Add SMS bulk delay configuration and validate coupon phone function

app/Services/SmsMessageAnalyzer.php

@@ -0,0 +1,65 @@
+<?php
+
+namespace App\Services;
+
+class SmsMessageAnalyzer
+{
+    private const GSM_SINGLE_LIMIT = 160;
+
+    private const GSM_MULTI_LIMIT = 153;
+
+    private const UCS2_SINGLE_LIMIT = 70;
+
+    private const UCS2_MULTI_LIMIT = 67;
+
+    public function characterCount(string $message): int
+    {
+        return mb_strlen($message);
+    }
+
+    public function isGsm7(string $message): bool
+    {
+        if ($message === '') {
+            return true;
+        }
+
+        return ! preg_match('/[^\x00-\x7F]/', $message);
+    }
+
+    public function estimatedParts(string $message): int
+    {
+        $length = $this->characterCount($message);
+
+        if ($length === 0) {
+            return 0;
+        }
+
+        if ($this->isGsm7($message)) {
+            if ($length <= self::GSM_SINGLE_LIMIT) {
+                return 1;
+            }
+
+            return (int) ceil($length / self::GSM_MULTI_LIMIT);
+        }
+
+        if ($length <= self::UCS2_SINGLE_LIMIT) {
+            return 1;
+        }
+
+        return (int) ceil($length / self::UCS2_MULTI_LIMIT);
+    }
+
+    public function summary(string $message): string
+    {
+        $characters = $this->characterCount($message);
+        $parts = $this->estimatedParts($message);
+
+        if ($parts === 0) {
+            return '0 characters';
+        }
+
+        $partLabel = $parts === 1 ? '1 SMS' : "{$parts} SMS";
+
+        return "{$characters} characters · {$partLabel}";
+    }
+}