Implementação da lógica de conversão de moeda e roteamento de API.

src/CurrencyConverter.php

@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App;
+
+class CurrencyConverter
+{
+    private const CURRENCY_SYMBOLS = [
+        'BRL' => 'R$',
+        'USD' => '$',
+        'EUR' => '€',
+    ];
+
+    public function convert(
+        float $amount,
+        string $from,
+        string $to,
+        float $rate
+    ): array {
+        $validFrom = isset(self::CURRENCY_SYMBOLS[$from]);
+        $validTo = isset(self::CURRENCY_SYMBOLS[$to]);
+
+        if (!$validFrom || !$validTo) {
+            throw new \InvalidArgumentException(
+                'Invalid source or destination currency'
+            );
+        }
+
+        if ($rate <= 0 || $amount < 0) {
+            throw new \InvalidArgumentException('Invalid rate or amount');
+        }
+
+        $convertedAmount = $amount * $rate;
+
+        return [
+            'valorConvertido' => round($convertedAmount, 2),
+            'simboloMoeda' => self::CURRENCY_SYMBOLS[$to],
+        ];
+    }
+}

src/index.php

@@ -1,18 +1,36 @@
 <?php
-/**
- * Back-end Challenge.
- *
- * PHP version 7.4
- *
- * Este será o arquivo chamado na execução dos testes automátizados.
- *
- * @category Challenge
- * @package  Back-end
- * @author   Seu Nome <seu-email@seu-provedor.com>
- * @license  http://opensource.org/licenses/MIT MIT
- * @link     https://github.com/apiki/back-end-challenge
- */
+
 declare(strict_types=1);
 
 require __DIR__ . '/../vendor/autoload.php';
 
+use App\CurrencyConverter;
+
+header('Content-Type: application/json');
+
+$requestUri = $_SERVER['REQUEST_URI'];
+$path = (string) parse_url($requestUri, PHP_URL_PATH);
+
+$pattern = '/^\/exchange\/([0-9.]+)\/([A-Z]{3})\/([A-Z]{3})\/([0-9.]+)$/';
+if (preg_match($pattern, $path, $matches)) {
+    $amount = (float) $matches[1];
+    $from = $matches[2];
+    $to = $matches[3];
+    $rate = (float) $matches[4];
+
+    try {
+        $converter = new CurrencyConverter();
+        $result = $converter->convert($amount, $from, $to, $rate);
+        echo json_encode($result);
+        http_response_code(200);
+    } catch (\InvalidArgumentException $e) {
+        http_response_code(400);
+        echo json_encode(['error' => $e->getMessage()]);
+    } catch (\Throwable $e) {
+        http_response_code(500);
+        echo json_encode(['error' => 'Internal Server Error']);
+    }
+} else {
+    http_response_code(400);
+    echo json_encode(['error' => 'Invalid URL or missing parameters']);
+}