From dd5b45ae9648f8142aaab7d5b295552de6d646aa Mon Sep 17 00:00:00 2001
From: Jens Scherbl <jens@scherbl.com>
Date: Fri, 9 Aug 2024 11:29:23 +0200
Subject: [PATCH] Adds `Number` class as thin wrapper for `BCMath`

---
 composer.json  |   1 +
 src/Number.php | 144 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 145 insertions(+)
 create mode 100644 src/Number.php

diff --git a/composer.json b/composer.json
index 5a83d4a..d3a2902 100644
--- a/composer.json
+++ b/composer.json
@@ -47,6 +47,7 @@
     "require":
     {
         "php":        "^8.3",
+        "ext-bcmath": "*",
         "brick/math": "^0.12"
     },
     "require-dev":
diff --git a/src/Number.php b/src/Number.php
new file mode 100644
index 0000000..1db84e9
--- /dev/null
+++ b/src/Number.php
@@ -0,0 +1,144 @@
+<?php declare(strict_types=1);
+
+namespace Kensho\Chart;
+
+use InvalidArgumentException;
+use Stringable;
+use function bcadd;
+use function bccomp;
+use function bcdiv;
+use function bcmul;
+use function bcsub;
+use function floatval;
+use function number_format;
+use function preg_match;
+use function strval;
+
+/**
+ * Keeps numbers as strings internally for
+ * arbitrary precision calculations. Just a
+ * thin wrapper for BCMath.
+ */
+final readonly class Number implements Stringable
+{
+    private const int SCALE = 16;
+
+    private string $value;
+
+    public function __construct(string|int $value)
+    {
+        $this->value = $this->parse(value: $value);
+    }
+
+    private function parse(self|string|int $value): string
+    {
+        if ($value instanceof self) {
+            return $value->__toString();
+        } else {
+            $parsed = strval(value: $value);
+
+            if (!preg_match(
+                pattern: '/^[+-]?[0-9]*(\.[0-9]*)?$/',
+                subject: $parsed
+            )) {
+                throw new InvalidArgumentException(
+                    message: 'Invalid number.'
+                );
+            }
+            return $parsed;
+        }
+    }
+
+    public function __toString(): string
+    {
+        return $this->value;
+    }
+
+    public function plus(self|string|int $value): self
+    {
+        $value  = $this->parse(value: $value);
+        $result = bcadd(num1: $this->value, num2: $value, scale: self::SCALE);
+
+        return new self(value: $result);
+    }
+
+    public function minus(self|string|int $value): self
+    {
+        $value  = $this->parse(value: $value);
+        $result = bcsub(num1: $this->value, num2: $value, scale: self::SCALE);
+
+        return new self(value: $result);
+    }
+
+    public function multipliedBy(self|string|int $value): self
+    {
+        $value  = $this->parse(value: $value);
+        $result = bcmul(num1: $this->value, num2: $value, scale: self::SCALE);
+
+        return new self(value: $result);
+    }
+
+    public function dividedBy(self|string|int $value): self
+    {
+        $value  = $this->parse(value: $value);
+        $result = bcdiv(num1: $this->value, num2: $value, scale: self::SCALE);
+
+        return new self(value: $result);
+    }
+
+    public function abs(): self
+    {
+        $isNegative = $this->isNegative();
+
+        if ($isNegative) {
+            $result = bcmul(num1: $this->value, num2: '-1', scale: self::SCALE);
+
+            return new self(value: $result);
+        }
+        return $this;
+    }
+
+    public function isZero(): bool
+    {
+        $result = bccomp(num1: $this->value, num2: '0', scale: self::SCALE);
+
+        return $result === 0;
+    }
+
+    public function isPositive(): bool
+    {
+        $result = bccomp(num1: $this->value, num2: '0', scale: self::SCALE);
+
+        return $result === 1;
+    }
+
+    public function isNegative(): bool
+    {
+        $result = bccomp(num1: $this->value, num2: '0', scale: self::SCALE);
+
+        return $result === -1;
+    }
+
+    public function isGreaterThan(self|string|int $value): bool
+    {
+        $value  = $this->parse(value: $value);
+        $result = bccomp(num1: $this->value, num2: $value, scale: self::SCALE);
+
+        return $result === 1;
+    }
+
+    public function isLessThan(self|string|int $value): bool
+    {
+        $value  = $this->parse(value: $value);
+        $result = bccomp(num1: $this->value, num2: $value, scale: self::SCALE);
+
+        return $result === -1;
+    }
+
+    public function round(int $scale): string
+    {
+        $number = floatval(value: $this->value);
+
+        return number_format(num: $number, decimals: $scale, thousands_separator: '');
+    }
+}