<?php
/**
 * request_new_otp.php — Resend OTP during the 2-factor login flow
 *
 * Called by: login page AJAX "Resend OTP" button on the OTP input screen.
 * Input:     All data sourced from $_SESSION (written by login_otp.php).
 *            No new user input is accepted.
 *
 * This endpoint regenerates a fresh TOTP and resends the OTP email without
 * requiring the user to re-enter their username and password.  It is only
 * reachable while a pending login exists: login_otp.php verified the password
 * less than LOGIN_PENDING_SECONDS ago (password_verified_at). The password
 * itself is never kept in the session, so it is not re-checked here.
 *
 * Full flow:
 *   1. Require a fresh pending login; otherwise HTTP 401 (code "login_restart").
 *   2. Throttle: per client IP, per user, and at most LOGIN_OTP_MAX_RESENDS
 *      resends per pending login (HTTP 429).
 *   3. Fetch the user row (password hash for the OTP, email to send to).
 *   4. Generate a fresh 6-digit TOTP (new timestamp → new OTP) and a random
 *      6-letter reference number.
 *   5. Send the OTP email with the same SMTP choice as login_otp.php: the
 *      default company's SMTP when configured, otherwise the system $SMTP.
 *   6. Write the new OTP state (the wrong-attempt counter restarts).
 *   7. Return { success: 1, message: "Login Complete!" }.
 *
 * Session keys read:
 *   login_user_id, password_verified_at, otp_resends
 *
 * Session keys overwritten:
 *   otp, otpTime, reference, user_email, otp_attempts, otp_resends
 */

require_once '../../../session.php';
require_once '../../../config.php';
require_once '../../../preset.php';
define('UNAUTHENTICATED_ROUTE', true);
require_once '../../../assets/utils/db_auth.php';
require_once '../../../assets/utils/rate_limit.php';
require_once '../login_helpers.php';

// ── Step 1: Require a pending login ───────────────────────────────────────────
if (!login_pending_valid()) {
    $_SESSION = [];
    login_fail(401, 'Your sign-in has expired. Please enter your username and password again.', ['code' => 'login_restart']);
}
$user_id = (int)$_SESSION["login_user_id"];

// ── Step 2: Throttle resends ──────────────────────────────────────────────────
if ((int)($_SESSION['otp_resends'] ?? 0) >= LOGIN_OTP_MAX_RESENDS) {
    rate_limit_reject();
}
rate_limit_guard($pdo1, [
    ['otp_resend_ip',   rate_limit_client_ip(), 10, 900],
    ['otp_resend_user', (string)$user_id,        5, 900],
]);

// ── Step 3: Fetch user record ─────────────────────────────────────────────────
$sth = $pdo1->prepare("select * from user where user_id = :user_id limit 1;");
$sth->execute([":user_id" => $user_id]);
$temp = $sth->fetch(PDO::FETCH_ASSOC);

if (!$temp) {
    $_SESSION = [];
    login_fail(401, 'Your sign-in has expired. Please enter your username and password again.', ['code' => 'login_restart']);
}

$user_email = $temp["email"];

// ── Step 4: Generate fresh 6-digit TOTP + random reference ────────────────────
// Same HMAC-SHA1 algorithm as login_otp.php and login_confirm.php.
// A new $otpTime is captured so the OTP window resets from this moment.
$otpTime          = time();
$otp              = login_generate_otp($temp["password"], $otpTime);
$reference_number = login_random_reference();

// ── Step 5: Send OTP email ────────────────────────────────────────────────────
// Company SMTP of the user's default company when configured, otherwise the
// system-level $SMTP from config.php.
$smtp_config     = $SMTP;
$default_company = (int)($temp["default_company"] ?? 0);
if ($default_company > 0) {
    $sth = $pdo1->prepare("SELECT * FROM company_smtp WHERE company_id = :cid LIMIT 1");
    $sth->execute([":cid" => $default_company]);
    $smtp_row = $sth->fetch(PDO::FETCH_ASSOC);
    if (!empty($smtp_row)) {
        $smtp_config = $smtp_row;
    }
}

require "../../../assets/utils/module/mailer.php";

$mailer = new mailer(["pdo1" => $pdo1, "pdo2" => $pdo2]);

$mailer->send_email([
    "company_id"   => $smtp_config === $SMTP ? 0 : $default_company,
    "smtp"         => $smtp_config,
    "subject"      => "One Time Password (OTP) For reference number " . $reference_number,
    "message"      => implode("\n", [
        "Dear WMS user,",
        "",
        "You requested a One-Time Password (OTP) to log in to WMS.",
        "",
        "Please use the OTP below to complete your request:",
        "• OTP code: " . $otp,
        "• Reference number: " . $reference_number,
        "",
        "Please note:",
        "• This code will expire in 3 minutes. Please complete your action promptly.",
        "• Do not share this code with anyone to keep your account secure.",
        "• If you did not request this code, please ignore this email.",
    ]),
    "channel_name" => "WMS LOGIN OTP ",
    "to"           => $user_email,
    "key"          => $pinkey,
]);

// ── Step 6: Write the new OTP state ───────────────────────────────────────────
// The pending-login keys (login_data, login_user_id, password_verified_at) stay
// as they are; only the OTP state is replaced.
$_SESSION["otp"]          = $otp;
$_SESSION["otpTime"]      = $otpTime;     // new timestamp — login_confirm.php uses this
$_SESSION["reference"]    = $reference_number;
$_SESSION["user_email"]   = $user_email;
$_SESSION["otp_attempts"] = 0;
$_SESSION["otp_resends"]  = (int)($_SESSION["otp_resends"] ?? 0) + 1;

// ── Step 7: Respond ───────────────────────────────────────────────────────────
$answer["success"] = 1;
$answer["message"] = "Login Complete!";
exit(json_encode($answer));