Add option addFieldFilter([]) to the QueryBuilder

Signed-off-by: davidarendsen <davidarendsen@hey.com>

src/Exception/FunctionInvalidInputException.php

@@ -0,0 +1,9 @@
+<?php
+
+namespace Arendsen\FluxQueryBuilder\Exception;
+
+use Exception;
+
+class FunctionInvalidInputException extends Exception
+{
+}

src/Functions/Filter.php

@@ -2,22 +2,49 @@
 
 namespace Arendsen\FluxQueryBuilder\Functions;
 
+use Arendsen\FluxQueryBuilder\Exception\FunctionInvalidInputException;
 use Arendsen\FluxQueryBuilder\Expression\KeyValue;
 
 class Filter extends Base
 {
     /**
-     * @var KeyValue $keyValue
+     * @var mixed $filter
      */
-    private $keyValue;
+    private $filter;
 
-    public function __construct(KeyValue $keyValue)
+    public function __construct($filter)
     {
-        $this->keyValue = $keyValue;
+        $this->filter = $filter;
     }
 
     public function __toString()
     {
-        return '|> filter(fn: (r) => ' . $this->keyValue . ') ';
+        return '|> filter(fn: (r) => ' . $this->format() . ') ';
+    }
+
+    /**
+     * @throws FunctionInvalidInputException
+     */
+    protected function format(): string
+    {
+        if ($this->filter instanceof KeyValue) {
+            return $this->filter->__toString();
+        } elseif (is_array($this->filter)) {
+            $filterCounter = 0;
+            $filterString = '';
+            foreach ($this->filter as $filter) {
+                if ($filterCounter > 0) {
+                    $filterString .= ' or ';
+                }
+
+                $filterString .= 'r._field == "' . $filter . '"';
+
+                $filterCounter++;
+            }
+
+            return $filterString;
+        }
+
+        throw new FunctionInvalidInputException('Filter input is incorrect.');
     }
 }

src/QueryBuilder.php

@@ -91,6 +91,15 @@ class QueryBuilder
         return $this;
     }
 
+    public function addFieldFilter(array $fields): QueryBuilder
+    {
+        $this->addToQueryArray(
+            self::FLUX_PART_FILTERS,
+            new Filter($fields)
+        );
+        return $this;
+    }
+
     public function addRange(DateTime $start, ?DateTime $stop = null): QueryBuilder
     {
         $this->addRequiredData(self::REQUIRED_INPUT_RANGE, [$start, $stop]);