codes.txt

app/Services/CouponCodePool.php

@@ -0,0 +1,77 @@
+<?php
+
+namespace App\Services;
+
+use App\Models\Coupon;
+
+class CouponCodePool
+{
+    /** @var list<string>|null */
+    private ?array $allCodesCache = null;
+
+    public function __construct(
+        private ?string $codesPath = null,
+    ) {}
+
+    /**
+     * @return list<string>
+     */
+    public function allCodes(): array
+    {
+        if ($this->allCodesCache !== null) {
+            return $this->allCodesCache;
+        }
+
+        $path = $this->codesPath ?? resource_path('codes/codes.txt');
+
+        if (! is_readable($path)) {
+            throw new \RuntimeException("Coupon codes file is not readable: {$path}");
+        }
+
+        $lines = file($path, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
+
+        if ($lines === false) {
+            throw new \RuntimeException("Unable to read coupon codes file: {$path}");
+        }
+
+        $codes = array_values(array_filter(array_map(trim(...), $lines)));
+
+        if ($codes === []) {
+            throw new \RuntimeException("Coupon codes file is empty: {$path}");
+        }
+
+        return $this->allCodesCache = $codes;
+    }
+
+    /**
+     * @return list<string>
+     */
+    public function usedCodes(): array
+    {
+        return Coupon::query()->pluck('code')->all();
+    }
+
+    /**
+     * @return list<string>
+     */
+    public function availableCodes(): array
+    {
+        return array_values(array_diff($this->allCodes(), $this->usedCodes()));
+    }
+
+    public function hasAvailable(): bool
+    {
+        return $this->availableCodes() !== [];
+    }
+
+    public function pickRandom(): ?string
+    {
+        $available = $this->availableCodes();
+
+        if ($available === []) {
+            return null;
+        }
+
+        return $available[array_rand($available)];
+    }
+}