<?php

// No need to register any attributes, just use block style's compiler
add_filter( 'register_block_type_args', 'gtm_register_line_clamp_support', 10, 2 );
function gtm_register_line_clamp_support( $args, $name ) {
	add_filter( "gtm.BlockStyleCompiler.{$name}", 'gtm_compile_css_line_clamp', 10, 3 );

	return $args;
}

function gtm_compile_css_line_clamp( $output, $attributes, $blockName ) {
	$block_style = ['classes' => [], 'style' => []];

	if ( isset( $attributes['gtmLineClamp'] ) ) {
		gtm_css_compileCssVar( $block_style,
			'line-clamp',
			$attributes['gtmLineClamp']
		);
	}

	////////////////////

	// Check rendered style to avoid unnecessary operation
	// Because this feature is applied on all blocks
	if ( ! empty( $block_style['style'] ) || ! empty( $block_style['style'] ) ) {
		// Apply to output
		$block_style['style'] = ['{{BLOCK}}' => $block_style['style']];

		return [
			'classes' => array_merge( $output['classes'], $block_style['classes'] ),
			'style'   => array_replace_recursive( $output['style'], $block_style['style'] ),
		];
	} else {
		// No changes
		return $output;
	}
}