<?php
/**
 * All Forms screen controller.
 *
 * @package FormPilot
 * @since   1.0.0
 */

declare( strict_types = 1 );

namespace FormPilot\Admin\Pages;

use FormPilot\Admin\ListTables\FormsListTable;
use FormPilot\Database\Repositories\FormRepository;
use FormPilot\Security\Capabilities;
use FormPilot\Security\Nonce;
use FormPilot\Security\Request;
use FormPilot\Security\SecurityManager;

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

/**
 * Lists the existing forms and runs the row and bulk actions.
 *
 * Every write goes through a nonce check, a capability check and a redirect,
 * so a reload can never repeat a deletion.
 *
 * @since 1.0.0
 */
final class FormsPage extends AbstractPage {

	/**
	 * Page slug.
	 */
	public const SLUG = 'formpilot-forms';

	/**
	 * Query argument carrying the result of an action.
	 */
	public const MESSAGE_ARG = 'formpilot_message';

	/**
	 * Query argument carrying how many rows an action touched.
	 */
	public const COUNT_ARG = 'formpilot_count';

	/**
	 * List table, built once the screen is loaded.
	 *
	 * @var FormsListTable|null
	 */
	private ?FormsListTable $list_table = null;

	/**
	 * Constructor.
	 *
	 * @param FormRepository $forms Repository to read through.
	 */
	public function __construct( private FormRepository $forms ) {}

	/**
	 * Returns the nonce action guarding a row action.
	 *
	 * @param string $action  Action name.
	 * @param int    $form_id Form the action targets.
	 */
	public static function row_nonce_action( string $action, int $form_id ): string {
		return Nonce::action( 'form', $action, $form_id );
	}

	/**
	 * Returns the browser title.
	 */
	public function page_title(): string {
		return __( 'Forms', 'devplugins-custom-form-builder' );
	}

	/**
	 * Returns the menu label.
	 */
	public function menu_title(): string {
		return __( 'All Forms', 'devplugins-custom-form-builder' );
	}

	/**
	 * Returns the required capability.
	 */
	public function capability(): string {
		return Capabilities::get( Capabilities::MANAGE_FORMS );
	}

	/**
	 * Handles the row and bulk actions, then prepares the list table.
	 */
	public function load(): void {
		if ( ! current_user_can( $this->capability() ) ) {
			return;
		}

		$this->handle_actions();

		add_screen_option(
			'per_page',
			array(
				'label'   => __( 'Forms per page', 'devplugins-custom-form-builder' ),
				'default' => FormsListTable::PER_PAGE_DEFAULT,
				'option'  => FormsListTable::PER_PAGE_OPTION,
			)
		);

		$this->list_table = new FormsListTable( $this->forms );
		$this->list_table->prepare_items();
	}

	/**
	 * Returns the view path.
	 */
	protected function view(): string {
		return 'admin/forms/list';
	}

	/**
	 * Returns the data passed to the view.
	 *
	 * @return array<string, mixed> Variables exposed to the template.
	 */
	protected function data(): array {
		return array(
			'page_title'  => $this->page_title(),
			'add_new_url' => add_query_arg( array( 'page' => FormEditPage::SLUG ), admin_url( 'admin.php' ) ),
			'list_table'  => $this->list_table,
			'notice'      => $this->notice(),
			'search'      => Request::text( 's' ),
			'page_slug'   => self::SLUG,
		);
	}

	/**
	 * Dispatches the requested action.
	 */
	private function handle_actions(): void {
		$action = $this->requested_action();

		if ( '' === $action ) {
			return;
		}

		$selection = Request::ids( 'forms' );

		if ( array() !== $selection ) {
			$this->handle_bulk_action( $action, $selection );

			return;
		}

		$form_id = Request::int( 'form' );

		if ( 0 === $form_id ) {
			return;
		}

		match ( $action ) {
			'delete'    => $this->delete_form( $form_id ),
			'duplicate' => $this->duplicate_form( $form_id ),
			default     => null,
		};
	}

	/**
	 * Deletes a single form.
	 *
	 * @param int $form_id Form to delete.
	 */
	private function delete_form( int $form_id ): void {
		SecurityManager::verify_admin_request(
			self::row_nonce_action( 'delete', $form_id ),
			Capabilities::MANAGE_FORMS
		);

		$deleted = $this->forms->delete( $form_id );

		$this->redirect( $deleted ? 'deleted' : 'error', $deleted ? 1 : 0 );
	}

	/**
	 * Duplicates a single form.
	 *
	 * @param int $form_id Form to copy.
	 */
	private function duplicate_form( int $form_id ): void {
		SecurityManager::verify_admin_request(
			self::row_nonce_action( 'duplicate', $form_id ),
			Capabilities::MANAGE_FORMS
		);

		$new_id = $this->forms->duplicate( $form_id );

		$this->redirect( $new_id > 0 ? 'duplicated' : 'error', $new_id > 0 ? 1 : 0 );
	}

	/**
	 * Runs a bulk action over the selected forms.
	 *
	 * @param string          $action    Requested action.
	 * @param array<int, int> $selection Selected form IDs.
	 */
	private function handle_bulk_action( string $action, array $selection ): void {
		if ( 'delete' !== $action ) {
			return;
		}

		// Nonce emitted by WP_List_Table::display() for the "forms" plural.
		SecurityManager::verify_admin_request( 'bulk-formpilot-forms', Capabilities::MANAGE_FORMS );

		$deleted = 0;

		foreach ( $selection as $form_id ) {
			if ( $this->forms->delete( $form_id ) ) {
				++$deleted;
			}
		}

		$this->redirect( $deleted > 0 ? 'deleted' : 'error', $deleted );
	}

	/**
	 * Sends the browser back to a clean list URL.
	 *
	 * @param string $message Message key describing the outcome.
	 * @param int    $count   Number of affected rows.
	 */
	private function redirect( string $message, int $count ): void {
		$args = array(
			self::MESSAGE_ARG => $message,
			self::COUNT_ARG   => $count,
		);

		$search = Request::text( 's' );

		if ( '' !== $search ) {
			$args['s'] = $search;
		}

		$paged = Request::int( 'paged' );

		if ( $paged > 1 ) {
			$args['paged'] = $paged;
		}

		wp_safe_redirect( $this->url( $args ) );

		exit;
	}

	/**
	 * Builds the notice shown after an action.
	 *
	 * @return array{type: string, text: string}|null The notice, or null when there is nothing to report.
	 */
	private function notice(): ?array {
		$message = Request::key( self::MESSAGE_ARG );

		if ( '' === $message ) {
			return null;
		}

		$count = max( 0, Request::int( self::COUNT_ARG ) );

		return match ( $message ) {
			'created'    => array(
				'type' => 'success',
				'text' => __( 'Form created.', 'devplugins-custom-form-builder' ),
			),
			'updated'    => array(
				'type' => 'success',
				'text' => __( 'Form updated.', 'devplugins-custom-form-builder' ),
			),
			'duplicated' => array(
				'type' => 'success',
				'text' => __( 'Form duplicated.', 'devplugins-custom-form-builder' ),
			),
			'deleted'    => array(
				'type' => 'success',
				'text' => sprintf(
					/* translators: %s: Number of deleted forms. */
					_n( '%s form deleted.', '%s forms deleted.', $count, 'devplugins-custom-form-builder' ),
					number_format_i18n( $count )
				),
			),
			'missing'    => array(
				'type' => 'error',
				'text' => __( 'That form no longer exists.', 'devplugins-custom-form-builder' ),
			),
			default      => array(
				'type' => 'error',
				'text' => __( 'The action could not be completed.', 'devplugins-custom-form-builder' ),
			),
		};
	}

}