feat: implement global autoresponder plugin

exec/lib/RepeatState.php

@@ -0,0 +1,48 @@
+<?php
+declare(strict_types=1);
+
+final class RepeatState
+{
+    public function __construct(private string $baseDir = Settings::STATE_DIR, private ?int $now = null)
+    {
+    }
+
+    public function shouldSend(string $owner, string $ruleId, string $recipient, string $sender, int $repeatMinutes): bool
+    {
+        if ($repeatMinutes <= 0) {
+            return true;
+        }
+        $path = $this->path($owner, $ruleId, $recipient, $sender);
+        if (!is_file($path)) {
+            return true;
+        }
+        $data = json_decode((string)file_get_contents($path), true);
+        $last = is_array($data) ? (int)($data['last_sent_at'] ?? 0) : 0;
+        return ($this->time() - $last) >= ($repeatMinutes * 60);
+    }
+
+    public function record(string $owner, string $ruleId, string $recipient, string $sender): void
+    {
+        $path = $this->path($owner, $ruleId, $recipient, $sender);
+        $dir = dirname($path);
+        if (!is_dir($dir)) {
+            mkdir($dir, 0700, true);
+        }
+        file_put_contents($path, json_encode(['last_sent_at' => $this->time()], JSON_PRETTY_PRINT), LOCK_EX);
+        @chmod($path, 0600);
+    }
+
+    private function path(string $owner, string $ruleId, string $recipient, string $sender): string
+    {
+        if (!preg_match('/^[A-Za-z0-9._-]+$/', $owner)) {
+            throw new InvalidArgumentException('Invalid owner');
+        }
+        $hash = hash('sha256', implode('|', [$owner, $ruleId, strtolower($recipient), strtolower($sender)]));
+        return rtrim($this->baseDir, '/') . '/replies/' . $owner . '/' . $hash . '.json';
+    }
+
+    private function time(): int
+    {
+        return $this->now ?? time();
+    }
+}