<?php


/**
 * Class for managing oracle database connection
 */

require_once('ykval-log.php');
require_once('ykval-db.php');

class DbImpl extends Db
{
  /**
   * Constructor
   *
   * @param string $host Database host
   * @param string $user Database user
   * @param string $pwd  Database password
   * @param string $name Database table name
   * @return void
   *
   */
  public function __construct($db_dsn, $db_username, $db_password, $db_options, $name='ykval-db')
  {
    $this->db_dsn=$db_dsn;
    $this->db_username=$db_username;
    $this->db_password=$db_password;
    $this->db_options=$db_options;

    if(substr($db_dsn, 0, 4) == 'oci:') {
      # "oci:" prefix needs to be removed before passing db_dsn to OCI
      $this->db_dsn = substr($this->db_dsn, 4);
    }

    $this->myLog=new Log($name);
  }

  /**
   * function to connect to database defined in config.php
   *
   * @return boolean True on success, otherwise false.
   *
   */
  public function connect(){
    $this->dbh = oci_connect($this->db_username, $this->db_password, $this->db_dsn);
    if (!$this->dbh) {
      $error = oci_error();
      $this->myLog->log(LOG_CRIT, "Database connection error: " . $error["message"]);
      $this->dbh=Null;
      return false;
    }
    return true;
  }

  protected function query($query, $returnresult=false) {
    if(!$this->isConnected()) {
      $this->connect();
    }
    if($this->isConnected()) {
      $this->myLog->log(LOG_DEBUG, 'DB query is: ' . $query);
      # OCI mode
      $result = oci_parse($this->dbh, $query);
      if(!oci_execute($result)) {
	$this->myLog->log(LOG_INFO, 'Database query error: ' . preg_replace('/\n/',' ',print_r(oci_error($result), true)));
	$this->dbh = Null;
	return false;
      }
      $this->result = $result;
      if ($returnresult) return $this->result;
      else return true;
    } else {
      $this->myLog->log(LOG_CRIT, 'No database connection');
      return false;
    }
  }

  /**
   * function to get a row from the query result
   * Once all rows have been fetch, function closeCursor needs to be called
   *
   * @param object $result Query result object or null to use the current one
   * @return array a query row
   *
   */
  public function fetchArray($result=null){
    if(!$result) $result = $this->result;
    if(!$result) return null;

    $res = oci_fetch_array($result, OCI_ASSOC);
    return array_change_key_case($res, CASE_LOWER);
  }

  /**
   * function to close the cursor after having fetched rows
   * 
   * @param object $result Query result object or null to use the current one
   *
   */
  public function closeCursor($result=null){
  }

  /**
   * main function used to get rows by multiple key=>value pairs from Db table.
   *
   * @param string $table Database table to update row in
   * @param array $where Array with column=>values to select rows by
   * @param int $nr Number of rows to collect. NULL=>inifinity. Default=NULL.
   * @param int $rev rev=1 indicates order should be reversed. Default=NULL.
   * @param string distinct Select rows with distinct columns, Default=NULL
   * @return mixed Array with values from Db row or 2d-array with multiple rows
   *
   */
  public function findByMultiple($table, $where, $nr=null, $rev=null, $distinct=null)
  {
    $value=""; /* quiet the PHP Notice */
    $match=null; /* quiet the PHP Notice */
    $query="SELECT";

    if($nr!=null){
       # LIMIT doesn't exist in Oracle, so we encapsulate the query to be
       # able to filter a given number of rows afterwars (after ordering)
       $query.= " * FROM (SELECT";
    }

    if ($distinct!=null) {
      $query.= " DISTINCT " . $distinct;
    } else {
      $query.= " *";
    }
    $query.= " FROM " . $table;
    if ($where!=null){
      foreach ($where as $key=>$value) {
	if ($key!=null) {
	  if ($value!=null) $match.= " ". $key . " = '" . $value . "' and";
	  else $match.= " ". $key . " is NULL and";
	}
      }
      if ($match!=null) $query .= " WHERE" . $match;
      $query=rtrim($query, "and");
      $query=rtrim($query);
    }
    if ($rev==1) $query.= " ORDER BY id DESC";
    if ($nr!=null) {
      $query .= ") WHERE rownum < " . ($nr+1);
    }

    $result = $this->query($query, true);
    if (!$result) return false;

    if ($nr==1) {
      $row = $this->fetchArray($result);
      $this->closeCursor($result);
      return $row;
    }
    else {
      $collection=array();
      while($row = $this->fetchArray($result)){
	$collection[]=$row;
      }
      $this->closeCursor($result);
      return $collection;
    }
  }

  /**
   * main function used to delete rows by multiple key=>value pairs from Db table.
   *
   * @param string $table Database table to delete row in
   * @param array $where Array with column=>values to select rows by
   * @param int $nr Number of rows to collect. NULL=>inifinity. Default=NULL.
   * @param int $rev rev=1 indicates order should be reversed. Default=NULL.
   * @param string distinct Select rows with distinct columns, Default=NULL
   * @return boolean True on success, otherwise false.
   *
   */
  public function deleteByMultiple($table, $where, $nr=null, $rev=null)
  {
    $query="DELETE";
    $query.= " FROM " . $table;
    $query .= " WHERE id IN (SELECT id FROM " . $table;
    if ($where!=null){
      $query.= " WHERE";
      foreach ($where as $key=>$value) {
	$query.= " ". $key . " = '" . $value . "' and";
      }
      $query=rtrim($query, "and");
      $query=rtrim($query);
    }
    if ($rev==1) $query.= " ORDER BY id DESC";

    $query .= ")";
    if ($nr!=null) $query.= " and rownum < " . ($nr+1);

    return $this->query($query, false);
  }

  /**
   * Function to get the number of rows
   *
   * @param object $result Query result object or null to use the current one
   * @return int number of rows affected by last statement or 0 if database connection is not functional.
   *
   */
  public function rowCount($result=null)
  {
    if(!$result) $result = $this->result;
    if($result) {
      return oci_num_rows($result);
    } else {
      return 0;
    }
  }
}


?>