<?php

declare(strict_types=1);

namespace App\Framework\Http;

/**
 * Value Object für IP-Adressen
 */
final readonly class IpAddress
{
    public function __construct(
        public string $value
    ) {
        if (! filter_var($value, FILTER_VALIDATE_IP)) {
            throw new \InvalidArgumentException("Invalid IP address: {$value}");
        }
    }

    // Factory Methods
    public static function from(string $ip): self
    {
        return new self($ip);
    }

    public static function fromRequest(ServerEnvironment $server): ?self
    {
        $keys = [
            ServerKey::HTTP_CF_CONNECTING_IP,     // Cloudflare
            ServerKey::HTTP_CLIENT_IP,            // Proxy
            ServerKey::HTTP_X_FORWARDED_FOR,      // Load balancer/proxy
            ServerKey::HTTP_X_FORWARDED,          // Proxy
            ServerKey::HTTP_X_CLUSTER_CLIENT_IP,  // Cluster
            ServerKey::HTTP_FORWARDED_FOR,        // Proxy
            ServerKey::HTTP_FORWARDED,            // Proxy
            ServerKey::REMOTE_ADDR,                // Standard
        ];

        foreach ($keys as $key) {
            $value = $server->get($key);
            if ($value !== null && $value !== '') {
                $ip = trim(explode(',', $value)[0]);
                if (self::isValid($ip)) {
                    return new self($ip);
                }
            }
        }

        return null;
    }

    public static function localhost(): self
    {
        return new self('127.0.0.1');
    }

    // Validation
    public static function isValid(string $ip): bool
    {
        return filter_var($ip, FILTER_VALIDATE_IP) !== false;
    }

    // Basic checks
    public function isPrivate(): bool
    {
        return ! filter_var($this->value, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE);
    }

    public function isPublic(): bool
    {
        return ! $this->isPrivate() && ! $this->isReserved();
    }

    public function isReserved(): bool
    {
        return filter_var($this->value, FILTER_VALIDATE_IP, FILTER_FLAG_NO_RES_RANGE) === false;
    }

    public function isLoopback(): bool
    {
        if ($this->isV4()) {
            return str_starts_with($this->value, '127.');
        }

        return $this->value === '::1';
    }

    /**
     * Check if IP is considered local (private or loopback)
     */
    public function isLocal(): bool
    {
        return $this->isPrivate() || $this->isLoopback();
    }

    public function isV4(): bool
    {
        return filter_var($this->value, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4) !== false;
    }

    public function isV6(): bool
    {
        return filter_var($this->value, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) !== false;
    }

    // Comparison
    public function equals(IpAddress $other): bool
    {
        return $this->value === $other->value;
    }

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