<?php
namespace Footloom;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

// Go links like /go/summer-sale. The click is recorded on the server, then the visitor is sent on
// to the external URL. Answered on plugins_loaded, like tracking requests, so redirects stay fast.
// Visitor ids live in the browser, so clicks are counted on their own and not tied to a visitor.
class Redirects {

	public static function register() {
		add_action( 'plugins_loaded', array( self::class, 'handle' ), 1 );
	}

	public static function prefix() {
		return (string) get_option( 'footloom_redirect_prefix', 'go' );
	}

	public static function all() {
		return (array) get_option( 'footloom_redirects', array() );
	}

	public static function go_url( $slug ) {
		return home_url( '/' . self::prefix() . '/' . $slug );
	}

	public static function handle() {
		$uri  = isset( $_SERVER['REQUEST_URI'] ) ? sanitize_text_field( wp_unslash( $_SERVER['REQUEST_URI'] ) ) : '';
		$path = trim( strtolower( (string) wp_parse_url( $uri, PHP_URL_PATH ) ), '/' );

		// Sites installed in a subfolder have it at the start of every path.
		$home = trim( strtolower( (string) wp_parse_url( home_url(), PHP_URL_PATH ) ), '/' );
		if ( '' !== $home ) {
			if ( 0 !== strpos( $path . '/', $home . '/' ) ) {
				return;
			}
			$path = ltrim( substr( $path, strlen( $home ) ), '/' );
		}

		if ( ! preg_match( '#^' . preg_quote( self::prefix(), '#' ) . '/([a-z0-9_-]+)$#', $path, $m ) ) {
			return;
		}

		$redirect = null;
		foreach ( self::all() as $item ) {
			if ( $item['slug'] === $m[1] ) {
				$redirect = $item;
				break;
			}
		}
		// Unknown slugs fall through to WordPress, which shows its normal 404.
		if ( ! $redirect ) {
			return;
		}

		$ua = isset( $_SERVER['HTTP_USER_AGENT'] ) ? sanitize_text_field( wp_unslash( $_SERVER['HTTP_USER_AGENT'] ) ) : '';
		if ( ! Collector::is_bot( $ua ) && ! Collector::is_excluded_user() ) {
			list( $device, $browser, $os ) = Collector::parse_ua( $ua );
			$referrer = isset( $_SERVER['HTTP_REFERER'] ) ? esc_url_raw( wp_unslash( $_SERVER['HTTP_REFERER'] ) ) : '';

			Collector::insert( Plugin::table( 'clicks' ), array(
				'slug'          => $redirect['slug'],
				'created_at'    => gmdate( 'Y-m-d H:i:s' ),
				'referrer_host' => Collector::referrer_host( $referrer ),
				'country'       => Geo::country(),
				'device'        => $device,
				'browser'       => $browser,
				'os'            => $os,
			) );
		}

		// 302 and no-store, so browsers and caches come back to us every time and each click is counted.
		nocache_headers();
		header( 'X-Robots-Tag: noindex' );
		// phpcs:ignore WordPress.Security.SafeRedirect.wp_redirect_wp_redirect -- Go links point to external sites on purpose. Only admins can set them.
		wp_redirect( $redirect['url'], 302, 'Footloom' );
		exit;
	}
}