<?php

declare(strict_types=1);

namespace GeoIp2\Record;

abstract class AbstractRecord implements \JsonSerializable
{
    private $record;

    /**
     * @ignore
     */
    public function __construct(?array $record)
    {
        $this->record = isset($record) ? $record : [];
    }

    /**
     * @ignore
     */
    public function __get(string $attr)
    {
        // XXX - kind of ugly but greatly reduces boilerplate code
        $key = $this->attributeToKey($attr);

        if ($this->__isset($attr)) {
            return $this->record[$key];
        } elseif ($this->validAttribute($attr)) {
            if (preg_match('/^is_/', $key)) {
                return false;
            }

            return null;
        }
        throw new \RuntimeException("Unknown attribute: $attr");
    }

    public function __isset(string $attr): bool
    {
        return $this->validAttribute($attr) &&
             isset($this->record[$this->attributeToKey($attr)]);
    }

    private function attributeToKey(string $attr): string
    {
        return strtolower(preg_replace('/([A-Z])/', '_\1', $attr));
    }

    private function validAttribute(string $attr): bool
    {
        return \in_array($attr, $this->validAttributes, true);
    }

    public function jsonSerialize(): ?array
    {
        return $this->record;
    }
}