future-public: add set leverage request

src/Requests/ChangeLeverageRequestContract.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Msr\LaravelBitunixApi\Requests;
+
+use Psr\Http\Message\ResponseInterface;
+
+interface ChangeLeverageRequestContract
+{
+    /**
+     * Change leverage for a trading pair
+     *
+     * @param string $symbol Trading pair (e.g., 'BTCUSDT')
+     * @param string $marginCoin Margin coin (e.g., 'USDT')
+     * @param int $leverage Leverage value
+     * @return ResponseInterface
+     */
+    public function changeLeverage(string $symbol, string $marginCoin, int $leverage): ResponseInterface;
+}
+

src/Requests/Header.php

@@ -4,47 +4,126 @@ namespace Msr\LaravelBitunixApi\Requests;
 
 class Header
 {
-    public static function sortQueryParameters(array $parameters): ?array
+    /**
+     * Sort query parameters in ascending ASCII order by Key
+     * 
+     * @param array $parameters
+     * @return array
+     */
+    public static function sortQueryParameters(array $parameters): array
     {
-        $sortableParameters = $parameters;
-
-        if (!count($sortableParameters)) {
+        if (empty($parameters)) {
             return [];
         }
 
-        ksort($sortableParameters, SORT_LOCALE_STRING);
-        return $sortableParameters;
+        ksort($parameters, SORT_STRING);
+        return $parameters;
     }
 
-    public static function digestQueryParameters(array $parameters): ?string
+    /**
+     * Convert sorted parameters to string format
+     * Example: ["id" => "1", "uid" => "200"] becomes "id1uid200"
+     * 
+     * @param array $parameters
+     * @return string
+     */
+    public static function digestQueryParameters(array $parameters): string
     {
-        if (!count($parameters)) {
-            return null;
+        if (empty($parameters)) {
+            return '';
         }
 
         $sortedParameters = self::sortQueryParameters($parameters);
-        return implode('', array_map(
-            fn($k, $v) => $k . $v,
-            array_keys($sortedParameters),
-            array_values($sortedParameters)
-        ));
+        $result = '';
+        
+        foreach ($sortedParameters as $key => $value) {
+            $result .= $key . $value;
+        }
+        
+        return $result;
     }
 
-    public static function generateNonce(): ?string
+    /**
+     * Generate a random 32-bit nonce string
+     * 
+     * @return string
+     */
+    public static function generateNonce(): string
     {
-        return md5(uniqid(mt_rand(), true));
+        return bin2hex(random_bytes(16)); // 32 characters
     }
 
-    public static function generateSignValue(array $queryParams = [], string $body = '', string $randomNonce = ''): string
+    /**
+     * Generate current timestamp in milliseconds
+     * 
+     * @return string
+     */
+    public static function generateTimestamp(): string
+    {
+        return (string) round(microtime(true) * 1000);
+    }
+
+    /**
+     * Generate signature according to Bitunix API documentation
+     * 
+     * Steps:
+     * 1. Sort all queryParams in ascending ASCII order by Key
+     * 2. Remove all spaces from body string
+     * 3. Create digest: SHA256(nonce + timestamp + api-key + queryParams + body)
+     * 4. Create sign: SHA256(digest + secretKey)
+     * 
+     * @param array $queryParams
+     * @param string $body
+     * @param string $nonce
+     * @param string $timestamp
+     * @return string
+     */
+    public static function generateSignValue(array $queryParams = [], string $body = '', string $nonce = '', string $timestamp = ''): string
     {
         $apiKey = config('bitunix-api.api_key');
         $apiSecret = config('bitunix-api.api_secret');
-        $timeStamp = (string)round(microtime(true) * 1000);
-        $digestedQueryParam = self::digestQueryParameters($queryParams);
+        
+        if (empty($apiKey) || empty($apiSecret)) {
+            throw new \InvalidArgumentException('API key and secret must be configured');
+        }
 
-        $digestedHeader = $randomNonce . $timeStamp . $apiKey . $digestedQueryParam . $body;
-        $hash = hash('sha256', $digestedHeader);
-        $sign = $hash . $apiSecret;
-        return hash('sha256', $sign);
+        // Step 1: Sort query parameters in ascending ASCII order
+        $queryParamsString = self::digestQueryParameters($queryParams);
+        
+        // Step 2: Remove all spaces from body (already done if JSON encoded properly)
+        $bodyString = trim($body);
+        
+        // Step 3: Create digest: SHA256(nonce + timestamp + api-key + queryParams + body)
+        $digestInput = $nonce . $timestamp . $apiKey . $queryParamsString . $bodyString;
+        $digest = hash('sha256', $digestInput);
+        
+        // Step 4: Create sign: SHA256(digest + secretKey)
+        $signInput = $digest . $apiSecret;
+        $sign = hash('sha256', $signInput);
+        
+        return $sign;
+    }
+
+    /**
+     * Generate complete headers for authenticated requests
+     * 
+     * @param array $queryParams
+     * @param string $body
+     * @return array
+     */
+    public static function generateHeaders(array $queryParams = [], string $body = ''): array
+    {
+        $nonce = self::generateNonce();
+        $timestamp = self::generateTimestamp();
+        $sign = self::generateSignValue($queryParams, $body, $nonce, $timestamp);
+        
+        return [
+            'api-key' => config('bitunix-api.api_key'),
+            'sign' => $sign,
+            'nonce' => $nonce,
+            'timestamp' => $timestamp,
+            'language' => config('bitunix-api.language', 'en-US'),
+            'Content-Type' => 'application/json',
+        ];
     }
 }