<?php

namespace Bitrix\Main\DB;

use Bitrix\Main\ArgumentException;
use Bitrix\Main\ORM\Fields\ScalarField;

/**
 * Class OracleConnection
 *
 * Class for Oracle database connections.
 * @package Bitrix\Main\DB
 */
class OracleConnection extends Connection
{
	private $transaction = OCI_COMMIT_ON_SUCCESS;
	protected $lastInsertedId;

	/**********************************************************
	 * SqlHelper
	 **********************************************************/

	protected function createSqlHelper()
	{
		return new OracleSqlHelper($this);
	}

	/***********************************************************
	 * Connection and disconnection
	 ***********************************************************/

	/**
	 * Establishes a connection to the database.
	 * Includes php_interface/after_connect_d7.php on success.
	 * Throws exception on failure.
	 *
	 * @return void
	 * @throws ConnectionException
	 */
	protected function connectInternal()
	{
		if ($this->isConnected)
		{
			return;
		}

		if ($this->isPersistent())
		{
			$connection = oci_pconnect($this->login, $this->password, $this->database);
		}
		else
		{
			$connection = oci_new_connect($this->login, $this->password, $this->database);
		}

		if (!$connection)
		{
			throw new ConnectionException('Oracle connect error', $this->getErrorMessage());
		}

		$this->isConnected = true;
		$this->resource = $connection;

		$this->afterConnected();
	}

	/**
	 * Disconnects from the database.
	 * Does nothing if there was no connection established.
	 *
	 * @return void
	 */
	protected function disconnectInternal()
	{
		if (!$this->isConnected)
		{
			return;
		}

		$this->isConnected = false;
		oci_close($this->resource);
	}

	/*********************************************************
	 * Query
	 *********************************************************/

	/**
	 * @inheritDoc
	 */
	protected function queryInternal($sql, array $binds = null, \Bitrix\Main\Diag\SqlTrackerQuery $trackerQuery = null)
	{
		$this->connectInternal();

		$trackerQuery?->startQuery($sql, $binds);

		$result = oci_parse($this->resource, $sql);

		if (!$result)
		{
			$trackerQuery?->finishQuery();

			throw new SqlQueryException("", $this->getErrorMessage($this->resource), $sql);
		}

		$executionMode = $this->transaction;

		/** @var \OCI_Lob[] $clob */
		$clob = [];

		if (!empty($binds))
		{
			$executionMode = OCI_DEFAULT;
			foreach ($binds as $key => $val)
			{
				$clob[$key] = oci_new_descriptor($this->resource);
				oci_bind_by_name($result, ":" . $key, $clob[$key], -1, OCI_B_CLOB);
			}
		}

		if (!oci_execute($result, $executionMode))
		{
			$trackerQuery?->finishQuery();

			throw new SqlQueryException("", $this->getErrorMessage($result), $sql);
		}

		if (!empty($binds))
		{
			if (oci_num_rows($result) > 0)
			{
				foreach ($binds as $key => $val)
				{
					if ($clob[$key])
					{
						$clob[$key]->save($val);
					}
				}
			}

			if ($this->transaction == OCI_COMMIT_ON_SUCCESS)
			{
				oci_commit($this->resource);
			}

			foreach ($binds as $key => $val)
			{
				if ($clob[$key])
				{
					$clob[$key]->free();
				}
			}
		}

		$trackerQuery?->finishQuery();

		$this->lastQueryResult = $result;

		return $result;
	}

	/**
	 * @inheritDoc
	 */
	protected function createResult($result, \Bitrix\Main\Diag\SqlTrackerQuery $trackerQuery = null)
	{
		return new OracleResult($result, $this, $trackerQuery);
	}

	/**
	 * @inheritDoc
	 */
	public function query($sql)
	{
		[$sql, $binds, $offset, $limit] = self::parseQueryFunctionArgs(func_get_args());

		if (!empty($binds))
		{
			$binds1 = $binds2 = "";
			foreach ($binds as $key => $value)
			{
				if ($value <> '')
				{
					if ($binds1 != "")
					{
						$binds1 .= ",";
						$binds2 .= ",";
					}

					$binds1 .= $key;
					$binds2 .= ":" . $key;
				}
			}

			if ($binds1 != "")
			{
				$sql .= " RETURNING " . $binds1 . " INTO " . $binds2;
			}
		}

		return parent::query($sql, $binds, $offset, $limit);
	}

	/**
	 * @inheritDoc
	 */
	public function add($tableName, array $data, $identity = "ID")
	{
		if ($identity !== null && !isset($data[$identity]))
		{
			$data[$identity] = $this->getNextId("sq_" . $tableName);
		}

		$insert = $this->getSqlHelper()->prepareInsert($tableName, $data);

		$binds = $insert[2];

		$sql =
			"INSERT INTO " . $tableName . "(" . $insert[0] . ") " .
			"VALUES (" . $insert[1] . ")";

		$this->queryExecute($sql, $binds);

		$this->lastInsertedId = $data[$identity];

		return $data[$identity];
	}

	/**
	 * Gets next value from the database sequence.
	 * <p>
	 * Sequence name may contain only A-Z,a-z,0-9 and _ characters.
	 *
	 * @param string $name Name of the sequence.
	 *
	 * @return null|string
	 * @throws \Bitrix\Main\ArgumentNullException
	 */
	public function getNextId($name = "")
	{
		$name = preg_replace("/[^A-Za-z0-9_]+/i", "", $name);
		$name = trim($name);

		if ($name == '')
		{
			throw new \Bitrix\Main\ArgumentNullException("name");
		}

		$sql = "SELECT " . $this->getSqlHelper()->quote($name) . ".NEXTVAL FROM DUAL";

		$result = $this->query($sql);
		if ($row = $result->fetch())
		{
			return array_shift($row);
		}

		return null;
	}

	/**
	 * @inheritDoc
	 */
	public function getInsertedId()
	{
		return $this->lastInsertedId;
	}

	/**
	 * @inheritDoc
	 */
	public function getAffectedRowsCount()
	{
		return oci_num_rows($this->lastQueryResult);
	}

	/**
	 * @inheritDoc
	 */
	public function isTableExists($tableName)
	{
		if (empty($tableName))
		{
			return false;
		}

		$result = $this->queryScalar("
			SELECT COUNT(TABLE_NAME)
			FROM USER_TABLES
			WHERE TABLE_NAME LIKE UPPER('" . $this->getSqlHelper()->forSql($tableName) . "')
		");
		return ($result > 0);
	}

	/**
	 * @inheritDoc
	 */
	public function isIndexExists($tableName, array $columns)
	{
		return $this->getIndexName($tableName, $columns) !== null;
	}

	/**
	 * @inheritDoc
	 */
	public function getIndexName($tableName, array $columns, $strict = false)
	{
		if (empty($columns))
		{
			return null;
		}

		$isFunc = false;
		$indexes = [];

		$result = $this->query("SELECT * FROM USER_IND_COLUMNS WHERE TABLE_NAME = upper('" . $this->getSqlHelper()->forSql($tableName) . "')");
		while ($ar = $result->fetch())
		{
			$indexes[$ar["INDEX_NAME"]][$ar["COLUMN_POSITION"] - 1] = $ar["COLUMN_NAME"];
			if (strncmp($ar["COLUMN_NAME"], "SYS_NC", 6) === 0)
			{
				$isFunc = true;
			}
		}

		if ($isFunc)
		{
			$result = $this->query("SELECT * FROM USER_IND_EXPRESSIONS WHERE TABLE_NAME = upper('" . $this->getSqlHelper()->forSql($tableName) . "')");
			while ($ar = $result->fetch())
			{
				$indexes[$ar["INDEX_NAME"]][$ar["COLUMN_POSITION"] - 1] = $ar["COLUMN_EXPRESSION"];
			}
		}

		return static::findIndex($indexes, $columns, $strict);
	}

	/**
	 * @inheritDoc
	 */
	public function getTableFields($tableName)
	{
		if (!isset($this->tableColumnsCache[$tableName]))
		{
			$this->connectInternal();

			$query = $this->queryInternal("SELECT * FROM " . $this->getSqlHelper()->quote($tableName) . " WHERE ROWNUM = 0");

			$result = $this->createResult($query);

			$this->tableColumnsCache[$tableName] = $result->getFields();
		}
		return $this->tableColumnsCache[$tableName];
	}

	/**
	 * @inheritDoc
	 */
	public function createTable($tableName, $fields, $primary = [], $autoincrement = [])
	{
		$sql = 'CREATE TABLE ' . $this->getSqlHelper()->quote($tableName) . ' (';
		$sqlFields = [];

		foreach ($fields as $columnName => $field)
		{
			if (!($field instanceof ScalarField))
			{
				throw new ArgumentException(sprintf(
					'Field `%s` should be an Entity\ScalarField instance', $columnName
				));
			}

			$realColumnName = $field->getColumnName();

			$sqlFields[] = $this->getSqlHelper()->quote($realColumnName)
				. ' ' . $this->getSqlHelper()->getColumnTypeByField($field)
				. ' ' . (in_array($columnName, $primary, true) ? 'NOT NULL' : 'NULL');
		}

		$sql .= join(', ', $sqlFields);

		if (!empty($primary))
		{
			foreach ($primary as &$primaryColumn)
			{
				$realColumnName = $fields[$primaryColumn]->getColumnName();
				$primaryColumn = $this->getSqlHelper()->quote($realColumnName);
			}

			$sql .= ', PRIMARY KEY(' . join(', ', $primary) . ')';
		}

		$sql .= ')';

		$this->query($sql);

		// autoincrement field
		if (!empty($autoincrement))
		{
			foreach ($autoincrement as $autoincrementColumn)
			{
				$autoincrementColumn = $fields[$autoincrementColumn]->getColumnName();

				if ($autoincrementColumn == 'ID')
				{
					// old-school hack
					$aiName = $tableName;
				}
				else
				{
					$aiName = $tableName . '_' . $autoincrementColumn;
				}

				$this->query('CREATE SEQUENCE ' . $this->getSqlHelper()->quote('sq_' . $aiName));

				$this->query('CREATE OR REPLACE TRIGGER ' . $this->getSqlHelper()->quote($aiName . '_insert') . '
						BEFORE INSERT
						ON ' . $this->getSqlHelper()->quote($tableName) . '
						FOR EACH ROW
							BEGIN
							IF :NEW.' . $this->getSqlHelper()->quote($autoincrementColumn) . ' IS NULL THEN
								SELECT ' . $this->getSqlHelper()->quote('sq_' . $aiName) . '.NEXTVAL
									INTO :NEW.' . $this->getSqlHelper()->quote($autoincrementColumn) . ' FROM dual;
							END IF;
						END;'
				);
			}
		}
	}

	/**
	 * @inheritDoc
	 */
	public function renameTable($currentName, $newName)
	{
		$this->query('RENAME ' . $this->getSqlHelper()->quote($currentName) . ' TO ' . $this->getSqlHelper()->quote($newName));

		// handle auto increment: rename primary sequence for ID
		// properly we should check PRIMARY fields instead of ID: $aiName = $currentName.'_'.$fieldName, see createTable
		$aiName = $currentName;

		if ($this->queryScalar("SELECT 1 FROM user_sequences WHERE sequence_name=upper('" . $this->getSqlHelper()->forSql('sq_' . $aiName) . "')"))
		{
			// for fields excpet for ID here should be $newName.'_'.$fieldName, see createTable
			$newAiName = $newName;

			// rename sequence
			$this->query('RENAME ' . $this->getSqlHelper()->quote('sq_' . $aiName) . ' TO ' . $this->getSqlHelper()->quote('sq_' . $newAiName));

			// recreate trigger
			$this->query('DROP TRIGGER ' . $this->getSqlHelper()->quote($aiName . '_insert'));

			$this->query('CREATE OR REPLACE TRIGGER ' . $this->getSqlHelper()->quote($newAiName . '_insert') . '
						BEFORE INSERT
						ON ' . $this->getSqlHelper()->quote($newName) . '
						FOR EACH ROW
							BEGIN
							IF :NEW.' . $this->getSqlHelper()->quote('ID') . ' IS NULL THEN
								SELECT ' . $this->getSqlHelper()->quote('sq_' . $newAiName) . '.NEXTVAL
									INTO :NEW.' . $this->getSqlHelper()->quote('ID') . ' FROM dual;
							END IF;
						END;'
			);
		}
	}

	/**
	 * @inheritDoc
	 */
	public function dropTable($tableName)
	{
		$this->query('DROP TABLE ' . $this->getSqlHelper()->quote($tableName) . ' CASCADE CONSTRAINTS');

		// handle auto increment: delete primary sequence for ID
		// properly we should check PRIMARY fields instead of ID: $aiName = $currentName.'_'.$fieldName, see createTable
		$aiName = $tableName;

		if ($this->queryScalar("SELECT 1 FROM user_sequences WHERE sequence_name=upper('" . $this->getSqlHelper()->forSql('sq_' . $aiName) . "')"))
		{
			$this->query('DROP SEQUENCE ' . $this->getSqlHelper()->quote('sq_' . $aiName));
		}
	}

	/*********************************************************
	 * Transaction
	 *********************************************************/

	/**
	 * @inheritDoc
	 */
	public function startTransaction()
	{
		$this->transaction = OCI_DEFAULT;
	}

	/**
	 * @inheritDoc
	 */
	public function commitTransaction()
	{
		$this->connectInternal();
		OCICommit($this->resource);
		$this->transaction = OCI_COMMIT_ON_SUCCESS;
	}

	/**
	 * @inheritDoc
	 */
	public function rollbackTransaction()
	{
		$this->connectInternal();
		OCIRollback($this->resource);
		$this->transaction = OCI_COMMIT_ON_SUCCESS;
	}

	/*********************************************************
	 * Type, version, cache, etc.
	 *********************************************************/

	/**
	 * Returns database type.
	 * <ul>
	 * <li> oracle
	 * </ul>
	 *
	 * @return string
	 * @see Connection::getType
	 */
	public function getType()
	{
		return "oracle";
	}

	/**
	 * @inheritDoc
	 */
	public function getVersion()
	{
		if ($this->version == null)
		{
			$version = $this->queryScalar('SELECT BANNER FROM v$version');
			if ($version != null)
			{
				$version = trim($version);
				$this->versionExpress = (mb_strpos($version, "Express Edition") > 0);
				preg_match("#[0-9]+\\.[0-9]+\\.[0-9]+#", $version, $arr);
				$this->version = $arr[0];
			}
		}

		return [$this->version, $this->versionExpress];
	}

	/**
	 * @inheritDoc
	 */
	public function getErrorMessage($resource = null)
	{
		if ($resource)
		{
			$error = oci_error($resource);
		}
		else
		{
			$error = oci_error();
		}

		if (!$error)
		{
			return "";
		}

		$result = sprintf("[%s] %s", $error["code"], $error["message"]);
		if (!empty($error["sqltext"]))
		{
			$result .= sprintf(" (%s)", $error["sqltext"]);
		}

		return $result;
	}
}