<?php
//
// cmSlu CMS POC
//
//   Database MySQLi interface
//

// Result interface
class DBResult_mysqli extends DBResult {
  // mysqli_stmt
  private $st;
  // field names in order
  private $fields;
  // pointer to hold mother-query object to keep it from destruction
  private $q;
  // constructor
  public function __construct(&$if, &$st, &$p) {
    // save parent
    $this->q = &$p;
    // save statement
    $this->st = &$st;
    // determine what fields we have (to emulate get_result())
    $md = $this->st->result_metadata();
    $this->fields = array();
    if($md != FALSE) {
      while($field = $md->fetch_field()) {
        $this->fields[] = $field->name;
      }
      $md->free();
    }
  }

  // destructor
  public function __destruct() {
      @$this->st->free_result();
  }

  // number of rows
  public function NumRows() {
    return $this->st->num_rows();
  }
  
  // affected rows
  public function AffectedRows() {
    return $this->st->affected_rows;
  }

  // insert id
  public function InsertId() {
    return $this->st->insert_id;
  }

  // seek
  public function Seek($offset) {
    $this->st->data_seek($offset);
  }

  // fetch
  public function FetchRow($how = DBResult::FT_BOTH) {
    $n = count($this->fields);
    // array of values and pointers to values
    $a = array_fill(0, $n, NULL);
    $p = array();
    for($i = 0; $i < $n; $i++) $p[] = &$a[$i];

    // bind it
    call_user_func_array(array($this->st, 'bind_result'), $p);

    // it there is no more rows, bail out
    if($this->st->fetch() == FALSE) return NULL;

    $r = array();
    if(($how & (DBResult::FT_NUM)) != 0)   $r = array_merge($r, $a);
    if(($how & (DBResult::FT_ASSOC)) != 0) $r = array_merge($r, array_combine($this->fields, $a));

    return $r;
  }
}

// Query interface
class DBQuery_mysqli extends DBQuery {
  // mysqli
  private $if;
  // mysqli_stmt
  private $stmt;
  // parameters array
  private $params;
  // constructor
  public function __construct(&$if, $query, $limit, $start) {
    // find all parameters
    if(preg_match_all('#\?\(([A-Za-z0-9_]+)\)#', $query, $matches) == 0) {
      $this->params = array();
    } else {
      // fill parameters array
      foreach($matches[1] as $m) {
        if(ctype_digit(substr($m, 0, 1)))
          throw new Exception("Query parameter names cannot start with digit!");
        $this->params[] = array(
          'name' => $m,
          'value' => NULL,
          'type' => NULL
        );
      }
      // replace all with mysqli prepared statements
      $query = preg_replace('#\?\([A-Za-z0-9_]+\)#', '?', $query);
    }
    // add limit
    if(!is_null($limit)) {
      $query .= ' LIMIT ';
      if(!is_null($start)) $query .= $start . ',';
      $query .= $limit;
    }
    // actually construct query
    $this->if = &$if;
    $this->stmt = $if->prepare($query);
  }

  // destructor
  public function __destruct() {
    @$this->stmt->close();
  }

  // bind parameter
  private function RealBindParameter($id, $value, $type) {
    // check type
    switch($type) {
      case DBQuery::PT_INTEGER:
        settype($value, 'int');
        break;
      case DBQuery::PT_BOOLEAN:
        settype($value, 'bool');
        break;
      case DBQuery::PT_FLOAT:
        settype($value, 'float');
        break;
      case DBQuery::PT_STRING:
        settype($value, 'string');
        break;
      // auto-determine
      case DBQuery::PT_AUTO:
      default:
        if(is_array($value) || is_object($value)) {
          throw new Exception("Parameter value cannot be an array or an object!");
        }
        if(is_string($value)) $type = DBQuery::PT_STRING;
        else $type = DBQuery::PT_INTEGER;
    }
    $this->params[$id]['type'] = $type;
    $this->params[$id]['value'] = $value;
  }

  // bind parameter interface
  public function SetParameter($name, $value, $type = DBQuery::PT_AUTO) {
    //if id suppled
    if(is_int($name)) {
      if(!isset($this->params[$name]))
        throw new Exception("Parameter #" . $name . " is not defined in the query");
      return $this->RealBindParameter($name, $value, $type);
    }
    //else check if its name is defined
    foreach($this->params as $id=>&$param) {
      if(strcmp($name, $param['name']) == 0) {
        return $this->RealBindParameter($id, $value, $type);
      }
    }
    throw new Exception("Parameter " . $name . " is not defined in the query");
  }

  // execute query
  public function Execute() {
    // reset (if called more than once)
    $this->stmt->reset();
    // bind parameters
    if(count($this->params) > 0) {
      $qs = '';
      $qa = array();
      foreach($this->params as &$param) {
        if($param['type'] === NULL) {
          throw new Exception("Unset parameter " . $param['name'] . " while executing the query!");
        }
        switch($param['type']) {
          case DBQuery::PT_INTEGER: $qs .= 'i'; break;
          case DBQuery::PT_BOOLEAN: $qs .= 'b'; break;
          case DBQuery::PT_FLOAT:   $qs .= 'd'; break;
          case DBQuery::PT_STRING:  $qs .= 's'; break;
        }
        $qa[] = &$param['value'];
      }
      call_user_func_array(array($this->stmt, 'bind_param'), array_merge(array($qs), $qa));
    }
    // execute it!
    if($this->stmt->execute() == FALSE) {
      throw new Exception('Database query error mysqli #' .
        $this->stmt->errno . ': ' . $this->stmt->error);
    }
    // store result
    $this->stmt->store_result();
    // return result abstraction
    return new DBResult_mysqli($this->if, $this->stmt, $this);
  }
}

// Database interface
class DB_mysqli extends DB {
  // interface
  private $mysqli;
  // constructor
  public function __construct($host, $user, $pass, $db) {
    $this->mysqli = mysqli_init();
    if(defined('DB_CHARSET')) {
      // WARNING! MYSQLI_SET_CHARSET_NAME is UNDOCUMENTED in PHP API, but legal in C API.
      $this->mysqli->options(MYSQLI_SET_CHARSET_NAME, DB_CHARSET);
    }
    if(!$this->mysqli->real_connect($host, $user, $pass, $db)) {
      throw new Exception('Database connect error mysqli #' .
        $this->mysqli->connect_errno . ': ' . $this->mysqli->connect_error);
    }
  }
  // destructor
  public function __destruct() {
    @$this->mysqli->close();
  }
  // query factory
  public function ConstructQuery($query, $limit, $start) {
    return new DBQuery_mysqli($this->mysqli, $query, $limit, $start);
  }
}

?>