<?php
/**
 * Copyright © 2016 Magento. All rights reserved.
 * See COPYING.txt for license details.
 */
namespace Magento\Framework\Data\Tree;

/**
 * Data DB tree
 *
 * Data model:
 * id  |  pid  |  level | order
 *
 * @author      Magento Core Team <core@magentocommerce.com>
 */
class Db extends \Magento\Framework\Data\Tree
{
    const ID_FIELD = 'id';

    const PARENT_FIELD = 'parent';

    const LEVEL_FIELD = 'level';

    const ORDER_FIELD = 'order';

    /**
     * DB connection
     *
     * @var \Magento\Framework\DB\Adapter\AdapterInterface
     */
    protected $_conn;

    /**
     * Data table name
     *
     * @var string
     */
    protected $_table;

    /**
     * SQL select object
     *
     * @var \Magento\Framework\DB\Select
     */
    protected $_select;

    /**
     * Tree structure field name: _idField
     *
     * @var string
     */
    protected $_idField;

    /**
     * Tree structure field name: _parentField
     *
     * @var string
     */
    protected $_parentField;

    /**
     * Tree structure field name: _levelField
     *
     * @var string
     */
    protected $_levelField;

    /**
     * Tree structure field name: _orderField
     *
     * @var string
     */
    protected $_orderField;

    /**
     * Db tree constructor
     *
     * $fields = array(
     *      \Magento\Framework\Data\Tree\Db::ID_FIELD       => string,
     *      \Magento\Framework\Data\Tree\Db::PARENT_FIELD   => string,
     *      \Magento\Framework\Data\Tree\Db::LEVEL_FIELD    => string
     *      \Magento\Framework\Data\Tree\Db::ORDER_FIELD    => string
     * )
     *
     * @param \Magento\Framework\DB\Adapter\AdapterInterface $connection
     * @param string $table
     * @param array $fields
     * @throws \Exception
     */
    public function __construct(\Magento\Framework\DB\Adapter\AdapterInterface $connection, $table, $fields)
    {
        parent::__construct();

        if (!$connection) {
            throw new \Exception('Wrong "$connection" parametr');
        }

        $this->_conn = $connection;
        $this->_table = $table;

        if (!isset(
            $fields[self::ID_FIELD]
        ) || !isset(
            $fields[self::PARENT_FIELD]
        ) || !isset(
            $fields[self::LEVEL_FIELD]
        ) || !isset(
            $fields[self::ORDER_FIELD]
        )
        ) {
            throw new \Exception('"$fields" tree configuratin array');
        }

        $this->_idField = $fields[self::ID_FIELD];
        $this->_parentField = $fields[self::PARENT_FIELD];
        $this->_levelField = $fields[self::LEVEL_FIELD];
        $this->_orderField = $fields[self::ORDER_FIELD];

        $this->_select = $this->_conn->select();
        $this->_select->from($this->_table, array_values($fields));
    }

    /**
     * @return \Magento\Framework\DB\Select
     */
    public function getDbSelect()
    {
        return $this->_select;
    }

    /**
     * @param \Magento\Framework\DB\Select $select
     * @return void
     */
    public function setDbSelect($select)
    {
        $this->_select = $select;
    }

    /**
     * Load tree
     *
     * @param   int|Node $parentNode
     * @param   int $recursionLevel recursion level
     * @return  $this
     * @throws \Exception
     */
    public function load($parentNode = null, $recursionLevel = 100)
    {
        if ($parentNode === null) {
            $this->_loadFullTree();
            return $this;
        } elseif ($parentNode instanceof Node) {
            $parentId = $parentNode->getId();
        } elseif (is_numeric($parentNode)) {
            $parentId = $parentNode;
            $parentNode = null;
        } else {
            throw new \Exception('root node id is not defined');
        }

        $select = clone $this->_select;
        $select->order($this->_table . '.' . $this->_orderField . ' ASC');
        $condition = $this->_conn->quoteInto("{$this->_table}.{$this->_parentField}=?", $parentId);
        $select->where($condition);
        $arrNodes = $this->_conn->fetchAll($select);
        foreach ($arrNodes as $nodeInfo) {
            $node = new Node($nodeInfo, $this->_idField, $this, $parentNode);
            $this->addNode($node, $parentNode);

            if ($recursionLevel) {
                $node->loadChildren($recursionLevel - 1);
            }
        }
        return $this;
    }

    /**
     * @param mixed $nodeId
     * @return Node
     */
    public function loadNode($nodeId)
    {
        $select = clone $this->_select;
        $condition = $this->_conn->quoteInto("{$this->_table}.{$this->_idField}=?", $nodeId);
        $select->where($condition);
        $node = new Node($this->_conn->fetchRow($select), $this->_idField, $this);
        $this->addNode($node);
        return $node;
    }

    /**
     * @param Node $data
     * @param Node $parentNode
     * @param Node $prevNode
     * @return Node
     */
    public function appendChild($data, $parentNode, $prevNode = null)
    {
        $orderSelect = $this->_conn->select();
        $orderSelect->from(
            $this->_table,
            new \Zend_Db_Expr('MAX(' . $this->_conn->quoteIdentifier($this->_orderField) . ')')
        )->where(
            $this->_conn->quoteIdentifier($this->_parentField) . '=' . $parentNode->getId()
        );

        $order = $this->_conn->fetchOne($orderSelect);
        $data[$this->_parentField] = $parentNode->getId();
        $data[$this->_levelField] = $parentNode->getData($this->_levelField) + 1;
        $data[$this->_orderField] = $order + 1;

        $this->_conn->insert($this->_table, $data);
        $data[$this->_idField] = $this->_conn->lastInsertId();

        return parent::appendChild($data, $parentNode, $prevNode);
    }

    /**
     * Move tree node
     *
     * @param Node $node
     * @param Node $parentNode
     * @param Node $prevNode
     * @return void
     * @throws \Exception
     */
    public function moveNodeTo($node, $parentNode, $prevNode = null)
    {
        $data = [];
        $data[$this->_parentField] = $parentNode->getId();
        $data[$this->_levelField] = $parentNode->getData($this->_levelField) + 1;
        // New node order
        if ($prevNode === null || $prevNode->getData($this->_orderField) === null) {
            $data[$this->_orderField] = 1;
        } else {
            $data[$this->_orderField] = $prevNode->getData($this->_orderField) + 1;
        }
        $condition = $this->_conn->quoteInto("{$this->_idField}=?", $node->getId());

        // For reorder new node branch
        $dataReorderNew = [
            $this->_orderField => new \Zend_Db_Expr($this->_conn->quoteIdentifier($this->_orderField) . '+1'),
        ];
        $conditionReorderNew = $this->_conn->quoteIdentifier(
            $this->_parentField
        ) . '=' . $parentNode->getId() . ' AND ' . $this->_conn->quoteIdentifier(
            $this->_orderField
        ) . '>=' . $data[$this->_orderField];

        // For reorder old node branch
        $dataReorderOld = [
            $this->_orderField => new \Zend_Db_Expr($this->_conn->quoteIdentifier($this->_orderField) . '-1'),
        ];
        $conditionReorderOld = $this->_conn->quoteIdentifier(
            $this->_parentField
        ) . '=' . $node->getData(
            $this->_parentField
        ) . ' AND ' . $this->_conn->quoteIdentifier(
            $this->_orderField
        ) . '>' . $node->getData(
            $this->_orderField
        );

        $this->_conn->beginTransaction();
        try {
            // Prepare new node branch
            $this->_conn->update($this->_table, $dataReorderNew, $conditionReorderNew);
            // Move node
            $this->_conn->update($this->_table, $data, $condition);
            // Update old node branch
            $this->_conn->update($this->_table, $dataReorderOld, $conditionReorderOld);
            $this->_updateChildLevels($node->getId(), $data[$this->_levelField]);
            $this->_conn->commit();
        } catch (\Exception $e) {
            $this->_conn->rollBack();
            throw new \Exception('Can\'t move tree node');
        }
    }

    /**
     * @param mixed $parentId
     * @param int $parentLevel
     * @return $this
     */
    protected function _updateChildLevels($parentId, $parentLevel)
    {
        $select = $this->_conn->select()->from(
            $this->_table,
            $this->_idField
        )->where(
            $this->_parentField . '=?',
            $parentId
        );
        $ids = $this->_conn->fetchCol($select);

        if (!empty($ids)) {
            $this->_conn->update(
                $this->_table,
                [$this->_levelField => $parentLevel + 1],
                $this->_conn->quoteInto($this->_idField . ' IN (?)', $ids)
            );
            foreach ($ids as $id) {
                $this->_updateChildLevels($id, $parentLevel + 1);
            }
        }
        return $this;
    }

    /**
     * @return $this
     */
    protected function _loadFullTree()
    {
        $select = clone $this->_select;
        $select->order($this->_table . '.' . $this->_levelField)->order($this->_table . '.' . $this->_orderField);

        $arrNodes = $this->_conn->fetchAll($select);

        foreach ($arrNodes as $nodeInfo) {
            $node = new Node($nodeInfo, $this->_idField, $this);
            $parentNode = $this->getNodeById($nodeInfo[$this->_parentField]);
            $this->addNode($node, $parentNode);
        }

        return $this;
    }

    /**
     * @param Node $node
     * @return $this
     * @throws \Exception
     */
    public function removeNode($node)
    {
        // For reorder old node branch
        $dataReorderOld = [
            $this->_orderField => new \Zend_Db_Expr($this->_conn->quoteIdentifier($this->_orderField) . '-1'),
        ];
        $conditionReorderOld = $this->_conn->quoteIdentifier(
            $this->_parentField
        ) . '=' . $node->getData(
            $this->_parentField
        ) . ' AND ' . $this->_conn->quoteIdentifier(
            $this->_orderField
        ) . '>' . $node->getData(
            $this->_orderField
        );

        $this->_conn->beginTransaction();
        try {
            $condition = $this->_conn->quoteInto("{$this->_idField}=?", $node->getId());
            $this->_conn->delete($this->_table, $condition);
            // Update old node branch
            $this->_conn->update($this->_table, $dataReorderOld, $conditionReorderOld);
            $this->_conn->commit();
        } catch (\Exception $e) {
            $this->_conn->rollBack();
            throw new \Exception('Can\'t remove tree node');
        }
        parent::removeNode($node);
        return $this;
    }
}