<?php
/**
 * A-04 Forms.
 *
 * @package ForensixDigital
 */

declare(strict_types=1);

namespace ForensixDigital\Apps\Forms;

defined( 'ABSPATH' ) || exit;

use ForensixDigital\Apps\AppDefinition;
use ForensixDigital\Apps\AppInterface;
use ForensixDigital\Apps\SiteScan\SiteScanApp;
use ForensixDigital\Core\Plugin;
use ForensixDigital\Services\Entitlements\Edition;
use ForensixDigital\Services\Findings\FindingStore;
use ForensixDigital\Services\Permissions\Capabilities;

/**
 * Contact and quote forms with an inbox. While the app is off it adds no hooks, no shortcode
 * and no front-end output; the forms and entries stay stored.
 *
 * Public forms cannot use a WordPress nonce (pages are cached and visitors are not logged in),
 * so the submission handler relies on SpamGuard (hidden field, signed timestamp) and a rate
 * limit instead. It never trusts the data: every field is validated and every output escaped.
 */
final class FormsApp implements AppInterface {

	public const ID = 'forms';

	private const STATE_QUERY = 'forensix_r';
	private const STATE_TTL   = 300;

	/**
	 * Registry entry.
	 */
	public static function definition(): AppDefinition {
		return new AppDefinition(
			array(
				'id'                   => self::ID,
				'name'                 => __( 'Forms', 'forensix-digital' ),
				'description'          => __( 'Contact and quote forms with spam protection and an inbox. Messages are saved before any email is sent, so a failing mail never loses one.', 'forensix-digital' ),
				'category'             => 'forms',
				'edition'              => Edition::FREE,
				'features'             => array(
					'F-FORMS-01' => Edition::FREE,
					'F-FORMS-02' => Edition::FREE,
					'F-FORMS-03' => Edition::FREE,
					'F-FORMS-04' => Edition::FREE,
					'F-FORMS-05' => Edition::FREE,
					'F-FORMS-06' => Edition::FREE,
				),
				'deactivation_effects' => array(
					__( 'Forms on your pages disappear. Visitors can no longer send messages through them.', 'forensix-digital' ),
					__( 'Saved forms and messages stay in the database and you can still read them after turning the app on again.', 'forensix-digital' ),
				),
				'factory'              => static fn(): self => new self(),
			)
		);
	}

	/**
	 * Hooks the app while it is active.
	 */
	public function register(): void {
		add_shortcode( 'forensix_form', array( $this, 'shortcode' ) );
		add_action( 'admin_post_nopriv_forensix_form_submit', array( $this, 'handle_submission' ) );
		add_action( 'admin_post_forensix_form_submit', array( $this, 'handle_submission' ) );
		add_action( Retention::HOOK, array( $this, 'run_retention' ) );
		( new Privacy( new EntryStore() ) )->register();
		add_action( 'rest_api_init', array( $this, 'register_routes' ) );
		add_filter( 'forensix_admin_screens', array( $this, 'add_screen' ) );
		add_action( 'init', array( $this, 'register_block' ) );
		add_action( 'elementor/widgets/register', array( $this, 'register_widget' ) );
		add_filter( 'forensix_scan_stored_checks', array( $this, 'add_stored_checks' ) );
	}

	/**
	 * Adds the failed-notification check to a site scan.
	 *
	 * @param mixed $checks Stored-content checks of the scan.
	 * @return mixed
	 */
	public function add_stored_checks( $checks ) {
		if ( ! is_array( $checks ) ) {
			return $checks;
		}
		$checks[] = new MailFailureCheck( SiteScanApp::ID, Plugin::container()->get( FindingStore::class ), new EntryStore() );
		return $checks;
	}

	/**
	 * Registers the Gutenberg block.
	 */
	public function register_block(): void {
		( new FormBlock( array( self::class, 'render_form' ) ) )->register();
	}

	/**
	 * Registers the Elementor widget, when Elementor is active.
	 *
	 * @param mixed $manager Elementor widgets manager.
	 */
	public function register_widget( $manager ): void {
		if ( class_exists( '\Elementor\Widget_Base' ) && $manager instanceof \Elementor\Widgets_Manager ) {
			ElementorWidget::add( $manager );
		}
	}

	/**
	 * Registers the REST routes for the editor and the inbox.
	 */
	public function register_routes(): void {
		( new FormsRoutes( new FormStore(), new EntryStore() ) )->register();
	}

	/**
	 * Adds the Forms page to the Forensix menu.
	 *
	 * @param array $screens Screens.
	 * @phpstan-param array<string, array{key: string, title: string, capability: string}> $screens
	 * @return array<string, array{key: string, title: string, capability: string}>
	 */
	public function add_screen( array $screens ): array {
		$screens['forensix-forms'] = array(
			'key'        => 'forms',
			'title'      => __( 'Forms', 'forensix-digital' ),
			'capability' => Capabilities::VIEW_FORM_ENTRIES,
		);
		return $screens;
	}

	/**
	 * Creates the tables and schedules the daily clean-up.
	 */
	public function activate(): void {
		FormStore::install();
		if ( false === wp_next_scheduled( Retention::HOOK ) ) {
			wp_schedule_event( time() + HOUR_IN_SECONDS, 'daily', Retention::HOOK );
		}
	}

	/**
	 * Deletes entries older than each form's retention period.
	 */
	public function run_retention(): void {
		( new Retention( new FormStore(), new EntryStore() ) )->run();
	}

	/**
	 * Removes the hooks. Forms and entries stay.
	 */
	public function deactivate(): void {
		remove_shortcode( 'forensix_form' );
		remove_action( 'rest_api_init', array( $this, 'register_routes' ) );
		remove_action( 'init', array( $this, 'register_block' ) );
		remove_action( 'elementor/widgets/register', array( $this, 'register_widget' ) );
		( new FormBlock( array( self::class, 'render_form' ) ) )->unregister();
		remove_filter( 'forensix_admin_screens', array( $this, 'add_screen' ) );
		remove_action( 'admin_post_nopriv_forensix_form_submit', array( $this, 'handle_submission' ) );
		remove_action( 'admin_post_forensix_form_submit', array( $this, 'handle_submission' ) );
		remove_action( Retention::HOOK, array( $this, 'run_retention' ) );
		( new Privacy( new EntryStore() ) )->unregister();
		wp_clear_scheduled_hook( Retention::HOOK );
	}

	/**
	 * Drops the tables.
	 */
	public function delete_data(): void {
		FormStore::drop();
		delete_option( Captcha::OPTION );
	}

	/**
	 * The [forensix_form id="1"] shortcode.
	 *
	 * @param mixed $atts Shortcode attributes.
	 */
	public function shortcode( $atts ): string {
		$atts = shortcode_atts( array( 'id' => '0' ), is_array( $atts ) ? $atts : array(), 'forensix_form' );
		return self::render_form( absint( $atts['id'] ) );
	}

	/**
	 * The markup of a form for shortcode, block and Elementor widget.
	 *
	 * @param int $form_id Form id.
	 */
	public static function render_form( int $form_id ): string {
		$state = array();
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Only reads the key of a short-lived result; it is checked against the form id below.
		$key = isset( $_GET[ self::STATE_QUERY ] ) ? preg_replace( '/[^A-Za-z0-9]/', '', sanitize_text_field( wp_unslash( (string) $_GET[ self::STATE_QUERY ] ) ) ) : '';
		if ( is_string( $key ) && '' !== $key ) {
			$saved = get_transient( 'forensix_fs_' . $key );
			if ( is_array( $saved ) && (int) ( $saved['form_id'] ?? 0 ) === $form_id ) {
				$state = $saved;
			}
		}

		/**
		 * Filters what the form starts with: the result of the last submission, or for example
		 * answers an add-on saved earlier. Keys: status, message, errors, values (by field id).
		 *
		 * @param array $state   State, empty when nothing was sent.
		 * @param int   $form_id Form id.
		 */
		$state = self::state_shape( apply_filters( 'forensix_form_state', $state, $form_id ), $state );

		$permalink = get_permalink();
		$return    = false !== $permalink ? $permalink : home_url( '/' );
		$html      = ( new FormRenderer( new FormStore() ) )->render( $form_id, $state, time(), $return );
		if ( '' !== $html ) {
			self::enqueue_assets();
		}
		return FormMarkup::escape( $html );
	}

	/**
	 * Front-end script of the forms (shows the value of range fields).
	 */
	private static function enqueue_assets(): void {
		wp_enqueue_script(
			'fxd-forms',
			FORENSIX_URL . 'assets/forms.js',
			array(),
			FORENSIX_VERSION,
			array(
				'in_footer' => true,
				'strategy'  => 'defer',
			)
		);
	}

	/**
	 * Takes the result of the forensix_form_state filter if it has the right shape.
	 *
	 * @param mixed                $candidate Filter result.
	 * @param array<string, mixed> $fallback  State before the filter.
	 * @return array{status?: string, message?: string, errors?: array<string, string>, values?: array<string, string>}
	 */
	private static function state_shape( mixed $candidate, array $fallback ): array {
		$source = is_array( $candidate ) ? $candidate : $fallback;
		$state  = array();
		if ( is_scalar( $source['status'] ?? null ) ) {
			$state['status'] = (string) $source['status'];
		}
		if ( is_scalar( $source['message'] ?? null ) ) {
			$state['message'] = (string) $source['message'];
		}
		if ( is_array( $source['errors'] ?? null ) ) {
			$state['errors'] = self::strings( $source['errors'] );
		}
		if ( is_array( $source['values'] ?? null ) ) {
			$state['values'] = self::strings( $source['values'] );
		}
		return $state;
	}

	/**
	 * The text values of a list, by text key.
	 *
	 * @param array<mixed> $items List.
	 * @return array<string, string>
	 */
	private static function strings( array $items ): array {
		$out = array();
		foreach ( $items as $key => $value ) {
			if ( is_scalar( $value ) ) {
				$out[ (string) $key ] = (string) $value;
			}
		}
		return $out;
	}

	/**
	 * Receives a submission, then sends the visitor back to the page with the result.
	 */
	public function handle_submission(): void {
		// phpcs:disable WordPress.Security.NonceVerification.Missing -- Public form; protected by SpamGuard and the rate limit, see the class comment.
		$back    = isset( $_POST['forensix_return'] ) ? esc_url_raw( wp_unslash( (string) $_POST['forensix_return'] ) ) : '';
		$back    = wp_validate_redirect( $back, home_url( '/' ) );
		$post    = FormInput::post( (array) wp_unslash( $_POST ) ); // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- FormInput::post() sanitises every key and value.
		$form_id = absint( $post['form_id'] ?? 0 );
		$ip      = isset( $_SERVER['REMOTE_ADDR'] ) ? (string) filter_var( sanitize_text_field( wp_unslash( $_SERVER['REMOTE_ADDR'] ) ), FILTER_VALIDATE_IP ) : '';
		$files   = FormInput::files( $_FILES ); // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- FormInput::files() sanitises every part and keeps only real uploads.
		// phpcs:enable

		$result = ( new Submitter( new FormStore(), new EntryStore() ) )->handle( $form_id, $post, time(), $ip, $files );

		if ( 'sent' === $result['status'] && '' !== $result['redirect'] ) {
			wp_redirect( $result['redirect'] ); // phpcs:ignore WordPress.Security.SafeRedirect.wp_redirect_wp_redirect -- The address was set by the form's editor and checked to be http(s).
			exit;
		}

		$key = wp_generate_password( 12, false );
		set_transient(
			'forensix_fs_' . $key,
			array(
				'form_id' => $form_id,
				'status'  => $result['status'],
				'message' => $result['message'],
				'errors'  => $result['errors'],
				'values'  => $result['values'],
			),
			self::STATE_TTL
		);
		wp_safe_redirect( add_query_arg( self::STATE_QUERY, $key, $back ) . '#fxd-' . $form_id );
		exit;
	}
}