PDFPatcher/App/Processor/PdfActionExporter.MuPDF.cs

using System;
using System.Xml;
using MuPDF;
using MuPDF.Extensions;
using PDFPatcher.Common;

namespace PDFPatcher.Processor;

partial class PdfActionExporter
{
	internal void ExportGotoAction(Document pdf, PdfObject dest, PdfDictionary names, XmlWriter target) {
		target.WriteAttributeString(Constants.DestinationAttributes.Action, Constants.ActionType.Goto);
		string name;
		if (dest.IsString) {
			name = StringHelper.ReplaceControlAndBomCharacters((dest as PdfString).Value);
		}
		else if (dest.IsName) {
			name = dest.ToString();
		}
		else {
			goto ARRAY;
		}
		target.WriteAttributeString(Constants.DestinationAttributes.Named, name);
		dest = names.GetObject(name);
		if (dest.IsNull) {
			return;
		}
		if (dest.IsDictionary) {
			dest = ((PdfDictionary)dest).GetObject(PdfNames.D);
		}
		// dest 可能是 Array，转到下面处理
	ARRAY:
		if (dest.IsArray) {
			var a = (PdfArray)dest;
			if (a.Count > 0) {
				var p = a[0];
				int pn = 0;
				if (p.IsIndirect) {
					pn = pdf.LookupPageNumber(a[0]) + 1;
				}
				else if (p.IsNumber) {
					pn = p.IntegerValue + 1;
				}
				if (pn > 0) {
					target.WriteAttributeString(Constants.DestinationAttributes.Page, pn.ToText());
				}
			}
			ExportDestinationView(target, a);
		}
	}

	void ExportDestinationView(XmlWriter target, PdfArray dest) {
		if (dest.Count < 2) {
			return;
		}
		if (dest[1] is not PdfName pn) {
			return;
		}
		var m = GetDestFriendlyName(pn.PredefinedValue) ?? "无效";
		target.WriteAttributeString(Constants.DestinationAttributes.View, m);
		var p = new string[dest.Count - 2];
		PdfObject o;
		for (int i = 0; i < p.Length; i++) {
			o = dest[i + 2];
			p[i] = (o.IsNumber) ? (pn.PredefinedValue == PdfNames.XYZ && i == 2
						? o.FloatValue
						: _unitConverter.FromPoint(o.FloatValue)).ToText()
				: (o.IsNull) ? Constants.Coordinates.Unchanged
				: o.ToString();
		}
		switch (pn.PredefinedValue) {
			case PdfNames.XYZ:
				if (p.Length < 1) {
					goto default;
				}
				target.WriteAttributeString(Constants.Coordinates.Left, p[0]);
				if (p.Length > 1) {
					target.WriteAttributeString(Constants.Coordinates.Top, p[1]);
				}
				if (p.Length > 2) {
					target.WriteAttributeString(Constants.Coordinates.ScaleFactor, p[2]);
				}
				break;
			case PdfNames.Fit:
			case PdfNames.FitB:
				break;
			case PdfNames.FitBH:
			case PdfNames.FitH:
				if (p.Length < 1) {
					goto default;
				}
				target.WriteAttributeString(Constants.Coordinates.Top, p[0]);
				break;
			case PdfNames.FitV:
			case PdfNames.FitBV:
				if (p.Length < 1) {
					goto default;
				}
				target.WriteAttributeString(Constants.Coordinates.Left, p[0]);
				break;
			case PdfNames.FitR:
				if (p.Length < 1) {
					goto default;
				}
				target.WriteAttributeString(Constants.Coordinates.Left, p[0]);
				if (p.Length > 1) {
					target.WriteAttributeString(Constants.Coordinates.Bottom, p[1]);
				}
				if (p.Length > 2) {
					target.WriteAttributeString(Constants.Coordinates.Right, p[2]);
				}
				if (p.Length > 3) {
					target.WriteAttributeString(Constants.Coordinates.Top, p[3]);
				}
				break;
			default:
				System.Diagnostics.Trace.WriteLine("目标位置无效");
				break;
		}
	}

	internal static string GetDestFriendlyName(PdfNames destName) {
		return destName switch {
			PdfNames.XYZ => Constants.DestinationAttributes.ViewType.XYZ,
			PdfNames.Fit => Constants.DestinationAttributes.ViewType.Fit,
			PdfNames.FitB => Constants.DestinationAttributes.ViewType.FitB,
			PdfNames.FitBH => Constants.DestinationAttributes.ViewType.FitBH,
			PdfNames.FitBV => Constants.DestinationAttributes.ViewType.FitBV,
			PdfNames.FitV => Constants.DestinationAttributes.ViewType.FitV,
			PdfNames.FitH => Constants.DestinationAttributes.ViewType.FitH,
			PdfNames.FitR => Constants.DestinationAttributes.ViewType.FitR,
			_ => null
		};
	}

	internal void ExportAction(Document pdf, PdfDictionary action, PdfDictionary names, XmlWriter target) {
		PdfObject dest;
		if (action is null) {
			return;
		}
		switch (((action[PdfNames.S] as PdfName)?.PredefinedValue ?? PdfNames.GoTo)) {
			case PdfNames.GoTo:
				dest = action.GetObject(PdfNames.D);
				if (!dest.IsNull) {
					ExportGotoAction(pdf, dest, names, target);
				}
				return;
			case PdfNames.URI:
				target.WriteAttributeString(Constants.DestinationAttributes.Action, Constants.ActionType.Uri);
				target.WriteAttributeString(Constants.DestinationAttributes.Path, PdfHelper.GetValidXmlString(action.Get<PdfString>(PdfNames.URI)?.Value));
				return;
			case PdfNames.GoToR:
				target.WriteAttributeString(Constants.DestinationAttributes.Action, Constants.ActionType.GotoR);
				dest = action[PdfNames.D];
				if (dest.IsString) {
					target.WriteAttributeString(Constants.DestinationAttributes.Named, PdfHelper.GetValidXmlString(dest.ToString()));
				}
				else if (dest.IsName) {
					target.WriteAttributeString(Constants.DestinationAttributes.NamedN, PdfHelper.GetValidXmlString(dest.ToString()));
				}
				else if (dest.IsArray) {
					var arr = (PdfArray)dest;
					if (arr.Count > 0 && arr[0].IsNumber) {
						target.WriteAttributeString(Constants.DestinationAttributes.Page, PdfHelper.GetValidXmlString((arr[0].IntegerValue + 1).ToText()));
						ExportDestinationView(target, arr);
					}
				}
				var file = GetFile(action);
				if (file.IsNull == false) {
					ExportFileLocation(target, file);
				}
				var newWindow = action.Get<PdfBoolean>(PdfNames.NewWindow);
				if (newWindow is not null) {
					target.WriteAttributeString(Constants.DestinationAttributes.NewWindow, newWindow.Value ? Constants.Boolean.True : Constants.Boolean.False);
				}
				return;
			case PdfNames.Launch:
				target.WriteAttributeString(Constants.DestinationAttributes.Action, Constants.ActionType.Launch);
				file = GetFile(action);
				if (file.IsNull == false) {
					ExportFileLocation(target, file);
				}
				return;
			case PdfNames.JavaScript:
				target.WriteAttributeString(Constants.DestinationAttributes.Action, Constants.ActionType.Javascript);
				target.WriteAttributeString(Constants.DestinationAttributes.ScriptContent, action.Get<PdfString>(PdfNames.JS)?.Value);
				return;
		}
	}

	internal void ExportFileLocation(XmlWriter w, PdfObject file) {
		switch (file.TypeKind) {
			case Kind.Dictionary:
				var fs = file as PdfDictionary;
				if (fs.ContainsKey(PdfNames.UF)) {
					w.WriteAttributeString(Constants.DestinationAttributes.Path, PdfHelper.GetValidXmlString(fs.Get<PdfString>(PdfNames.UF)?.Value));
				}
				else if (fs.ContainsKey(PdfNames.F)) {
					w.WriteAttributeString(Constants.DestinationAttributes.Path, PdfHelper.GetValidXmlString(fs.Get<PdfString>(PdfNames.F)?.Value));
				}
				break;
			case Kind.String:
				w.WriteAttributeString(Constants.DestinationAttributes.Path, PdfHelper.GetValidXmlString(((PdfString)file).Decode(AppContext.Encodings.BookmarkEncoding)));
				break;
		}
	}

	static PdfObject GetFile(PdfDictionary action) {
		var r = action.GetValue(PdfNames.F).UnderlyingObject;
		return !r.IsNull
			? r
			: action.GetValue("Win").UnderlyingObject;
	}
}