<?php
/**
 * Front-end maintenance gate.
 *
 * Decides, on every front-end request, whether the visitor should see
 * the maintenance template or the normal site, then renders the
 * selected template with a 503 status when appropriate.
 */

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

class ABSD_Maintenance {

	/**
	 * @var ABSD_Settings
	 */
	private $settings;

	/**
	 * @var ABSD_Templates
	 */
	private $templates;

	/**
	 * @var ABSD_Access
	 */
	private $access;

	public function __construct( ABSD_Settings $settings, ABSD_Templates $templates, ABSD_Access $access ) {
		$this->settings  = $settings;
		$this->templates = $templates;
		$this->access    = $access;
	}

	/**
	 * Hook into WordPress. Priority 10 on template_redirect runs after
	 * WP has resolved the request but before any template output, and
	 * template_redirect does not fire for REST/AJAX/cron requests.
	 */
	public function init() {
		add_action( 'template_redirect', array( $this, 'maybe_show_maintenance_page' ) );
	}

	/**
	 * Core gate logic.
	 */
	public function maybe_show_maintenance_page() {
		$this->maybe_render_admin_preview();

		if ( ! $this->settings->get( 'maintenance_mode', false ) ) {
			return;
		}

		if ( $this->should_bypass() ) {
			return;
		}

		$this->render_maintenance_page();
	}

	/**
	 * Admin-only preview: a real, bookmarkable/refreshable URL
	 * (home_url('/') . '?absd_um_admin_preview=1') that always renders the
	 * maintenance page from the currently *saved* settings — regardless of
	 * whether Maintenance Mode is actually toggled on — so an admin can
	 * open it, save changes on the settings page, and refresh to see the
	 * latest version. Exits on match; does nothing otherwise.
	 */
	private function maybe_render_admin_preview() {
		if ( empty( $_GET['absd_um_admin_preview'] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended -- read-only, capability-gated below.
			return;
		}

		if ( ! current_user_can( 'manage_options' ) ) {
			return;
		}

		nocache_headers();

		$settings = $this->settings->get_settings();

		echo $this->render_template_preview( $settings, $settings['template'] ); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- already-escaped template markup, same as the real front-end render.

		exit;
	}

	/**
	 * Determine whether the current request/visitor should bypass the
	 * maintenance screen and see the normal site.
	 *
	 * @return bool
	 */
	private function should_bypass() {
		// Always allow WordPress core/system endpoints so the admin
		// area, login, cron and REST/AJAX keep functioning.
		if ( $this->is_system_request() ) {
			return true;
		}

		// Logged-in users who can manage the site always bypass.
		if ( is_user_logged_in() && current_user_can( 'manage_options' ) ) {
			return true;
		}

		// Private access: token in the URL for this request, or a
		// previously-issued signed cookie.
		if ( $this->settings->get( 'private_access', false ) ) {
			if ( ! empty( $_GET[ ABSD_Access::QUERY_VAR ] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
				$token = sanitize_text_field( wp_unslash( $_GET[ ABSD_Access::QUERY_VAR ] ) ); // phpcs:ignore WordPress.Security.NonceVerification.Recommended
				if ( $this->access->is_valid_token( $token ) ) {
					return true;
				}
			}

			if ( $this->access->visitor_has_bypass_cookie() ) {
				return true;
			}
		}

		/**
		 * Final filter so other plugins/mu-plugins can add their own
		 * bypass rules (e.g. allow specific IPs) without editing core.
		 *
		 * @param bool $bypass Whether to bypass the maintenance screen.
		 */
		return (bool) apply_filters( 'absd_um_bypass_maintenance', false );
	}

	/**
	 * Requests that must never be blocked, to avoid breaking WordPress
	 * core functionality or creating redirect loops.
	 *
	 * @return bool
	 */
	private function is_system_request() {
		if ( is_admin() ) {
			return true;
		}

		if ( wp_doing_ajax() || wp_doing_cron() ) {
			return true;
		}

		if ( defined( 'REST_REQUEST' ) && REST_REQUEST ) {
			return true;
		}

		if ( defined( 'XMLRPC_REQUEST' ) && XMLRPC_REQUEST ) {
			return true;
		}

		$request_uri = isset( $_SERVER['REQUEST_URI'] ) ? wp_unslash( $_SERVER['REQUEST_URI'] ) : ''; // phpcs:ignore WordPress.Security.ValidatedSanitizedInput

		$always_allow = array(
			'wp-login.php',
			'wp-cron.php',
			'/wp-json/',
			'wp-admin',
		);

		foreach ( $always_allow as $needle ) {
			if ( false !== strpos( $request_uri, $needle ) ) {
				return true;
			}
		}

		return false;
	}

	/**
	 * Output the maintenance template with the correct headers and
	 * terminate the request.
	 */
	private function render_maintenance_page() {
		if ( ! headers_sent() ) {
			status_header( 503 );
			header( 'Retry-After: 3600' );
			nocache_headers();
		}

		$template_id = $this->settings->get( 'template', $this->templates->get_default_id() );
		$file        = $this->templates->get_template_file( $template_id );
		$context     = $this->build_template_context();

		wp_enqueue_style( 'absd-um-base', ABSD_UM_URL . 'public/css/base.css', array(), ABSD_UM_VERSION );
		wp_add_inline_style( 'absd-um-base', $this->build_inline_css( $context ) );

		/**
		 * Fires immediately before a maintenance template is rendered.
		 *
		 * @param string $template_id Template slug being rendered.
		 * @param array  $context     Template context data.
		 */
		do_action( 'absd_um_before_render', $template_id, $context );

		// Extract into local scope for simple, readable template files.
		// All keys are controlled by build_template_context() below.
		extract( $context, EXTR_SKIP ); // phpcs:ignore WordPress.PHP.DontExtract.extract_extract

		include $file;

		do_action( 'absd_um_after_render', $template_id );

		exit;
	}

	/**
	 * Render a maintenance template to an HTML string using an arbitrary
	 * (already-sanitized, not necessarily saved) settings array.
	 *
	 * Used by the admin live-preview AJAX endpoint so the settings page
	 * can show what the page will look like before the user hits Save.
	 * Unlike render_maintenance_page(), this never sends headers, fires
	 * the render hooks, or exits — it just returns markup.
	 *
	 * @param array  $settings    Sanitized settings array (see ABSD_Settings::sanitize_input()).
	 * @param string $template_id Template slug to render.
	 * @return string
	 */
	public function render_template_preview( array $settings, $template_id ) {
		$file    = $this->templates->get_template_file( $template_id );
		$context = $this->build_template_context( $settings );

		wp_enqueue_style( 'absd-um-base', ABSD_UM_URL . 'public/css/base.css', array(), ABSD_UM_VERSION );
		wp_add_inline_style( 'absd-um-base', $this->build_inline_css( $context ) );

		// Extract into local scope for simple, readable template files.
		// All keys are controlled by build_template_context() below.
		extract( $context, EXTR_SKIP ); // phpcs:ignore WordPress.PHP.DontExtract.extract_extract

		ob_start();
		include $file;
		return ob_get_clean();
	}

	/**
	 * Builds the per-request CSS custom properties (accent color, overlay
	 * opacity) attached to the 'absd-um-base' handle via wp_add_inline_style()
	 * — these two settings are chosen on the admin settings page, so they
	 * can't be baked into the static public/css/base.css file.
	 *
	 * @param array $context Template context from build_template_context().
	 * @return string
	 */
	private function build_inline_css( array $context ) {
		$accent  = sanitize_hex_color( $context['absd_accent_color'] );
		$opacity = absint( $context['absd_overlay_opacity'] );

		return sprintf(
			':root{--absd-accent:%s;--absd-overlay-opacity:%s;}',
			$accent ? $accent : '#c9a15a',
			$opacity / 100
		);
	}

	/**
	 * Build the (already-escaped-where-needed) data made available to
	 * template files.
	 *
	 * @param array|null $settings Settings array to render from. Defaults
	 *                             to the currently saved settings; pass an
	 *                             explicit array (e.g. from the live preview
	 *                             AJAX endpoint) to render unsaved values.
	 * @return array
	 */
	private function build_template_context( array $settings = null ) {
		$settings = null === $settings
			? $this->settings->get_settings()
			: wp_parse_args( $settings, ABSD_Settings::get_defaults() );

		$logo_url       = $settings['logo_id'] ? wp_get_attachment_image_url( $settings['logo_id'], 'medium' ) : '';
		$background_url = $settings['background_id'] ? wp_get_attachment_image_url( $settings['background_id'], 'full' ) : '';
		$icon_id        = $this->templates->icon_exists( $settings['icon'] ?? '' ) ? $settings['icon'] : $this->templates->get_default_icon_id();

		// "custom" has no SVG partial — it's a user-uploaded image instead.
		// Fall back to the default built-in icon if "custom" is selected
		// but nothing has been uploaded yet.
		$icon_is_custom  = false;
		$icon_custom_url = '';

		if ( 'custom' === $icon_id && ! empty( $settings['icon_custom_id'] ) ) {
			$custom_url = wp_get_attachment_image_url( $settings['icon_custom_id'], 'thumbnail' );
			if ( $custom_url ) {
				$icon_is_custom  = true;
				$icon_custom_url = $custom_url;
			}
		}

		$icon_file = $icon_is_custom ? '' : $this->templates->get_icon_file( 'custom' === $icon_id ? $this->templates->get_default_icon_id() : $icon_id );

		return array(
			'absd_heading'         => $settings['heading'],
			'absd_description'     => $settings['description'],
			'absd_small_text'      => $settings['small_text'],
			'absd_footer_text'     => $settings['footer_text'],
			'absd_retry_text'      => $settings['retry_text'],
			'absd_show_icon'       => (bool) $settings['show_icon'],
			'absd_icon_file'       => $icon_file,
			'absd_icon_is_custom'  => $icon_is_custom,
			'absd_icon_custom_url' => $icon_custom_url,
			'absd_show_contact'    => (bool) $settings['show_contact'],
			'absd_contact_text'    => $settings['contact_text'],
			'absd_overlay_opacity' => absint( $settings['overlay_opacity'] ),
			'absd_accent_color'    => $settings['accent_color'],
			'absd_logo_url'        => $logo_url ? $logo_url : '',
			'absd_background_url'  => $background_url ? $background_url : '',
		);
	}
}