// 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;
}

function twilioAxios() {
  const { accountSid, authToken } = twilioAuth();
  return {
    accountSid,
    client: axios.create({
      auth: { username: accountSid, password: authToken },
      timeout: 30_000,
    }),
  };
}

function unavailable(reason, extra = {}) {
  return { available: false, reason, data: null, ...extra };
}

/**
 * Fetch the Programmable Voice Call resource (duration, price, timestamps).
 */
export async function fetchCallResource(callSid) {
  if (!callSid) return unavailable('no callSid');
  try {
    const { accountSid, client } = twilioAxios();
    const url = `https://api.twilio.com/2010-04-01/Accounts/${accountSid}/Calls/${callSid}.json`;
    const resp = await client.get(url);
    const d = resp.data || {};
    return {
      available: true,
      data: {
        sid: d.sid,
        status: d.status,
        duration: d.duration != null ? Number(d.duration) : null,
        startTime: d.start_time || d.date_created,
        endTime: d.end_time,
        from: d.from,
        to: d.to,
        direction: d.direction,
        price: d.price,
        priceUnit: d.price_unit,
        answeredBy: d.answered_by,
        forwardedFrom: d.forwarded_from,
        callerName: d.caller_name,
        queueTime: d.queue_time,
      },
      raw: d,
    };
  } catch (err) {
    const status = err.response?.status;
    const msg = err.response?.data?.message || err.message;
    logger(LOG_SCOPE, `fetchCallResource ${callSid} failed: ${msg}`, 'warn');
    return unavailable(status ? `HTTP ${status}: ${msg}` : msg, { status });
  }
}

async function fetchInsightsUrl(path) {
  const { client } = twilioAxios();
  const url = `https://insights.twilio.com/v1/Voice/${path}`;
  const resp = await client.get(url);
  return resp.data;
}

/**
 * Voice Insights call summary (requires Advanced Features on the account).
 */
export async function fetchCallInsightsSummary(callSid) {
  if (!callSid) return unavailable('no callSid');
  try {
    const data = await fetchInsightsUrl(`${callSid}/Summary`);
    return {
      available: true,
      data: {
        callSid: data.call_sid || callSid,
        callState: data.call_state,
        processingState: data.processing_state,
        startTime: data.start_time,
        endTime: data.end_time,
        duration: data.duration,
        connectDuration: data.connect_duration,
        from: data.from,
        to: data.to,
        carrierEdge: data.carrier_edge,
        sdkEdge: data.sdk_edge,
        tags: data.tags,
        attributes: data.attributes,
        properties: data.properties,
      },
      raw: data,
    };
  } catch (err) {
    const status = err.response?.status;
    const msg = err.response?.data?.message || err.message;
    if (status === 404 || status === 403) {
      return unavailable(
        status === 403
          ? 'Voice Insights Advanced Features may not be enabled'
          : 'Insights summary not ready or not found',
        { status, retryable: status === 404 },
      );
    }
    logger(LOG_SCOPE, `fetchCallInsightsSummary ${callSid} failed: ${msg}`, 'warn');
    return unavailable(status ? `HTTP ${status}: ${msg}` : msg, { status });
  }
}

/**
 * Voice Insights per-call metrics (carrier_edge for PSTN outbound).
 */
export async function fetchCallInsightsMetrics(callSid, edge = 'carrier_edge') {
  if (!callSid) return unavailable('no callSid');
  try {
    const data = await fetchInsightsUrl(`${callSid}/Metrics?Edge=${encodeURIComponent(edge)}`);
    const metrics = Array.isArray(data.metrics) ? data.metrics : [];
    const highlights = { maxJitter: null, maxPacketLoss: null, minMos: null };
    for (const m of metrics) {
      const name = String(m.name || '').toLowerCase();
      const vals = m.values || m.samples || [];
      for (const v of vals) {
        const num = Number(v?.value ?? v?.avg ?? v);
        if (!Number.isFinite(num)) continue;
        if (name.includes('jitter') && (highlights.maxJitter == null || num > highlights.maxJitter)) {
          highlights.maxJitter = num;
        }
        if (name.includes('packet') && name.includes('loss') && (highlights.maxPacketLoss == null || num > highlights.maxPacketLoss)) {
          highlights.maxPacketLoss = num;
        }
        if (name.includes('mos') && (highlights.minMos == null || num < highlights.minMos)) {
          highlights.minMos = num;
        }
      }
    }
    return {
      available: true,
      data: { edge, metrics, highlights },
      raw: data,
    };
  } catch (err) {
    const status = err.response?.status;
    const msg = err.response?.data?.message || err.message;
    if (status === 404 || status === 403) {
      return unavailable(
        status === 403
          ? 'Voice Insights Advanced Features may not be enabled'
          : 'Insights metrics not ready or not found',
        { status, retryable: status === 404 },
      );
    }
    logger(LOG_SCOPE, `fetchCallInsightsMetrics ${callSid} failed: ${msg}`, 'warn');
    return unavailable(status ? `HTTP ${status}: ${msg}` : msg, { status });
  }
}

export default {
  isTwilioConfigured,
  isCallTestEnabled,
  createOutboundCall,
  validateTwilioSignature,
  fetchCallResource,
  fetchCallInsightsSummary,
  fetchCallInsightsMetrics,
};