<?php

class PostgreSQL implements Service
{
    private $con; //Conexão com o banco de dados
    private $config; //Configuração
    public  $error = false; //Armazena um erro caso ocorra
    
    public function find ( $uri, $justthese = false, $criteria = false ){
    
	$criteria = ($criteria !== false) ? $this->parseCriteria ( $criteria ) : '';

	$justthese = $justthese ? '"'.implode('", "', $justthese).'"' : '*';

	return $this->execResultSql( 'SELECT '.$justthese.' FROM '.$uri['concept'].' '.$criteria );
    }

   public function read ( $uri, $justthese = false ){
   
      $justthese = $justthese ? '"'.implode('", "', $justthese).'"' : '*';

      return $this->execResultSql( 'SELECT '.$justthese.' FROM '.$uri['concept'].' WHERE id = \''.addslashes( $uri['id'] ).'\'', true );
    }
	
    public function deleteAll ( $uri,   $justthese = false, $criteria = false ){	
	    if(!self::parseCriteria ( $criteria )) return false; //Validador para não apagar tabela inteira
	    return $this->execSql( 'DELETE FROM '.$uri['concept'].' '.self::parseCriteria ( $criteria ) );
    }

    public function delete ( $uri, $justthese = false ){
	    return $this->execSql('DELETE FROM '.$uri['concept'].' WHERE id = '.addslashes($uri['id']));
    }

    public function replace ( $uri,  $data, $criteria = false ){
	    return $this->execSql('UPDATE '.$uri['concept'].' '. self::parseUpdateData( $data ).' '.self::parseCriteria($criteria));
    }
		
    public function update ( $uri,  $data ){
	    return $this->execSql('UPDATE '.$uri['concept'].' '. self::parseUpdateData( $data ).' WHERE id = \''. addslashes( $uri['id']) .'\'');
    }

    public function create ( $uri,  $data ){	
	    return $this->execResultSql( 'INSERT INTO '.$uri['concept'].' '.self::parseInsertData( $data ), true );
    }

    private function execSql( $sql ){
	    if(!$this->con)	$this->open( $this->config );

	    $rs = pg_query( $this->con, $sql );

	    if ( !$rs ){
		    $this->error = pg_last_error ( $this->con );
		    return false;
	    }

	    return $rs;
    }
	
    public function execResultSql( $sql, $unique = false ){
	    $rs = $this->execSql( $sql );

	    if( $rs && $rs > 0 )
		return self::parseSelectResult( $rs , $unique );

	    return $rs;
    }

    public function begin( $uri ) {
   
	if(!$this->con)
	    $this->open( $this->config );
        
        $this->error = false;
	pg_query($this->con, "BEGIN WORK"); 
    }

    public function commit($uri ) {
   
	if( $this->error !== false )
	{
	    $error = $this->error;
	    $this->error = false;

	    throw new Exception( $error );
	}

	pg_query($this->con, "COMMIT");

	return( true );
    }

    public function rollback( $uri ){
    
	pg_query($this->con, "ROLLBACK");
    }

    public function open  ( $config ){
        
        $this->config = $config;
        
        $rs = '';
        $rs .= ( isset($this->config['host']) && $this->config['host'] )  ? ' host='.$this->config['host'] : '' ;
        $rs .= ( isset($this->config['user']) && $this->config['user'] )  ? ' user='.$this->config['user'] : '' ;
        $rs .= ( isset($this->config['password']) && $this->config['password'] )  ? ' password='.$this->config['password'] : '' ;
        $rs .= ( isset($this->config['dbname']) && $this->config['dbname'] )  ? ' dbname='.$this->config['dbname'] : '' ;
        $rs .= ( isset($this->config['port']) && $this->config['port'] )  ? ' port='.$this->config['port'] : '' ;
                
	    return( $this->con = pg_connect( $rs ) );
	    //$this->con = pg_connect('host='.$config['host'].' user='.$config['user'].' password='.$config['password'].' dbname='.$config['dbname'].'  options=\'--client_encoding=UTF8\'');
    }

    public function close(){

	    pg_close($this->con);
            
            $this->con = false;

    }

    public function setup(){}

    public function teardown(){}

    private static function parseInsertData( $data ){
	    
	    $ind = array();
	    $val = array();
	    
	    foreach ($data as $i => $v){
		    $ind[] = $i;
		    $val[] = '\''.addslashes($v).'\'';
	    }
	    
	    return '('.implode(',', $ind).') VALUES ('.implode(',', $val).') RETURNING id';
    }
	
    private static function parseUpdateData( $data ){
	    
	    $d = array();

	    foreach ($data as $i => $v)
	       	$d[] = $i.' = \''.addslashes ($v).'\'';
	    
	    return 'SET '.implode(',', $d);
    }
	
    private static function parseSelectResult( $result , $unique = false){
	    
	    $return = array();
	    
	    if  (!$result) return false;
	    if (pg_num_rows($result) === 0) return $return;
	    else
	      while( $row = pg_fetch_assoc( $result ))
		      $return[] = $row;	
	    
	    if($unique === true) return $return[0];
	    
	    return $return;
    }
	
    private static function parseCriteria( $criteria ){               
	    
	    $result = '';
	
	    if( isset($criteria["filter"]) && $criteria["filter"] !== NULL )
	    {
		    /*
		  * ex: array   ( 
		  *		  [0] 'OR',
		  *		  [1] array( 'OR', array( array( '=', 'campo', 'valor' ) ), 
		  *		  [2] array( '=', 'campo' , 'valor' ),
		  *		  [3] array( 'IN', 'campo', array( '1' , '2' , '3' ) )
		  *		)
		  * OR
		  *	    array( '=' , 'campo' , 'valor' )
		*/

		    $result .= 'WHERE '.self::parseFilter( $criteria['filter'] );
	    }
	    /*
	      * ex: array( 'table1' => 'table2' ,  'table1' => 'table2')
	      *		
	      */
	    if( isset($criteria["join"]) )
	    {
		foreach ($criteria["join"] as $i => $v)
		    $result .= ' AND '.$i.' = '.$v.' ';
	    }
	    
	    if( isset($criteria["group"]) )
	    {
		    $result .= ' GROUP BY '.( is_array($criteria["group"]) ? implode(', ', $criteria["group"]) : $criteria["group"] ).' ';
	    }
	    
	    if( isset($criteria["order"]) )
	    {
		    $result .= ' ORDER BY '.( is_array($criteria["order"]) ? implode(', ', $criteria["order"]) : $criteria["order"] ).' ';
	    }
	    if( isset($criteria["limit"]) )
	    {
		    $result .= ' LIMIT '. $criteria["limit"] .' ';
	    }
	    if( isset($criteria["offset"]) )
	    {
		    $result .= ' OFFSET '. $criteria["offset"] .' ';
	    }
	    
	    return $result;
    }
    
    private static function parseFilter( $filter ){
    
	if( !is_array( $filter ) || count($filter) <= 0) return null;

	$op = self::parseOperator( array_shift( $filter ) );

	if( is_array($filter[0]) )
	{
	    $nested = array();

	    foreach( $filter as $i => $f )
		$nested[] = self::parseFilter( $f );

	    return( '('.implode( ' '.$op.' ', $nested ).')' );
	}

	$igSuffix = $igPrefix = '';

	if( strpos( $op[0], 'i' ) === 0 )
	{
	    $op[0] = substr( $op[0], 1 );
	    $filter[0] = 'upper("'.$filter[0].'")';
	    $igPrefix = 'upper(';
	    $igSuffix = ')';
	}

	if( is_array($filter[1]) )
	    return( $filter[0].' '.$op[0]." ($igPrefix'".implode( "'$igSuffix,$igPrefix'", array_map("addslashes" , $filter[1]) )."'$igSuffix)" );

	return( $filter[0].' '.$op[0]." $igPrefix'".$op[1].addslashes( $filter[1] ).$op[2]."'$igSuffix" );
    }

    private static function parseOperator( $op ){
    
	switch(strtolower($op))
	{
	    case 'and':
	    case 'or': return( $op );
	    case 'in': return array( $op );
	    case '^': return array( 'like', '%',  '' );
	    case '$': return array( 'like',  '', '%' );
	    case '*': return array( 'like', '%', '%' );
	    case 'i^': return array( 'ilike', '%',  '' );
	    case 'i$': return array( 'ilike',  '', '%' );
	    case 'i*': return array( 'ilike', '%', '%' );
	    default : return array( $op,  '',  '' );
	}
    }
	
}

?>