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<?php
/**
 * Gravity Perks // GF Nested Forms // Auto-attach File Uploads to Parent Form Notifications
 * http://gravitywiz.com/documentation/gravity-forms-nested-forms/
 */
add_filter( 'gform_notification', function( $notification, $form, $entry ) {

	if( ! is_callable( 'gp_nested_forms' ) ) {
		return $notification;
	}

	$nested_form_fields = GFCommon::get_fields_by_type( $form, array( 'form' ) );
	if( empty( $nested_form_fields ) ) {
		return $notification;
	}

	$parent_entry = new GPNF_Entry( $entry );
	$attachments = array();

	foreach( $nested_form_fields as $nested_form_field ) {

		$child_entries = $parent_entry->get_child_entries( $nested_form_field->id );
		if( empty( $child_entries ) ) {
			continue;
		}

		$child_form    = GFAPI::get_form( $nested_form_field->gpnfForm );
		$upload_fields = GFCommon::get_fields_by_type( $child_form, array( 'fileupload' ) );
		$upload_root   = GFFormsModel::get_upload_root();

		foreach( $child_entries as $child_entry ) {
			foreach ( $upload_fields as $upload_field ) {

				// Get field value.
				$attachment_urls = rgar( $child_entry, $upload_field->id );

				// If field value is empty, skip.
				if ( empty( $attachment_urls ) ) {
					continue;
				}

				// Convert to array.
				$attachment_urls = $upload_field->multipleFiles ? json_decode( stripslashes( $attachment_urls ), true ) : array( $attachment_urls );

				// Loop through attachment URLs; replace URL with path and add to attachments.
				foreach ( $attachment_urls as $attachment_url ) {
					$attachment_url = preg_replace( '|^(.*?)/gravity_forms/|', $upload_root, $attachment_url );
					$attachments[]  = $attachment_url;
				}

			}
		}

		$notification['attachments'] = array_merge( rgar( $notification, 'attachments', array() ), $attachments );

		return $notification;
	}

}, 10, 3 );