/* Copyright 2020 Tusky Contributors
 *
 * This file is part of Tusky.
 *
 * Tusky is free software: you can redistribute it and/or modify it under the terms of the GNU
 * Lesser General Public License as published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * Tusky 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 Lesser
 * General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with Tusky. If
 * not, see <http://www.gnu.org/licenses/>. */

package com.keylesspalace.tusky.util

import android.content.Context
import android.os.Build
import androidx.preference.PreferenceManager
import com.keylesspalace.tusky.BuildConfig
import okhttp3.Cache
import okhttp3.OkHttp
import okhttp3.OkHttpClient
import okhttp3.tls.HandshakeCertificates
import java.io.ByteArrayInputStream
import java.net.InetSocketAddress
import java.net.Proxy
import java.security.cert.CertificateFactory
import java.security.cert.X509Certificate
import java.util.concurrent.TimeUnit

fun okhttpClient(context: Context): OkHttpClient.Builder {
    val preferences = PreferenceManager.getDefaultSharedPreferences(context)

    val httpProxyEnabled = preferences.getBoolean("httpProxyEnabled", false)
    val httpServer = preferences.getNonNullString("httpProxyServer", "")
    val httpPort = preferences.getNonNullString("httpProxyPort", "-1").toIntOrNull() ?: -1

    val cacheSize = 25 * 1024 * 1024 // 25 MiB
    val builder = OkHttpClient.Builder()
        .addInterceptor { chain ->
            /**
             * Add a custom User-Agent that contains Tusky, Android and Okhttp Version to all requests
             * Example:
             * User-Agent: Tusky/1.1.2 Android/5.0.2
             * */
            val requestWithUserAgent = chain.request().newBuilder()
                .header(
                    "User-Agent",
                    "Tusky/${BuildConfig.VERSION_NAME} Android/${Build.VERSION.RELEASE} OkHttp/${OkHttp.VERSION}"
                )
                .build()
            chain.proceed(requestWithUserAgent)
        }
        .readTimeout(30, TimeUnit.SECONDS)
        .writeTimeout(30, TimeUnit.SECONDS)
        .cache(Cache(context.cacheDir, cacheSize.toLong()))

    if (httpProxyEnabled && httpServer.isNotEmpty() && httpPort > 0 && httpPort < 65535) {
        val address = InetSocketAddress.createUnresolved(httpServer, httpPort)
        builder.proxy(Proxy(Proxy.Type.HTTP, address))
    }

    // trust the new Let's Encrypt root certificate that is not available on Android < 7.1.1
    // new cert https://letsencrypt.org/certs/isrgrootx1.pem
    // see https://letsencrypt.org/2020/11/06/own-two-feet.html
    // see https://stackoverflow.com/questions/64844311/certpathvalidatorexception-connecting-to-a-lets-encrypt-host-on-android-m-or-ea
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) {
        val isgCert = """
        -----BEGIN CERTIFICATE-----
        MIIFazCCA1OgAwIBAgIRAIIQz7DSQONZRGPgu2OCiwAwDQYJKoZIhvcNAQELBQAw
        TzELMAkGA1UEBhMCVVMxKTAnBgNVBAoTIEludGVybmV0IFNlY3VyaXR5IFJlc2Vh
        cmNoIEdyb3VwMRUwEwYDVQQDEwxJU1JHIFJvb3QgWDEwHhcNMTUwNjA0MTEwNDM4
        WhcNMzUwNjA0MTEwNDM4WjBPMQswCQYDVQQGEwJVUzEpMCcGA1UEChMgSW50ZXJu
        ZXQgU2VjdXJpdHkgUmVzZWFyY2ggR3JvdXAxFTATBgNVBAMTDElTUkcgUm9vdCBY
        MTCCAiIwDQYJKoZIhvcNAQEBBQADggIPADCCAgoCggIBAK3oJHP0FDfzm54rVygc
        h77ct984kIxuPOZXoHj3dcKi/vVqbvYATyjb3miGbESTtrFj/RQSa78f0uoxmyF+
        0TM8ukj13Xnfs7j/EvEhmkvBioZxaUpmZmyPfjxwv60pIgbz5MDmgK7iS4+3mX6U
        A5/TR5d8mUgjU+g4rk8Kb4Mu0UlXjIB0ttov0DiNewNwIRt18jA8+o+u3dpjq+sW
        T8KOEUt+zwvo/7V3LvSye0rgTBIlDHCNAymg4VMk7BPZ7hm/ELNKjD+Jo2FR3qyH
        B5T0Y3HsLuJvW5iB4YlcNHlsdu87kGJ55tukmi8mxdAQ4Q7e2RCOFvu396j3x+UC
        B5iPNgiV5+I3lg02dZ77DnKxHZu8A/lJBdiB3QW0KtZB6awBdpUKD9jf1b0SHzUv
        KBds0pjBqAlkd25HN7rOrFleaJ1/ctaJxQZBKT5ZPt0m9STJEadao0xAH0ahmbWn
        OlFuhjuefXKnEgV4We0+UXgVCwOPjdAvBbI+e0ocS3MFEvzG6uBQE3xDk3SzynTn
        jh8BCNAw1FtxNrQHusEwMFxIt4I7mKZ9YIqioymCzLq9gwQbooMDQaHWBfEbwrbw
        qHyGO0aoSCqI3Haadr8faqU9GY/rOPNk3sgrDQoo//fb4hVC1CLQJ13hef4Y53CI
        rU7m2Ys6xt0nUW7/vGT1M0NPAgMBAAGjQjBAMA4GA1UdDwEB/wQEAwIBBjAPBgNV
        HRMBAf8EBTADAQH/MB0GA1UdDgQWBBR5tFnme7bl5AFzgAiIyBpY9umbbjANBgkq
        hkiG9w0BAQsFAAOCAgEAVR9YqbyyqFDQDLHYGmkgJykIrGF1XIpu+ILlaS/V9lZL
        ubhzEFnTIZd+50xx+7LSYK05qAvqFyFWhfFQDlnrzuBZ6brJFe+GnY+EgPbk6ZGQ
        3BebYhtF8GaV0nxvwuo77x/Py9auJ/GpsMiu/X1+mvoiBOv/2X/qkSsisRcOj/KK
        NFtY2PwByVS5uCbMiogziUwthDyC3+6WVwW6LLv3xLfHTjuCvjHIInNzktHCgKQ5
        ORAzI4JMPJ+GslWYHb4phowim57iaztXOoJwTdwJx4nLCgdNbOhdjsnvzqvHu7Ur
        TkXWStAmzOVyyghqpZXjFaH3pO3JLF+l+/+sKAIuvtd7u+Nxe5AW0wdeRlN8NwdC
        jNPElpzVmbUq4JUagEiuTDkHzsxHpFKVK7q4+63SM1N95R1NbdWhscdCb+ZAJzVc
        oyi3B43njTOQ5yOf+1CceWxG1bQVs5ZufpsMljq4Ui0/1lvh+wjChP4kqKOJ2qxq
        4RgqsahDYVvTH9w7jXbyLeiNdd8XM2w9U/t7y0Ff/9yi0GE44Za4rF2LN9d11TPA
        mRGunUHBcnWEvgJBQl9nJEiU0Zsnvgc/ubhPgXRR4Xq37Z0j4r7g1SgEEzwxA57d
        emyPxgcYxn/eR44/KJ4EBs+lVDR3veyJm+kXQ99b21/+jh5Xos1AnX5iItreGCc=
        -----END CERTIFICATE-----
         """.trimIndent()
        val cf = CertificateFactory.getInstance("X.509")
        val isgCertificate = cf.generateCertificate(ByteArrayInputStream(isgCert.toByteArray(charset("UTF-8"))))
        val certificates = HandshakeCertificates.Builder()
            .addTrustedCertificate(isgCertificate as X509Certificate)
            .addPlatformTrustedCertificates()
            .build()
        builder.sslSocketFactory(
            certificates.sslSocketFactory(),
            certificates.trustManager
        )
    }
    return builder
}