feat(pay): enforce VIP free-download daily quota like zibll

inc/helpers/aksrt-vip.php

@@ -149,6 +149,160 @@ function aksrt_get_vip_badge_text(): string {
     return sanitize_text_field($vip_settings['badge_text'] ?? 'VIP');
 }
 
+/**
+ * Daily free-download limit for a user (0 = unlimited).
+ * Aligns with zibll pay_download_limit / pay_download_limit_vip_{n}.
+ */
+if (!function_exists('aksrt_get_user_free_download_limit')) {
+    function aksrt_get_user_free_download_limit(int $user_id = 0): int {
+        if ($user_id <= 0) {
+            $user_id = get_current_user_id();
+        }
+        if ($user_id <= 0 || !class_exists('AKSRT_Settings')) {
+            return 0;
+        }
+
+        $vip = AKSRT_Settings::get_payment_vip_settings();
+        $level = function_exists('aksrt_get_user_vip_level') ? aksrt_get_user_vip_level($user_id) : 0;
+        $levels = is_array($vip['levels'] ?? null) ? $vip['levels'] : [];
+        $benefit = is_array($vip['benefit'] ?? null) ? $vip['benefit'] : [];
+
+        if ($level >= 1 && !empty($levels[$level]['enabled'])) {
+            return max(0, (int) ($levels[$level]['download_limit'] ?? 0));
+        }
+
+        return max(0, (int) ($benefit['download_limit'] ?? 0));
+    }
+}
+
+/**
+ * Download speed cap in KB/s for a user (0 = unlimited).
+ */
+if (!function_exists('aksrt_get_user_download_speed')) {
+    function aksrt_get_user_download_speed(int $user_id = 0): int {
+        if ($user_id <= 0) {
+            $user_id = get_current_user_id();
+        }
+        if ($user_id <= 0 || !class_exists('AKSRT_Settings')) {
+            return 0;
+        }
+
+        $vip = AKSRT_Settings::get_payment_vip_settings();
+        $level = function_exists('aksrt_get_user_vip_level') ? aksrt_get_user_vip_level($user_id) : 0;
+        $levels = is_array($vip['levels'] ?? null) ? $vip['levels'] : [];
+        $benefit = is_array($vip['benefit'] ?? null) ? $vip['benefit'] : [];
+
+        if ($level >= 1 && !empty($levels[$level]['enabled'])) {
+            return max(0, (int) ($levels[$level]['download_speed'] ?? 0));
+        }
+
+        return max(0, (int) ($benefit['download_speed'] ?? 0));
+    }
+}
+
+/**
+ * Count free downloads used today for a user (zibll pay_down_number).
+ */
+if (!function_exists('aksrt_get_user_free_downloaded_number')) {
+    function aksrt_get_user_free_downloaded_number(int $user_id = 0): int {
+        if ($user_id <= 0) {
+            $user_id = get_current_user_id();
+        }
+        if ($user_id <= 0) {
+            return 0;
+        }
+
+        $day = current_time('Y-m-d');
+        $mate = get_user_meta($user_id, 'aksrt_pay_down_number', true);
+        if (!is_array($mate) || empty($mate[$day]) || !is_array($mate[$day])) {
+            return 0;
+        }
+        return count($mate[$day]);
+    }
+}
+
+/**
+ * Record a free download for daily quota (zibll pay_down_number).
+ */
+if (!function_exists('aksrt_record_user_free_download')) {
+    function aksrt_record_user_free_download(int $user_id, int $post_id): void {
+        if ($user_id <= 0 || $post_id <= 0) {
+            return;
+        }
+        $day = current_time('Y-m-d');
+        $mate = get_user_meta($user_id, 'aksrt_pay_down_number', true);
+        if (!is_array($mate)) {
+            $mate = [];
+        }
+        // Drop old days to keep meta small.
+        foreach (array_keys($mate) as $k) {
+            if ($k !== $day) {
+                unset($mate[$k]);
+            }
+        }
+        if (!isset($mate[$day]) || !is_array($mate[$day])) {
+            $mate[$day] = [];
+        }
+        $mate[$day][(string) $post_id] = 1;
+        update_user_meta($user_id, 'aksrt_pay_down_number', $mate);
+    }
+}
+
+/**
+ * Whether a free download is allowed under daily quota.
+ * Paid downloads (cost > 0) always pass.
+ *
+ * @return true|WP_Error
+ */
+if (!function_exists('aksrt_check_free_download_quota')) {
+    function aksrt_check_free_download_quota(int $user_id, int $cost = 0) {
+        if ($cost > 0) {
+            return true;
+        }
+        if ($user_id <= 0) {
+            return true; // login gate handled elsewhere
+        }
+
+        $limit = aksrt_get_user_free_download_limit($user_id);
+        if ($limit <= 0) {
+            return true; // unlimited
+        }
+
+        $used = aksrt_get_user_free_downloaded_number($user_id);
+        if ($used >= $limit) {
+            return new WP_Error(
+                'aksrt_download_limit',
+                __('您今日下载免费资源个数已超限，请明日再下载。', 'aksrt'),
+                [
+                    'status' => 429,
+                    'limit'  => $limit,
+                    'used'   => $used,
+                ]
+            );
+        }
+
+        return true;
+    }
+}
+
+/**
+ * Remaining free downloads today (null = unlimited).
+ */
+if (!function_exists('aksrt_get_free_download_surplus')) {
+    function aksrt_get_free_download_surplus(int $user_id = 0): ?int {
+        if ($user_id <= 0) {
+            $user_id = get_current_user_id();
+        }
+        $limit = aksrt_get_user_free_download_limit($user_id);
+        if ($limit <= 0) {
+            return null;
+        }
+        $used = aksrt_get_user_free_downloaded_number($user_id);
+        return max(0, $limit - $used);
+    }
+}
+
+
 /**
  * 渲染 VIP 徽标 HTML
  *