ability to insert before and after

Author: parisholley

.gitignore

@@ -0,0 +1,3 @@
+composer.lock
+vendor
+.idea/

src/PHPHtmlParser/Dom/InnerNode.php

@@ -104,7 +104,7 @@ public function countChildren()
      * @return bool
      * @throws CircularException
      */
-    public function addChild(AbstractNode $child)
+    public function addChild(AbstractNode $child, $before = null)
     {
         $key = null;
 
@@ -118,22 +118,51 @@ public function addChild(AbstractNode $child)
             throw new CircularException('Can not set itself as a child.');
         }
 
+		$next = null;
+
         if ($this->hasChildren()) {
-            if (isset($this->children[$child->id()])) {
-                // we already have this child
-                return false;
-            }
-            $sibling                      = $this->lastChild();
-            $key                          = $sibling->id();
-            $this->children[$key]['next'] = $child->id();
+			if (isset($this->children[$child->id()])) {
+				// we already have this child
+				return false;
+			}
+
+			if ($before) {
+				if (!isset($this->children[$before])) {
+					return false;
+				}
+
+				$key = $this->children[$before]['prev'];
+
+				if($key){
+					$this->children[$key]['next'] = $child->id();
+				}
+
+				$this->children[$before]['prev'] = $child->id();
+				$next = $before;
+			} else {
+				$sibling = $this->lastChild();
+				$key = $sibling->id();
+
+				$this->children[$key]['next'] = $child->id();
+			}
         }
 
-        // add the child
-        $this->children[$child->id()] = [
-            'node' => $child,
-            'next' => null,
-            'prev' => $key,
-        ];
+		$keys = array_keys($this->children);
+
+		$insert = [
+			'node' => $child,
+			'next' => $next,
+			'prev' => $key,
+		];
+
+		$index = $key ? (array_search($key, $keys, true) + 1) : 0;
+		array_splice($keys, $index, 0, $child->id());
+
+		$children = array_values($this->children);
+		array_splice($children, $index, 0, [$insert]);
+
+		// add the child
+		$this->children = array_combine($keys, $children);
 
         // tell child I am the new parent
         $child->setParent($this);
@@ -144,6 +173,36 @@ public function addChild(AbstractNode $child)
         return true;
     }
 
+	/**
+	 * Insert element before child with provided id
+	 *
+	 * @param AbstractNode $child
+	 * @return bool
+	 * @param int $id
+	 */
+	public function insertBefore(AbstractNode $child, $id){
+		$this->addChild($child, $id);
+	}
+
+	/**
+	 * Insert element before after with provided id
+	 *
+	 * @param AbstractNode $child
+	 * @return bool
+	 * @param int $id
+	 */
+	public function insertAfter(AbstractNode $child, $id){
+		if (!isset($this->children[$id])) {
+			return false;
+		}
+
+		if ($this->children[$id]['next']) {
+			return $this->addChild($child, $this->children[$id]['next']);
+		}
+
+		return $this->addChild($child);
+	}
+
     /**
      * Removes the child by id.
      *

tests/Node/ParentTest.php

@@ -137,6 +137,78 @@ public function testLastChild()
         $this->assertEquals($child3->id(), $parent->lastChild()->id());
     }
 
+	public function testInsertBeforeFirst()
+	{
+		$parent = new Node;
+		$child  = new Node;
+		$child2 = new Node;
+		$child3 = new Node;
+		$parent->addChild($child2);
+		$parent->addChild($child3);
+
+		$parent->insertBefore($child, $child2->id());
+
+		$this->assertTrue($parent->isChild($child->id()));
+		$this->assertEquals($parent->firstChild()->id(), $child->id());
+		$this->assertEquals($child->nextSibling()->id(), $child2->id());
+		$this->assertEquals($child2->nextSibling()->id(), $child3->id());
+		$this->assertEquals($parent->lastChild()->id(), $child3->id());
+	}
+
+	public function testInsertBeforeLast()
+	{
+		$parent = new Node;
+		$child  = new Node;
+		$child2 = new Node;
+		$child3 = new Node;
+		$parent->addChild($child);
+		$parent->addChild($child3);
+
+		$parent->insertBefore($child2, $child3->id());
+
+		$this->assertTrue($parent->isChild($child2->id()));
+		$this->assertEquals($parent->firstChild()->id(), $child->id());
+		$this->assertEquals($child->nextSibling()->id(), $child2->id());
+		$this->assertEquals($child2->nextSibling()->id(), $child3->id());
+		$this->assertEquals($parent->lastChild()->id(), $child3->id());
+	}
+
+	public function testInsertAfterFirst()
+	{
+		$parent = new Node;
+		$child  = new Node;
+		$child2 = new Node;
+		$child3 = new Node;
+		$parent->addChild($child);
+		$parent->addChild($child3);
+
+		$parent->insertAfter($child2, $child->id());
+
+		$this->assertTrue($parent->isChild($child2->id()));
+		$this->assertEquals($parent->firstChild()->id(), $child->id());
+		$this->assertEquals($child->nextSibling()->id(), $child2->id());
+		$this->assertEquals($child2->nextSibling()->id(), $child3->id());
+		$this->assertEquals($parent->lastChild()->id(), $child3->id());
+	}
+
+	public function testInsertAfterLast()
+	{
+		$parent = new Node;
+		$child  = new Node;
+		$child2 = new Node;
+		$child3 = new Node;
+		$parent->addChild($child);
+		$parent->addChild($child2);
+
+		$parent->insertAfter($child3, $child2->id());
+
+		$this->assertTrue($parent->isChild($child2->id()));
+		$this->assertEquals($parent->firstChild()->id(), $child->id());
+		$this->assertEquals($child->nextSibling()->id(), $child2->id());
+		$this->assertEquals($child2->nextSibling()->id(), $child3->id());
+		$this->assertEquals($parent->lastChild()->id(), $child3->id());
+	}
+
     public function testReplaceChild()
     {
         $parent = new Node;