/**
 * SMS notification service using Twilio.
 *
 * Reads TWILIO_ACCOUNT_SID, TWILIO_AUTH_TOKEN, TWILIO_PHONE_NUMBER from the
 * app_config table first, then falls back to env vars. If any of those are
 * missing, sendSms is a no-op that returns { success: false } and logs a
 * warning. This keeps the app running in environments where Twilio has not
 * been provisioned yet.
 */

import twilio, { type Twilio } from "twilio";
import { childLogger } from "../_core/logger.js";
import { getConfigValue } from "../db.js";

const log = childLogger("sms");

let cachedClient: Twilio | null = null;
let cachedClientSid: string | null = null;

async function resolveTwilioConfig(): Promise<{
  sid: string | null;
  token: string | null;
  phone: string | null;
}> {
  const [sid, token, phone] = await Promise.all([
    getConfigValue("TWILIO_ACCOUNT_SID"),
    getConfigValue("TWILIO_AUTH_TOKEN"),
    getConfigValue("TWILIO_PHONE_NUMBER"),
  ]);
  return {
    sid: sid ?? process.env.TWILIO_ACCOUNT_SID ?? null,
    token: token ?? process.env.TWILIO_AUTH_TOKEN ?? null,
    phone: phone ?? process.env.TWILIO_PHONE_NUMBER ?? null,
  };
}

export async function isSmsConfigured(): Promise<boolean> {
  const cfg = await resolveTwilioConfig();
  return Boolean(cfg.sid && cfg.token && cfg.phone);
}

async function getClient(): Promise<{ client: Twilio; from: string } | null> {
  const cfg = await resolveTwilioConfig();
  if (!cfg.sid || !cfg.token || !cfg.phone) return null;
  if (cachedClient && cachedClientSid === cfg.sid) {
    return { client: cachedClient, from: cfg.phone };
  }
  try {
    cachedClient = twilio(cfg.sid, cfg.token);
    cachedClientSid = cfg.sid;
    return { client: cachedClient, from: cfg.phone };
  } catch (err) {
    log.error({ err }, "failed to initialise Twilio client");
    return null;
  }
}

function normalizePhone(input: string): string {
  const trimmed = input.trim();
  if (trimmed.startsWith("+")) return trimmed;
  const digits = trimmed.replace(/[^0-9]/g, "");
  return `+${digits}`;
}

export async function sendSms(
  to: string,
  body: string
): Promise<{ success: boolean; messageId?: string; error?: string }> {
  const ctx = await getClient();
  if (!ctx) {
    log.warn({ to: to.slice(0, 4) + "***" }, "Twilio not configured — SMS skipped");
    return { success: false, error: "Twilio non configuré" };
  }

  const normalized = normalizePhone(to);

  try {
    const msg = await ctx.client.messages.create({
      to: normalized,
      from: ctx.from,
      body,
    });
    log.info({ messageId: msg.sid, to: normalized.slice(0, 4) + "***" }, "SMS sent");
    return { success: true, messageId: msg.sid };
  } catch (err) {
    const errorMessage = err instanceof Error ? err.message : String(err);
    log.error({ err, to: normalized.slice(0, 4) + "***" }, "SMS send failed");
    return { success: false, error: errorMessage };
  }
}