<?php
/**
 * Small manifest helpers. Never mix file-savings totals with actual browser traffic.
 *
 * @package AffStackDevImageManager
 */

namespace AffStackDev\ImageManager;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}
/**
 * The copies of a picture as its manifest keeps them: every copy and alternative, their types and the names Image
 * Manager gives their files.
 */
final class Variants {
	/**
	 * A variant and its alternatives, each as one copy.
	 *
	 * @param array $v A manifest variant.
	 * @return array The copies.
	 */
	public static function choices( array $v ): array {
		$all = array();
		if ( ! empty( $v['file'] ) ) {
			$copy = $v;
			unset( $copy['alternatives'] );
			$all[] = $copy;
		}
		foreach ( $v['alternatives'] ?? array() as  $other ) {
			if ( is_array( $other ) && ! empty( $other['file'] ) ) {
				unset( $other['alternatives'] );
				$all[] = $other;
			}
		}
		return array_slice( $all, 0, 4 );
	}
	/**
	 * Every copy file of a manifest: copies, display sizes and watermarked copies; with retired copies asked for, also
	 * pending, retired and draft copies.
	 *
	 * @param array $manifest The manifest.
	 * @param bool  $retired  Whether to include copies kept only for cached pages.
	 * @return array The copies, one per file.
	 */
	public static function flatten( array $manifest, bool $retired = false ): array {
		$out = array();
		foreach ( $manifest['variants'] ?? array() as  $v ) {
			foreach ( self::choices( $v ) as  $c ) {
				$out[ $c['file'] ] = $c;
			}
		}
		foreach ( array_merge( $manifest['responsive'] ?? array(), $manifest['watermarked'] ?? array() ) as  $v ) {
			foreach ( self::choices( $v ) as  $c ) {
				$out[ $c['file'] ] = $c;
			}
		}
		if ( $retired ) {
			foreach ( array_merge( $manifest['pending'] ?? array(), $manifest['retired'] ?? array() ) as  $v ) {
				foreach ( self::choices( $v ) as  $c ) {
					$out[ $c['file'] ] = $c;
				}
			}
			if ( ! empty( $manifest['draft'] ) ) {
				foreach ( self::flatten( $manifest['draft'], true ) as  $c ) {
					$out[ $c['file'] ] = $c;
				}
			}
		}
		return array_values( $out );
	}
	/**
	 * The file extension for a copy's type.
	 *
	 * @param string $mime The MIME type.
	 * @return string jpg, png, webp or avif, or an empty string.
	 */
	public static function extension( string $mime ): string {
		return array(
			'image/jpeg' => 'jpg',
			'image/png'  => 'png',
			'image/webp' => 'webp',
			'image/avif' => 'avif',
		)[ $mime ] ?? '';
	}
	/**
	 * A copy's type (WebP for copies of releases that recorded none).
	 *
	 * @param array $v The copy.
	 * @return string The MIME type.
	 */
	public static function mime( array $v ): string {
		return $v['output_mime'] ?? 'image/webp';
	}
	/**
	 * Whether a name is one Image Manager gives its copy files.
	 *
	 * @param string $name The file name.
	 * @return bool True when it is.
	 */
	public static function filename( string $name ): bool {
		return (bool) preg_match( '/^(?:t|d|w)?[1-9][0-9]*-[a-f0-9]{64}\.(?:webp|jpg|png|avif)$/D', $name );
	}
}