feat(Percentage)!: Tax renamed Vat, Percent renamed Discount

README.md

@@ -127,24 +127,24 @@ $formats->get('decimal')->format(1000.1235); // 1 000,124
 $formats->get('currency')->format(1000.1235); // 1 000,12 Kč
 ```
 
-## Tax
+## Vat
 
 ```php
 use h4kuna\Format\Number;
 
-$tax = new Number\Tax(20);
-echo $tax->add(100); // 120
-echo $tax->deduct(120); // 100.0
+$tax = new Number\Vat(20);
+echo $tax->with(100); // 120
+echo $tax->without(120); // 100.0
 echo $tax->diff(120); // 20.0
 ```
 
-## Percent
+## Discount
 
 ```php
 use h4kuna\Format\Number;
 
-$percent = new Number\Percent(20);
-echo $percent->add(100); // 120.0
+$percent = new Number\Discount(20);
+echo $percent->with(100); // 120.0
 echo $percent->deduct(120); // 96.0
 echo $percent->diff(120); // 24.0
 ```

changelog.md

@@ -12,9 +12,9 @@ back compatibility with v5
 use h4kuna;
 class_alias(h4kuna\Format\Number\Formats::class, 'h4kuna\Number\Utils\Formats');
 class_alias(h4kuna\Format\Number\NumberFormat::class, 'h4kuna\Number\Format');
-class_alias(h4kuna\Format\Number\Percent::class, 'h4kuna\Number\Percent');
+class_alias(h4kuna\Format\Number\Discount::class, 'h4kuna\Number\Percent');
 class_alias(h4kuna\Format\Number\Round::class, 'h4kuna\Number\Utils\Round');
-class_alias(h4kuna\Format\Number\Tax::class, 'h4kuna\Number\Tax');
+class_alias(h4kuna\Format\Number\Vat::class, 'h4kuna\Number\Tax');
 class_alias(h4kuna\Format\Number\UnitValue::class, 'h4kuna\Number\Utils\UnitValue');
 
 // parameters

src/Number/Discount.php

@@ -0,0 +1,30 @@
+<?php declare(strict_types=1);
+
+namespace h4kuna\Format\Number;
+
+use h4kuna\Format\Utils;
+
+/**
+ * properties will become readonly
+ */
+final class Discount extends Percentage
+{
+
+	public function diff(float $number): float
+	{
+		return Utils\Percentage::diffDeduct($this->percentage, $number);
+	}
+
+
+	public function deduct(float $number): float
+	{
+		return Utils\Percentage::deduct($this->percentage, $number);
+	}
+
+
+	public function diffWith(float $number): float
+	{
+		return Utils\Percentage::diffWith($this->ratio, $number);
+	}
+
+}

src/Number/Percentage.php

@@ -0,0 +1,35 @@
+<?php declare(strict_types=1);
+
+namespace h4kuna\Format\Number;
+
+use h4kuna\Format\Utils;
+
+abstract class Percentage
+{
+	public float $ratio;
+
+	public float $smallRatio;
+
+
+	public function __construct(public float $percentage)
+	{
+		$this->smallRatio = Utils\Percentage::smallRatio($this->percentage);
+		$this->ratio = Utils\Percentage::ratio($this->smallRatio);
+	}
+
+
+	public function with(float $number): float
+	{
+		return Utils\Percentage::with($this->ratio, $number);
+	}
+
+
+	abstract public function diff(float $number): float;
+
+
+	public function __toString()
+	{
+		return (string) $this->percentage;
+	}
+
+}

src/Number/Vat.php

@@ -0,0 +1,24 @@
+<?php declare(strict_types=1);
+
+namespace h4kuna\Format\Number;
+
+use h4kuna\Format\Utils;
+
+/**
+ * properties will become readonly
+ */
+class Vat extends Percentage
+{
+
+	public function diff(float $number): float
+	{
+		return Utils\Percentage::diffWithout($this->ratio, $number);
+	}
+
+
+	public function without(float $number): float
+	{
+		return Utils\Percentage::without($this->ratio, $number);
+	}
+
+}

src/Utils/Percentage.php

@@ -0,0 +1,81 @@
+<?php declare(strict_types=1);
+
+namespace h4kuna\Format\Utils;
+
+/**
+ * Parameter $percentage is float represent percent, for example 17.5% -> 17.5
+ */
+final class Percentage
+{
+	/**
+	 * 17.5% -> 0.175
+	 */
+	public static function smallRatio(float $percentage): float
+	{
+		return $percentage / 100;
+	}
+
+
+	/**
+	 * 17.5% -> 1.175
+	 */
+	public static function ratio(float $smallRatio): float
+	{
+		return $smallRatio + 1.0;
+	}
+
+
+	/**
+	 * N + 17.5% -> N * 1.175
+	 */
+	public static function with(float $ratio, float $number): float
+	{
+		return $number * $ratio;
+	}
+
+
+	/**
+	 * N * 1.175 - N
+	 */
+	public static function diffWith(float $ratio, float $number): float
+	{
+		return self::with($ratio, $number) - $number;
+	}
+
+
+	/**
+	 * If you have price with percentage, and you need price without percentage.
+	 * N / 1.175
+	 */
+	public static function without(float $ratio, float $number): float
+	{
+		return $number / $ratio;
+	}
+
+
+	/**
+	 * N - (N / 1.175)
+	 */
+	public static function diffWithout(float $ratio, float $number): float
+	{
+		return $number - self::without($ratio, $number);
+	}
+
+
+	/**
+	 *  N - ((N * 17.5) / 100)
+	 */
+	public static function deduct(float $percentage, float $number): float
+	{
+		return $number - self::diffDeduct($percentage, $number);
+	}
+
+
+	/**
+	 * (N * 17.5) / 100
+	 */
+	public static function diffDeduct(float $percentage, float $number): float
+	{
+		return self::smallRatio($number * $percentage);
+	}
+}

tests/src/Number/DiscountTest.php

@@ -0,0 +1,32 @@
+<?php declare(strict_types=1);
+
+namespace h4kuna\Format\Tests\Number;
+
+use h4kuna\Format\Number\Discount;
+use h4kuna\Format\Tests\TestCase;
+use Tester\Assert;
+
+require __DIR__ . '/../../bootstrap.php';
+
+/**
+ * @testCase
+ */
+final class DiscountTest extends TestCase
+{
+
+	public function testDiscount(): void
+	{
+		$discount = new Discount(20);
+		Assert::same(120.0, $discount->with(100));
+		Assert::same(96.0, $discount->deduct(120));
+		Assert::same(24.0, $discount->diff(120));
+		Assert::same(20.0, $discount->diffWith(100));
+		Assert::same(20.0, $discount->percentage);
+		Assert::same(1.20, $discount->ratio);
+		Assert::same(0.20, $discount->smallRatio);
+		Assert::same('20', (string) $discount);
+	}
+
+}
+
+(new DiscountTest)->run();