<?php

class SqlResultProvider
{
    /**
     * @var array
     */
    private $result_items;

    private $result_items_base;

    /**
     * @param $result_items array
     */
    public function __construct($result_items)
    {
        $this->result_items = $result_items;
    }

    public function assoc($field, $assoc_as_array = false)
    {
        if (is_null($this->result_items_base)) {
            $this->result_items_base = $this->result_items;
        }
        $result_items_assoc = array();
        foreach ($this->result_items_base as $item) {
            if (!isset($item->{$field})) {
                throw new ErrorException('Undefined field. ' . $field);
            }
            if ($assoc_as_array) {
                if (!isset($result_items_assoc[$item->{$field}])) {
                    $result_items_assoc[$item->{$field}] = array();
                }
                $result_items_assoc[$item->{$field}][] = $item;
            } else {
                if (isset($result_items_assoc[$item->{$field}])) {
                    throw new ErrorException('Field not unique. May be use assoc_as_array. ' . $field);
                }
                $result_items_assoc[$item->{$field}] = $item;
            }
        }
        // Ассоциирование внутри каждого элемента массива
        if ($assoc_as_array) {
            foreach ($result_items_assoc as &$value) {
                $value = new SqlResultProvider($value);
            }
        }
        $this->result_items = $result_items_assoc;
        return $this;
    }

    public function getKeys()
    {
        return array_keys($this->result_items);
    }

    public function fetchAll()
    {
        return $this->result_items;
    }

    /**
     * @param $key
     * @return mixed
     * TODO: метод актуален только после вызова assoc
     */
    public function fetchKey($key)
    {
        return $this->result_items[$key];
    }

    /**
     * @param $field
     * @return mixed
     * TODO: метод не актуален после вызова assoc с параметров assoc_as_array = true
     */
    public function fetchField($field)
    {
        return current($this->result_items)->{$field};
    }

    public function fetch()
    {
        return current($this->result_items);
    }
}