Feat: Adds multi currency support (#88)

app/Models/Currency.php

@@ -0,0 +1,100 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Support\Collection;
+use Illuminate\Support\Number;
+
+class Currency extends Model
+{
+    protected $hidden = [];
+
+    protected $primaryKey = 'currency';
+
+    protected $keyType = 'string';
+
+    /**
+     * The attributes that are mass assignable.
+     *
+     * @var array
+     */
+    protected $fillable = [
+        'currency',
+        'label',
+    ];
+
+    /**
+     * Get the attributes that should be cast.
+     *
+     * @return array<string, string>
+     */
+    protected function casts(): array
+    {
+        return [
+            'created_at' => 'datetime',
+            'updated_at' => 'datetime',
+        ];
+    }
+
+    public static function forHumans(int|float $number, ?string $currency = null, ?string $locale = null): string
+    {
+        $symbol = Number::currencySymbol($currency, $locale);
+
+        return $symbol.Number::forHumans($number);
+    }
+
+    /**
+     * Returns a list of supported currencies
+     *
+     * @param  bool|null  $withAliases  Whether to include aliases in list of currencies
+     */
+    public static function list(?bool $withAliases = true): Collection
+    {
+        $aliases = $withAliases ? collect(config('investbrain.currency_aliases'))->map(function ($value, $currency) {
+            return [
+                'currency' => $currency,
+                'label' => $value['label'],
+            ];
+        })->values() : collect();
+
+        return $aliases->merge(self::get()->map->only(['currency', 'label']));
+    }
+
+    /**
+     * Converts between supported currencies
+     *
+     * @param  string|null  $to  (defaults to base currency)
+     */
+    public static function convert(?float $value, string $from, ?string $to = null, mixed $date = null): float
+    {
+        if (empty($value)) {
+            return 0;
+        }
+
+        // Assume converting to base
+        if (empty($to)) {
+            $to = config('investbrain.base_currency');
+        }
+
+        // Get rate
+        [$from, $to] = [
+            cache()->remember($from.'_rate_'.$date, 10, function () use ($from, $date) {
+                return CurrencyRate::historic($from, $date);
+            }),
+            cache()->remember($to.'_rate_'.$date, 10, function () use ($to, $date) {
+                return CurrencyRate::historic($to, $date);
+            }),
+        ];
+
+        // get from rate
+        $rate_to_base = 1 / $from;
+
+        // get value in base currency
+        $base_currency_value = $value * $rate_to_base;
+
+        return (float) $base_currency_value * $to;
+    }
+}