<?php

namespace rbRedirection;

defined( 'ABSPATH' ) || exit;

/**
 * The front end: a request that matches a redirect is sent on; one that ends
 * in "not found" is logged, and sent to the 404 fallback if there is one.
 */
class Handler {

	public static function init(): void {
		// before WordPress looks for the page: an old address of a deleted post still redirects
		add_action( 'template_redirect', array( self::class, 'handle' ), 1 );
	}

	public static function handle(): void {
		if ( is_admin() || wp_doing_ajax() || wp_doing_cron() || ( defined( 'REST_REQUEST' ) && REST_REQUEST ) || is_customize_preview() || is_preview() ) {
			return;
		}
		$uri   = Url::current_request();
		$match = Redirects::match( $uri );

		// An automatic redirect stands in for a post's old address only while nothing
		// answers there, like WordPress's own old-slug redirect: a post or page
		// published at that address since is what visitors get. A redirect made by
		// hand still sends visitors away from a live page - that one is meant.
		if ( $match && Redirects::is_automatic( $match['row'] ) && ! is_404() ) {
			$match = null;
		}

		if ( $match ) {
			$row = $match['row'];
			if ( Settings::get( 'countHits' ) ) {
				Redirects::hit( (int) $row->id );
			}
			if ( (int) $row->code === 410 ) {
				self::gone();
				return;
			}
			$to = self::with_query( $match['to'], $uri );
			// never into a loop: a redirect to the address being asked for does nothing
			if ( Url::normalize( $to ) === Url::normalize( $uri ) && self::is_local( $to ) ) {
				return;
			}
			self::send( $to, (int) $row->code );
			return;
		}

		if ( ! is_404() ) {
			return;
		}
		if ( Settings::get( 'log404' ) ) {
			NotFoundLog::record( $uri );
		}
		$fallback = (string) Settings::get( 'fallback404' );
		if ( $fallback === 'home' ) {
			self::send( home_url( '/' ), (int) Settings::get( 'fallback404Code' ) );
		} elseif ( $fallback === 'url' && Settings::get( 'fallback404Url' ) ) {
			$to = Url::absolute( (string) Settings::get( 'fallback404Url' ) );
			if ( Url::normalize( $to ) !== Url::normalize( $uri ) ) {
				self::send( $to, (int) Settings::get( 'fallback404Code' ) );
			}
		}
	}

	/** the visitor's query string goes along, unless the target has its own */
	private static function with_query( string $to, string $uri ): string {
		if ( ! Settings::get( 'keepQuery' ) || strpos( $to, '?' ) !== false ) {
			return $to;
		}
		$query = (string) wp_parse_url( $uri, PHP_URL_QUERY );
		return $query === '' ? $to : $to . '?' . $query;
	}

	private static function is_local( string $url ): bool {
		$host = wp_parse_url( $url, PHP_URL_HOST );
		return ! $host || strcasecmp( (string) $host, (string) wp_parse_url( home_url(), PHP_URL_HOST ) ) === 0;
	}

	private static function send( string $to, int $code ): void {
		/**
		 * The redirect is about to be sent.
		 */
		// phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- rb_redirection_ is this plugin's prefix (constants, options, tables, functions and hooks); Plugin Check only guesses rbRedirection from the namespace
		do_action( 'rb_redirection_before_redirect', $to, $code );
		nocache_headers();
		header( 'X-Redirect-By: RB Links Redirection' );
		// wp_redirect, not wp_safe_redirect: a redirect may go to another site on purpose
		wp_redirect( $to, $code, 'RB Links Redirection' ); // phpcs:ignore WordPress.Security.SafeRedirect.wp_redirect_wp_redirect
		exit;
	}

	/** 410: the page is gone for good; the theme's 404 template shows */
	private static function gone(): void {
		global $wp_query;
		$wp_query->set_404();
		status_header( 410 );
		nocache_headers();
	}
}