<?php

//helper function
function prepare_mysqli_where_helper($param_type, $conditions) {
  $get_condition_values = function($key) use ($conditions) {
    return $conditions[$key];
  };

  $keys             = array_keys($param_type);
  $condition_query  = array();
  foreach ($keys as $column_name) {
    $condition_query[] = "`{$column_name}` = ?";
  }

  $where_condition  = implode(' AND ', $condition_query);
  $types            = implode('', array_values($param_type));
  $values           = array_map($get_condition_values, $keys);
  $types_and_values = array_merge([$types], $values);

  return compact("where_condition", "types", "values", "types_and_values");
}

function refValues($arr) {
  if (strnatcmp(phpversion(),'5.3') >= 0) //Reference is required for PHP 5.3+
  {
    $refs = array();
    foreach($arr as $key => $value)
      $refs[$key] = &$arr[$key];
    return $refs;
  }
  return $arr;
}

function filter_table($kota,$usia,$profesi,$jeniskelamin) {
  $main_query = "SELECT tbl_polling.image AS Gambar, tbl_polling.nama AS Nama , COUNT(*) AS Jumlah FROM tbl_choice INNER JOIN tbl_polling ON tbl_choice.pilihan=tbl_polling.id";
  $group_order = "GROUP BY tbl_choice.pilihan ORDER BY Jumlah DESC";
  $conditions = array();
  $param_type = array();

  if ($kota != 'semuakota') {
    $conditions["kota"] = $kota;
    $param_type["kota"] = 's';
  }
  if ($usia != 'semuausia') {
    $conditions["usia"] = $usia;
    $param_type["usia"] = 's';
  }
  if ($jeniskelamin != 'semuajeniskelamin') {
    $conditions["jk"] = $jeniskelamin;
    $param_type["jk"] = 's';
  }
  if ($profesi != 'semuaprofesi') {
    $conditions["profesi"] = $profesi;
    $param_type["profesi"] = 's';
  }
  //call helper
  $helper = prepare_mysqli_where_helper($param_type, $conditions);
  //build query
  $query = $main_query;
  if (count($conditions) > 0) {
    $query .= ' WHERE ' . $helper['where_condition'];
  }
  $query .= $group_order;
  //mysqli statement prepare and bind params
  $stmt = $mysqli->prepare($query);
  call_user_func_array(array($stmt, "bind_param"), refValues($helper['types_and_values']));
  //execute and return
  $result = $stmt->execute();
  return $result;
}