/*
 * Tinc App, an Android binding and user interface for the tinc mesh VPN daemon
 * Copyright (C) 2017-2018 Pacien TRAN-GIRARD
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package org.pacien.tincapp.commands

import org.pacien.tincapp.R
import org.pacien.tincapp.commands.Executor.runAsyncTask
import org.pacien.tincapp.context.App
import org.pacien.tincapp.context.AppPaths
import org.pacien.tincapp.data.TincConfiguration
import org.pacien.tincapp.data.VpnInterfaceConfiguration
import org.pacien.tincapp.utils.PemUtils
import java.io.FileNotFoundException

/**
 * @author pacien
 */
object TincApp {
  private val SCRIPT_SUFFIXES = listOf("-up", "-down", "-created", "-accepted")
  private val STATIC_SCRIPTS = listOf("tinc", "host", "subnet", "invitation").flatMap { s -> SCRIPT_SUFFIXES.map { s + it } }

  private fun listScripts(netName: String) = AppPaths.confDir(netName).listFiles { f -> f.name in STATIC_SCRIPTS } +
    AppPaths.hostsDir(netName).listFiles { f -> SCRIPT_SUFFIXES.any { f.name.endsWith(it) } }

  fun listPrivateKeys(netName: String) = try {
    TincConfiguration.fromTincConfiguration(AppPaths.existing(AppPaths.tincConfFile(netName))).let {
      listOf(
        it.privateKeyFile ?: AppPaths.defaultRsaPrivateKeyFile(netName),
        it.ed25519PrivateKeyFile ?: AppPaths.defaultEd25519PrivateKeyFile(netName))
    }
  } catch (e: FileNotFoundException) {
    throw FileNotFoundException(App.getResources().getString(R.string.notification_error_message_network_config_not_found_format, e.message!!))
  }

  fun removeScripts(netName: String) = runAsyncTask {
    listScripts(netName).forEach { it.delete() }
  }

  fun generateIfaceCfg(netName: String) = runAsyncTask {
    VpnInterfaceConfiguration
      .fromInvitation(AppPaths.invitationFile(netName))
      .write(AppPaths.netConfFile(netName))
  }

  fun generateIfaceCfgTemplate(netName: String) = runAsyncTask {
    App.getResources().openRawResource(R.raw.network).use { inputStream ->
      AppPaths.netConfFile(netName).outputStream().use { inputStream.copyTo(it) }
    }
  }

  fun setPassphrase(netName: String, currentPassphrase: String? = null, newPassphrase: String?) = runAsyncTask {
    listPrivateKeys(netName)
      .filter { it.exists() }
      .map { Pair(PemUtils.read(it), it) }
      .map { Pair(PemUtils.decrypt(it.first, currentPassphrase), it.second) }
      .map { Pair(if (newPassphrase?.isNotEmpty() == true) PemUtils.encrypt(it.first, newPassphrase) else it.first, it.second) }
      .forEach { PemUtils.write(it.first, it.second.writer()) }
  }
}