/**
 * 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.List;
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.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.message.BasicNameValuePair;
import org.april.hebdobot.HebdobotException;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

import fr.devinsy.strings.StringList;

/**
 * The Class PastebinClient.
 */
public class PrivatebinClient
{
    private String serverUrl;
    private Compression compression;

    /**
     * Instantiates a new privatebin client.
     *
     * @param serverUrl
     *            the server url
     */
    public PrivatebinClient(final String serverUrl)
    {
        this.serverUrl = serverUrl;
        this.compression = Compression.ZLIB;
    }

    /**
     * Paste.
     *
     * @param serverUrl
     *            the server url
     * @param expirationDate
     *            the expiration
     * @param burnAfterReading
     *            the burn after reading
     * @param openDiscussion
     *            the open discussion
     * @return the string
     * @throws HebdobotException
     *             the hebdobot exception
     * @throws PrivatebinException
     */
    public String paste(final String text, final Expiration expiration, final Formatter formatter, final BurnAfterReading burnAfterReading,
            final OpenDiscussion openDiscussion) throws PrivatebinException
    {
        String result;

        result = null;
        try
        {
            if (expiration == null)
            {
                throw new IllegalArgumentException("Null parameter expiration.");
            }
            else if (formatter == null)
            {
                throw new IllegalArgumentException("Null parameter formatter.");
            }
            else if (burnAfterReading == null)
            {
                throw new IllegalArgumentException("Null parameter burn after reading.");
            }
            else if (openDiscussion == null)
            {
                throw new IllegalArgumentException("Null parameter open discussion.");
            }
            else
            {
                // 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

                // Optional parameters
                // ===================

                // Location of local file to attach, leave quotes empty for no
                // file
                String localAttachmentFilename = "";
                // Paste attachment name, leave quotes empty for no file
                String pasteAttachmentFilename = "";
                // Read file contents into paste, leave quotes empty no no file
                String plaintextFileLocation = "";
                // Set paste password, leave quotes empty for no password
                String userPastePassword = "";

                //

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

                // 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);

                // Build message to encrypt.
                String pasteData = "{\"paste\":\"" + text + "\"}";

                // Compression.
                byte[] pasteDataBytes;
                if (StringUtils.equals(this.compression.toString(), "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 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).append("\"");
                gcmTagString.append("]");
                gcmTagString.append(",");
                gcmTagString.append("\"").append(formatter).append("\"").append(",");
                gcmTagString.append(openDiscussion).append(",");
                gcmTagString.append(burnAfterReading);
                gcmTagString.append("]");
                byte[] gcmBytes = gcmTagString.toString().getBytes();

                System.out.println("gcm=" + gcmTagString.toString());

                // 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);

                // 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(expiration).append("\"}");
                payload.append("}");

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

                // Server response.
                int responseCode = pasteRequest.getResponseCode();
                System.out.println("Server response: " + responseCode);
                if (responseCode == 200)
                {

                    String out = IOUtils.toString(pasteRequest.getInputStream(), "UTF-8");
                    System.out.println("===> " + 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;
                        System.out.println("SUCESS");
                        System.out.println("Paste URL: " + finalURL);
                        System.out.println("Delete URL: " + deleteURL);
                    }
                    else
                    {
                        String output = parser.get("message").toString();
                        System.out.println("message=" + output);
                        throw new PrivatebinException(out);
                    }
                }
            }
        }
        catch (BadPaddingException | IllegalBlockSizeException | InvalidAlgorithmParameterException | InvalidKeyException | InvalidKeySpecException
                | NoSuchAlgorithmException | NoSuchPaddingException | ParseException | UnsupportedEncodingException
                | ClientProtocolException exception)
        {
            throw new PrivatebinException(exception);
        }
        catch (IOException exception)
        {
            exception.printStackTrace();
            throw new PrivatebinException(exception);
        }

        //
        return result;
    }

    /**
     * Sets the parameter.
     *
     * @param params
     *            the params
     * @param name
     *            the name
     * @param value
     *            the value
     */
    private static void setParameter(final List<NameValuePair> params, final String name, final String value)
    {
        if (value != null)
        {
            params.add(new BasicNameValuePair(name, value));
        }
    }
}