<?php
/**
 * Admin page controller base class.
 *
 * @package FormPilot
 * @since   1.0.0
 */

declare( strict_types = 1 );

namespace FormPilot\Admin\Pages;

use FormPilot\Core\Template;
use FormPilot\Security\Request;

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

/**
 * One screen in wp-admin.
 *
 * A page describes itself — its slug, its titles and the capability it needs —
 * and names the view it renders; the base class enforces the capability and
 * hands off to the template. Subclasses never emit markup themselves.
 *
 * @since 1.0.0
 */
abstract class AbstractPage {

	/**
	 * Page slug used in the `page` query argument. Every screen redeclares it.
	 */
	protected const SLUG = '';

	/**
	 * Returns the title rendered in the browser title bar.
	 */
	abstract public function page_title(): string;

	/**
	 * Returns the label rendered in the admin menu.
	 */
	abstract public function menu_title(): string;

	/**
	 * Returns the WordPress capability required to open the screen.
	 */
	abstract public function capability(): string;

	/**
	 * Returns the view rendered by this controller.
	 */
	abstract protected function view(): string;

	/**
	 * Returns the page slug used in the `page` query argument.
	 */
	public function slug(): string {
		return static::SLUG;
	}

	/**
	 * Runs before the screen is rendered, while headers can still be sent.
	 *
	 * Form submissions, redirects and screen options belong here.
	 */
	public function load(): void {}

	/**
	 * Returns the action requested through a row link or the bulk dropdown.
	 *
	 * WordPress sends `-1` from the unselected dropdown and repeats the control
	 * at the foot of the table as `action2`, so both have to be read.
	 *
	 * @return string The action name, or an empty string.
	 */
	protected function requested_action(): string {
		$action = Request::key( 'action' );

		if ( '' === $action || '-1' === $action ) {
			$action = Request::key( 'action2' );
		}

		return '-1' === $action ? '' : $action;
	}

	/**
	 * Enforces the capability and hands off to the view.
	 */
	public function render(): void {
		if ( ! current_user_can( $this->capability() ) ) {
			wp_die(
				esc_html__( 'You do not have permission to access this page.', 'devplugins-custom-form-builder' ),
				esc_html__( 'Permission denied', 'devplugins-custom-form-builder' ),
				array( 'response' => 403 )
			);
		}

		Template::render( $this->view(), $this->data() );
	}

	/**
	 * Returns the admin URL of the screen.
	 *
	 * @param array<string, string|int> $args Optional. Extra query arguments. Default empty.
	 */
	public function url( array $args = array() ): string {
		$args = array_merge( array( 'page' => $this->slug() ), $args );

		return add_query_arg( $args, admin_url( 'admin.php' ) );
	}

	/**
	 * Returns the data passed to the view.
	 *
	 * @return array<string, mixed> Variables exposed to the template.
	 */
	protected function data(): array {
		return array();
	}
}