<?php
/**
 * Thumbnail Regenerator Class
 *
 * Regenerates thumbnail files for media library images
 *
 * @package AI_Thumbnails_Maker
 * @since 1.0.0
 */

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

/**
 * Thumbnail Regenerator class
 */
class AITM_Thumbnail_Regenerator {

	/**
	 * Regenerate thumbnails for an attachment
	 *
	 * @param int   $attachment_id Attachment ID.
	 * @param array $options Regeneration options.
	 * @return array Result data.
	 */
	public function regenerate_attachment( $attachment_id, $options = array() ) {
		$attachment = get_post( $attachment_id );

		if ( ! $attachment || $attachment->post_type !== 'attachment' ) {
			return array(
				'success'       => false,
				'message'       => __( 'Invalid attachment', 'ai-thumbnails-maker' ),
				'attachment_id' => $attachment_id,
			);
		}

		// Check if it's an image
		if ( ! wp_attachment_is_image( $attachment_id ) ) {
			return array(
				'success'       => false,
				'message'       => __( 'Attachment is not an image', 'ai-thumbnails-maker' ),
				'attachment_id' => $attachment_id,
				'title'         => $attachment->post_title,
			);
		}

		// Get fullsize image path
		$fullsizepath = get_attached_file( $attachment_id );

		if ( ! $fullsizepath || ! file_exists( $fullsizepath ) ) {
			return array(
				'success'       => false,
				'message'       => __( 'Original image file not found', 'ai-thumbnails-maker' ),
				'attachment_id' => $attachment_id,
				'title'         => $attachment->post_title,
			);
		}

		// Parse options
		$only_missing = isset( $options['only_missing'] ) ? (bool) $options['only_missing'] : true;
		$delete_old   = isset( $options['delete_old'] ) ? (bool) $options['delete_old'] : false;

		// Get old metadata before regeneration
		$old_metadata = wp_get_attachment_metadata( $attachment_id );

		// Filter to skip existing thumbnails if needed
		if ( $only_missing ) {
			add_filter( 'intermediate_image_sizes_advanced', array( $this, 'filter_only_missing_sizes' ), 10, 3 );
			$this->old_metadata     = $old_metadata;
			$this->skipped_sizes    = array();
			$this->current_att_id = $attachment_id;
		}

		// Regenerate thumbnails
		require_once ABSPATH . 'wp-admin/includes/image.php';
		$new_metadata = wp_generate_attachment_metadata( $attachment_id, $fullsizepath );

		// Restore skipped thumbnails
		if ( $only_missing ) {
			foreach ( $this->skipped_sizes as $skipped_size ) {
				if ( ! empty( $old_metadata['sizes'][ $skipped_size ] ) ) {
					$new_metadata['sizes'][ $skipped_size ] = $old_metadata['sizes'][ $skipped_size ];
				}
			}
			remove_filter( 'intermediate_image_sizes_advanced', array( $this, 'filter_only_missing_sizes' ), 10 );
		}

		// Delete old unregistered thumbnails
		if ( $delete_old ) {
			$this->delete_old_thumbnails( $attachment_id, $old_metadata, $new_metadata );
		}

		// Update metadata
		wp_update_attachment_metadata( $attachment_id, $new_metadata );

		// Count generated sizes
		$sizes_generated = isset( $new_metadata['sizes'] ) ? count( $new_metadata['sizes'] ) : 0;

		return array(
			'success'         => true,
			'message'         => __( 'Thumbnails regenerated successfully', 'ai-thumbnails-maker' ),
			'attachment_id'   => $attachment_id,
			'title'           => $attachment->post_title,
			'sizes_generated' => $sizes_generated,
			'thumbnail_url'   => wp_get_attachment_image_url( $attachment_id, 'thumbnail' ),
		);
	}

	/**
	 * Old metadata for comparison
	 *
	 * @var array
	 */
	private $old_metadata = array();

	/**
	 * Skipped thumbnail sizes
	 *
	 * @var array
	 */
	private $skipped_sizes = array();

	/**
	 * Current attachment ID being processed
	 *
	 * @var int
	 */
	private $current_att_id = 0;

	/**
	 * Filter to only regenerate missing thumbnail sizes
	 *
	 * @param array  $sizes         Array of thumbnail sizes.
	 * @param array  $metadata      Current attachment metadata.
	 * @param int    $attachment_id Attachment ID.
	 * @return array Filtered sizes.
	 */
	public function filter_only_missing_sizes( $sizes, $metadata, $attachment_id ) {
		if ( $attachment_id !== $this->current_att_id ) {
			return $sizes;
		}

		if ( empty( $this->old_metadata['sizes'] ) || ! is_array( $this->old_metadata['sizes'] ) ) {
			return $sizes;
		}

		foreach ( $sizes as $size_name => $size_data ) {
			// Check if this size already exists
			if ( isset( $this->old_metadata['sizes'][ $size_name ] ) ) {
				$old_size = $this->old_metadata['sizes'][ $size_name ];

				// Check if dimensions match
				if ( isset( $old_size['width'], $old_size['height'] ) &&
					$old_size['width'] == $size_data['width'] &&
					$old_size['height'] == $size_data['height'] ) {

					// Check if file exists
					$upload_dir = wp_upload_dir();
					$file_path  = path_join( $upload_dir['basedir'], dirname( $this->old_metadata['file'] ) );
					$file_path  = path_join( $file_path, $old_size['file'] );

					if ( file_exists( $file_path ) ) {
						// Skip this size
						$this->skipped_sizes[] = $size_name;
						unset( $sizes[ $size_name ] );
					}
				}
			}
		}

		return $sizes;
	}

	/**
	 * Delete old unregistered thumbnail files
	 *
	 * @param int   $attachment_id Attachment ID.
	 * @param array $old_metadata  Old metadata.
	 * @param array $new_metadata  New metadata.
	 */
	private function delete_old_thumbnails( $attachment_id, $old_metadata, $new_metadata ) {
		if ( empty( $old_metadata['sizes'] ) ) {
			return;
		}

		$registered_sizes = get_intermediate_image_sizes();
		$upload_dir       = wp_upload_dir();
		$file_path        = path_join( $upload_dir['basedir'], dirname( $old_metadata['file'] ) );

		foreach ( $old_metadata['sizes'] as $size_name => $size_data ) {
			// Skip if size is still registered
			if ( in_array( $size_name, $registered_sizes, true ) ) {
				continue;
			}

			// Delete the file
			$old_file = path_join( $file_path, $size_data['file'] );
			if ( file_exists( $old_file ) ) {
				wp_delete_file( $old_file );
			}
		}
	}

	/**
	 * Get all registered thumbnail sizes
	 *
	 * @return array List of thumbnail sizes.
	 */
	public function get_registered_sizes() {
		global $_wp_additional_image_sizes;

		$sizes = array();

		// Get default WordPress sizes
		$default_sizes = array( 'thumbnail', 'medium', 'medium_large', 'large' );

		foreach ( $default_sizes as $size_name ) {
			$width  = get_option( $size_name . '_size_w' );
			$height = get_option( $size_name . '_size_h' );
			$crop   = get_option( $size_name . '_crop' );

			if ( ! $width && ! $height ) {
				continue;
			}

			$sizes[ $size_name ] = array(
				'label'  => ucfirst( str_replace( '_', ' ', $size_name ) ),
				'width'  => $width,
				'height' => $height,
				'crop'   => $crop,
			);
		}

		// Get additional sizes registered by themes/plugins
		if ( isset( $_wp_additional_image_sizes ) && is_array( $_wp_additional_image_sizes ) ) {
			foreach ( $_wp_additional_image_sizes as $size_name => $size_data ) {
				$sizes[ $size_name ] = array(
					'label'  => ucfirst( str_replace( array( '_', '-' ), ' ', $size_name ) ),
					'width'  => isset( $size_data['width'] ) ? $size_data['width'] : 0,
					'height' => isset( $size_data['height'] ) ? $size_data['height'] : 0,
					'crop'   => isset( $size_data['crop'] ) ? $size_data['crop'] : false,
				);
			}
		}

		return $sizes;
	}
}