<?php

class WPML_ACF_Attachments implements \IWPML_Backend_Action, \IWPML_Frontend_Action, \IWPML_DIC_Action {
	/**
	 * @var array Pairs of original - translation for already processed attachments during custom field copying.
	 */
	private static $attachment_fields_copied = array();

	/**
	 * Registers hooks related to attachments.
	 */
	public function add_hooks() {
		add_filter( 'acf/load_value/type=gallery', array( $this, 'load_translated_attachment' ) );
		add_filter( 'acf/load_value/type=image', array( $this, 'load_translated_attachment' ) );
		add_filter( 'acf/load_value/type=file', array( $this, 'load_translated_attachment' ) );
		add_action( 'wpml_after_update_attachment_texts', array( $this, 'copy_attachment_fields_to_translation' ), 10, 2 );
	}

	/**
	 * @param array|string|int $attachments array of attachment ids or single attachment id
	 *
	 * @return array|string|int translated attachemnt id or attachments' ids
	 */
	public function load_translated_attachment( $attachments ) {

		/**
		 * If it detects an ID ( (int)100 or (string)"203") it passes it to `wpml_object_id`
		 *
		 * @param mixed $maybeAttachmentId
		 *
		 * @return mixed|null
		 */
		$safeConvert = function ( $maybeAttachmentId ) {
			return is_int( $maybeAttachmentId ) || ( $maybeAttachmentId === ( (string) (int) $maybeAttachmentId ) )
				? apply_filters( 'wpml_object_id', $maybeAttachmentId, 'attachment', true )
				: $maybeAttachmentId;
		};

		$attachments = maybe_unserialize( $attachments );

		$translatedAttachments = [];
		if ( is_array( $attachments ) ) {
			$isArrayList = array_keys( $attachments ) === range( 0, count( $attachments ) - 1 );

			foreach ( $attachments as $key => $value ) {
				if ( $isArrayList || in_array( $key, [ 'id', 'ID' ] ) ) {
					$value = $safeConvert( $value );
				}
				$translatedAttachments[ $key ] = $value;
			}
		} else {
			$translatedAttachments = $safeConvert( $attachments );
		}

		return $translatedAttachments;
	}

	/**
	 * Copies ACF custom fields from original attachment to translation.
	 *
	 * @param int    $original_id Original post ID.
	 * @param object $translation Translation object.
	 */
	public function copy_attachment_fields_to_translation( $original_id, $translation ) {
		if ( function_exists( 'get_fields' )
			&& function_exists( 'acf_get_field' )

			/*
			 * \WPML_Media_Attachments_Duplication::synchronize_attachment_metadata runs duplication twice,
			 * I don't know why it happens, but no reason to duplicate metadata again for the same attachments pair.
			 */
			&& ! isset( self::$attachment_fields_copied[ $original_id ][ $translation->element_id ] ) ) {
			$acf_fields = get_fields( $original_id );
			if ( is_array( $acf_fields ) ) {
				foreach ( $acf_fields as $acf_field_name => $acf_field_value ) {
					$acf_field = acf_get_field( $acf_field_name );
					if ( isset( $acf_field['wpml_cf_preferences'] ) ) {
						switch ( $acf_field['wpml_cf_preferences'] ) {
							case ( WPML_COPY_CUSTOM_FIELD ):
								update_post_meta( $translation->element_id, $acf_field_name, $acf_field_value );
								break;
							case ( WPML_COPY_ONCE_CUSTOM_FIELD ):
								$translated_post_meta = get_post_meta( $translation->element_id, $acf_field_name, true );
								if ( ! $translated_post_meta ) {
									update_post_meta( $translation->element_id, $acf_field_name, $acf_field_value );
								}
								break;
						}
					}
				}
			}
			self::$attachment_fields_copied[ $original_id ][ $translation->element_id ] = 1;
		}
	}
}