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<?php

/**
 * MvcCore
 *
 * This source file is subject to the BSD 3 License
 * For the full copyright and license information, please view
 * the LICENSE.md file that are distributed with this source code.
 *
 * @copyright   Copyright (c) 2016 Tom Flidr (https://github.com/mvccore)
 * @license  https://mvccore.github.io/docs/mvccore/5.0.0/LICENCE.md
 */

namespace MvcCore\Ext\Models\Db\Providers\Connections;

class       PgSql 
extends     \MvcCore\Ext\Models\Db\Connection
implements  \MvcCore\Ext\Models\Db\Model\IConstants,
            \MvcCore\Ext\Models\Db\Models\PgSqls\IConstants {
    
    /**
     * `TRUE` for SQL `READ WRITE` or `READ ONLY` start transaction property support.
     * @var bool|NULL
     */
    protected $transReadWriteSupport = NULL;

    /**
     * `TRUE` for SQL `REPEATABLE READ` or `READ UNCOMMITTED` start transaction property support.
     * @var bool|NULL
     */
    protected $transAllIsolationsSupport = NULL;
    
    /**
     * `TRUE` for SQL `[NOT] DEFERRABLE` start transaction property support.
     * @var bool|NULL
     */
    protected $transDeferrableSupport = NULL;

    /**
     * @inheritDocs
     * @param string $identifierName
     * @return string
     */
    public function QuoteName ($identifierName) {
        return '"'.$identifierName.'"';
    }
    
    /**
     * @inheritDocs
     * @param int $flags Transaction isolation, read/write mode and consistent snapshot option.
     * @param string $name String without spaces to identify transaction in logs.
     * @throws \PDOException|\RuntimeException
     * @return bool
     */
    public function BeginTransaction ($flags = 0, $name = NULL) {
        if ($flags === 0) $flags = self::TRANS_READ_WRITE;

        $readWrite = NULL;
        if (($flags & self::TRANS_READ_WRITE) > 0) {
            $readWrite = TRUE;
        } else if (($flags & self::TRANS_READ_ONLY) > 0) {
            $readWrite = FALSE;
        }

        if ($this->inTransaction) {
            $cfg = $this->GetConfig();
            unset($cfg['password']);
            $toolClass = \MvcCore\Application::GetInstance()->GetToolClass();
            throw new \RuntimeException(
                'Connection has opened transaction already ('.($toolClass::EncodeJson($cfg)).').'
            );
        }

        $sqlItems = [];

        $isolationLevel = '';
        $readWrite = '';
        $deferrable = '';
        
        if ($this->transReadWriteSupport) {
            if ($readWrite === TRUE) {
                $readWrite = ' READ WRITE';
            } else if ($readWrite === FALSE) {
                $readWrite = ' READ ONLY';
            }
        }

        if (
            $this->transAllIsolationsSupport && 
            ($flags & self::TRANS_ISOLATION_REPEATABLE_READ) > 0
        ) {
            $isolationLevel = ' ISOLATION LEVEL REPEATABLE READ';
        } else if (
            ($flags & self::TRANS_ISOLATION_READ_COMMITTED) > 0
        ) {
            $isolationLevel = ' ISOLATION LEVEL READ COMMITTED';
        } else if (
            $this->transAllIsolationsSupport && 
            ($flags & self::TRANS_ISOLATION_READ_UNCOMMITTED) > 0
        ) {
            $isolationLevel = ' ISOLATION LEVEL READ UNCOMMITTED';
        } else if (
            ($flags & self::TRANS_ISOLATION_SERIALIZABLE) > 0
        ) {
            $isolationLevel = ' ISOLATION LEVEL SERIALIZABLE';
        }

        if ($this->transDeferrableSupport) {
            if (($flags & self::TRANS_DEFERRABLE) > 0) {
                $deferrable = ' DEFERRABLE';
            } else if (($flags & self::TRANS_NOT_DEFERRABLE) > 0) {
                $deferrable = ' NOT DEFERRABLE';
            }
        }

        if ($name !== NULL) {
            $toolClass = \MvcCore\Application::GetInstance()->GetToolClass();
            $this->transactionName = $toolClass::GetUnderscoredFromPascalCase($name);
            $sqlItems[] = "/* trans_start:{$this->transactionName} */";
        }
        
        $sqlItems[] = "START TRANSACTION{$isolationLevel}{$readWrite}{$deferrable};";
        
        
        $this->provider->exec(implode("\n", $sqlItems));

        $this->inTransaction = TRUE;

        return TRUE;
    }

    /**
     * @inheritDocs
     * @param int $flags Transaction chaininig.
     * @throws \PDOException
     * @return bool
     */
    public function Commit ($flags = 0) {
        if (!$this->inTransaction) return FALSE;
        $sqlItems = [];

        if ($this->transactionName !== NULL) 
            $sqlItems[] = "/* trans_commit:{$this->transactionName} */";

        $sqlItems[] = "COMMIT;";
        
        $this->provider->exec(implode("\n", $sqlItems));
        
        $this->inTransaction  = FALSE;
        $this->transactionName = NULL;

        return TRUE;
    }

    /**
     * Rolls back a transaction.
     * @param int $flags Transaction chaininig.
     * @throws \PDOException
     * @return bool
     */
    public function RollBack ($flags = NULL) {
        if (!$this->inTransaction) return FALSE;
        $sqlItems = [];

        if ($this->transactionName !== NULL) 
            $sqlItems[] = "/* trans_rollback:{$this->transactionName} */";

        $sqlItems[] = "ROLLBACK;";

        $this->provider->exec(implode("\n", $sqlItems));
        
        $this->inTransaction  = FALSE;
        $this->transactionName = NULL;
        
        return TRUE;
    }



    /**
     * @inheritDocs
     * @see https://stackoverflow.com/questions/7942154/mysql-error-2006-mysql-server-has-gone-away
     * @param \Throwable $e 
     * @return bool
     */
    protected function isConnectionLost (\Throwable $e) {
        return FALSE;
    }

    /**
     * Set up connection specific properties depends on this driver.
     * @return void
     */
    protected function setUpConnectionSpecifics () {
        parent::setUpConnectionSpecifics();
        
        $this->transReadWriteSupport = (
            version_compare($this->version, '7.4', '>=')
        );
        $this->transAllIsolationsSupport = (
            version_compare($this->version, '8.0', '>=')
        );
        $this->transDeferrableSupport = (
            version_compare($this->version, '9.1', '>=')
        );
    }
}