package org.xmlrpc.android;

import android.annotation.SuppressLint;
import android.net.SSLCertificateSocketFactory;
import android.os.Build;

import org.apache.http.conn.scheme.SocketFactory;
import org.apache.http.conn.ssl.BrowserCompatHostnameVerifier;
import org.apache.http.conn.ssl.SSLSocketFactory;

import org.wordpress.android.networking.SelfSignedSSLCertsManager;
import org.wordpress.android.networking.WPTrustManager;
import org.wordpress.android.util.AppLog;
import org.wordpress.android.util.AppLog.T;

import java.io.IOException;
import java.net.InetAddress;
import java.net.Socket;
import java.security.GeneralSecurityException;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;


import javax.net.ssl.SSLPeerUnverifiedException;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.TrustManager;


/**
 * Custom SSLSocketFactory that adds Self-Signed (trusted) certificates,
 * and SNI support.
 *
 * Loosely based on: http://blog.dev001.net/post/67082904181/android-using-sni-and-tlsv1-2-with-apache-httpclient
 *
 * Ref: https://github.com/wordpress-mobile/WordPress-Android/issues/1288
 *
 */
public class TrustUserSSLCertsSocketFactory extends SSLSocketFactory {
    private SSLCertificateSocketFactory mFactory;
    private static final BrowserCompatHostnameVerifier mHostnameVerifier = new BrowserCompatHostnameVerifier();

    public TrustUserSSLCertsSocketFactory() throws IOException, GeneralSecurityException {
        super(null);
        // No handshake timeout used
        mFactory = (SSLCertificateSocketFactory) SSLCertificateSocketFactory.getDefault(0);
        TrustManager[] trustAllowedCerts;
        try {
            trustAllowedCerts = new TrustManager[]{
                    new WPTrustManager(SelfSignedSSLCertsManager.getInstance(null).getLocalKeyStore())
            };
            mFactory.setTrustManagers(trustAllowedCerts);
        } catch (GeneralSecurityException e1) {
            AppLog.e(T.API, "Cannot set TrustAllSSLSocketFactory on our factory. Proceding without it...", e1);
        }
    }

    public static SocketFactory getDefault() throws IOException, GeneralSecurityException {
        return new TrustUserSSLCertsSocketFactory();
    }

    public Socket createSocket() throws IOException {
        return mFactory.createSocket();
    }

    @Override
    public Socket createSocket(Socket plainSocket, String host, int port, boolean autoClose) throws IOException {
        if (autoClose) {
            // we don't need the plainSocket
            plainSocket.close();
        }

        SSLSocket ssl = (SSLSocket) mFactory.createSocket(InetAddress.getByName(host), port);
        return enableSNI(ssl, host);
    }

    @SuppressLint("NewApi")
    private Socket enableSNI(SSLSocket ssl, String host) throws SSLPeerUnverifiedException {
        // enable TLSv1.1/1.2 if available
        // (see https://github.com/rfc2822/davdroid/issues/229)
        ssl.setEnabledProtocols(ssl.getSupportedProtocols());

        // set up SNI before the handshake
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
            AppLog.i(T.API, "Setting SNI hostname");
            mFactory.setHostname(ssl, host);
        } else {
            AppLog.i(T.API,  "No documented SNI support on Android <4.2, trying with reflection");
            try {
                java.lang.reflect.Method setHostnameMethod = ssl.getClass().getMethod("setHostname", String.class);
                setHostnameMethod.invoke(ssl, host);
            } catch (Exception e) {
                AppLog.e(T.API, "SNI not useable", e);
            }
        }

        // verify hostname and certificate
        SSLSession session = ssl.getSession();
        if (!mHostnameVerifier.verify(host, session)) {
            // the verify failed. We need to check if the current certificate is in Trusted Store.
            try {
                Certificate[] errorChain = ssl.getSession().getPeerCertificates();
                X509Certificate[] X509CertificateChain = new X509Certificate[errorChain.length];
                for (int i = 0; i < errorChain.length; i++) {
                    X509Certificate x509Certificate = (X509Certificate) errorChain[0];
                    X509CertificateChain[i] = x509Certificate;
                }

                if (X509CertificateChain.length == 0) {
                    throw new SSLPeerUnverifiedException("Cannot verify hostname: " + host);
                }

                if (!SelfSignedSSLCertsManager.getInstance(null).isCertificateTrusted(X509CertificateChain[0])) {
                    SelfSignedSSLCertsManager.getInstance(null).setLastFailureChain(X509CertificateChain);
                    throw new SSLPeerUnverifiedException("Cannot verify hostname: " + host);
                }
            } catch (GeneralSecurityException e) {
                AppLog.e(T.API, "GeneralSecurityException occurred when trying to verify a certificate that has failed" +
                        " the host name verifier check", e);
                throw new SSLPeerUnverifiedException("Cannot verify hostname: " + host);
            } catch (IOException e) {
                AppLog.e(T.API, "IOException occurred when trying to verify a certificate that has failed" +
                        " the host name verifier check", e);
                throw new SSLPeerUnverifiedException("Cannot verify hostname: " + host);
            } catch (Exception e) {
                // We don't want crash the app here for an unexpected error
                AppLog.e(T.API, "An Exception occurred when trying to verify a certificate that has failed" +
                        " the host name verifier check", e);
                throw new SSLPeerUnverifiedException("Cannot verify hostname: " + host);
            }
        }

        AppLog.i(T.API, "Established " + session.getProtocol()
                + " connection with " + session.getPeerHost()
                + " using " + session.getCipherSuite());

        return ssl;
    }

    public Socket createSocket(InetAddress inaddr, int i, InetAddress inaddr1, int j) throws IOException {
       SSLSocket ssl =  (SSLSocket) mFactory.createSocket(inaddr, i, inaddr1, j);
       return enableSNI(ssl, inaddr.getHostName());
    }

    public Socket createSocket(InetAddress inaddr, int i) throws IOException {
        SSLSocket ssl =  (SSLSocket) mFactory.createSocket(inaddr, i);
        return enableSNI(ssl, inaddr.getHostName());
    }

    public Socket createSocket(String s, int i, InetAddress inaddr, int j) throws IOException {
       SSLSocket ssl =  (SSLSocket) mFactory.createSocket(s, i, inaddr, j);
       return enableSNI(ssl, inaddr.getHostName());
    }

    public Socket createSocket(String s, int i) throws IOException {
        SSLSocket ssl =  (SSLSocket) mFactory.createSocket(s, i);
        return enableSNI(ssl, s);
    }

    public String[] getDefaultCipherSuites() { return mFactory.getDefaultCipherSuites(); }
    public String[] getSupportedCipherSuites() { return mFactory.getSupportedCipherSuites(); }
}