {
    baseUrl: optional('FRONTEND_BASE_URL', 'http://localhost:3001'),
  },
  database: {
    path: process.env.BOT_DATABASE_PATH || null, // Defaults to ./data/bot.db in database.ts
  },
  bot: {
    maxTicketsPerPurchase: optionalInt('MAX_TICKETS_PER_PURCHASE', 100),
    paymentPollIntervalMs: optionalInt('PAYMENT_POLL_INTERVAL_MS', 5000),
    paymentPollTimeoutMs: optionalInt('PAYMENT_POLL_TIMEOUT_MS', 900000), // 15 minutes
    invoiceExpiryMinutes: optionalInt('INVOICE_EXPIRY_MINUTES', 15),
  },
  logging: {
    level: optional('LOG_LEVEL', 'info'),
  },
  nodeEnv: optional('NODE_ENV', 'development'),
};

export default config;