<?php

namespace RoosterLMS\UI;

defined( 'ABSPATH' ) || exit;

final class CardImage {

	private const FIRST_WIDTH = 300;

	private static bool $given = false;

	public static function lead(): bool {
		if ( self::$given || ! wp_high_priority_element_flag() || ( self::engine() && \Rooster\Core\Performance::has_lcp() ) ) {
			return false;
		}
		self::$given = true;
		return true;
	}

	public static function html( int $attachment_id, string $size, int $index, int $row ): string {
		$phone = function_exists( 'rooster_device_class' ) && 'mobile' === rooster_device_class();
		$attr  = array( 'alt' => '' );
		if ( $row > 0 && 0 === $index ) {
			$attr['loading']       = 'eager';
			$attr['fetchpriority'] = 'high';
		} elseif ( $row > 0 && ! $phone && $index < $row ) {
			$attr['loading'] = 'eager';
		}
		$html = wp_get_attachment_image( $attachment_id, $size, false, $attr );
		if ( '' === $html || ! self::engine() ) {
			return $html;
		}
		if ( isset( $attr['fetchpriority'] ) ) {
			return self::lead_paint( $html, $phone );
		}
		return $phone && ! isset( $attr['loading'] ) ? \Rooster\Core\Defer::later_image( $html ) : $html;
	}

	private static function lead_paint( string $html, bool $phone ): string {
		$tags = new \WP_HTML_Tag_Processor( $html );
		if ( ! $tags->next_tag( 'img' ) ) {
			return $html;
		}
		$srcset = (string) $tags->get_attribute( 'srcset' );
		$sizes  = (string) $tags->get_attribute( 'sizes' );
		$small  = $phone && '' !== $srcset ? \Rooster\Core\Performance::small_candidate( $srcset, self::FIRST_WIDTH ) : '';
		if ( '' === $small ) {
			\Rooster\Core\Performance::lcp_image( (string) $tags->get_attribute( 'src' ), $srcset, $sizes, true );
			return $html;
		}
		$tags->set_attribute( 'data-rooster-srcset', $srcset );
		$tags->set_attribute( 'data-rooster-sizes', $sizes );
		$tags->set_attribute( 'src', $small );
		$tags->remove_attribute( 'srcset' );
		$tags->remove_attribute( 'sizes' );
		\Rooster\Core\Performance::lcp_image( $small, '', '', true );
		\Rooster\Core\Defer::enqueue();
		return $tags->get_updated_html();
	}

	private static function engine(): bool {
		return method_exists( 'Rooster\Core\Defer', 'later_image' ) && method_exists( 'Rooster\Core\Defer', 'enabled' ) && method_exists( 'Rooster\Core\Defer', 'enqueue' )
			&& method_exists( 'Rooster\Core\Performance', 'small_candidate' ) && method_exists( 'Rooster\Core\Performance', 'lcp_image' ) && method_exists( 'Rooster\Core\Performance', 'has_lcp' )
			&& \Rooster\Core\Defer::enabled();
	}

	public static function reset(): void {
		self::$given = false;
	}
}