/**
 * Copyright (C) 2017-2021 Christian Pierre MOMON <cmomon@april.org>
 * Copyright (C) 2011-2013 Nicolas Vinot <aeris@imirhil.fr>
 *
 * This file is part of (April) Hebdobot.
 *
 * Hebdobot is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Hebdobot is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with Hebdobot.  If not, see <http://www.gnu.org/licenses/>
 */
package org.april.hebdobot.privatebin;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import java.util.Arrays;
import java.util.Base64;
import java.util.Random;
import java.util.zip.Deflater;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.GCMParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import javax.net.ssl.HttpsURLConnection;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.http.client.ClientProtocolException;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import fr.devinsy.strings.StringList;

/**
 * The Class PastebinClient.
 */
public class PrivatebinClient extends PrivatebinSettings
{
    private static final Logger logger = LoggerFactory.getLogger(PrivatebinClient.class);

    /**
     * Instantiates a new privatebin client.
     *
     * @param settings
     *            the settings
     */
    public PrivatebinClient(final PrivatebinSettings settings)
    {
        super(settings);
    }

    /**
     * Instantiates a new privatebin client.
     *
     * @param url
     *            the url
     */
    public PrivatebinClient(final URL url)
    {
        super();
        setServerUrl(url);
    }

    /**
     * Paste.
     *
     * @param text
     *            the text
     * @return the string
     * @throws PrivatebinException
     *             the privatebin exception
     */
    public String paste(final String text) throws PrivatebinException
    {
        String result;

        result = null;
        try
        {
            // Note: the following code is based on:
            // https://github.com/PrivateBin/PrivateBin/wiki/API
            // https://github.com/kkingsley-BF/PrivateBin-Groovy/blob/master/Paste.groovy

            // Build message to encrypt.
            JSONObject pasteDataJson = new JSONObject();
            pasteDataJson.put("paste", text);
            String pasteData = pasteDataJson.toJSONString();
            // logger.debug("pasteData={}", pasteData);

            // Compression.
            byte[] pasteDataBytes;
            if (this.compression == Compression.ZLIB)
            {
                Deflater zipDeflater = new Deflater();
                ByteArrayOutputStream stream = new ByteArrayOutputStream();
                zipDeflater.setInput(pasteData.getBytes());
                zipDeflater.finish();
                byte[] buffer = new byte[1024];
                while (!zipDeflater.finished())
                {
                    int count = zipDeflater.deflate(buffer);
                    stream.write(buffer, 0, count);
                }
                byte[] output;
                output = stream.toByteArray();
                stream.close();
                zipDeflater.end();
                // Need to remove the header
                pasteDataBytes = Arrays.copyOfRange(output, 2, output.length - 4);
            }
            else
            {
                pasteDataBytes = pasteData.getBytes();
            }

            // Generate password.
            KeyGenerator keyGen = KeyGenerator.getInstance("AES");
            keyGen.init(192);
            String randomPassword = Base64.getEncoder().encodeToString(keyGen.generateKey().getEncoded());
            String customPassword = randomPassword + this.password;

            // Generate IV.
            byte[] cipherIVBytes = new byte[16];
            new Random().nextBytes(cipherIVBytes);
            String cipherIVEncoded = Base64.getEncoder().encodeToString(cipherIVBytes);

            // Generate salt.
            byte[] kdfSaltBytes = new byte[8];
            new Random().nextBytes(kdfSaltBytes);
            String kdfSaltEncoded = Base64.getEncoder().encodeToString(kdfSaltBytes);

            // Generate secret key for cipher.
            SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
            KeySpec passwordBasedEncryptionKeySpec = new PBEKeySpec(customPassword.toCharArray(), kdfSaltBytes, 100000, 256);
            SecretKey secret = new SecretKeySpec(factory.generateSecret(passwordBasedEncryptionKeySpec).getEncoded(), "AES");

            // Cipher AAD.
            StringList gcmTagString = new StringList();
            gcmTagString.append("[");
            gcmTagString.append("[");
            gcmTagString.append("\"").append(cipherIVEncoded).append("\"").append(",");
            gcmTagString.append("\"").append(kdfSaltEncoded).append("\"").append(",");
            gcmTagString.append("100000,256,128,");
            gcmTagString.append("\"").append("aes").append("\"").append(",");
            gcmTagString.append("\"").append("gcm").append("\"").append(",");
            gcmTagString.append("\"").append(this.compression.toString()).append("\"");
            gcmTagString.append("]");
            gcmTagString.append(",");
            gcmTagString.append("\"").append(this.formatter.toString()).append("\"").append(",");
            gcmTagString.append(this.openDiscussion.toString()).append(",");
            gcmTagString.append(this.burnAfterReading.toString());
            gcmTagString.append("]");
            byte[] gcmBytes = gcmTagString.toString().getBytes();

            // Generate cipher text.
            Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
            GCMParameterSpec spec = new GCMParameterSpec(128, cipherIVBytes);
            cipher.init(Cipher.ENCRYPT_MODE, secret, spec);
            cipher.updateAAD(gcmBytes);
            byte[] cipherTextBytes = cipher.doFinal(pasteDataBytes);
            String cipherText = Base64.getEncoder().encodeToString(cipherTextBytes);
            // logger.debug("cipherText={}", cipherText);

            // Create POST payload.
            StringList payload = new StringList();
            payload.append("{");
            payload.append("\"v\":2,");
            payload.append("\"adata\":").append(gcmTagString.toString()).append(",");
            payload.append("\"ct\":\"").append(cipherText).append("\",");
            payload.append("\"meta\":{\"expire\":\"").append(this.expiration).append("\"}");
            payload.append("}");
            // logger.debug("PAYLOAD={}", payload.toString());

            // POST Request.
            HttpsURLConnection pasteRequest = (HttpsURLConnection) this.serverUrl.openConnection();
            pasteRequest.setRequestMethod("POST");
            pasteRequest.setDoOutput(true);
            pasteRequest.setRequestProperty("X-Requested-With", "JSONHttpRequest");
            pasteRequest.getOutputStream().write(payload.toString().getBytes());

            // Server response.
            int responseCode = pasteRequest.getResponseCode();
            logger.debug("Server response: {}", responseCode);
            if (responseCode == 200)
            {
                String out = IOUtils.toString(pasteRequest.getInputStream(), "UTF-8");
                logger.info("===> {}", out);

                JSONObject parser = (JSONObject) new JSONParser().parse(out);
                String status = parser.get("status").toString();
                if (StringUtils.equals(status, "0"))
                {
                    String id = parser.get("id").toString();
                    String pasteURL = parser.get("url").toString();
                    String deleteToken = parser.get("deletetoken").toString();
                    String finalURL = this.serverUrl + pasteURL + "#" + Base58.encode(randomPassword.getBytes());
                    String deleteURL = this.serverUrl + pasteURL + "&deletetoken=" + deleteToken;
                    logger.info("Pastebin SUCESS");
                    logger.debug("Paste URL: {}", finalURL);
                    logger.debug("Delete URL: {}", deleteURL);
                    result = finalURL;
                }
                else
                {
                    String output = parser.get("message").toString();
                    logger.warn("message={}", output);
                    throw new PrivatebinException(out);
                }
            }
        }
        catch (BadPaddingException | IllegalBlockSizeException | InvalidAlgorithmParameterException | InvalidKeyException | InvalidKeySpecException
                | NoSuchAlgorithmException | NoSuchPaddingException | ParseException | UnsupportedEncodingException |

                ClientProtocolException exception)
        {
            exception.printStackTrace();
            throw new PrivatebinException(exception);
        }
        catch (IOException exception)
        {
            exception.printStackTrace();
            throw new PrivatebinException(exception);
        }

        //
        return result;
    }
}