// integrations/twilio/client.js
// Thin Twilio Voice client for /calltest outbound calls + webhook validation.
// Uses axios (already a project dep) instead of the twilio SDK to keep the
// install surface small.

import axios from 'axios';
import twilio from 'twilio';
import { logger } from '../../utils/logger.js';

const LOG_SCOPE = 'twilio:client';

function requireEnv(name) {
  const v = process.env[name];
  if (!v || !String(v).trim()) {
    throw new Error(`Missing required env: ${name}`);
  }
  return String(v).trim();
}

export function isTwilioConfigured() {
  return !!(
    process.env.TWILIO_ACCOUNT_SID
    && process.env.TWILIO_AUTH_TOKEN
    && process.env.TWILIO_FROM_NUMBER
    && process.env.TWILIO_WEBHOOK_BASE_URL
  );
}

export function isCallTestEnabled() {
  const flag = String(process.env.CALLTEST_ENABLED || '').toLowerCase();
  return flag === 'true' || flag === '1' || flag === 'yes';
}

function twilioAuth() {
  const accountSid = requireEnv('TWILIO_ACCOUNT_SID');
  const authToken = requireEnv('TWILIO_AUTH_TOKEN');
  return { accountSid, authToken };
}

/**
 * Twilio request signature validation (delegates to the official SDK, which
 * handles array params, port variants, and legacy query-string encoding).
 * @see https://www.twilio.com/docs/usage/security#validating-requests
 */
export function validateTwilioSignature(signature, url, params) {
  const { authToken } = twilioAuth();
  if (!signature || !url) return false;
  return twilio.validateRequest(authToken, signature, url, params || {});
}

/**
 * Place an outbound voice call. Twilio fetches `voiceUrl` when the callee answers.
 */
export async function createOutboundCall({ to, voiceUrl, statusCallback, timeoutSec = 30 }) {
  const from = requireEnv('TWILIO_FROM_NUMBER');
  const { accountSid, authToken } = twilioAuth();

  logger(LOG_SCOPE, `Creating outbound call to ${to} from ${from}`, 'debug');

  const body = new URLSearchParams({
    To: to,
    From: from,
    Url: voiceUrl,
    Method: 'POST',
    StatusCallback: statusCallback,
    StatusCallbackMethod: 'POST',
    Timeout: String(timeoutSec),
  });
  for (const event of ['initiated', 'ringing', 'answered', 'completed']) {
    body.append('StatusCallbackEvent', event);
  }

  const url = `https://api.twilio.com/2010-04-01/Accounts/${accountSid}/Calls.json`;
  const resp = await axios.post(url, body.toString(), {
    auth: { username: accountSid, password: authToken },
    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    timeout: 30_000,
  });

  const call = resp.data;
  logger(LOG_SCOPE, `Call created sid=${call.sid} status=${call.status}`, 'debug');
  return call;
}

export default {
  isTwilioConfigured,
  isCallTestEnabled,
  createOutboundCall,
  validateTwilioSignature,
};