<?php

if (defined('GTM_VERSION')) {
	return;
}

add_action('init', 'gtmt_fallback_init', 11);
function gtmt_fallback_init() {
	add_filter('get_block_templates', 'gtmt_strip_gutenmate_templates', 10, 3);
	add_filter('get_block_template', 'gtmt_strip_gutenmate_template', 10, 3);
	add_filter('body_class', 'gtmt_fallback_body_class', 10, 1);

	// Add fallback style to editor
	add_editor_style('fallback.css');

	gtmt_add_image_size_fallback();
}

/**
 * Additional body classes for css styling
 */
function gtmt_fallback_body_class($classes) {
	$comment_args = array(
		'post_id' => get_queried_object_id(),
		'count'   => true,
		'status'  => 'approve',
	);

	if (is_singular() && (comments_open() || have_comments() || get_comments($comment_args))) {
		$classes = array_merge($classes, ['gtm-has-comments-section']);
	}

	return $classes;
}

/**
 * Add fallback assets for FSE
 */
add_action('admin_enqueue_scripts', 'gtmt_fallback_fse_assets');
function gtmt_fallback_fse_assets() {
	$should_enqueue = true;

	if (is_admin()) {
		$should_enqueue = false;

		$screen = get_current_screen();
		if (isset($screen->id) && in_array($screen->id, ['site-editor', 'appearance_page_gutenberg-edit-site'])) {
			$should_enqueue = true;
		} else if (isset($screen->base) && $screen->base == 'post') {
			$should_enqueue = true;
		}
	}

	if ($should_enqueue) {
		// Workaround since FSE can't handle dynamic inline style
		// https://github.com/WordPress/gutenberg/issues/18571
		wp_enqueue_style('gtmt-fallback-inline-style', get_theme_file_uri('/assets/css/dummy-with-preview-support.css'), [], GTMT_VERSION);

		/**
		 * Perform action
		 * Use `wp_add_inline_style` to add an inline style such as Google Font css into the `gtmt-fallback-inline-style` handler
		 */
		do_action('gtmt-fallback-inline-style');
	}
}

/**
 * Strip all templates from the list and use fallback templates instead
 */
function gtmt_strip_gutenmate_templates($query_result, $query, $template_type) {
	if (!empty($query_result)) {
		$query_result = array_filter($query_result, function ($block_template) use ($template_type) {
			if (gtmt_is_fallbackable_template($block_template)) {
				$fallback_content = gtmt_get_fallback_template($block_template->slug, $template_type);

				if (!empty($fallback_content)) {
					// Keep this template but replace the content with content of fallback template
					$block_template->content = $fallback_content;
				} else {
					// Strip this template
					return null;
				}
			}

			return $block_template;
		});
	}

	return $query_result;
}

/**
 * Fallback a single template, Used in REST
 */
function gtmt_strip_gutenmate_template($block_template, $id, $template_type) {
	if (gtmt_is_fallbackable_template($block_template)) {
		$block_template->content = gtmt_get_fallback_template($block_template->slug, $template_type) ?: $block_template->content;
	}

	return $block_template;
}

/**
 * Determine the certain template is able to replace with fallback template
 */
function gtmt_is_fallbackable_template($template) {
	return ($template->source == 'theme' && is_null($template->origin));
}

/**
 * Get fallback template content, Null if not available
 */
function gtmt_get_fallback_template($slug, $template_type = 'wp_template') {
	if ('wp_template_part' === $template_type) {
		$fallback_template = get_theme_file_path("fallback-parts/{$slug}.html");
	} else { // wp_template
		$fallback_template = get_theme_file_path("fallback-templates/{$slug}.html");
	}

	$wp_filesystem = gtmt_get_wp_filesystem();

	// Return content or null if not exists
	if (file_exists($fallback_template)) {
		return $wp_filesystem->get_contents($fallback_template);
	}
}

/**
 * Fallback for image size registration when Gutenmate plugin does not activated
 */

function gtmt_add_image_size_fallback() {
	if (!defined('GTM_VERSION')) {
		$image_sizes = get_theme_support('gutenmate-image-sizes', []);

		if (!empty($image_sizes[0])) {
			foreach ($image_sizes[0] as $name => $dimension) {
				add_image_size($name, $dimension['width'] ?? 0, $dimension['height'] ?? 0, $dimension['crop'] ?? false);
			}
		}
	}
}