// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package com.tailscale.ipn

import android.app.PendingIntent
import android.content.Context
import android.content.Intent
import androidx.core.app.NotificationCompat
import androidx.work.CoroutineWorker
import androidx.work.Data
import androidx.work.WorkerParameters
import com.tailscale.ipn.UninitializedApp.Companion.STATUS_CHANNEL_ID
import com.tailscale.ipn.ui.localapi.Client
import com.tailscale.ipn.ui.model.Ipn
import com.tailscale.ipn.ui.notifier.Notifier
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Job

class UseExitNodeWorker(appContext: Context, workerParams: WorkerParameters) :
    CoroutineWorker(appContext, workerParams) {
  override suspend fun doWork(): Result {
    val app = UninitializedApp.get() ?: return Result.failure()

    suspend fun runAndGetResult(): String? {
      val exitNodeName = inputData.getString(EXIT_NODE_NAME)

      val exitNodeId =
          if (exitNodeName.isNullOrEmpty()) {
            null
          } else {
            if (app.isAbleToStartVPN() != true) {
              return app.getString(R.string.vpn_is_not_ready_to_start)
            }

            val peers =
                (Notifier.netmap.value
                        ?: run {
                          return@runAndGetResult app.getString(R.string.tailscale_is_not_setup)
                        })
                    .Peers
                    ?: run {
                      return@runAndGetResult app.getString(R.string.no_peers_found)
                    }

            val filteredPeers = peers.filter { it.displayName == exitNodeName }.toList()

            if (filteredPeers.isEmpty()) {
              return app.getString(R.string.no_peers_with_name_found, exitNodeName)
            } else if (filteredPeers.size > 1) {
              return app.getString(R.string.multiple_peers_with_name_found, exitNodeName)
            } else if (!filteredPeers[0].isExitNode) {
              return app.getString(R.string.peer_with_name_is_not_an_exit_node, exitNodeName)
            }

            filteredPeers[0].StableID
          }

      val allowLanAccess = inputData.getBoolean(ALLOW_LAN_ACCESS, false)
      val prefsOut = Ipn.MaskedPrefs()
      prefsOut.ExitNodeID = exitNodeId
      prefsOut.ExitNodeAllowLANAccess = allowLanAccess

      val scope = CoroutineScope(Dispatchers.Default + Job())
      var result: String? = null
      Client(scope).editPrefs(prefsOut) {
        result =
            if (it.isFailure) {
              it.exceptionOrNull()?.message
            } else {
              null
            }
      }

      scope.coroutineContext[Job]?.join()

      return result
    }

    val result = runAndGetResult()

    return if (result != null) {
      val intent =
          Intent(app, MainActivity::class.java).apply {
            flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
          }
      val pendingIntent: PendingIntent =
          PendingIntent.getActivity(
              app, 1, intent, PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE)

      val notification =
          NotificationCompat.Builder(app, STATUS_CHANNEL_ID)
              .setSmallIcon(R.drawable.ic_notification)
              .setContentTitle(app.getString(R.string.use_exit_node_intent_failed))
              .setContentText(result)
              .setPriority(NotificationCompat.PRIORITY_DEFAULT)
              .setContentIntent(pendingIntent)
              .build()

      app.notifyStatus(notification)

      Result.failure(Data.Builder().putString(ERROR_KEY, result).build())
    } else {
      Result.success()
    }
  }

  companion object {
    const val EXIT_NODE_NAME = "EXIT_NODE_NAME"
    const val ALLOW_LAN_ACCESS = "ALLOW_LAN_ACCESS"
    const val ERROR_KEY = "error"
  }
}