<?php
class LP_Block_Template_Utils {
	protected static $instance = null;

	const PLUGIN_SLUG = 'learnpress/learnpress';

	public function supports_block_templates() {
		if ( ( ! function_exists( 'wp_is_block_theme' ) || ! wp_is_block_theme() ) && ( ! function_exists( 'gutenberg_supports_block_templates' ) || ! gutenberg_supports_block_templates() ) ) {
			return false;
		}

		return true;
	}

	public function theme_has_template( $template_name ) {
		return is_readable( get_template_directory() . '/block-templates/' . $template_name . '.html' ) || is_readable( get_stylesheet_directory() . '/block-templates/' . $template_name . '.html' );
	}

	public function create_new_block_template_object( $template_file, $template_type, $template_slug, $template_is_from_theme = false ) {
		$theme_name = wp_get_theme()->get( 'TextDomain' );

		$new_template_item = array(
			'slug'        => $template_slug,
			'id'          => $template_is_from_theme ? $theme_name . '//' . $template_slug : self::PLUGIN_SLUG . '//' . $template_slug,
			'path'        => $template_file,
			'type'        => $template_type,
			'theme'       => $template_is_from_theme ? $theme_name : self::PLUGIN_SLUG,
			// Plugin was agreed as a valid source value despite existing inline docs at the time of creating: https://github.com/WordPress/gutenberg/issues/36597#issuecomment-976232909.
			'source'      => $template_is_from_theme ? 'theme' : 'plugin',
			'title'       => $this->convert_slug_to_title( $template_slug ),
			'description' => '',
			'post_types'  => array(), // Don't appear in any Edit Post template selector dropdown.
		);

		return (object) $new_template_item;
	}

	public function gutenberg_get_template_paths( $base_directory ) {
		$path_list = array();
		if ( file_exists( $base_directory ) ) {
			$nested_files      = new \RecursiveIteratorIterator( new \RecursiveDirectoryIterator( $base_directory ) );
			$nested_html_files = new \RegexIterator( $nested_files, '/^.+\.html$/i', \RecursiveRegexIterator::GET_MATCH );
			foreach ( $nested_html_files as $path => $file ) {
				$path_list[] = $path;
			}
		}
		return $path_list;
	}

	public function generate_template_slug_from_path( $path, $directory_name = 'block-templates' ) {
		return substr( $path, strpos( $path, $directory_name . DIRECTORY_SEPARATOR ) + 1 + strlen( $directory_name ), -5 );
	}

	public function convert_slug_to_title( $template_slug ) {
		switch ( $template_slug ) {
			case 'single-lp_course':
				return __( 'Single Course', 'learnpress' );
			case 'archive-lp_course':
				return __( 'Archive Course Page', 'learnpress' );
			case 'taxonomy-lp_course_cat':
				return __( 'Course Category Page', 'learnpress' );
			case 'taxonomy-lp_course_tag':
				return __( 'Course Tag Page', 'learnpress' );
			default:
				// Replace all hyphens and underscores with spaces.
				return ucwords( preg_replace( '/[\-_]/', ' ', $template_slug ) );
		}
	}

	public static function gutenberg_build_template_result_from_post( $post ) {
		$terms = get_the_terms( $post, 'wp_theme' );

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

		if ( ! $terms ) {
			return new \WP_Error( 'template_missing_theme', __( 'No theme is defined for this template.', 'learnpress' ) );
		}

		$theme          = $terms[0]->name;
		$has_theme_file = true;

		$template                 = new \WP_Block_Template();
		$template->wp_id          = $post->ID;
		$template->id             = $theme . '//' . $post->post_name;
		$template->theme          = $theme;
		$template->content        = $post->post_content;
		$template->slug           = $post->post_name;
		$template->source         = 'custom';
		$template->type           = $post->post_type;
		$template->description    = $post->post_excerpt;
		$template->title          = $post->post_title;
		$template->status         = $post->post_status;
		$template->has_theme_file = $has_theme_file;
		$template->is_custom      = false;
		$template->post_types     = array(); // Don't appear in any Edit Post template selector dropdown.

		if ( 'wp_template_part' === $post->post_type ) {
			$type_terms = get_the_terms( $post, 'wp_template_part_area' );
			if ( ! is_wp_error( $type_terms ) && false !== $type_terms ) {
				$template->area = $type_terms[0]->name;
			}
		}

		if ( self::PLUGIN_SLUG === $theme || 'learnpress' === strtolower( $theme ) ) {
			$template->origin = 'plugin';
		}

		return $template;
	}

	public function gutenberg_build_template_result_from_file( $template_file, $template_type ) {
		$template_file = (object) $template_file;

		// If the theme has an archive-course.html template but does not have course taxonomy templates
		// then we will load in the archive-course.html template from the theme to use for course taxonomies on the frontend.
		$template_is_from_theme = 'theme' === $template_file->source;
		$theme_name             = wp_get_theme()->get( 'TextDomain' );

		// phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
		$template_content  = file_get_contents( $template_file->path );
		$template          = new \WP_Block_Template();
		$template->id      = $template_is_from_theme ? $theme_name . '//' . $template_file->slug : self::PLUGIN_SLUG . '//' . $template_file->slug;
		$template->theme   = $template_is_from_theme ? $theme_name : self::PLUGIN_SLUG;
		$template->content = $this->gutenberg_inject_theme_attribute_in_content( $template_content );
		// Plugin was agreed as a valid source value despite existing inline docs at the time of creating: https://github.com/WordPress/gutenberg/issues/36597#issuecomment-976232909.
		$template->source         = $template_file->source ? $template_file->source : 'plugin';
		$template->slug           = $template_file->slug;
		$template->type           = $template_type;
		$template->title          = ! empty( $template_file->title ) ? $template_file->title : $this->convert_slug_to_title( $template_file->slug );
		$template->status         = 'publish';
		$template->has_theme_file = true;
		$template->origin         = $template_file->source;
		$template->is_custom      = false; // Templates loaded from the filesystem aren't custom, ones that have been edited and loaded from the DB are.
		$template->post_types     = array(); // Don't appear in any Edit Post template selector dropdown.

		if ( 'wp_template_part' === $template_type ) {
			$template->area = 'uncategorized';
		}

		return $template;
	}

	public function gutenberg_inject_theme_attribute_in_content( $template_content ) {
		$has_updated_content = false;
		$new_content         = '';
		$template_blocks     = parse_blocks( $template_content );

		$blocks = $this->gutenberg_flatten_blocks( $template_blocks );
		foreach ( $blocks as &$block ) {
			if (
				'core/template-part' === $block['blockName'] &&
				! isset( $block['attrs']['theme'] )
			) {
				$block['attrs']['theme'] = wp_get_theme()->get_stylesheet();
				$has_updated_content     = true;
			}
		}

		if ( $has_updated_content ) {
			foreach ( $template_blocks as &$block ) {
				$new_content .= serialize_block( $block );
			}

			return $new_content;
		}

		return $template_content;
	}

	public function gutenberg_flatten_blocks( &$blocks ) {
		$all_blocks = array();
		$queue      = array();
		foreach ( $blocks as &$block ) {
			$queue[] = &$block;
		}
		$queue_count = count( $queue );

		while ( $queue_count > 0 ) {
			$block = &$queue[0];
			array_shift( $queue );
			$all_blocks[] = &$block;

			if ( ! empty( $block['innerBlocks'] ) ) {
				foreach ( $block['innerBlocks'] as &$inner_block ) {
					$queue[] = &$inner_block;
				}
			}

			$queue_count = count( $queue );
		}

		return $all_blocks;
	}

	public static function instance() {
		if ( ! self::$instance ) {
			self::$instance = new self();
		}

		return self::$instance;
	}
}