<?php
/**
 * Data Dictionary for DB2.
 *
 * This file is part of ADOdb, a Database Abstraction Layer library for PHP.
 *
 * @package ADOdb
 * @link https://adodb.org Project's web site and documentation
 * @link https://github.com/ADOdb/ADOdb Source code and issue tracker
 *
 * The ADOdb Library is dual-licensed, released under both the BSD 3-Clause
 * and the GNU Lesser General Public Licence (LGPL) v2.1 or, at your option,
 * any later version. This means you can use it in proprietary products.
 * See the LICENSE.md file distributed with this source code for details.
 * @license BSD-3-Clause
 * @license LGPL-2.1-or-later
 *
 * @copyright 2000-2013 John Lim
 * @copyright 2014 Damien Regad, Mark Newnham and the ADOdb community
 */

// security - hide paths
if (!defined('ADODB_DIR')) die();

class ADODB2_db2 extends ADODB_DataDict {

	var $databaseType = 'db2';
	var $seqField = false;
	var $dropCol = 'ALTER TABLE %s DROP COLUMN %s';

	public $blobAllowsDefaultValue = true;
	public $blobAllowsNotNull      = true;

	
 	function ActualType($meta)
	{
		$meta = strtoupper($meta);
		
		/*
		* Add support for custom meta types. We do this
		* first, that allows us to override existing types
		*/
		if (isset($this->connection->customMetaTypes[$meta]))
			return $this->connection->customMetaTypes[$meta]['actual'];
		
		switch($meta) {
		case 'C': return 'VARCHAR';
		case 'XL': return 'CLOB';
		case 'X': return 'VARCHAR(3600)';

		case 'C2': return 'VARCHAR'; // up to 32K
		case 'X2': return 'VARCHAR(3600)'; // up to 32000, but default page size too small

		case 'B': return 'BLOB';

		case 'D': return 'DATE';
		case 'TS':
		case 'T': return 'TIMESTAMP';

		case 'L': return 'SMALLINT';
		case 'I': return 'INTEGER';
		case 'I1': return 'SMALLINT';
		case 'I2': return 'SMALLINT';
		case 'I4': return 'INTEGER';
		case 'I8': return 'BIGINT';

		case 'F': return 'DOUBLE';
		case 'N': return 'DECIMAL';
		default:
			return $meta;
		}
	}

	// return string must begin with space
	function _createSuffix($fname, &$ftype, $fnotnull, $fdefault, $fautoinc, $fconstraint, $funsigned, $fprimary, &$pkey)
	{
		$suffix = '';
		if ($fautoinc) return ' GENERATED ALWAYS AS IDENTITY'; # as identity start with
		if (strlen($fdefault)) $suffix .= " DEFAULT $fdefault";
		if ($fnotnull) $suffix .= ' NOT NULL';
		if ($fconstraint) $suffix .= ' '.$fconstraint;
		return $suffix;
	}

	function alterColumnSQL($tabname, $flds, $tableflds='',$tableoptions='')
	{
		$tabname = $this->TableName ($tabname);
		$sql = array();
		list($lines,$pkey,$idxs) = $this->_GenFields($flds);
		// genfields can return FALSE at times
		if ($lines == null) $lines = array();
		$alter = 'ALTER TABLE ' . $tabname . $this->alterCol . ' ';

		$dataTypeWords = array('SET','DATA','TYPE');
		
		foreach($lines as $v) 
		{
			/*
			 * We must now post-process the line to insert the 'SET DATA TYPE'
			 * text into the alter statement
			 */
			$e = explode(' ',$v);
			
			array_splice($e,1,0,$dataTypeWords);
			
			$v = implode(' ',$e);
			
			$sql[] = $alter . $v;
		}
		if (is_array($idxs)) 
		{
			foreach($idxs as $idx => $idxdef) {
				$sql_idxs = $this->CreateIndexSql($idx, $tabname, $idxdef['cols'], $idxdef['opts']);
				$sql = array_merge($sql, $sql_idxs);
			}

		}
		return $sql;
	}


	
	function dropColumnSql($tabname, $flds, $tableflds='',$tableoptions='')
	{
		
		
		$metaTables = $this->metaTables('T','',$tabname);
		if ( $metaTables === false ) {
			return false;
		}
		$tabname = $metaTables[0];
		//$tabname = $this->connection->getMetaCasedValue($tabname);
		//$flds    = $this->connection->getMetaCasedValue($flds);
		
		if (ADODB_ASSOC_CASE  == ADODB_ASSOC_CASE_NATIVE )
		{
			/*
			 * METACASE_NATIVE
			 */
			$tabname = $this->connection->nameQuote . $tabname . $this->connection->nameQuote;
			$flds    = $this->connection->nameQuote . $flds . $this->connection->nameQuote;
		}
		$sql = sprintf($this->dropCol, $tabname, $flds);
		return (array)$sql;

	}

	/**
	 * Renames a table
	 * 
	 * @param string $tabname Current table name
	 * @param string $newname New table name
	 * 
	 * @return array
	 */
	function renameTableSQL($tabname, $newname)
	{
		
		$ttype = 'T';
		$schema = '';
		$mask = $tabname;
		$tabname = $this->metaTables($ttype, $schema, $mask);
		 /*
		  * If the table does not exist, return false
		  */

		if ($tabname === false ) {
			return false;
		}

		
		return parent::renameTableSQL($tabname[0], $newname);
		
	}
    

	function changeTableSQL($tablename, $flds, $tableoptions = false, $dropOldFields=false)
	{

		/**
		  Allow basic table changes to DB2 databases
		  DB2 will fatally reject changes to non character columns

		*/

		$validTypes = array("CHAR","VARC");
		$invalidTypes = array("BIGI","BLOB","CLOB","DATE", "DECI","DOUB", "INTE", "REAL","SMAL", "TIME");
		// check table exists
		
		
		$cols = $this->metaColumns($tablename);
		if ( empty($cols)) {
			return $this->createTableSQL($tablename, $flds, $tableoptions);
		}

		// already exists, alter table instead
		list($lines,$pkey) = $this->_GenFields($flds);
		$alter = 'ALTER TABLE ' . $this->tableName($tablename);
		$sql = array();

		foreach ( $lines as $id => $v ) {
			/*
			 * If the metaCasing was NATIVE the col returned with nameQuotes
			 * around the field. We need to remove this for the metaColumn
			 * match
			 */
			$id = str_replace($this->connection->nameQuote,'',$id);
			if ( isset($cols[$id]) && is_object($cols[$id]) ) {
				/**
				  If the first field of $v is the fieldname, and
				  the second is the field type/size, we assume its an
				  attempt to modify the column size, so check that it is allowed
				  $v can have an indeterminate number of blanks between the
				  fields, so account for that too
				 */
				$vargs = explode(' ' , $v);
				// assume that $vargs[0] is the field name.
				$i=0;
				// Find the next non-blank value;
				for ($i=1;$i<sizeof($vargs);$i++)
					if ($vargs[$i] != '')
						break;

				// if $vargs[$i] is one of the following, we are trying to change the
				// size of the field, if not allowed, simply ignore the request.
				if (in_array(substr($vargs[$i],0,4),$invalidTypes))
					continue;
				// insert the appropriate DB2 syntax
				if (in_array(substr($vargs[$i],0,4),$validTypes)) {
					array_splice($vargs,$i,0,array('SET','DATA','TYPE'));
				}

				// Now Look for the NOT NULL statement as this is not allowed in
				// the ALTER table statement. If it is in there, remove it
				if (in_array('NOT',$vargs) && in_array('NULL',$vargs)) {
					for ($i=1;$i<sizeof($vargs);$i++)
					if ($vargs[$i] == 'NOT')
						break;
					array_splice($vargs,$i,2,'');
				}
				$v = implode(' ',$vargs);
				$sql[] = $alter . $this->alterCol . ' ' . $v;
			} else {
				$sql[] = $alter . $this->addCol . ' ' . $v;
			}
		}

		return $sql;
	}

}
