<?php
/**
 * Detects + caches paths to the external image binaries.
 *
 * @package H4B\ImageOptim
 */

namespace H4B\ImageOptim;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

final class Tools {

	private const REQUIRED = [ 'cwebp', 'cjpeg', 'djpeg', 'jpegtran', 'jpegoptim' ];
	private const OPTIONAL = [ 'avifenc', 'avifdec', 'pngquant', 'optipng' ];

	/**
	 * @return array<string,string|null> Map of tool name → absolute path or null.
	 */
	public static function detect(): array {
		static $cache = null;
		if ( null !== $cache ) {
			return $cache;
		}
		$cache = [];
		foreach ( array_merge( self::REQUIRED, self::OPTIONAL ) as $bin ) {
			$cache[ $bin ] = self::which( $bin );
		}
		return $cache;
	}

	public static function path( string $bin ): ?string {
		$tools = self::detect();
		return $tools[ $bin ] ?? null;
	}

	public static function missing_required(): array {
		$tools = self::detect();
		$missing = [];
		foreach ( self::REQUIRED as $bin ) {
			if ( empty( $tools[ $bin ] ) ) {
				$missing[] = $bin;
			}
		}
		return $missing;
	}

	public static function has_avif(): bool {
		return ! empty( self::path( 'avifenc' ) );
	}

	private static function which( string $bin ): ?string {
		// Common locations first, then fall back to PATH lookup.
		foreach ( [ '/usr/bin/', '/usr/local/bin/', '/opt/local/bin/' ] as $prefix ) {
			$candidate = $prefix . $bin;
			if ( is_executable( $candidate ) ) {
				return $candidate;
			}
		}
		if ( ! function_exists( 'shell_exec' ) ) {
			return null;
		}
		$out = trim( (string) @shell_exec( 'command -v ' . escapeshellarg( $bin ) . ' 2>/dev/null' ) );
		return $out !== '' && is_executable( $out ) ? $out : null;
	}
}