<?php
require_once __DIR__ . '/ClientIpResolver.php';
require_once __DIR__ . '/FpUrlHelper.php';

/**
 * 二次风控（byApiRisk）Session 缓存：同 Session 内复用判定结果，IP 变化时失效。
 */
class RiskSecondaryCache
{
    const SESSION_KEY = 'cloak_risk_cache';

    /**
     * @param array{result:string,reason?:string,fp_url?:string,ip?:string} $payload
     */
    public static function store(array $payload)
    {
        $ip = ClientIpResolver::normalizeIp($payload['ip'] ?? ClientIpResolver::resolve());
        if ($ip === null) {
            return;
        }

        $_SESSION[self::SESSION_KEY] = [
            'ip'          => $ip,
            'result'      => ($payload['result'] ?? '') === 'true' ? 'true' : 'false',
            'reason'      => (string) ($payload['reason'] ?? ''),
            'fp_url'      => (string) ($payload['fp_url'] ?? ''),
            'risk_number' => defined('CLOAK_RISK_NUMBER') ? (int) CLOAK_RISK_NUMBER : 0,
            'campaign_id' => defined('COSTM_IP_SCORE') ? (string) COSTM_IP_SCORE : '',
            'cached_at'   => time(),
        ];
    }

    /**
     * @param string|null $currentIp 为空时使用 ClientIpResolver::resolve()
     * @return array|null
     */
    public static function get($currentIp = null)
    {
        if (empty($_SESSION[self::SESSION_KEY]) || !is_array($_SESSION[self::SESSION_KEY])) {
            return null;
        }

        $cached = $_SESSION[self::SESSION_KEY];
        $ip     = ClientIpResolver::normalizeIp($currentIp !== null && $currentIp !== '' ? $currentIp : ClientIpResolver::resolve());
        $cachedIp = ClientIpResolver::normalizeIp($cached['ip'] ?? '');

        $invalidate = false;
        if ($ip === null || $cachedIp === null || $ip !== $cachedIp) {
            $invalidate = true;
        } elseif (defined('CLOAK_RISK_NUMBER') && (int) ($cached['risk_number'] ?? -1) !== (int) CLOAK_RISK_NUMBER) {
            $invalidate = true;
        } elseif (defined('COSTM_IP_SCORE') && (string) ($cached['campaign_id'] ?? '') !== (string) COSTM_IP_SCORE) {
            $invalidate = true;
        }

        if ($invalidate) {
            self::clear();
            $_SESSION['visit_to_3'] = '1';
            return null;
        }

        return $cached;
    }

    public static function clear()
    {
        unset($_SESSION[self::SESSION_KEY]);
    }

    /**
     * 将缓存同步到 visit_to_3 / check_result，供 RouteResolver 等复用。
     *
     * @param array $cached
     */
    public static function applyToSession(array $cached)
    {
        $_SESSION['visit_to_3']   = 3;
        $_SESSION['check_result'] = ($cached['result'] ?? '') === 'true' ? 'true' : 'false';
    }

    public static function hitReason()
    {
        return '二次风控缓存命中';
    }

    /**
     * @param array $cached
     * @return array{result:bool,reason:string,link:string}
     */
    public static function toApiResponse(array $cached)
    {
        $passed = ($cached['result'] ?? '') === 'true';
        $link   = (string) ($cached['fp_url'] ?? '');

        if ($passed && $link === '') {
            $link = FpUrlHelper::fallbackUrl();
        }
        if (!$passed && $link === '' && defined('DB_ZP')) {
            $link = (string) DB_ZP;
        }

        return [
            'result' => $passed,
            'reason' => self::hitReason(),
            'link'   => $link,
        ];
    }
}