From db83565c54a2b97ad9cf3e83314775193876be43 Mon Sep 17 00:00:00 2001
From: Li Zhineng <im@zhineng.li>
Date: Mon, 12 May 2025 19:27:10 +0800
Subject: determine if clean energy

---
 src/RegistrationNumber.php | 38 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

(limited to 'src/RegistrationNumber.php')

diff --git a/src/RegistrationNumber.php b/src/RegistrationNumber.php
index 6e729e3..3f6edcc 100644
--- a/src/RegistrationNumber.php
+++ b/src/RegistrationNumber.php
@@ -134,10 +134,23 @@ final readonly class RegistrationNumber
         'F', 'G', 'H', 'J', 'K',
     ];
 
+    /**
+     * @var string[]
+     */
+    private const array BATTERY_ELECTRIC_LETTERS = [
+        'D', 'A', 'B', 'C', 'E',
+    ];
+
+    public string $region;
+
+    public string $authority;
+
+    public string $sequence;
+
     private function __construct(
         public string $registrationNumber
     ) {
-        //
+        $this->parse($registrationNumber);
     }
 
     public static function make(string $registrationNumber): static
@@ -250,4 +263,27 @@ final readonly class RegistrationNumber
             'The registration number "%s" is invalid.', $registrationNumber
         ));
     }
+
+    private function parse(string $registrationNumber): void
+    {
+        $this->region = mb_substr($registrationNumber, 0, 1);
+        $this->authority = mb_substr($registrationNumber, 1, 1);
+        $this->sequence = mb_substr($registrationNumber, 2);
+    }
+
+    public function isCleanEnergy(): bool
+    {
+        return strlen($this->sequence) === 6;
+    }
+
+    public function isBatteryElectric(): bool
+    {
+        if (! $this->isCleanEnergy()) {
+            return false;
+        }
+
+        $code = mb_substr($this->sequence, 0, 1);
+
+        return in_array($code, self::BATTERY_ELECTRIC_LETTERS);
+    }
 }
-- 
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