<?php
declare(strict_types=1);

require_once dirname(__DIR__, 4) . '/backend/OtpProvider.php';
require_once dirname(__DIR__, 4) . '/backend/JwtToken.php';
require_once dirname(__DIR__, 4) . '/backend/ApiAuth.php';
require_once dirname(__DIR__) . '/_bootstrap.php';
api_method('POST');

$body = json_decode(file_get_contents('php://input') ?: '', true);
$challengeId = is_array($body) ? ($body['challenge_id'] ?? null) : null;
$code = is_array($body) ? ($body['code'] ?? null) : null;
$displayName = is_array($body) ? ($body['display_name'] ?? null) : null;
$deviceUuid = is_array($body) ? ($body['device_uuid'] ?? null) : null;
$platform = is_array($body) ? ($body['platform'] ?? null) : null;
if (!is_string($challengeId) || !preg_match('/^[0-9a-f-]{36}$/i', $challengeId) || !is_string($code) || !preg_match('/^[0-9]{6}$/', $code)) {
    api_json(['error' => 'invalid_verification_payload'], 400);
}
if ($displayName !== null && (!is_string($displayName) || mb_strlen($displayName) > 100)) {
    api_json(['error' => 'invalid_display_name'], 400);
}
if ($deviceUuid !== null && (!is_string($deviceUuid) || !preg_match('/^[0-9a-f-]{36}$/i', $deviceUuid))) {
    api_json(['error' => 'invalid_device_uuid'], 400);
}
if ($platform !== null && !in_array($platform, ['ios', 'android', 'web'], true)) {
    api_json(['error' => 'invalid_platform'], 400);
}

try {
    AppConfig::loadEnvironment();
    $hashKey = AppConfig::required('OTP_HASH_KEY');
    if (strlen($hashKey) < 32) {
        throw new RuntimeException('OTP_HASH_KEY must be at least 32 bytes');
    }
    $jwtKey = AppConfig::required('JWT_SIGNING_KEY');
    if (strlen($jwtKey) < 32) {
        throw new RuntimeException('JWT_SIGNING_KEY must be at least 32 bytes');
    }
    $db = Database::getInstance();
    $connection = $db->getConnection();
    $connection->begin_transaction();
    $challengeQuery = $db->prepare('SELECT challenge_uuid, phone_e164, purpose, code_digest, attempt_count, max_attempts, device_uuid FROM otp_challenges WHERE challenge_uuid = ? AND consumed_at IS NULL AND expires_at > UTC_TIMESTAMP() FOR UPDATE');
    $challengeQuery->bind_param('s', $challengeId);
    $challengeQuery->execute();
    $challenge = $challengeQuery->get_result()->fetch_assoc();
    $challengeQuery->close();
    if (!$challenge || (int) $challenge['attempt_count'] >= (int) $challenge['max_attempts']) {
        $connection->rollback();
        api_json(['error' => 'invalid_or_expired_challenge'], 400);
    }
    if ($deviceUuid !== null && $challenge['device_uuid'] !== null && !hash_equals($challenge['device_uuid'], $deviceUuid)) {
        $connection->rollback();
        api_json(['error' => 'invalid_verification_payload'], 400);
    }

    $expectedDigest = hash_hmac('sha256', $challengeId . '|' . $challenge['phone_e164'] . '|' . $code, $hashKey);
    if (!hash_equals($challenge['code_digest'], $expectedDigest)) {
        $fail = $db->prepare('UPDATE otp_challenges SET attempt_count = attempt_count + 1 WHERE challenge_uuid = ?');
        $fail->bind_param('s', $challengeId);
        $fail->execute();
        $fail->close();
        $connection->commit();
        api_json(['error' => 'invalid_code'], 400);
    }

    $consume = $db->prepare('UPDATE otp_challenges SET consumed_at = UTC_TIMESTAMP() WHERE challenge_uuid = ? AND consumed_at IS NULL');
    $consume->bind_param('s', $challengeId);
    $consume->execute();
    if ($consume->affected_rows !== 1) {
        $consume->close();
        $connection->rollback();
        api_json(['error' => 'invalid_or_expired_challenge'], 400);
    }
    $consume->close();

    $userQuery = $db->prepare('SELECT id, uuid, account_role, is_active FROM users WHERE phone_e164 = ? LIMIT 1 FOR UPDATE');
    $userQuery->bind_param('s', $challenge['phone_e164']);
    $userQuery->execute();
    $user = $userQuery->get_result()->fetch_assoc();
    $userQuery->close();
    if (!$user && $challenge['purpose'] === 'login') {
        $connection->rollback();
        api_json(['error' => 'verification_failed'], 400);
    }
    if ($user && !(bool) $user['is_active']) {
        $connection->rollback();
        api_json(['error' => 'account_inactive'], 403);
    }
    if (!$user) {
        $userUuid = sprintf('%04x%04x-%04x-4%03x-%04x-%04x%04x%04x', random_int(0, 0xffff), random_int(0, 0xffff), random_int(0, 0xffff), random_int(0, 0xfff), random_int(0, 0x3fff) | 0x8000, random_int(0, 0xffff), random_int(0, 0xffff), random_int(0, 0xffff));
        $userInsert = $db->prepare('INSERT INTO users (uuid, phone_e164, phone_verified_at, full_name, account_role, is_active) VALUES (?, ?, UTC_TIMESTAMP(), ?, \'member\', 1)');
        $fullName = $displayName ?: 'مستخدم SportPath';
        $userInsert->bind_param('sss', $userUuid, $challenge['phone_e164'], $fullName);
        $userInsert->execute();
        $userId = (int) $connection->insert_id;
        $userInsert->close();
        $user = ['id' => $userId, 'uuid' => $userUuid, 'account_role' => 'member'];
    } else {
        $userId = (int) $user['id'];
        $verified = $db->prepare('UPDATE users SET phone_verified_at = COALESCE(phone_verified_at, UTC_TIMESTAMP()) WHERE id = ?');
        $verified->bind_param('i', $userId);
        $verified->execute();
        $verified->close();
    }

    $resolvedDevice = $deviceUuid ?: ($challenge['device_uuid'] ?: null);
    if ($resolvedDevice !== null) {
        $devicePlatform = $platform ?: 'web';
        $deviceInsert = $db->prepare('INSERT INTO user_devices (user_id, device_uuid, platform, display_name, last_seen_at) VALUES (?, ?, ?, ?, UTC_TIMESTAMP()) ON DUPLICATE KEY UPDATE platform = VALUES(platform), revoked_at = NULL, last_seen_at = UTC_TIMESTAMP()');
        $deviceName = $displayName ?: null;
        $deviceInsert->bind_param('isss', $userId, $resolvedDevice, $devicePlatform, $deviceName);
        $deviceInsert->execute();
        $deviceInsert->close();
    }

    $sessionId = sprintf('%04x%04x-%04x-4%03x-%04x-%04x%04x%04x', random_int(0, 0xffff), random_int(0, 0xffff), random_int(0, 0xffff), random_int(0, 0xfff), random_int(0, 0x3fff) | 0x8000, random_int(0, 0xffff), random_int(0, 0xffff), random_int(0, 0xffff));
    $familyId = $sessionId;
    $refreshToken = bin2hex(random_bytes(48));
    $refreshDigest = hash('sha256', $refreshToken);
    $refreshDays = max(1, min(90, AppConfig::integer('JWT_REFRESH_TTL_DAYS', 30)));
    $sessionInsert = $db->prepare('INSERT INTO auth_sessions (session_uuid, family_uuid, user_id, device_uuid, refresh_token_digest, expires_at) VALUES (?, ?, ?, ?, ?, UTC_TIMESTAMP() + INTERVAL ? DAY)');
    $sessionInsert->bind_param('ssissi', $sessionId, $familyId, $userId, $resolvedDevice, $refreshDigest, $refreshDays);
    $sessionInsert->execute();
    $sessionInsert->close();
    $connection->commit();

    $accessTtl = max(60, min(3600, AppConfig::integer('JWT_ACCESS_TTL_SECONDS', 900)));
    api_json([
        'user' => ['id' => $userId, 'uuid' => $user['uuid'], 'phone_e164' => $challenge['phone_e164'], 'account_role' => $user['account_role']],
        'access_token' => JwtToken::issue($userId, $sessionId, $accessTtl),
        'token_type' => 'Bearer',
        'expires_in_seconds' => $accessTtl,
        'refresh_token' => $refreshToken,
        'refresh_expires_in_days' => $refreshDays,
    ]);
} catch (Throwable $exception) {
    if (isset($connection) && $connection instanceof mysqli) {
        try { $connection->rollback(); } catch (Throwable $ignored) {}
    }
    error_log('OTP verification failed: ' . $exception->getMessage());
    api_json(['error' => 'service_unavailable'], 503);
}