<?php
/**
 * Core: settings storage and front-end interception.
 *
 * @package SiteHold
 */

defined( 'ABSPATH' ) || exit;

class SiteHold {

	const OPTION = 'sitehold_settings';
	const COOKIE = 'sitehold_bypass';
	const MODES  = array( 'off', 'coming_soon', 'maintenance' );

	/**
	 * Default settings.
	 *
	 * @return array
	 */
	public static function defaults() {
		return array(
			'mode'              => 'off',

			// Content.
			'cs_headline'       => __( "We're launching soon", 'sitehold' ),
			'cs_message'        => __( 'Something awesome is on its way. Stay tuned!', 'sitehold' ),
			'mt_headline'       => __( 'Under maintenance', 'sitehold' ),
			'mt_message'        => __( 'We are performing scheduled maintenance. We will be back online shortly. Thank you for your patience.', 'sitehold' ),
			'contact_email'     => '',
			'show_login_link'   => 1,

			// Countdown.
			'countdown_enabled' => 0,
			'launch_date'       => '',
			'auto_disable'      => 0,

			// Design.
			'logo_id'           => 0,
			'bg_image_id'       => 0,
			'bg_color'          => '#0f172a',
			'overlay'           => 60,
			'text_color'        => '#ffffff',
			'accent_color'      => '#6366f1',

			// Social.
			'social_facebook'   => '',
			'social_x'          => '',
			'social_instagram'  => '',
			'social_linkedin'   => '',
			'social_youtube'    => '',

			// Access.
			'bypass_roles'      => array( 'administrator' ),
			'bypass_key'        => '',
			'bypass_days'       => 2,
			'allowed_ips'       => '',
			'excluded_paths'    => '',
			'block_rest'        => 0,

			// SEO & advanced.
			'meta_title'        => '',
			'meta_description'  => '',
			'noindex'           => 1,
			'retry_after'       => 1,
		);
	}

	public static function init() {
		add_action( 'template_redirect', array( __CLASS__, 'maybe_show' ), 0 );
		add_filter( 'rest_authentication_errors', array( __CLASS__, 'maybe_block_rest' ) );
	}

	public static function activate() {
		if ( false === get_option( self::OPTION ) ) {
			$settings               = self::defaults();
			$settings['bypass_key'] = self::generate_key();
			add_option( self::OPTION, $settings );
		}
	}

	public static function generate_key() {
		return strtolower( wp_generate_password( 16, false, false ) );
	}

	/**
	 * Get all settings, or a single key.
	 *
	 * @param string|null $key Setting key.
	 * @return mixed
	 */
	public static function get( $key = null ) {
		$settings = wp_parse_args( (array) get_option( self::OPTION, array() ), self::defaults() );
		if ( null === $key ) {
			return $settings;
		}
		return isset( $settings[ $key ] ) ? $settings[ $key ] : null;
	}

	public static function set_mode( $mode ) {
		if ( ! in_array( $mode, self::MODES, true ) ) {
			return;
		}
		$settings         = self::get();
		$settings['mode'] = $mode;
		update_option( self::OPTION, $settings );
	}

	public static function is_active() {
		return 'off' !== self::get( 'mode' );
	}

	/**
	 * Launch date as a Unix timestamp in the site timezone, or 0.
	 *
	 * @return int
	 */
	public static function launch_timestamp() {
		$date = self::get( 'launch_date' );
		if ( ! $date ) {
			return 0;
		}
		try {
			$dt = new DateTime( $date, wp_timezone() );
			return $dt->getTimestamp();
		} catch ( Exception $e ) {
			return 0;
		}
	}

	/**
	 * Turn the site live automatically once the countdown has passed.
	 */
	private static function maybe_auto_disable() {
		$s = self::get();
		if ( 'off' === $s['mode'] || ! $s['countdown_enabled'] || ! $s['auto_disable'] ) {
			return;
		}
		$ts = self::launch_timestamp();
		if ( $ts && time() >= $ts ) {
			self::set_mode( 'off' );
		}
	}

	/**
	 * Whether the current visitor is allowed to see the real site.
	 *
	 * @return bool
	 */
	public static function visitor_can_bypass() {
		$s = self::get();

		if ( is_user_logged_in() ) {
			if ( current_user_can( 'manage_options' ) ) {
				return true;
			}
			$user = wp_get_current_user();
			if ( array_intersect( (array) $user->roles, (array) $s['bypass_roles'] ) ) {
				return true;
			}
		}

		if ( $s['bypass_key'] && isset( $_COOKIE[ self::COOKIE ] ) ) {
			$cookie = sanitize_text_field( wp_unslash( $_COOKIE[ self::COOKIE ] ) );
			if ( hash_equals( self::cookie_value( $s['bypass_key'] ), $cookie ) ) {
				return true;
			}
		}

		$ip = isset( $_SERVER['REMOTE_ADDR'] ) ? sanitize_text_field( wp_unslash( $_SERVER['REMOTE_ADDR'] ) ) : '';
		if ( $ip && in_array( $ip, self::lines( $s['allowed_ips'] ), true ) ) {
			return true;
		}

		return false;
	}

	private static function cookie_value( $key ) {
		return hash_hmac( 'sha256', $key, wp_salt( 'auth' ) );
	}

	private static function lines( $text ) {
		return array_values( array_filter( array_map( 'trim', preg_split( '/\r\n|\r|\n/', (string) $text ) ) ) );
	}

	/**
	 * Whether the requested path matches an excluded path rule.
	 *
	 * @return bool
	 */
	private static function is_excluded_path() {
		$rules = self::lines( self::get( 'excluded_paths' ) );
		if ( ! $rules ) {
			return false;
		}

		$uri  = isset( $_SERVER['REQUEST_URI'] ) ? esc_url_raw( wp_unslash( $_SERVER['REQUEST_URI'] ) ) : '/';
		$path = (string) wp_parse_url( $uri, PHP_URL_PATH );

		// Make the path relative to the home URL (sub-directory installs).
		$home_path = untrailingslashit( (string) wp_parse_url( home_url(), PHP_URL_PATH ) );
		if ( $home_path && 0 === strpos( $path, $home_path ) ) {
			$path = substr( $path, strlen( $home_path ) );
		}
		$path = '/' . trim( $path, '/' );

		foreach ( $rules as $rule ) {
			$rule = '/' . trim( wp_parse_url( $rule, PHP_URL_PATH ) ?? $rule, '/' );
			if ( '*' === substr( $rule, -1 ) ) {
				if ( 0 === strpos( $path, rtrim( substr( $rule, 0, -1 ), '/' ) ) ) {
					return true;
				}
			} elseif ( $path === $rule ) {
				return true;
			}
		}
		return false;
	}

	/**
	 * Handle the secret bypass link: ?sitehold_bypass=KEY.
	 */
	private static function maybe_handle_bypass_link() {
		if ( ! isset( $_GET['sitehold_bypass'] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
			return;
		}
		$given = sanitize_key( wp_unslash( $_GET['sitehold_bypass'] ) ); // phpcs:ignore WordPress.Security.NonceVerification.Recommended
		$key   = self::get( 'bypass_key' );
		if ( ! $key || ! hash_equals( $key, $given ) ) {
			return;
		}
		$days = max( 1, (int) self::get( 'bypass_days' ) );
		setcookie( self::COOKIE, self::cookie_value( $key ), time() + $days * DAY_IN_SECONDS, COOKIEPATH ? COOKIEPATH : '/', COOKIE_DOMAIN, is_ssl(), true );
		wp_safe_redirect( remove_query_arg( 'sitehold_bypass' ) );
		exit;
	}

	/**
	 * Main front-end gate.
	 */
	public static function maybe_show() {
		if ( is_admin() || wp_doing_ajax() || wp_doing_cron() || is_robots() || ( defined( 'WP_CLI' ) && WP_CLI ) ) {
			return;
		}

		// Admin preview: ?sitehold_preview=coming_soon|maintenance.
		if ( isset( $_GET['sitehold_preview'] ) && current_user_can( 'manage_options' ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
			$mode = sanitize_key( wp_unslash( $_GET['sitehold_preview'] ) ); // phpcs:ignore WordPress.Security.NonceVerification.Recommended
			self::render( 'maintenance' === $mode ? 'maintenance' : 'coming_soon' );
		}

		self::maybe_auto_disable();
		if ( ! self::is_active() ) {
			return;
		}

		self::maybe_handle_bypass_link();

		if ( self::visitor_can_bypass() || self::is_excluded_path() ) {
			return;
		}

		self::render( self::get( 'mode' ) );
	}

	/**
	 * Output the holding page and stop.
	 *
	 * @param string $mode coming_soon|maintenance.
	 */
	public static function render( $mode ) {
		$s = self::get();

		if ( ! defined( 'DONOTCACHEPAGE' ) ) {
			define( 'DONOTCACHEPAGE', true ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedConstantFound -- Standard constant read by caching plugins.
		}
		nocache_headers();

		if ( 'maintenance' === $mode ) {
			status_header( 503 );
			header( 'Retry-After: ' . max( 1, (int) $s['retry_after'] ) * HOUR_IN_SECONDS );
		} else {
			status_header( 200 );
		}
		if ( $s['noindex'] ) {
			header( 'X-Robots-Tag: noindex, nofollow', true );
		}
		header( 'Content-Type: text/html; charset=' . get_bloginfo( 'charset' ) );

		self::enqueue_assets();

		$template = apply_filters( 'sitehold_template', SITEHOLD_DIR . 'templates/page.php', $mode );
		include $template;
		exit;
	}

	/**
	 * Register the holding page assets. The page is a standalone document, so the
	 * template prints them with wp_print_styles() / wp_print_scripts().
	 */
	private static function enqueue_assets() {
		$s        = self::get();
		foreach ( array( 'bg_color', 'text_color', 'accent_color' ) as $k ) {
			$color  = sanitize_hex_color( $s[ $k ] );
			$s[ $k ] = $color ? $color : self::defaults()[ $k ];
		}
		$bg_image = $s['bg_image_id'] ? wp_get_attachment_image_url( $s['bg_image_id'], 'full' ) : '';

		wp_enqueue_style( 'sitehold-front', SITEHOLD_URL . 'assets/front.css', array(), SITEHOLD_VERSION );

		$vars = sprintf(
			':root{--sh-bg:%1$s;--sh-bg-rgb:%2$s;--sh-text:%3$s;--sh-accent:%4$s;--sh-overlay:%5$s;%6$s}',
			$s['bg_color'],
			self::hex_to_rgb( $s['bg_color'] ),
			$s['text_color'],
			$s['accent_color'],
			$bg_image ? (string) ( (int) $s['overlay'] / 100 ) : '0',
			$bg_image ? '--sh-bg-image:url("' . esc_url( $bg_image ) . '");' : ''
		);
		wp_add_inline_style( 'sitehold-front', $vars );

		if ( $s['countdown_enabled'] && self::launch_timestamp() > time() ) {
			wp_enqueue_script( 'sitehold-front', SITEHOLD_URL . 'assets/front.js', array(), SITEHOLD_VERSION, true );
		}
	}

	/**
	 * Convert a sanitized hex colour to an "r,g,b" string.
	 *
	 * @param string $hex Hex colour.
	 * @return string
	 */
	private static function hex_to_rgb( $hex ) {
		$hex = ltrim( (string) $hex, '#' );
		if ( 3 === strlen( $hex ) ) {
			$hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
		}
		return hexdec( substr( $hex, 0, 2 ) ) . ',' . hexdec( substr( $hex, 2, 2 ) ) . ',' . hexdec( substr( $hex, 4, 2 ) );
	}

	/**
	 * Optionally block the REST API for visitors while active.
	 *
	 * @param WP_Error|null|true $result Existing result.
	 * @return WP_Error|null|true
	 */
	public static function maybe_block_rest( $result ) {
		if ( null !== $result || ! self::is_active() || ! self::get( 'block_rest' ) || self::visitor_can_bypass() ) {
			return $result;
		}
		return new WP_Error( 'sitehold_rest_disabled', __( 'The site is currently unavailable.', 'sitehold' ), array( 'status' => 503 ) );
	}
}