using PDFPatcher.Common;

namespace PDFPatcher.Processor
{
	sealed class ChangeZoomRateProcessor : IPdfInfoXmlProcessor
	{
		public string ZoomMethod { get; }
		public float ZoomRate { get; }

		public ChangeZoomRateProcessor(object zoomRate) {
			if (zoomRate is string || zoomRate == null) {
				ZoomMethod = zoomRate as string;
				ZoomRate = -1;
			}
			else if (zoomRate is float f) {
				ZoomRate = f;
			}
		}

		#region IInfoDocProcessor 成员

		public string Name => "更改缩放比例";

		public IUndoAction Process(System.Xml.XmlElement item) {
			UndoActionGroup undo;
			if (ZoomRate >= 0) {
				undo = new UndoActionGroup();
				undo.SetAttribute(item, Constants.DestinationAttributes.View, Constants.DestinationAttributes.ViewType.XYZ);
				undo.SetAttribute(item, Constants.Coordinates.ScaleFactor, ZoomRate.ToText());
			}
			else if (string.IsNullOrEmpty(ZoomMethod)) {
				undo = new UndoActionGroup();
				undo.SetAttribute(item, Constants.DestinationAttributes.View, Constants.DestinationAttributes.ViewType.XYZ);
				undo.RemoveAttribute(item, Constants.Coordinates.ScaleFactor);
			}
			else {
				return UndoAttributeAction.GetUndoAction(item, Constants.DestinationAttributes.View, ZoomMethod);
			}
			return undo;
		}

		#endregion
	}
}