<?php
/*******************************************************************************
* Copyright 2008 Rafael Marques Martins
*
* This file is part of SQLReactor.
* 
* SQLReactor is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* 
* SQLReactor is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
* 
* You should have received a copy of the GNU General Public License
* along with SQLReactor; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
* 
*******************************************************************************/

	class SQLReactorClause{
		public $query;
		public $leftOperand;
		public $operator;
		public $rightOperand;
		
		public function __construct( &$query, $leftOperand, $operator, $rightOperand ){
			$this->query = $query;
			$this->leftOperand = $leftOperand;
			$this->operator = $operator;
			$this->rightOperand = $rightOperand;
		}
		
		protected function getColumn( $operand ){
			$tmpClause = explode( "->", $operand );
			$tmpInstance = $this->query->from;
			
			foreach( $tmpClause as $tmpName ){
				$column = $tmpInstance->_table->columns->$tmpName;
				if( $column instanceOf Backref || $column instanceOf ForeignKey ){
					$className = $column->config[ 'target' ][ 0 ];
					$tmpInstance = new $className();
				}
			}
            
			return $column;
		}
		
		protected function parseClause( $clause ){
			$operator = strtoupper( $clause->operator );
			
			if( $operator == 'OR' ){
				$leftClauses = array();
				$rightClauses = array();
				
				foreach( array( 'left', 'right' ) as $side ){
					$oper = "{$side}Operand";
					foreach( $clause->$oper as $tmpClause ){
						$clauseName = "{$side}Clauses";
						${$clauseName}[] = $this->parseClause( $tmpClause );
					}
					$$clauseName = implode( ' AND ', $$clauseName );
				}
				
				return "( ( {$leftClauses} ) OR ( {$rightClauses} ) )";
			}
			
			$escapeChar = $this->query->from->_connection->engine->escapeName;
			$column = $this->getColumn( $clause->leftOperand );
			$className = get_class( $column );
            
			$tmpColumn = new $className();
            $tmpColumn->setValueFromPHP( $clause->rightOperand );
            $rightOperand = $tmpColumn->getValueToDB();
            
            
			switch( $operator ){
                case 'IN':
                    $valueList = array();
                    foreach( $clause->rightOperand as $value ){
                        $tmpColumn->setValueFromPHP( $value );
                        $valueList[] = $tmpColumn->getValueToDB();
                    }
                    $rightOperand = '( ' . implode( ', ', $valueList ) . ' )';	
                    break;
                case 'BETWEEN':
                    $tmpColumn->setValueFromPHP( $clause->rightOperand[0] );
                    $value1 = $tmpColumn->getValueToDB();
                    
                    $tmpColumn->setValueFromPHP( $clause->rightOperand[1] );
                    $value2 = $tmpColumn->getValueToDB();
                    
                    $rightOperand = '( ' . $value1 . ' ) AND ( ' . $value2 . ' )';	
                case 'OR':
                case '=':
                case '>':
                case '>=':
                case '<':
                case '<=':
                case 'LIKE':
                    break;
				case '==':
					$operator = '=';
                    break;
                case '!=':
					$operator = '<>';
                    break;
                default:
                    throw new Exception( "Invalid operator \"{$operator}\"" );
			}
            
			if( $rightOperand === 'NULL' ){
				if( $operator == '=' ){
					$operator = 'IS';
				}else if( $operator == '!=' ){
					$operator = 'IS NOT';
				}
			}
            
            $tmpLeftOperand = implode( "->", array_slice( explode( "->", $clause->leftOperand ), 0, -1 ) );
            
            if( $this->query->sqlStructure->join[ $tmpLeftOperand ] ){
                $tmpName = $this->query->getTableName( $this->query->sqlStructure->join[ $tmpLeftOperand ] );
                return "( {$escapeChar}{$tmpName}{$escapeChar}.{$escapeChar}{$column->name}{$escapeChar} {$operator} " . $rightOperand . ' )';
            }
            
			return "( {$escapeChar}{$column->table->name}{$escapeChar}.{$escapeChar}{$column->name}{$escapeChar} {$operator} " . $rightOperand . ' )';
		}
		
		public function parse(){
			return $this->parseClause( $this );
		}
	}
?>