<?php
/**
 * Image origin marker helper.
 * File: inc/image-origin-marker.php
 *
 * - Hooks into attachment metadata generation.
 * - Writes a signed "origin marker" into JPEG EXIF (UserComment) and IPTC.
 * - Helps prove that an image was originally generated/uploaded on this site.
 *
 * @package BongotoWooCommerce
 */

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

/**
 * Secret used to sign the marker.
 *
 * Recommended:
 * define( 'BONGOTO_WOOCOMMERCE_IMAGE_MARKER_SECRET', 'your-long-random-secret-here-123...' );
 * in wp-config.php or a child theme.
 *
 * For back-compat:
 * If BONGOTO_IMAGE_MARKER_SECRET is defined, it will be used as fallback.
 */
if ( defined( 'BONGOTO_IMAGE_MARKER_SECRET' ) && ! defined( 'BONGOTO_WOOCOMMERCE_IMAGE_MARKER_SECRET' ) ) {
	// Old constant name → map to new one.
	define( 'BONGOTO_WOOCOMMERCE_IMAGE_MARKER_SECRET', BONGOTO_IMAGE_MARKER_SECRET );
}

if ( ! defined( 'BONGOTO_WOOCOMMERCE_IMAGE_MARKER_SECRET' ) ) {
	define( 'BONGOTO_WOOCOMMERCE_IMAGE_MARKER_SECRET', 'change_this_to_a_long_random_secret' );
}

/**
 * Hook: when WordPress generates attachment metadata, embed the marker.
 */
if ( ! function_exists( 'bongoto_woocommerce_embed_marker_on_upload' ) ) {
	add_filter( 'wp_generate_attachment_metadata', 'bongoto_woocommerce_embed_marker_on_upload', 10, 2 );

	/**
	 * Embed marker into original file and all intermediate sizes (JPEG only).
	 *
	 * @param array $meta   Attachment metadata.
	 * @param int   $att_id Attachment ID.
	 * @return array
	 */
	function bongoto_woocommerce_embed_marker_on_upload( $meta, $att_id ) {
		$file = get_attached_file( $att_id );
		if ( $file ) {
			bongoto_woocommerce_embed_marker_to_path( $file, bongoto_woocommerce_build_marker( $att_id ) );
		}

		// Also embed into all generated sizes under the same attachment.
		if ( ! empty( $meta['sizes'] ) && $file ) {
			$dir = dirname( $file );

			foreach ( $meta['sizes'] as $size ) {
				if ( empty( $size['file'] ) ) {
					continue;
				}
				$p = path_join( $dir, $size['file'] );
				bongoto_woocommerce_embed_marker_to_path( $p, bongoto_woocommerce_build_marker( $att_id ) );
			}
		}

		return $meta;
	}
}

/**
 * Build a signed marker string for the given attachment ID.
 *
 * @param int $att_id Attachment ID.
 * @return string
 */
if ( ! function_exists( 'bongoto_woocommerce_build_marker' ) ) {
	function bongoto_woocommerce_build_marker( $att_id ) {
		$att_id = (int) $att_id;

		$secret = (string) BONGOTO_WOOCOMMERCE_IMAGE_MARKER_SECRET;
		$data   = $att_id . '|' . home_url();
		$sig    = hash_hmac( 'sha256', $data, $secret );

		return 'origin=' . home_url() . '; att=' . $att_id . '; sig=' . $sig;
	}
}

/**
 * Embed the given marker string into a file path (JPEG only).
 *
 * Writes:
 * - EXIF UserComment via Imagick if available.
 * - IPTC fields via iptcembed().
 *
 * @param string $path   File system path to the image.
 * @param string $marker Marker string to embed.
 * @return void
 */
if ( ! function_exists( 'bongoto_woocommerce_embed_marker_to_path' ) ) {
	function bongoto_woocommerce_embed_marker_to_path( $path, $marker ) {
		$path   = (string) $path;
		$marker = (string) $marker;

		if ( '' === $path || '' === $marker || ! file_exists( $path ) ) {
			return;
		}

		$ext = strtolower( (string) pathinfo( $path, PATHINFO_EXTENSION ) );

		// Only act on JPEGs.
		if ( ! in_array( $ext, array( 'jpg', 'jpeg' ), true ) ) {
			return;
		}

		// 1) Write EXIF UserComment via Imagick if available.
		if ( class_exists( 'Imagick' ) ) {
			try {
				$img = new Imagick( $path ); // phpcs:ignore WordPress.NamingConventions.ValidVariableName.NotSnakeCaseMemberVar
				$img->setImageProperty( 'exif:UserComment', $marker );
				$img->writeImage( $path );
				$img->clear();
				$img->destroy();
			} catch ( Exception $e ) { // phpcs:ignore Generic.CodeAnalysis.EmptyStatement.DetectedIf
				// Silently ignore and continue to IPTC.
			}
		}

		// 2) Also write IPTC (works with JPEGs).
		$iptc = array(
			'2#116' => $marker,                  // Caption/Abstract.
			'2#110' => get_bloginfo( 'name' ),   // Credit.
			'2#115' => home_url(),               // Source.
			'2#085' => get_bloginfo( 'name' ),   // By-line.
			'2#090' => home_url(),               // City (reused as URL anchor).
		);

		$data = '';

		foreach ( $iptc as $tag => $str ) {
			$tag_num = (int) substr( $tag, 2 );
			$str     = (string) $str;

			$rec  = chr( 0x1C );
			$rec .= chr( 2 );
			$rec .= chr( $tag_num );
			$rec .= chr( strlen( $str ) );
			$rec .= $str;

			$data .= $rec;
		}

		// Suppress warnings from iptcembed/file_put_contents but only write if successful.
		$content = @iptcembed( $data, $path, 0 ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
		if ( false !== $content ) {
			require_once ABSPATH . 'wp-admin/includes/file.php';
				WP_Filesystem();
				global $wp_filesystem;
				if ( $wp_filesystem ) {
					$wp_filesystem->put_contents( $path, $content, FS_CHMOD_FILE );
				}

		}
	}
}