<?php
/**
 *
 * @author Daeus Tang 
 * @version Alpha
 *
 */

class SqliConvertor{

  private $db;
  private $query;

  public function __construct($host, $username, $password, $db_name) {

    $this->db = new mysqli($host, $username, $password, $db_name);
    if ($this->db->connect_errno) {
      throw Exception("Failed to connect: {$this->db->connect_error}");
    }   
  }   

  public function real_escape_string($q) {
    return $this->db->real_escape_string($q);
  }

  public function escape_string($q) {
    return $this->db->real_escape_string($q);
  }

  public function escape($q, $quote = false) {
    if($quote) {
      return "'" . $this->db->real_escape_string($q) . "'";

    } else {
      return $this->db->real_escape_string($q);
    }
  }

  public function query($sql) {
    $this->query = $this->db->query($sql);
    return $this->query;
  }

  public function error() {
    return $this->db->error;
  }

  public function numrows(&$query = NULL) {
    return $this->num_rows($query);
  }

  public function num_rows(&$query = NULL) {
    if($query !== NULL) {
      $this->query = $query;
    }

    return $this->query->num_rows;
  }

  public function fetch_array(&$query = NULL) {
    if($query !== NULL) {
      $this->query = $query;
    }

    return $this->query->fetch_array(); 
  }

  public function fetch_object(&$query, $className = 'stdClass', $params = NULL) {
    $this->query = $query;
    if($params === NULL) {
      return $query->fetch_object($className);

    } else {
      return $query->fetch_object($className, $params);
    }
  }

  public function result(&$query, $row, $field = 0) {
    $this->query = $query;

    //seek to row
    $query->data_seek($row);

    //seek field
    if(is_integer($field)) {
      $row = $query->fetch_row();
      $row->field_seek($field);
      return $result->fetch_field();

    } else {
      $row = $query->fetch_assoc();
      return $row[$field];
    }
  }

  public function insert_id() {
    return $this->db->insert_id;    
  }


  /**
   * Self-defined function
   */
  public function result_array($sql, $params = NULL, $field_name = NULL) {
    $sql = $this->build_sql($sql, $params);
    $query = $this->db->query($sql);
    if( !$query) {
      //throw new Exception("result_array error. Please check your SQL: " . $sql);
    }

    $result = ''; 
    if($field_name === NULL) {
      while($row = $query->fetch_assoc()) {
        $result[] = $row;
      }
    } else {
      while($row = $query->fetch_assoc()) {
        $result[] = $row[$field_name];
      }

    }
    return $result;
  }   

  public function run_query($sql, $params = NULL) {
    $sql = $this->build_sql($sql, $params);
    $query = $this->query($sql);

    if( !$query) {
      //throw new Exception("run_query error. Please check your SQL: " . $sql);
    }
    return $query;
  }

  public function insert($sql, $params = NULL) {
    $sql = $this->build_sql($sql, $params);
    $this->query = $this->db->query($sql);
    if( !$this->query ) {
      // TODO: 
      //throw new Exception("insert error. Please check your SQL: " . $sql);
    }

    return $this->db->insert_id;
  }   

  public function row_array($sql, $params = NULL, $field_name = NULL) {
    $sql = $this->build_sql($sql, $params);
    $this->query = $this->db->query($sql);
    if( !$this->query){
      // TODO:
      //throw new Exception("result_row error. Please check your SQL: " . $sql);
    }

    $row = $this->query->fetch_assoc();
    if( !$field_name == NULL) {
      return $row[$field_name];
    } else {
      return $row;
    }
  }   

  public function build_sql($sql, $params = NULL) {
    if( !$params == NULL ) {
      $sql = str_replace('?', '%s', $sql);

      if( is_array($params) ) {
        foreach($params as &$p) {
          $p = "'" . $this->db->real_escape_string($p) . "'";
        }

        return vsprintf($sql, $params);

      } else {
        $params = "'" . $this->db->real_escape_string($params) . "'";
        return sprintf($sql, $params);
      }
    }

    return $sql;
  }
}

?>