<?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 SQLReactorDepTree{
    protected $classes = array();
    protected $classFlags = array();
    protected $creationOrder = array();
    
    public function __construct( $classes ){
        $this->addClasses( $classes );
        $this->calculateCreationOrder();
    }
    
    protected function calculateCreationOrder(){
        while( $this->classes ){
            foreach( $this->classes as $class => $deps ){
                if( array_sum( $deps ) ) continue;
                
                $this->creationOrder[] = $class;
                unset( $this->classes[ $class ] );
                $this->classFlags[ $class ] = 0;
            }
        }
    }
    
    public function getCreationOrder(){
        return $this->creationOrder;
    }
    
    protected function addClasses( $classes ){
        foreach( $classes as $class ){
            $this->addClass( $class );
        }
    }
    
    protected function addClass( $class ){
        if( !isset( $this->classFlags[ $class ] ) ){
            $this->classFlags[ $class ] = 1;
        }
        $this->classes[ $class ] = $this->getClassDeps( $class );
    }
    
    protected function getClassDeps( $class ){
        $deps = array();
        
        $obj = new $class();
        foreach( $obj->_table->columns as $column ){
            if( $column instanceof ForeignKey && !$column->config[ 'weakRelation' ] ){
                if( is_array( $column->config[ 'target' ] ) ){
                    $target = $column->config[ 'target' ][ 0 ];
                }else{
                    $target = $column->config[ 'target' ];
                }
                
                if( $target == $class ) continue;
                
                if( !isset( $this->classFlags[ $target ] ) ){
                    $this->classFlags[ $target ] = 1;
                }
                $deps[] = &$this->classFlags[ $target ];
            }
        }
        
        return $deps;
    }
}
?>