<?php
/**
 * TOracleMetaData class file.
 *
 * @author Marcos Nobre <marconobre[at]gmail[dot]com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2014 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @package Prado\Data\Common\Oracle
 */

namespace Prado\Data\Common\Oracle;

/**
 * Load the base TDbMetaData class.
 */
Prado::using('System.Data.Common.TDbMetaData');
Prado::using('System.Data.Common.Oracle.TOracleTableInfo');
Prado::using('System.Data.Common.Oracle.TOracleTableColumn');

/**
 * TOracleMetaData loads Oracle database table and column information.
 *
 * @author Marcos Nobre <marconobre[at]gmail[dot]com>
 * @package Prado\Data\Common\Oracle
 * @since 3.1
 */
class TOracleMetaData extends TDbMetaData
{
	private $_defaultSchema = 'system';


	/**
	 * @return string TDbTableInfo class name.
	 */
	protected function getTableInfoClass()
	{
		return 'TOracleTableInfo';
	}

	/**
	 * @param string default schema.
	 */
	public function setDefaultSchema($schema)
	{
		$this->_defaultSchema=$schema;
	}

	/**
	 * @return string default schema.
	 */
	public function getDefaultSchema()
	{
		return $this->_defaultSchema;
	}

	/**
	 * @param string table name with optional schema name prefix, uses default schema name prefix is not provided.
	 * @return array tuple as ($schemaName,$tableName)
	 */
	protected function getSchemaTableName($table)
	{
		if(count($parts= explode('.', str_replace('"','',$table))) > 1)
			return array($parts[0], $parts[1]);
		else
			return array($this->getDefaultSchema(),$parts[0]);
	}

	/**
	 * Get the column definitions for given table.
	 * @param string table name.
	 * @return TOracleTableInfo table information.
	 */
	protected function createTableInfo($table)
	{
		list($schemaName,$tableName) = $this->getSchemaTableName($table);

		// This query is made much more complex by the addition of the 'attisserial' field.
		// The subquery to get that field checks to see if there is an internally dependent
		// sequence on the field.
		$sql =
<<<EOD
		SELECT
			a.COLUMN_ID,
			LOWER(a.COLUMN_NAME) as attname,
			a.DATA_TYPE || DECODE( a.DATA_TYPE, 'NUMBER', '('||a.DATA_PRECISION||','||DATA_SCALE||')' , '') as type,
			a.DATA_LENGTH as atttypmod,
			DECODE(a.NULLABLE, 'Y', '0', '1') as attnotnull,
			DECODE(a.DEFAULT_LENGTH, NULL, '0', '1') as atthasdef,
			DATA_DEFAULT as adsrc,
			'0' AS attisserial
		FROM
			ALL_TAB_COLUMNS a
		WHERE
			TABLE_NAME = '{$tableName}'
			AND OWNER = '{$schemaName}'
		ORDER BY a.COLUMN_ID
EOD;
		$this->getDbConnection()->setActive(true);
		$this->getDbConnection()->setAttribute(PDO::ATTR_CASE, PDO::CASE_LOWER);
		$command = $this->getDbConnection()->createCommand($sql);
		//$command->bindValue(':table', $tableName);
		//$command->bindValue(':schema', $schemaName);
		$tableInfo = $this->createNewTableInfo($schemaName, $tableName);
		$index=0;
		foreach($command->query() as $col)
		{
			$col['index'] = $index++;
			$this->processColumn($tableInfo, $col);
		}
		if($index===0)
			throw new TDbException('dbmetadata_invalid_table_view', $table);
		return $tableInfo;
	}

	/**
	 * @param string table schema name
	 * @param string table name.
	 * @return TOracleTableInfo
	 */
	protected function createNewTableInfo($schemaName,$tableName)
	{
		$info['SchemaName'] = $this->assertIdentifier($schemaName);
		$info['TableName']	= $this->assertIdentifier($tableName);
		$info['IsView'] 	= false;
		if($this->getIsView($schemaName,$tableName)) $info['IsView'] = true;
		list($primary, $foreign) = $this->getConstraintKeys($schemaName, $tableName);
		$class = $this->getTableInfoClass();
		return new $class($info,$primary,$foreign);
	}

	/**
	 * @param string table name, schema name or column name.
	 * @return string a valid identifier.
	 * @throws TDbException when table name contains a double quote (").
	 */
	protected function assertIdentifier($name)
	{
		if(strpos($name, '"')!==false)
		{
			$ref = 'http://www.oracle.com';
			throw new TDbException('dbcommon_invalid_identifier_name', $name, $ref);
		}
		return $name;
	}

	/**
	 * @param string table schema name
	 * @param string table name.
	 * @return boolean true if the table is a view.
	 */
	protected function getIsView($schemaName,$tableName)
	{
		$this->getDbConnection()->setAttribute(PDO::ATTR_CASE, PDO::CASE_LOWER);
		$sql =
<<<EOD
		select	OBJECT_TYPE
		from 	ALL_OBJECTS
		where	OBJECT_NAME = '{$tableName}'
		and 	OWNER = '{$schemaName}'
EOD;
		$this->getDbConnection()->setActive(true);
		$command = $this->getDbConnection()->createCommand($sql);
		//$command->bindValue(':schema',$schemaName);
		//$command->bindValue(':table', $tableName);
		return intval($command->queryScalar() === 'VIEW');
	}

	/**
	 * @param TOracleTableInfo table information.
	 * @param array column information.
	 */
	protected function processColumn($tableInfo, $col)
	{
		$columnId = strtolower($col['attname']); //use column name as column Id

		//$info['ColumnName'] 	= '"'.$columnId.'"'; //quote the column names!
		$info['ColumnName'] 	= $columnId; //NOT quote the column names!
		$info['ColumnId'] 		= $columnId;
		$info['ColumnIndex'] 	= $col['index'];
		if(! (bool)$col['attnotnull'] ) $info['AllowNull'] = true;
		if(in_array($columnId, $tableInfo->getPrimaryKeys())) $info['IsPrimaryKey'] = true;
		if($this->isForeignKeyColumn($columnId, $tableInfo)) $info['IsForeignKey'] = true;
		if( (int)$col['atttypmod'] > 0 ) $info['ColumnSize'] =  $col['atttypmod']; // - 4;
		if( (bool)$col['atthasdef'] ) $info['DefaultValue'] = $col['adsrc'];
		//
		// For a while Oracle Tables has no  associated AutoIncrement Triggers
		//
		/*
		if( $col['attisserial'] )
		{
			if(($sequence = $this->getSequenceName($tableInfo, $col['adsrc']))!==null)
			{
				$info['SequenceName'] = $sequence;
				unset($info['DefaultValue']);
			}
		}
		*/
		$matches = array();
		if(preg_match('/\((\d+)(?:,(\d+))?+\)/', $col['type'], $matches))
		{
			$info['DbType'] = preg_replace('/\(\d+(?:,\d+)?\)/','',$col['type']);
			if($this->isPrecisionType($info['DbType']))
			{
				$info['NumericPrecision'] = intval($matches[1]);
				if(count($matches) > 2)
					$info['NumericScale'] = intval($matches[2]);
			}
			else
				$info['ColumnSize'] = intval($matches[1]);
		}
		else
			$info['DbType'] = $col['type'];
		$tableInfo->Columns[$columnId] = new TOracleTableColumn($info);
	}

	/**
	 * @return string serial name if found, null otherwise.
	 */
	protected function getSequenceName($tableInfo,$src)
	{
		$matches = array();
		if(preg_match('/nextval\([^\']*\'([^\']+)\'[^\)]*\)/i',$src,$matches))
		{
			if(is_int(strpos($matches[1], '.')))
				return $matches[1];
			else
				return $tableInfo->getSchemaName().'.'.$matches[1];
		}
	}

	/**
	 * @return boolean true if column type if "numeric", "interval" or begins with "time".
	 */
	protected function isPrecisionType($type)
	{
		$type = strtolower(trim($type));
		return $type==='number'; // || $type==='interval' || strpos($type, 'time')===0;
	}

	/**
	 * Gets the primary and foreign key column details for the given table.
	 * @param string schema name
	 * @param string table name.
	 * @return array tuple ($primary, $foreign)
	 */
	protected function getConstraintKeys($schemaName, $tableName)
	{
		$this->getDbConnection()->setAttribute(PDO::ATTR_CASE, PDO::CASE_LOWER);
//		select decode( a.CONSTRAINT_TYPE, 'P', 'PRIMARY KEY (', 'FOREIGN KEY (' )||b.COLUMN_NAME||')' as consrc,
		$sql =
<<<EOD
		select b.COLUMN_NAME as consrc,
			   a.CONSTRAINT_TYPE as contype
		from ALL_CONSTRAINTS a, ALL_CONS_COLUMNS b
 		where (a.constraint_name = b.constraint_name AND a.table_name = b.table_name AND a.owner = b.owner)
		and	  a.TABLE_NAME = '{$tableName}'
		and   a.OWNER = '{$schemaName}'
		and   a.CONSTRAINT_TYPE in ('P','R')
EOD;
		$this->getDbConnection()->setActive(true);
		$command = $this->getDbConnection()->createCommand($sql);
		//$command->bindValue(':table', $tableName);
		//$command->bindValue(':schema', $schemaName);
		$primary = array();
		$foreign = array();
		foreach($command->query() as $row)
		{
			switch( strtolower( $row['contype'] ) )
			{
				case 'p':
					$primary = array_merge( $primary, array(strtolower( $row['consrc'] )) );
					/*
					$arr = $this->getPrimaryKeys($row['consrc']);
					$primary = array_merge( $primary, array(strtolower( $arr[0] )) );
					*/
					break;
				case 'r':
					$foreign = array_merge( $foreign, array(strtolower( $row['consrc'] )) );
					/*
					// if(($fkey = $this->getForeignKeys($row['consrc']))!==null)
					$fkey = $this->getForeignKeys( $row['consrc'] );
					$foreign = array_merge( $foreign, array(strtolower( $fkey )) );
					*/
					break;
			}
		}
		return array($primary,$foreign);
	}

	/**
	 * Gets the primary key field names
	 * @param string Oracle primary key definition
	 * @return array primary key field names.
	 */
	protected function getPrimaryKeys($src)
	{
		$matches = array();
		if(preg_match('/PRIMARY\s+KEY\s+\(([^\)]+)\)/i', $src, $matches))
			return preg_split('/,\s+/',$matches[1]);
		return array();
	}

	/**
	 * Gets foreign relationship constraint keys and table name
	 * @param string Oracle foreign key definition
	 * @return array foreign relationship table name and keys, null otherwise
	 */
	protected function getForeignKeys($src)
	{
		$matches = array();
		$brackets = '\(([^\)]+)\)';
		$find = "/FOREIGN\s+KEY\s+{$brackets}\s+REFERENCES\s+([^\(]+){$brackets}/i";
		if(preg_match($find, $src, $matches))
		{
			$keys = preg_split('/,\s+/', $matches[1]);
			$fkeys = array();
			foreach(preg_split('/,\s+/', $matches[3]) as $i => $fkey)
				$fkeys[$keys[$i]] = $fkey;
			return array('table' => str_replace('"','',$matches[2]), 'keys' => $fkeys);
		}
	}

	/**
	 * @param string column name.
	 * @param TOracleTableInfo table information.
	 * @return boolean true if column is a foreign key.
	 */
	protected function isForeignKeyColumn($columnId, $tableInfo)
	{
		foreach($tableInfo->getForeignKeys() as $fk)
		{
			if( $fk==$columnId )
			//if(in_array($columnId, array_keys($fk['keys'])))
				return true;
		}
		return false;
	}

        /**
	 * Returns all table names in the database.
	 * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
	 * If not empty, the returned table names will be prefixed with the schema name.
	 * @return array all table names in the database.
	 */
	public function findTableNames($schema='')
	{
		if($schema==='')
		{
			$sql=<<<EOD
SELECT table_name, '{$schema}' as table_schema FROM user_tables
EOD;
			$command=$this->getDbConnection()->createCommand($sql);
		}
		else
		{
			$sql=<<<EOD
SELECT object_name as table_name, owner as table_schema FROM all_objects
WHERE object_type = 'TABLE' AND owner=:schema
EOD;
			$command=$this->getDbConnection()->createCommand($sql);
			$command->bindParam(':schema',$schema);
		}

		$rows=$command->queryAll();
		$names=array();
		foreach($rows as $row)
		{
			if($schema===$this->getDefaultSchema() || $schema==='')
				$names[]=$row['TABLE_NAME'];
			else
				$names[]=$row['TABLE_SCHEMA'].'.'.$row['TABLE_NAME'];
		}
		return $names;
	}
}