<?php
/**
 * The post or template that a block ability reads or edits.
 *
 * @package SeebAbilities
 */

namespace SeebAbilities\Support;

use WP_Block_Template;
use WP_Error;
use WP_Post;

defined( 'ABSPATH' ) || exit;

/**
 * Block target.
 */
final class BlockTarget {

	/**
	 * Post, when the target is a post.
	 *
	 * @var WP_Post|null
	 */
	private ?WP_Post $post = null;

	/**
	 * Template, when the target is a template or template part.
	 *
	 * @var WP_Block_Template|null
	 */
	private ?WP_Block_Template $template = null;

	/**
	 * Resolves the target from the "id", "template" and "template_type" input.
	 *
	 * @param array $input Ability input.
	 *
	 * @return BlockTarget|WP_Error
	 */
	public static function from_input( array $input ) {

		$target = new self();

		if ( ! empty( $input['id'] ) ) {
			$post = Helpers::get_post( (int) $input['id'], Helpers::block_post_types() );

			if ( is_wp_error( $post ) ) {
				return $post;
			}

			$target->post = $post;

			return $target;
		}

		if ( ! empty( $input['template'] ) ) {
			$template = Templates::get( (string) $input['template'], $input['template_type'] ?? null );

			if ( is_wp_error( $template ) ) {
				return $template;
			}

			$target->template = $template;

			return $target;
		}

		return Helpers::error( 'missing_target', __( 'Pass "id" for a post, page, pattern or navigation menu, or "template" for a template or template part.', 'seeb-abilities' ) );
	}

	/**
	 * Permission check for block abilities.
	 *
	 * @param array $input Ability input.
	 * @param bool  $edit  Whether the ability changes the target.
	 *
	 * @return true|WP_Error
	 */
	public static function permission( array $input, bool $edit = true ) {

		$target = self::from_input( $input );

		if ( is_wp_error( $target ) ) {
			return $target;
		}

		if ( $target->template ) {
			return current_user_can( 'edit_theme_options' ) ? true : Helpers::forbidden( __( 'You need the edit_theme_options capability to work with templates.', 'seeb-abilities' ) );
		}

		if ( ! current_user_can( $edit ? 'edit_post' : 'read_post', $target->post->ID ) ) {
			return Helpers::forbidden();
		}

		if ( ! Helpers::can_read_content( $target->post ) ) {
			return Helpers::forbidden( __( 'This post is password protected. Only users who can edit it can read its blocks.', 'seeb-abilities' ) );
		}

		return true;
	}

	/**
	 * Current block markup.
	 *
	 * @return string
	 */
	public function content(): string {
		return $this->post ? $this->post->post_content : (string) $this->template->content;
	}

	/**
	 * Saves new block markup. Posts get a revision; theme templates get a customized copy.
	 *
	 * @param string $content Block markup.
	 *
	 * @return true|WP_Error
	 */
	public function save( string $content ) {

		if ( $this->post ) {
			Helpers::ensure_revision( $this->post->ID );

			$result = wp_update_post(
				wp_slash(
					[
						'ID'           => $this->post->ID,
						'post_content' => $content,
					]
				),
				true
			);

			if ( is_wp_error( $result ) ) {
				return $result;
			}

			$this->post = get_post( $this->post->ID );

			return true;
		}

		$template = Templates::update( $this->template, [ 'content' => $content ] );

		if ( is_wp_error( $template ) ) {
			return $template;
		}

		$this->template = $template;

		return true;
	}

	/**
	 * Describes the target for ability output.
	 *
	 * @return array
	 */
	public function describe(): array {

		if ( $this->post ) {
			return [
				'kind'  => 'post',
				'id'    => $this->post->ID,
				'type'  => $this->post->post_type,
				'title' => $this->post->post_title,
			];
		}

		return [
			'kind'  => 'template',
			'id'    => $this->template->id,
			'type'  => $this->template->type,
			'title' => Templates::format( $this->template )['title'],
		];
	}
}