/*
 * This class is part of the white paper entitled
 * "Digital Signatures for PDF documents"
 * written by Bruno Lowagie
 * 
 * For more info, go to: http://itextpdf.com/learn
 */

using System;
using System.Collections.Generic;
using Org.BouncyCastle.Tsp;
using Org.BouncyCastle.X509;
using iTextSharp.text;
using iTextSharp.text.log;
using iTextSharp.text.pdf;
using iTextSharp.text.pdf.security;

namespace signatures.chapter5 {
    class C5_02_SignatureInfo : C5_01_SignatureIntegrity {
        public const String EXAMPLE1 = "../../../../results/chapter2/step_4_signed_by_alice_bob_carol_and_dave.pdf";
        public const String EXAMPLE2 = "../../../../results/chapter3/hello_cacert_ocsp_ts.pdf";
        public const String EXAMPLE3 = "../../../../results/chapter3/hello_token.pdf";
        public const String EXAMPLE4 = "../../../../results/chapter2/hello_signed4.pdf";
        public const String EXAMPLE5 = "../../../../results/chapter4/hello_smartcard_Signature.pdf";
        public const String EXAMPLE6 = "../../../../results/chapter2/field_metadata.pdf";

	    public SignaturePermissions InspectSignature(AcroFields fields, String name, SignaturePermissions perms) {
		    IList<AcroFields.FieldPosition> fps = fields.GetFieldPositions(name);
		    if (fps != null && fps.Count > 0) {
			    AcroFields.FieldPosition fp = fps[0];
			    Rectangle pos = fp.position;
			    if (pos.Width == 0 || pos.Height == 0) {
				    Console.WriteLine("Invisible signature");
			    }
			    else {
				    Console.WriteLine("Field on page {0}; llx: {1}, lly: {2}, urx: {3}; ury: {4}",
					    fp.page, pos.Left, pos.Bottom, pos.Right, pos.Top);
			    }
		    }
    		
		    PdfPKCS7 pkcs7 = VerifySignature(fields, name);
		    Console.WriteLine("Digest algorithm: " + pkcs7.GetHashAlgorithm());
		    Console.WriteLine("Encryption algorithm: " + pkcs7.GetEncryptionAlgorithm());
		    Console.WriteLine("Filter subtype: " + pkcs7.GetFilterSubtype());
		    X509Certificate cert = pkcs7.SigningCertificate;
			    Console.WriteLine("Name of the signer: " + CertificateInfo.GetSubjectFields(cert).GetField("CN"));
		    if (pkcs7.SignName != null)
			    Console.WriteLine("Alternative name of the signer: " + pkcs7.SignName);
		    
		    Console.WriteLine("Signed on: " + pkcs7.SignDate.ToString("yyyy-MM-dd HH:mm:ss.ff"));
            if (!pkcs7.TimeStampDate.Equals(DateTime.MaxValue)) {
			    Console.WriteLine("TimeStamp: " + pkcs7.TimeStampDate.ToString("yyyy-MM-dd HH:mm:ss.ff"));
			    TimeStampToken ts = pkcs7.TimeStampToken;
			    Console.WriteLine("TimeStamp service: " + ts.TimeStampInfo.Tsa);
			    Console.WriteLine("Timestamp verified? " + pkcs7.VerifyTimestampImprint());
		    }
		    Console.WriteLine("Location: " + pkcs7.Location);
		    Console.WriteLine("Reason: " + pkcs7.Reason);
		    PdfDictionary sigDict = fields.GetSignatureDictionary(name);
		    PdfString contact = sigDict.GetAsString(PdfName.CONTACTINFO);
		    if (contact != null)
			    Console.WriteLine("Contact info: " + contact);
		    perms = new SignaturePermissions(sigDict, perms);
		    Console.WriteLine("Signature type: " + (perms.Certification ? "certification" : "approval"));
		    Console.WriteLine("Filling out fields allowed: " + perms.FillInAllowed);
		    Console.WriteLine("Adding annotations allowed: " + perms.AnnotationsAllowed);
		    foreach (SignaturePermissions.FieldLock Lock in perms.FieldLocks) {
			    Console.WriteLine("Lock: " + Lock);
		    }
            return perms;
	    }
    	
	    public void InspectSignatures(String path) {
		    Console.WriteLine(path);
            PdfReader reader = new PdfReader(path);
            AcroFields fields = reader.AcroFields;
            List<String> names = fields.GetSignatureNames();
            SignaturePermissions perms = null;
		    foreach (String name in names) {
			    Console.WriteLine("===== " + name + " =====");
			    perms = InspectSignature(fields, name, perms);
		    }
		    Console.WriteLine();
	    }
    	
	    static void Main(String[] args) {
		    LoggerFactory.GetInstance().SetLogger(new SysoLogger());
		    C5_02_SignatureInfo app = new C5_02_SignatureInfo();
		    app.InspectSignatures(EXAMPLE1);
		    app.InspectSignatures(EXAMPLE2);
		    app.InspectSignatures(EXAMPLE3);
		    app.InspectSignatures(EXAMPLE4);
		    app.InspectSignatures(EXAMPLE5);
		    app.InspectSignatures(EXAMPLE6);
	    }
    }
}