<?php

declare(strict_types=1);

namespace LinkCheckup\Features\Checking;

use LinkCheckup\Shared\Links\Reason;

use function preg_match;

final class AnswerJudge {

	private const FIRST_SUCCESS_CODE      = 200;
	private const LAST_SUCCESS_CODE       = 299;
	private const FIRST_SERVER_ERROR_CODE = 500;
	private const LAST_SERVER_ERROR_CODE  = 599;
	private const NO_HOST_PATTERN         =
		'/resolve host|name or service not known|getaddrinfo|dns/i';
	private const SSL_PATTERN             = '/ssl|certificate/i';
	private const STATUS_REASONS          = array(
		401 => Reason::Login,
		403 => Reason::Forbidden,
		404 => Reason::NotFound,
		410 => Reason::Gone,
		429 => Reason::RateLimited,
	);

	public function __construct( private HostLookup $host_lookup ) {
	}

	public function judge(
		string $requested_url,
		HttpAnswer $answer
	): Judgement {
		$status_code = $answer->status_code;

		if ( null === $status_code ) {
			return new Judgement(
				$this->reason_for_error(
					$requested_url,
					$answer->error_message
				),
				null,
				null
			);
		}

		$is_success = $this->is_between(
			$status_code,
			self::FIRST_SUCCESS_CODE,
			self::LAST_SUCCESS_CODE
		);

		if ( $is_success ) {
			return $this->success_judgement(
				$requested_url,
				$answer,
				$status_code
			);
		}

		return new Judgement(
			$this->reason_for_failure( $status_code ),
			$status_code,
			null
		);
	}

	private function success_judgement(
		string $requested_url,
		HttpAnswer $answer,
		int $status_code
	): Judgement {
		if ( $requested_url === $answer->final_url ) {
			return new Judgement( Reason::Ok, $status_code, null );
		}

		return new Judgement(
			Reason::Redirect,
			$answer->first_status_code,
			$answer->final_url
		);
	}

	private function reason_for_failure( int $status_code ): Reason {
		if ( isset( self::STATUS_REASONS[ $status_code ] ) ) {
			return self::STATUS_REASONS[ $status_code ];
		}

		$is_server_error = $this->is_between(
			$status_code,
			self::FIRST_SERVER_ERROR_CODE,
			self::LAST_SERVER_ERROR_CODE
		);

		return $is_server_error ? Reason::ServerError : Reason::Forbidden;
	}

	private function reason_for_error(
		string $requested_url,
		string $error_message
	): Reason {
		if ( 1 === preg_match( self::NO_HOST_PATTERN, $error_message ) ) {
			return Reason::NoHost;
		}

		$host = (string) wp_parse_url( $requested_url, PHP_URL_HOST );

		if ( ! $this->host_lookup->exists( $host ) ) {
			return Reason::NoHost;
		}

		return 1 === preg_match( self::SSL_PATTERN, $error_message )
			? Reason::Ssl
			: Reason::Timeout;
	}

	private function is_between(
		int $value,
		int $lowest,
		int $highest
	): bool {
		return $value >= $lowest && $value <= $highest;
	}
}