//
// PDFNet Copyright (c) 2001-2008 by PDFTron Systems Inc. All Rights Reserved.
//

using System;
using pdftron;
using pdftron.Common;
using pdftron.Filters;
using pdftron.SDF;
using pdftron.PDF;

namespace EncTestCS
{
	// A custom security handler used to obtain document password dynamically via user feedback. 
	class MySecurityHandler : StdSecurityHandler
	{
		public MySecurityHandler (Int32 key_len, Int32 enc_code) : base(key_len, enc_code) {}
		public MySecurityHandler (MySecurityHandler s) : base(s) {}

		// In this callback ask the user for password/authorization data. 
		// This may invlove a dialog box used to collect authorization data or something else.
		override public bool GetAuthorizationData (SecurityHandler.Permission p) 
		{ 
			Console.WriteLine("The input file requires user password.");
			Console.WriteLine("Please enter the password:");
			String pass = Console.ReadLine();
			InitPassword(pass);
			return true; 
		}

		// This callback could be used to customize security handler preferences.
		override public bool EditSecurityData(SDFDoc doc) { return false; }

		// This callback is used when authorization process fails. 
		override public void AuthorizeFailed() 
		{
			Console.WriteLine("Authorize failed...");
		}

		public static SecurityHandler Create(String name, Int32 key_len, Int32 enc_code) { return new MySecurityHandler(key_len, enc_code); }

		override public SecurityHandler Clone() { return new MySecurityHandler(this); }
	}

	/// <summary>
	//---------------------------------------------------------------------------------------
	// This sample shows encryption support in PDFNet. The sample reads an encrypted document and 
	// sets a new SecurityHandler. The sample also illustrates how password protection can 
	// be removed from an existing PDF document.
	//---------------------------------------------------------------------------------------
	/// </summary>
	class EncTestCS
	{
		static void Main(string[] args)
		{
			PDFNet.Initialize();
			PDFNet.SetResourcesPath("../../../../../resources");

			// Relative path to the folder containing test files.
			string input_path =  "../../../../TestFiles/";
			string output_path = "../../../../TestFiles/Output/";

			// Example 1: Securing a document with password protection and adjusting permissions 
			// on the document.
			try
			{
				// Open the test file
				Console.WriteLine("-------------------------------------------------");
				Console.WriteLine("Securing an existing document...");
				PDFDoc doc = new PDFDoc(input_path + "fish.pdf");

				if (!doc.InitSecurityHandler()) 
				{
					Console.WriteLine("Document authentication error...");
					PDFNet.Terminate();
					return;
				}
				
				// Perform some operation on the document. In this case we use low level SDF API
				// to replace the content stream of the first page with contents of file 'my_stream.txt'
				if (true)  // Optional
				{
					Console.WriteLine("Replacing the content stream, use flate compression...");

					// Get the first page dictionary using the following path: trailer/Root/Pages/Kids/0
					Obj page_dict = doc.GetTrailer().Get("Root").Value().
						Get("Pages").Value().Get("Kids").Value().GetAt(0);

					// Embed a custom stream (file mystream.txt) using Flate compression.
					StdFile embed_file = new StdFile(input_path + "my_stream.txt", StdFile.OpenMode.e_read_mode );
					FilterReader mystm = new FilterReader(embed_file);
					page_dict.Put("Contents", doc.CreateIndirectStream(mystm));
					embed_file.Close();
				}
			
				// Apply a new security handler with given security settings. 
				// In order to open saved PDF you will need a user password 'test'.
				StdSecurityHandler new_handler = new StdSecurityHandler();

				// Set a new password required to open a document
				string my_password = "test";				
				new_handler.ChangeUserPassword(my_password);

				// Set Permissions
				new_handler.SetPermission (SecurityHandler.Permission.e_print, true);
				new_handler.SetPermission (SecurityHandler.Permission.e_extract_content, false);

				// Note: document takes the ownership of new_handler.
				doc.SetSecurityHandler(new_handler);

				// Save the changes.
				Console.WriteLine("Saving modified file...");
				doc.Save(output_path + "secured.pdf", 0);
				doc.Close();

				Console.WriteLine("Done. Result saved in out.pdf...");
			}
			catch (PDFNetException e)
			{
				Console.WriteLine(e.Message);
			}

			// Example 2: Reading password protected document without user feedback.
			try
			{
				// In this sample case we will open an encrypted document that 
				// requires a user password in order to access the content.
				Console.WriteLine("-------------------------------------------------");
				Console.WriteLine("Open the password protected document from the first example...");
				PDFDoc doc = new PDFDoc(output_path + "secured.pdf");	// Open the encrypted document that we saved in the first example. 

				Console.WriteLine("Initializing security handler without any user interaction...");
				
				// At this point MySecurityHandler callbacks will be invoked. 
				// MySecurityHandler.GetAuthorizationData() should collect the password and 
				// AuthorizeFailed() is called if user repeatedly enters a wrong password.
				if (!doc.InitStdSecurityHandler("test")) 
				{
					Console.WriteLine("Document authentication error...");
					Console.WriteLine("The password is not valid.");
					return;
				}
				else 
				{
					Console.WriteLine("The password is correct! Document can now be used for reading and editing");

					// Remove the password security and save the changes to a new file.
					doc.SetSecurityHandler(null);
					doc.Save(output_path + "secured_nomore1.pdf", 0);
				}

				doc.Close();
			}
			catch (PDFNetException e)
			{
				Console.WriteLine(e.Message);
			}
			
			// Example 3: Reading password protected document with user feedback.
			try
			{
				// Register standard security. Reguired only once per application session.
				CreateDelegate del = new CreateDelegate(MySecurityHandler.Create);
				SecurityManagerSingleton.Instance().RegisterSecurityHandler("Standard", 
					new SecurityDescriptor("Standard Security", del));

				Console.WriteLine("-------------------------------------------------");
				Console.WriteLine("Open the password protected document from the first example...");
				PDFDoc doc = new PDFDoc(output_path + "secured.pdf"); // Open the encrypted document that we saved in the first example. 

				Console.WriteLine("Initializing security handler. The password will now be collected from the user");
				Console.WriteLine("Enter 'test' as the password.");

				// At this point MySecurityHandler callbacks will be invoked. 
				// MySecurityHandler.GetAuthorizationData() should collect the password and 
				// AuthorizeFailed() is called if user repeatedly enters a wrong password.
				if (!doc.InitSecurityHandler()) 
				{
					Console.WriteLine("Document authentication error...");
					Console.WriteLine("The password is not valid.");
					return;
				}
				else 
				{
					Console.WriteLine("The password is correct! Document can now be used for reading and editing");

					// Remove the password security and save the changes to a new file.
					doc.SetSecurityHandler(null);
					doc.Save(output_path + "secured_nomore2.pdf", 0);
				}

				doc.Close();
			}
			catch (PDFNetException e)
			{
				Console.WriteLine(e.Message);
			}

			PDFNet.Terminate();
		}
	}
}