/*
 * Copyright (C) 2008-2017, Juick
 *
 * This program 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.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.juick.components.s2s;

import com.juick.components.XMPPServer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlPullParserFactory;

import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.io.*;
import java.net.Socket;
import java.nio.charset.StandardCharsets;
import java.security.*;
import java.security.cert.CertificateException;
import java.time.Instant;
import java.util.UUID;

/**
 *
 * @author ugnich
 */
public class Connection {

    protected static final Logger logger = LoggerFactory.getLogger(Connection.class);

    public String streamID;
    public Instant created;
    public Instant updated;
    public long bytesLocal = 0;
    public long packetsLocal = 0;
    XMPPServer xmpp;
    Socket socket;
    public static final String NS_DB = "jabber:server:dialback";
    public static final String NS_TLS = "urn:ietf:params:xml:ns:xmpp-tls";
    public static final String NS_STREAM = "http://etherx.jabber.org/streams";
    XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
    XmlPullParser parser = factory.newPullParser();
    OutputStreamWriter writer;
    private boolean secured = false;
    SSLContext sc;
    private TrustManager[] trustAllCerts = new TrustManager[]{
            new X509TrustManager() {
                public void checkClientTrusted(java.security.cert.X509Certificate[] certs, String authType) {
                }

                public void checkServerTrusted(java.security.cert.X509Certificate[] certs, String authType) {
                }
                public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                    return null;
                }
            }
    };


    public Connection(XMPPServer xmpp) throws XmlPullParserException, KeyStoreException, CertificateException, NoSuchAlgorithmException, IOException, UnrecoverableKeyException, KeyManagementException {
        this.xmpp = xmpp;
        created = Instant.now();
        KeyStore ks = KeyStore.getInstance("JKS");
        try (InputStream ksIs = new FileInputStream(xmpp.keystore)) {
            ks.load(ksIs, xmpp.keystorePassword.toCharArray());
            KeyManagerFactory kmf = KeyManagerFactory.getInstance(KeyManagerFactory
                    .getDefaultAlgorithm());
            kmf.init(ks, xmpp.keystorePassword.toCharArray());
            sc = SSLContext.getInstance("TLSv1.2");
            sc.init(kmf.getKeyManagers(), trustAllCerts, new SecureRandom());
        } catch (Exception e) {
            logger.warn("tls unavailable");
        }
    }

    public void logParser() {
        if (streamID == null) {
            return;
        }
        String tag = "IN: <" + parser.getName();
        for (int i = 0; i < parser.getAttributeCount(); i++) {
            tag += " " + parser.getAttributeName(i) + "=\"" + parser.getAttributeValue(i) + "\"";
        }
        tag += ">...</" + parser.getName() + ">\n";
        logger.trace(tag);
    }

    public void sendStanza(String xml) {
        if (streamID != null) {
            logger.trace("OUT: {}\n", xml);
        }
        try {
            writer.write(xml);
            writer.flush();
        } catch (IOException e) {
            logger.error("send stanza failed", e);
        }

        updated = Instant.now();
        bytesLocal += xml.length();
        packetsLocal++;
    }

    public void closeConnection() {
        if (streamID != null) {
            logger.info("closing stream {}", streamID);
        }

        try {
            writer.write("</stream:stream>");
        } catch (Exception e) {
        }

        try {
            writer.close();
        } catch (Exception e) {
        }

        try {
            socket.close();
        } catch (Exception e) {
        }
    }

    public boolean isSecured() {
        return secured;
    }

    public void setSecured(boolean secured) {
        this.secured = secured;
    }

    public void restartParser() throws XmlPullParserException, IOException {
        streamID = UUID.randomUUID().toString();
        parser = factory.newPullParser();
        parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true);
        parser.setInput(new InputStreamReader(socket.getInputStream()));
        writer = new OutputStreamWriter(socket.getOutputStream(), StandardCharsets.UTF_8);
    }
}