<?php
/**
 * Image Converter Class
 *
 * @package AHS_Image_To_WebP
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class AHSITW_Converter {

	/**
	 * Constructor - Hook into WordPress.
	 */
	public function __construct() {
		add_filter( 'wp_generate_attachment_metadata', array( $this, 'handle_upload' ), 10, 2 );
	}

	/**
	 * Handle image upload.
	 *
	 * @param array $metadata
	 * @param int   $attachment_id
	 * @return array
	 */
	public function handle_upload( $metadata, $attachment_id ) {
		if ( ! AHSITW_Limiter::can_convert() ) {
			return $metadata;
		}

		$file = get_attached_file( $attachment_id );
		if ( ! $file || ! file_exists( $file ) ) {
			return $metadata;
		}

		$mime_type = get_post_mime_type( $attachment_id );
		$allowed_mimes = array( 'image/jpeg', 'image/png' );
		
		if ( ! in_array( $mime_type, $allowed_mimes, true ) ) {
			return $metadata;
		}

		// Convert and update metadata.
		return $this->update_attachment_to_webp( $attachment_id, $metadata );
	}

	/**
	 * Convert an attachment and all its sizes to WebP and update DB.
	 *
	 * @param int   $attachment_id
	 * @param array $metadata
	 * @return array Updated metadata.
	 */
	public function update_attachment_to_webp( $attachment_id, $metadata = array() ) {
		$file = get_attached_file( $attachment_id );
		if ( ! $file || ! file_exists( $file ) ) {
			update_post_meta( $attachment_id, '_AHSITW_converted', 'failed_missing' );
			return $metadata;
		}

		if ( empty( $metadata ) ) {
			$metadata = wp_get_attachment_metadata( $attachment_id );
		}

		$webp_file = $this->convert_image( $file );
		if ( $webp_file ) {
			// Update the attachment path and MIME type in WordPress.
			update_attached_file( $attachment_id, $webp_file );
			
			wp_update_post( array(
				'ID'             => $attachment_id,
				'post_mime_type' => 'image/webp',
			) );

			$old_ext = pathinfo( $file, PATHINFO_EXTENSION );
			if ( ! empty( $metadata['file'] ) ) {
				$metadata['file'] = str_replace( '.' . $old_ext, '.webp', $metadata['file'] );
			}

			// Convert all sub-sizes.
			if ( ! empty( $metadata['sizes'] ) && is_array( $metadata['sizes'] ) ) {
				$base_dir = trailingslashit( dirname( $file ) );
				foreach ( $metadata['sizes'] as $size => $size_data ) {
					if ( ! empty( $size_data['file'] ) ) {
						$size_file = $base_dir . $size_data['file'];
						$webp_size_file = $this->convert_image( $size_file );
						
						if ( $webp_size_file ) {
							$metadata['sizes'][ $size ]['file']      = basename( $webp_size_file );
							$metadata['sizes'][ $size ]['mime-type'] = 'image/webp';
						}
					}
				}
			}

			// Finalize metadata update in DB.
			wp_update_attachment_metadata( $attachment_id, $metadata );
			update_post_meta( $attachment_id, '_AHSITW_converted', current_time( 'mysql' ) );
			return $metadata;
		} else {
			// Mark as failed to avoid infinite loop.
			update_post_meta( $attachment_id, '_AHSITW_converted', 'failed_process' );
		}

		return false;
	}

	/**
	 * Convert a single image file to WebP.
	 *
	 * @param string $file_path
	 * @return string|bool Path to the WebP file on success, False on failure.
	 */
	public function convert_image( $file_path ) {
		if ( empty( $file_path ) || ! file_exists( $file_path ) ) {
			return false;
		}

		$ext = pathinfo( $file_path, PATHINFO_EXTENSION );
		if ( 'webp' === strtolower( $ext ) ) {
			return $file_path;
		}

		$webp_path = preg_replace( '/\.(jpe?g|png)$/i', '.webp', $file_path );
		if ( $webp_path === $file_path ) {
			$webp_path .= '.webp';
		}

		$editor = wp_get_image_editor( $file_path );
		if ( is_wp_error( $editor ) ) {
			return false;
		}

		$quality = absint( get_option( 'AHSITW_quality', 80 ) );
		$editor->set_quality( ( $quality >= 1 && $quality <= 100 ) ? $quality : 80 );
		
		$saved = $editor->save( $webp_path, 'image/webp' );

		if ( is_wp_error( $saved ) ) {
			return false;
		}

		return $webp_path;
	}

	/**
	 * Check if server supports WebP.
	 *
	 * @return bool
	 */
	public static function is_webp_supported() {
		return wp_image_editor_supports( array( 'mime_type' => 'image/webp' ) );
	}
}