<?php
/**
 * ICC profile handling — the critical fix for the Smush grey-wash bug.
 *
 * If an image has an ICC profile, KEEP IT. Stripping ICC + applying YCbCr
 * subsampling is what produced the grey-wash on rds.ink art.
 *
 * If an image has NO profile, the safest default is to embed a small sRGB v4
 * profile so browsers don't fall back to vendor-specific assumptions.
 *
 * @package H4B\ImageOptim
 */

namespace H4B\ImageOptim;

use Imagick;
use ImagickException;

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

final class ICC_Profile {

	/**
	 * Path to the bundled sRGB v4 ICC profile.
	 * If missing, we silently skip injection (the file's pixels will just
	 * be interpreted as implicit sRGB by the browser).
	 */
	public static function srgb_profile_path(): string {
		return H4B_IMG_OPTIM_DIR . 'assets/sRGB_v4_ICC_preference.icc';
	}

	/**
	 * Inspect an Imagick image and ensure an ICC profile is present.
	 * Does NOT modify the colour space — only attaches a profile.
	 *
	 * @return array{result:bool, source:string} result is true if a profile
	 *   is present/added. source is one of: 'original','injected','none'.
	 */
	public static function preserve_or_inject( Imagick $img ): array {
		try {
			$profiles = $img->getImageProfiles( 'icc', true );
		} catch ( ImagickException $e ) {
			$profiles = [];
		}
		if ( ! empty( $profiles ) ) {
			// Source has an ICC profile — leave it alone. This is the
			// common case for camera JPEGs and properly-saved Photoshop exports.
			return [ 'result' => true, 'source' => 'original' ];
		}

		// No profile. Try to inject sRGB v4 fallback.
		$profile_path = self::srgb_profile_path();
		if ( ! is_readable( $profile_path ) ) {
			return [ 'result' => false, 'source' => 'none' ];
		}

		try {
			$img->setImageColorspace( Imagick::COLORSPACE_SRGB );
			$img->profileImage( 'icc', (string) file_get_contents( $profile_path ) );
			return [ 'result' => true, 'source' => 'injected' ];
		} catch ( ImagickException $e ) {
			return [ 'result' => false, 'source' => 'none' ];
		}
	}
}