'---------------------------------------------------------------------------------------
' Copyright (c) 2001-2009 by PDFTron Systems Inc. All Rights Reserved.
' Consult legal.txt regarding legal and license information.
'---------------------------------------------------------------------------------------
Imports System

Imports pdftron
Imports pdftron.Common
Imports pdftron.Filters
Imports pdftron.SDF
Imports pdftron.PDF

'---------------------------------------------------------------------------------------
' 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.
'---------------------------------------------------------------------------------------
Module Module1

	' A custom security handler used to obtain document password dynamically via user feedback. 
	Public Class MySecurityHandler
		Inherits StdSecurityHandler

		Sub New(ByVal key_len As Int32, ByVal enc_code As Int32)
			MyBase.New(key_len, enc_code)
		End Sub

		Sub New(ByVal s As MySecurityHandler)
			MyBase.New(s)
		End Sub

		' In this callback ask the user for password/authorization data. 
		' This may invlove a dialog box used to collect authorization data or something else.
		Public Overrides Function GetAuthorizationData(ByVal p As SecurityHandler.Permission) As Boolean
			Console.WriteLine("The input file requires user password.")
			Console.WriteLine("Please enter the password:")
			Dim pass As String = Console.ReadLine()
			InitPassword(pass)
			Return True
		End Function

		' This callback could be used to customize security handler preferences.
        Public Overloads Function EditSecurityData(ByVal doc As SDFDoc) As Boolean
            Return False
        End Function

        ' This callback is used when authorization process fails. 
        Public Overloads Sub AuthorizeFailed()
            Console.WriteLine("Authorize failed...")
        End Sub

        Public Shared Function Create(ByVal name As String, ByVal key_len As Int32, ByVal enc_code As Int32) As SecurityHandler
            Return New MySecurityHandler(key_len, enc_code)
        End Function

        Public Overloads Function Clone() As SecurityHandler
            Return New MySecurityHandler(Me)
        End Function

    End Class


	Sub Main()

		PDFNet.Initialize()

		' Relative path to the folder containing test files.
		Dim input_path As String = "../../../TestFiles/"
		Dim output_path As String = "../../../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...")
			Dim doc As PDFDoc = New PDFDoc(input_path + "fish.pdf")

			If Not doc.InitSecurityHandler() Then
				Console.WriteLine("Document authentication error...")
				Return
			End If

			' 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) Then			  ' Optional
				Console.WriteLine("Replacing the content stream, use flate compression...")

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

				' Embed a custom stream (file mystream.txt) using Flate compression.
				Dim embed_file As StdFile = New StdFile(input_path + "my_stream.txt", StdFile.OpenMode.e_read_mode)
				Dim mystm As FilterReader = New FilterReader(embed_file)
				page_dict.Put("Contents", doc.CreateIndirectStream(mystm))
				embed_file.Close()
			End If

			' Apply a new security handler with given security settings. 
			' In order to open saved PDF you will need a user password 'test'.
			Dim new_handler As StdSecurityHandler = New StdSecurityHandler

			' Set a new password required to open a document
			Dim my_password As String = "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 e As PDFNetException
			Console.WriteLine(e.Message)
		End Try

		' 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...")
			Dim doc As PDFDoc = 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 Not doc.InitStdSecurityHandler("test") Then
				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(Nothing)
				doc.Save(output_path + "secured_nomore1.pdf", 0)
			End If

			doc.Close()
		Catch e As PDFNetException
			Console.WriteLine(e.Message)
		End Try

		' Example 3: Reading password protected document with user feedback.
		Try
			' Register standard security. Reguired only once per application session.
			Dim del As CreateDelegate = New CreateDelegate(AddressOf MySecurityHandler.Create)
			SecurityManagerSingleton.Instance().RegisterSecurityHandler("Standard", _
			 New SecurityDescriptor("Standard Security", del))

			Console.WriteLine("-------------------------------------------------")
			Console.WriteLine("Open the password protected document from the first example...")
			Dim doc As PDFDoc = 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 Not doc.InitSecurityHandler() Then
				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(Nothing)
				doc.Save(output_path + "secured_nomore2.pdf", 0)
			End If

			doc.Close()
		Catch e As PDFNetException
			Console.WriteLine(e.Message)
		End Try

		PDFNet.Terminate()


	End Sub
End Module