Nested check function

gistfile1.php

	public function diagnosticTree()
	{

		$errors = array();
		$this->_lock();
		


		// Test 0
		$sql = ' SELECT MIN(`left_key`) '
					.' FROM `#__wsshoppingcart_categories` '
					.' LIMIT 1 ';
		$this->_db->setQuery($sql);
		$result = $this->_db->loadResult();

		if ($result != 1)
		{
			$errors[0] = 'Minimal left_key is not 1!';
		}
		
		
		// Test 1
		$sql = ' SELECT `id`,`left_key`,`right_key`, `level` '
					.' FROM `#__wsshoppingcart_categories` '
					.' WHERE `left_key` >=`right_key` ';
		$this->_db->setQuery($sql);
		$result = $this->_db->loadObjectList();
		if ($result)
		{
			$errors[1] = $result;
		}
		
		// Test 2
		$sql = ' SELECT `id`, MOD((`right_key` - `left_key`) / 2)  AS `summ` '
					.' FROM `#__wsshoppingcart_categories` '
					.' WHERE `summ` = "0" ';
		$this->_db->setQuery($sql);
		$result = $this->_db->loadObjectList();
		if ($result)
		{
			$errors[2] = $result;
		}

		// Test 3
		$sql = ' SELECT `id`, MOD((`left_key` - `level` + 2) / 2)  AS `summ` '
					.' FROM `#__wsshoppingcart_categories` '
					.' WHERE `summ` = "1" ';
		$this->_db->setQuery($sql);
		$result = $this->_db->loadObjectList();
		if ($result)
		{
			$errors[3] = $result;
		}
		
			
		
		// Test 4
		$sql = ' SELECT `t1`.`id`, COUNT(`t1`.`id`) AS `rep`, MAX(`t3`.`right_key`) AS `max_right` '
					.' FROM `#__wsshoppingcart_categories` AS `t1`, `#__wsshoppingcart_categories` AS `t2`, `#__wsshoppingcart_categories` AS `t3` '
					.' WHERE `t1`.`left_key` <> `t2`.`left_key` AND  `t1`.`left_key` <> `t2`.`right_key` AND `t1`.`right_key` <> `t2`.`left_key` AND `t1`.`right_key` <> `t2`.`right_key` '
					.' GROUP BY `t1`.`id` '
					.' HAVING `max_right` <> SQRT(4 * `rep` + 1) + 1 ';
		$this->_db->setQuery($sql);
		$result = $this->_db->loadObjectList();
		if ($result)
		{
			$errors[4] = $result;
		}





		// Test 5
		$sql = ' SELECT * '
					.' FROM `#__wsshoppingcart_categories` '
					.' ORDER BY `left_key` '
					.' LIMIT 1 '
					;
		$this->_db->setQuery($sql);
		$result = $this->_db->loadObject();
		if (!$result || $result->level != 0)
		{
			$errors[5] = 'Invalid level for the top item!';
		}

		// Tests 6 - 14
		$sql = ' SELECT * '
					.' FROM `#__wsshoppingcart_categories` '
					.' ORDER BY `left_key` '
					;
		$this->_db->setQuery($sql);
		$result = $this->_db->loadAssocList();

		$a = array();
		$path = array();
		$count = count($result);
		for($i=0; $i<$count; $i++)
		{
			$f = $result[$i];
			if ($i && !count($path))
			{
				$errors[6] = "Out of top level node at id=".$f['id']." ";
				break;
			}

			if ($f['left_key'] >= $f['right_key'])
			{
				$errors[7] = "left_key [".$f['left_key']."] >= right_key [".$f['right_key']."] in ID: ".$f['id']."";
				break;
			}

			if (($f['right_key'] - $f['left_key']) % 2 != 1)
			{
				$errors[8] = "not a valid number of children for left_key [".$f['left_key']."] and right_key [".$f['right_key']."] ";
				break;
			}


			if (!empty($a[$f['left_key']]))
			{
				$errors[9] = "Repeatable left_key [".$f['left_key']."] ";
				break;
			}
		
		
			$a[$f['left_key']] = true;


			if (!empty($a[$f['right_key']]))
			{
				$errors[10] = "Repeatable right_key [".$f['right_key']."] ";
				break;
			}

			$cntpath = count($path);
			if ($f['level'] != $cntpath)
			{
				$errors[11] = "Level is invalid at id=".$f['id'].". ".$cntpath." expected.";
				break;
			}
		
		
			if ($i && !$f['level'])
			{
				$errors[12] = "Zero level at id=".$f['id']." ";
				break;
			}


			if (!$i)
			{
				$path[] = $f;
			}
			else
			{
				$c = count($path) - 1;
				if ($f['right_key'] > $f['left_key'] + 1 && $path[$c]['left_key'] < $f['left_key'] && $path[$c]['right_key'] > $f['right_key'])
				{
					$path[] = $f;
				}
				else
				{
					$right_key = $f['right_key'];
					while(count($path) && $path[$c]['right_key'] == $right_key + 1)
					{
						array_pop($path);
						$c--;
						$right_key++;
					}
				}
			}
			$a[$f['right_key']] = true;
		}

		$sql = ' SELECT * '
					.' FROM `#__wsshoppingcart_categories` '
					.' ORDER BY `left_key` '
					.' LIMIT 1 '
					;
		$this->_db->setQuery($sql);
		$result = $this->_db->loadObject();
		
		for($i = $result->left_key; $i <= $result->right_key; $i++)
		{
			if (empty($a[$i]))
			{
				$errors[13] = "Number missing [".$i."] ";
				break;
			}
		}
		
		if (count($a) != $result->right_key - $result->left_key + 1)
		{
			$errors[14] = "Invalid number of items";
		}
  
		$this->_unlock();
		return $errors;	
	}