Finish Builder

src/Builder.php

@@ -12,5 +12,44 @@ class Builder
 
     public function build()
     {
+        $prefix = "<?xml version='1.0' encoding='UTF-8'?><feed xmlns='http://www.w3.org/2005/Atom' xmlns:apps='http://schemas.google.com/apps/2006'>";
+        $suffix = '</feed>';
+
+        $xml = collect($this->filters)->map(function ($items) {
+            return $this->buildEntry($items);
+        })->implode('');
+
+        return $prefix . $xml . $suffix;
+    }
+
+    /**
+     * @param array $items
+     *
+     * @return string
+     */
+    private function buildEntry(array $items)
+    {
+        $entry = collect($items)->map(function ($value, $key) {
+            return $this->buildProperty($value, $key);
+        })->implode('');
+
+        return "<entry>{$entry}</entry>";
+    }
+
+    /**
+     * Build XML for a property.
+     *
+     * @param string $value
+     * @param string $key
+     *
+     * @return string
+     */
+    private function buildProperty($value, $key)
+    {
+        if ($key == 'from') {
+            $value = collect($value)->implode('|');
+        }
+
+        return "<apps:property name='{$key}' value='{$value}'/>";
     }
 }