Extended Key Space support by implementing COPY command (#866)

* Added support for COPY command

* Revert getCLient signature changes, used createClient instead

Co-authored-by: Vladyslav Vildanov <vladyslavvildanov@Vladyslav-Vildanov-MacBook-Pro.local>

src/ClientContextInterface.php

@@ -18,6 +18,7 @@ use Predis\Command\CommandInterface;
 /**
  * Interface defining a client-side context such as a pipeline or transaction.
  *
+ * @method $this copy(string $source, string $destination, int $db = -1, bool $replace = false)
  * @method $this del(array|string $keys)
  * @method $this dump($key)
  * @method $this exists($key)

src/ClientInterface.php

@@ -27,6 +27,7 @@ use Predis\Response\Status;
  * and more friendly interface to ease programming which is described in the
  * following list of methods:
  *
+ * @method int               copy(string $source, string $destination, int $db = -1, bool $replace = false)
  * @method int               del(string[]|string $keyOrKeys, string ...$keys = null)
  * @method string|null       dump(string $key)
  * @method int               exists(string $key)

src/Command/Redis/COPY.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace Predis\Command\Redis;
+use Predis\Command\Command as RedisCommand;
+use Predis\Command\Traits\DB;
+use Predis\Command\Traits\Replace;
+
+/**
+ * @link https://redis.io/commands/copy/
+ *
+ * This command copies the value stored at the source key to the destination key.
+ */
+class COPY extends RedisCommand
+{
+    use DB {
+        DB::setArguments as setDB;
+    }
+    use Replace {
+        Replace::setArguments as setReplace;
+    }
+
+    protected static $dbArgumentPositionOffset = 2;
+
+    public function getId()
+    {
+        return 'COPY';
+    }
+
+    public function setArguments(array $arguments)
+    {
+        $this->setDB($arguments);
+        $arguments = $this->getArguments();
+
+        $this->setReplace($arguments);
+    }
+}

src/Command/Traits/DB.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace Predis\Command\Traits;
+
+use UnexpectedValueException;
+
+trait DB
+{
+    private $dbModifier = 'DB';
+
+    public function setArguments(array $arguments)
+    {
+        $argumentsLength = count($arguments);
+
+        if (static::$dbArgumentPositionOffset >= $argumentsLength) {
+            parent::setArguments($arguments);
+            return;
+        }
+
+        if (!is_numeric($arguments[static::$dbArgumentPositionOffset])) {
+            throw new UnexpectedValueException('DB argument should be a valid numeric value');
+        }
+
+        if ($arguments[static::$dbArgumentPositionOffset] < 0) {
+            array_splice($arguments, static::$dbArgumentPositionOffset, 1);
+            parent::setArguments($arguments);
+            return;
+        }
+
+        $argument = $arguments[static::$dbArgumentPositionOffset];
+        $argumentsBefore = array_slice($arguments, 0, static::$dbArgumentPositionOffset);
+        $argumentsAfter = array_slice($arguments, static::$dbArgumentPositionOffset + 1);
+
+        parent::setArguments(array_merge(
+            $argumentsBefore,
+            [$this->dbModifier],
+            [$argument],
+            $argumentsAfter
+        ));
+    }
+}

src/Command/Traits/Replace.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace Predis\Command\Traits;
+
+use Predis\Command\Command;
+
+/**
+ * @mixin Command
+ */
+trait Replace
+{
+    public function setArguments(array $arguments)
+    {
+        $replace = array_pop($arguments);
+
+        if (is_bool($replace) && $replace) {
+            $arguments[] = 'REPLACE';
+        } else if (!is_bool($replace)) {
+            $arguments[] = $replace;
+        }
+
+        parent::setArguments($arguments);
+    }
+}