Add Plugin.php

Signed-off-by: Dylan Wu <i@dylanwu.space>

Plugin.php

@@ -0,0 +1,83 @@
+<?php
+/**
+ * 页面黑白显示插件（支持时间段、指定日期、每月/每年循环）
+ *
+ * @package GrayModePlugin
+ * @author Your
+ * @version 1.1.0
+ * @link https://your.site
+ */
+class GrayModePlugin implements Typecho_Plugin_Interface
+{
+    public static function activate()
+    {
+        Typecho_Plugin::factory('Widget_Archive')->header = [__CLASS__, 'changeheader'];
+    }
+
+    public static function deactivate() {}
+
+    public static function config(Typecho_Widget_Helper_Form $form)
+    {
+        $start = new Typecho_Widget_Helper_Form_Element_Text(
+            'startTime', NULL, '00:00', '开始时间', '格式如 08:00'
+        );
+        $end = new Typecho_Widget_Helper_Form_Element_Text(
+            'endTime', NULL, '23:59', '结束时间', '格式如 22:00'
+        );
+
+        $dates = new Typecho_Widget_Helper_Form_Element_Textarea(
+            'specialDates', NULL, '',
+            '灰白显示日期列表',
+            '支持多种格式：<br>
+             - 一次性：2025-09-18<br>
+             - 每年重复：04-04（每年4月4日）<br>
+             - 每月重复：-18（每月18日）<br>
+             多个值用英文逗号分隔，如：2025-09-18,04-04,-18'
+        );
+
+        $form->addInput($start);
+        $form->addInput($end);
+        $form->addInput($dates);
+    }
+
+    public static function personalConfig(Typecho_Widget_Helper_Form $form) {}
+
+    public static function changeheader()
+    {
+        $options = Typecho_Widget::widget('Widget_Options')->plugin('GrayModePlugin');
+
+        $start = $options->startTime;
+        $end = $options->endTime;
+        $dates = trim($options->specialDates);
+        $now = date('H:i');
+
+        // 判断是否在时间区间内
+        $inTimeRange = ($start <= $now && $now <= $end);
+
+        if (!$inTimeRange) return;
+
+        $today = date('Y-m-d');
+        $monthDay = date('m-d');
+        $dayOnly = date('d');
+
+        $dateList = array_filter(array_map('trim', explode(',', $dates)));
+
+        foreach ($dateList as $date) {
+            if (
+                $date === $today ||           // 一次性完整日期
+                $date === $monthDay ||        // 每年循环
+                $date === '-' . $dayOnly      // 每月循环
+            ) {
+                echo <<<EOT
+<style>
+html {
+    filter: grayscale(100%);
+    -webkit-filter: grayscale(100%);
+}
+</style>
+EOT;
+                break;
+            }
+        }
+    }
+}