<?php
// IPAddressRange.php
// Created: 2021-04-26
// Updated: 2023-01-01

namespace Index\Net;

use InvalidArgumentException;
use JsonSerializable;
use Stringable;
use Index\IEquatable;

final class IPAddressRange implements JsonSerializable, Stringable, IEquatable {
    private IPAddress $base;
    private int $mask;

    public function __construct(IPAddress $base, int $mask) {
        $this->base = $base;
        $this->mask = $mask;
    }

    public function getBaseAddress(): IPAddress {
        return $this->base;
    }

    public function getMask(): int {
        return $this->mask;
    }

    public function getCIDR(): string {
        return ((string)$this->base) . '/' . $this->getMask();
    }

    public function __toString(): string {
        return $this->getCIDR();
    }

    public function equals(mixed $other): bool {
        return $other instanceof IPAddressRange
            && $this->mask === $other->mask
            && $this->base->equals($other->base);
    }

    public function match(IPAddress $address): bool {
        $width = $this->base->getWidth();
        if($address->getWidth() !== $width)
            return false;

        if($this->mask < 1)
            return true;

        $base = $this->base->getRaw();
        $match = $address->getRaw();
        $remaining = $this->mask;

        for($i = 0; $i < $width && $remaining > 0; ++$i) {
            $b = ord($base[$i]);
            $m = ord($match[$i]);

            $remainingMod = $remaining % 8;
            if($remainingMod) {
                $mask = 0xFF << (8 - $remainingMod);
                $b &= $mask;
                $m &= $mask;
            }

            if($b !== $m)
                return false;

            $remaining -= 8;
        }

        return true;
    }

    public function jsonSerialize(): mixed {
        return $this->getCIDR();
    }

    public function __serialize(): array {
        return [
            'b' => $this->base->getRaw(),
            'm' => $this->mask,
        ];
    }
    public function __unserialize(array $serialized): void {
        $this->base = new IPAddress($serialized['b']);
        $this->mask = $serialized['m'];
    }

    public static function parse(string $cidr): IPAddressRange {
        $parts = explode('/', $cidr, 2);
        if(empty($parts[0]) || empty($parts[1]))
            throw new InvalidArgumentException('$cidr is not a valid CIDR range.');
        return new static(IPAddress::parse($parts[0]), (int)$parts[1]);
    }
}