feat: add expression normalizer

src/Normalizer.php

@@ -0,0 +1,86 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the PHP-CRON-EXPR package.
+ *
+ * (c) Jitendra Adhikari <jiten.adhikary@gmail.com>
+ *     <https://github.com/adhocore>
+ *
+ * Licensed under MIT license.
+ */
+
+namespace Ahc\Cron;
+
+class Normalizer
+{
+    const YEARLY      = '@yearly';
+    const ANNUALLY    = '@annually';
+    const MONTHLY     = '@monthly';
+    const WEEKLY      = '@weekly';
+    const DAILY       = '@daily';
+    const HOURLY      = '@hourly';
+    const ALWAYS      = '@always';
+    const FIVE_MIN    = '@5minutes';
+    const TEN_MIN     = '@10minutes';
+    const FIFTEEN_MIN = '@15minutes';
+    const THIRTY_MIN  = '@30minutes';
+
+    protected static $expressions = [
+        self::YEARLY      => '0 0 1 1 *',
+        self::ANNUALLY    => '0 0 1 1 *',
+        self::MONTHLY     => '0 0 1 * *',
+        self::WEEKLY      => '0 0 * * 0',
+        self::DAILY       => '0 0 * * *',
+        self::HOURLY      => '0 * * * *',
+        self::ALWAYS      => '* * * * *',
+        self::FIVE_MIN    => '*/5 * * * *',
+        self::TEN_MIN     => '*/10 * * * *',
+        self::FIFTEEN_MIN => '*/15 * * * *',
+        self::THIRTY_MIN  => '0,30 * * * *',
+    ];
+
+    protected static $literals = [
+        'sun' => 0,
+        'mon' => 1,
+        'tue' => 2,
+        'wed' => 3,
+        'thu' => 4,
+        'fri' => 5,
+        'sat' => 6,
+
+        'jan' => 1,
+        'feb' => 2,
+        'mar' => 3,
+        'apr' => 4,
+        'may' => 5,
+        'jun' => 6,
+        'jul' => 7,
+        'aug' => 8,
+        'sep' => 9,
+        'oct' => 10,
+        'nov' => 11,
+        'dec' => 12,
+    ];
+
+    public function normalizeExpr(string $expr): string
+    {
+        $expr = \trim($expr);
+
+        if (isset(static::$expressions[$expr])) {
+            return static::$expressions[$expr];
+        }
+
+        $expr  = \preg_replace('~\s+~', ' ', $expr);
+        $count = \substr_count($expr, ' ');
+
+        if ($count < 4 || $count > 5) {
+            throw new \UnexpectedValueException(
+                'Cron $expr should have 5 or 6 segments delimited by space'
+            );
+        }
+
+        return \str_ireplace(\array_keys(static::$literals), \array_values(static::$literals), $expr);
+    }
+}