import { Vonage } from '@vonage/server-sdk';
import { SMS } from '@vonage/messages';
import { Auth } from '@vonage/auth';
import { logger, maskPhone } from '../logger.js';

const VONAGE_API_KEY = process.env.VONAGE_API_KEY || '';
const VONAGE_API_SECRET = process.env.VONAGE_API_SECRET || '';
const VONAGE_APPLICATION_ID = process.env.VONAGE_APPLICATION_ID || '';
const VONAGE_PRIVATE_KEY_PATH = process.env.VONAGE_PRIVATE_KEY_PATH || '';
const VONAGE_PRIVATE_KEY = process.env.VONAGE_PRIVATE_KEY || '';

let vonageClient: Vonage | null = null;

/**
 * Resolve the private key for the Vonage SDK.
 *
 * Supports three modes (checked in order):
 *   1. VONAGE_PRIVATE_KEY — raw PEM string (starts with "-----BEGIN")
 *   2. VONAGE_PRIVATE_KEY — base64-encoded PEM (decode first)
 *   3. VONAGE_PRIVATE_KEY_PATH — path to a .key file on disk
 *
 * The Vonage Auth constructor accepts either a file path (string) or
 * the key content directly (string / Buffer).
 */
function resolvePrivateKey(): string | undefined {
  if (VONAGE_PRIVATE_KEY) {
    // Raw PEM passed directly
    if (VONAGE_PRIVATE_KEY.startsWith('-----BEGIN')) {
      return VONAGE_PRIVATE_KEY;
    }
    // Base64-encoded PEM (common for PaaS env vars)
    try {
      const decoded = Buffer.from(VONAGE_PRIVATE_KEY, 'base64').toString('utf-8');
      if (decoded.startsWith('-----BEGIN')) return decoded;
    } catch { /* fall through */ }
    // Treat as raw content anyway
    return VONAGE_PRIVATE_KEY;
  }
  if (VONAGE_PRIVATE_KEY_PATH) {
    return VONAGE_PRIVATE_KEY_PATH;
  }
  return undefined;
}

function getVonageClient(): Vonage | null {
  if (vonageClient) return vonageClient;

  const privateKey = resolvePrivateKey();
  if (!VONAGE_APPLICATION_ID || !privateKey) {
    return null;
  }

  vonageClient = new Vonage(new Auth({
    apiKey: VONAGE_API_KEY,
    apiSecret: VONAGE_API_SECRET,
    applicationId: VONAGE_APPLICATION_ID,
    privateKey,
  }));

  return vonageClient;
}

/**
 * Send an SMS reply via the Vonage Messages API.
 * Phone numbers should be in E.164 format (e.g. +14155550100).
 * Vonage expects numbers without the leading '+'.
 */
export async function sendSms(to: string, from: string, body: string): Promise<void> {
  const client = getVonageClient();

  if (!client) {
    logger.warn({ event: 'sms.send_skipped', to: maskPhone(to) }, 'No Vonage credentials configured, skipping SMS send');
    logger.info({ event: 'sms.would_send', body }, 'SMS body (dev mode)');
    return;
  }

  // Strip leading '+' — Vonage expects bare numbers
  const toNumber = to.replace(/^\+/, '');
  const fromNumber = from.replace(/^\+/, '');

  try {
    await client.messages.send(
      new SMS({ to: toNumber, from: fromNumber, text: body })
    );

    logger.info({ event: 'sms.sent', to: maskPhone(to) }, 'SMS sent');
  } catch (err) {
    const error = err as Error & { response?: { data?: unknown; status?: number } };
    logger.error({
      event: 'sms.send_error',
      error: error.message,
      status: error.response?.status,
      responseData: error.response?.data,
    }, 'SMS send error');
  }
}