package com.qimai.android.fetch.tool

import android.annotation.SuppressLint
import android.util.Log
import java.io.IOException
import java.io.InputStream
import java.security.KeyManagementException
import java.security.KeyStore
import java.security.NoSuchAlgorithmException
import java.security.cert.CertificateException
import java.security.cert.CertificateFactory
import java.security.cert.X509Certificate
import javax.net.ssl.*

/**
 *   @author wangwei

 *   @version 1.1.1
 *   @date 2019-08-14
 *   @Description
 *   @email wangwei_5521@163.com
 **/
object SSLUtils {

    val sslSocketFactory: SSLParams
        get() = getSslSocketFactoryBase(null, null, null)

    /**
     * 为了解决客户端不信任服务器数字证书的问题，网络上大部分的解决方案都是让客户端不对证书做任何检查，
     * 这是一种有很大安全漏洞的办法
     */
    var UnSafeTrustManager: X509TrustManager = object : X509TrustManager {
        @SuppressLint("TrustAllX509TrustManager")
        @Throws(CertificateException::class)
        override fun checkClientTrusted(chain: Array<X509Certificate>, authType: String) {
        }

        @SuppressLint("TrustAllX509TrustManager")
        @Throws(CertificateException::class)
        override fun checkServerTrusted(chain: Array<X509Certificate>, authType: String) {
        }

        override fun getAcceptedIssuers(): Array<X509Certificate> {

            return arrayOf()
        }
    }

    /**
     * 此类是用于主机名验证的基接口。 在握手期间，如果 URL 的主机名和服务器的标识主机名不匹配，
     * 则验证机制可以回调此接口的实现程序来确定是否应该允许此连接。策略可以是基于证书的或依赖于其他验证方案。
     * 当验证 URL 主机名使用的默认规则失败时使用这些回调。如果主机名是可接受的，则返回 true
     */
    var UnSafeHostnameVerifier: HostnameVerifier = HostnameVerifier { hostname, session -> true }

    class SSLParams {
        var sSLSocketFactory: SSLSocketFactory? = null
        var trustManager: X509TrustManager? = null
    }

    /**
     * https单向认证
     * 可以额外配置信任服务端的证书策略，否则默认是按CA证书去验证的，若不是CA可信任的证书，则无法通过验证
     */
    fun getSslSocketFactory(trustManager: X509TrustManager): SSLParams {
        return getSslSocketFactoryBase(
            trustManager,
            null,
            null
        )
    }

    /**
     * https单向认证
     * 用含有服务端公钥的证书校验服务端证书
     */
    fun getSslSocketFactory(vararg certificates: InputStream): SSLParams {
        return getSslSocketFactoryBase(
            null,
            null,
            null,
            *certificates
        )
    }

    /**
     * https双向认证
     * bksFile 和 password -> 客户端使用bks证书校验服务端证书
     * certificates -> 用含有服务端公钥的证书校验服务端证书
     */
    fun getSslSocketFactory(bksFile: InputStream?, password: String?, vararg certificates: InputStream): SSLParams {
        return getSslSocketFactoryBase(
            null,
            bksFile,
            password,
            *certificates
        )
    }

    /**
     * https双向认证
     * bksFile 和 password -> 客户端使用bks证书校验服务端证书
     * X509TrustManager -> 如果需要自己校验，那么可以自己实现相关校验，如果不需要自己校验，那么传null即可
     */
    fun getSslSocketFactory(bksFile: InputStream?, password: String, trustManager: X509TrustManager): SSLParams {
        return getSslSocketFactoryBase(
            trustManager,
            bksFile,
            password
        )
    }

    private fun getSslSocketFactoryBase(
        trustManager: X509TrustManager?,
        bksFile: InputStream?,
        password: String?,
        vararg certificates: InputStream
    ): SSLParams {
        val sslParams = SSLParams()
        try {
            val keyManagers =
                prepareKeyManager(bksFile, password)
            val trustManagers =
                prepareTrustManager(*certificates)
            val manager: X509TrustManager?
            if (trustManager != null) {
                //优先使用用户自定义的TrustManager
                manager = trustManager
            } else if (trustManagers != null) {
                //然后使用默认的TrustManager
                manager = chooseTrustManager(trustManagers)
            } else {
                //否则使用不安全的TrustManager
                manager = UnSafeTrustManager
            }
            // 创建TLS类型的SSLContext对象， that uses our TrustManager
            val sslContext = SSLContext.getInstance("TLS")
            // 用上面得到的trustManagers初始化SSLContext，这样sslContext就会信任keyStore中的证书
            // 第一个参数是授权的密钥管理器，用来授权验证，比如授权自签名的证书验证。第二个是被授权的证书管理器，用来验证服务器端的证书
            sslContext.init(keyManagers, arrayOf<TrustManager>(manager!!), null)
            // 通过sslContext获取SSLSocketFactory对象
            sslParams.sSLSocketFactory = sslContext.socketFactory
            sslParams.trustManager = manager
            return sslParams
        } catch (e: NoSuchAlgorithmException) {
            throw AssertionError(e)
        } catch (e: KeyManagementException) {
            throw AssertionError(e)
        }

    }

    private fun prepareKeyManager(bksFile: InputStream?, password: String?): Array<KeyManager>? {
        try {
            if (bksFile == null || password == null) return null
            val clientKeyStore = KeyStore.getInstance("BKS")
            clientKeyStore.load(bksFile, password.toCharArray())
            val kmf = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm())
            kmf.init(clientKeyStore, password.toCharArray())
            return kmf.keyManagers
        } catch (e: Exception) {
            Log.e("ssl", e.message)
        }

        return null
    }

    private fun prepareTrustManager(vararg certificates: InputStream): Array<TrustManager>? {
        if (certificates == null || certificates.isEmpty()) return null
        try {
            val certificateFactory = CertificateFactory.getInstance("X.509")
            // 创建一个默认类型的KeyStore，存储我们信任的证书
            val keyStore = KeyStore.getInstance(KeyStore.getDefaultType())
            keyStore.load(null)
            var index = 0
            for (certStream in certificates) {
                val certificateAlias = (index++).toString()
                // 证书工厂根据证书文件的流生成证书 cert
                val cert = certificateFactory.generateCertificate(certStream)
                // 将 cert 作为可信证书放入到keyStore中
                keyStore.setCertificateEntry(certificateAlias, cert)
                try {
                    certStream?.close()
                } catch (e: IOException) {
                    Log.e("ssl", e.message)
                }

            }
            //我们创建一个默认类型的TrustManagerFactory
            val tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm())
            //用我们之前的keyStore实例初始化TrustManagerFactory，这样tmf就会信任keyStore中的证书
            tmf.init(keyStore)
            //通过tmf获取TrustManager数组，TrustManager也会信任keyStore中的证书
            return tmf.trustManagers
        } catch (e: Exception) {
            Log.e("ssl", e.message)
        }

        return null
    }

    private fun chooseTrustManager(trustManagers: Array<TrustManager>): X509TrustManager? {
        for (trustManager in trustManagers) {
            if (trustManager is X509TrustManager) {
                return trustManager
            }
        }
        return null
    }
}
