/*
 * Copyright 2020 Paul Schaub.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.pgpainless.sop.commands;

import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPSecretKeyRing;
import org.bouncycastle.openpgp.PGPSignature;
import org.bouncycastle.util.io.Streams;
import org.pgpainless.PGPainless;
import org.pgpainless.algorithm.DocumentSignatureType;
import org.pgpainless.encryption_signing.EncryptionResult;
import org.pgpainless.encryption_signing.EncryptionStream;
import org.pgpainless.encryption_signing.ProducerOptions;
import org.pgpainless.encryption_signing.SigningOptions;
import org.pgpainless.key.SubkeyIdentifier;
import org.pgpainless.key.protection.SecretKeyRingProtector;
import org.pgpainless.sop.Print;
import picocli.CommandLine;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

import static org.pgpainless.sop.Print.err_ln;
import static org.pgpainless.sop.Print.print_ln;

@CommandLine.Command(name = "sign",
        description = "Create a detached signature on the data from standard input",
        exitCodeOnInvalidInput = 37)
public class Sign implements Runnable {

    public enum Type {
        binary,
        text
    }

    @CommandLine.Option(names = "--no-armor",
            description = "ASCII armor the output",
            negatable = true)
    boolean armor = true;

    @CommandLine.Option(names = "--as", description = "Defaults to 'binary'. If '--as=text' and the input data is not valid UTF-8, sign fails with return code 53.",
            paramLabel = "{binary|text}")
    Type type;

    @CommandLine.Parameters(description = "Secret keys used for signing",
            paramLabel = "KEY",
            arity = "1..*")
    File[] secretKeyFile;

    @Override
    public void run() {
        PGPSecretKeyRing[] secretKeys = new PGPSecretKeyRing[secretKeyFile.length];
        for (int i = 0, secretKeyFileLength = secretKeyFile.length; i < secretKeyFileLength; i++) {
            File file = secretKeyFile[i];
            try {
                PGPSecretKeyRing secretKey = PGPainless.readKeyRing().secretKeyRing(new FileInputStream(file));
                secretKeys[i] = secretKey;
            } catch (IOException | PGPException e) {
                err_ln("Error reading secret key ring " + file.getName());
                err_ln(e.getMessage());
                System.exit(1);
                return;
            }
        }
        try {
            SigningOptions signOpt = new SigningOptions();
            for (PGPSecretKeyRing signingKey : secretKeys) {
                signOpt.addDetachedSignature(SecretKeyRingProtector.unprotectedKeys(), signingKey,
                        type == Type.text ? DocumentSignatureType.CANONICAL_TEXT_DOCUMENT : DocumentSignatureType.BINARY_DOCUMENT);
            }
            ByteArrayOutputStream out = new ByteArrayOutputStream();

            EncryptionStream encryptionStream = PGPainless.encryptAndOrSign()
                    .onOutputStream(out)
                    .withOptions(ProducerOptions
                            .sign(signOpt)
                            .setAsciiArmor(armor));

            Streams.pipeAll(System.in, encryptionStream);
            encryptionStream.close();

            EncryptionResult result = encryptionStream.getResult();
            for (SubkeyIdentifier signingKey : result.getDetachedSignatures().keySet()) {
                for (PGPSignature signature : result.getDetachedSignatures().get(signingKey)) {
                    print_ln(Print.toString(signature.getEncoded(), armor));
                }
            }
        } catch (PGPException | IOException e) {
            err_ln("Error signing data.");
            err_ln(e.getMessage());
            System.exit(1);
        }
    }
}