package com.android.sdk.net.https;

import java.io.IOException;
import java.io.InputStream;
import java.security.KeyManagementException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.KeyManager;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;

/**
 * https://github.com/hongyangAndroid/okhttputils
 */
public class HttpsUtils {

    public static class SSLParams {
        public SSLSocketFactory sSLSocketFactory;
        public X509TrustManager trustManager;
    }

    /**
     * 创建SSLParams
     *
     * @param certificates 本地证书流
     * @param bksFile      用于双向验证，本地bks证书
     * @param password     本地证书密码
     * @return 创建的SSLParams
     */
    public static SSLParams getSslSocketFactory(InputStream[] certificates, InputStream bksFile, String password) {
        SSLParams sslParams = new SSLParams();
        try {
            TrustManager[] trustManagers = prepareTrustManager(certificates);
            KeyManager[] keyManagers = prepareKeyManager(bksFile, password);
            SSLContext sslContext = SSLContext.getInstance("TLS");
            X509TrustManager trustManager;
            if (trustManagers != null) {
                trustManager = new SafeTrustManager(chooseTrustManager(trustManagers));
            } else {
                trustManager = new UnSafeTrustManager();
            }
            sslContext.init(keyManagers, new TrustManager[]{trustManager}, null);
            sslParams.sSLSocketFactory = sslContext.getSocketFactory();
            sslParams.trustManager = trustManager;
            return sslParams;
        } catch (NoSuchAlgorithmException | KeyManagementException | KeyStoreException e) {
            throw new AssertionError(e);
        }
    }

    private class UnSafeHostnameVerifier implements HostnameVerifier {
        @Override
        public boolean verify(String hostname, SSLSession session) {
            return true;
        }
    }

    private static class UnSafeTrustManager implements X509TrustManager {
        @Override
        public void checkClientTrusted(X509Certificate[] chain, String authType)
                throws CertificateException {
        }

        @Override
        public void checkServerTrusted(X509Certificate[] chain, String authType)
                throws CertificateException {
        }

        @Override
        public X509Certificate[] getAcceptedIssuers() {
            return new java.security.cert.X509Certificate[]{};
        }
    }

    private static TrustManager[] prepareTrustManager(InputStream... certificates) {
        if (certificates == null || certificates.length <= 0) return null;
        try {
            CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
            KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
            keyStore.load(null);
            int index = 0;
            for (InputStream certificate : certificates) {
                String certificateAlias = Integer.toString(index++);
                keyStore.setCertificateEntry(certificateAlias, certificateFactory.generateCertificate(certificate));
                try {
                    if (certificate != null)
                        certificate.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            TrustManagerFactory trustManagerFactory;
            trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
            trustManagerFactory.init(keyStore);
            return trustManagerFactory.getTrustManagers();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    private static KeyManager[] prepareKeyManager(InputStream bksFile, String password) {
        try {
            if (bksFile == null || password == null) return null;
            KeyStore clientKeyStore = KeyStore.getInstance("BKS");
            clientKeyStore.load(bksFile, password.toCharArray());
            KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
            keyManagerFactory.init(clientKeyStore, password.toCharArray());
            return keyManagerFactory.getKeyManagers();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    private static X509TrustManager chooseTrustManager(TrustManager[] trustManagers) {
        for (TrustManager trustManager : trustManagers) {
            if (trustManager instanceof X509TrustManager) {
                return (X509TrustManager) trustManager;
            }
        }
        return null;
    }


    private static class SafeTrustManager implements X509TrustManager {

        private X509TrustManager defaultTrustManager;
        private X509TrustManager localTrustManager;

        SafeTrustManager(X509TrustManager localTrustManager) throws NoSuchAlgorithmException, KeyStoreException {
            TrustManagerFactory var4 = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
            var4.init((KeyStore) null);
            defaultTrustManager = chooseTrustManager(var4.getTrustManagers());
            this.localTrustManager = localTrustManager;
        }

        @Override
        public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }

        @Override
        public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
            try {
                defaultTrustManager.checkServerTrusted(chain, authType);
            } catch (CertificateException ce) {
                localTrustManager.checkServerTrusted(chain, authType);
            }
        }

        @Override
        public X509Certificate[] getAcceptedIssuers() {
            return new X509Certificate[0];
        }
    }
}
