/*
 * Copyright © 2017-2023 WireGuard LLC. All Rights Reserved.
 * SPDX-License-Identifier: Apache-2.0
 */
package com.wireguard.android.fragment

import android.os.Bundle
import android.view.LayoutInflater
import android.view.Menu
import android.view.MenuInflater
import android.view.MenuItem
import android.view.View
import android.view.ViewGroup
import androidx.core.view.MenuProvider
import androidx.databinding.DataBindingUtil
import androidx.lifecycle.Lifecycle
import androidx.lifecycle.lifecycleScope
import com.wireguard.android.R
import com.wireguard.android.backend.Tunnel
import com.wireguard.android.databinding.TunnelDetailFragmentBinding
import com.wireguard.android.databinding.TunnelDetailPeerBinding
import com.wireguard.android.model.ObservableTunnel
import com.wireguard.android.util.QuantityFormatter
import kotlinx.coroutines.delay
import kotlinx.coroutines.launch

/**
 * Fragment that shows details about a specific tunnel.
 */
class TunnelDetailFragment : BaseFragment(), MenuProvider {
    private var binding: TunnelDetailFragmentBinding? = null
    private var lastState = Tunnel.State.TOGGLE
    private var timerActive = true

    override fun onMenuItemSelected(menuItem: MenuItem): Boolean {
        return false
    }

    override fun onCreateMenu(menu: Menu, menuInflater: MenuInflater) {
        menuInflater.inflate(R.menu.tunnel_detail, menu)
    }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        super.onCreateView(inflater, container, savedInstanceState)
        binding = TunnelDetailFragmentBinding.inflate(inflater, container, false)
        binding?.executePendingBindings()
        return binding?.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        requireActivity().addMenuProvider(this, viewLifecycleOwner, Lifecycle.State.RESUMED)
    }

    override fun onDestroyView() {
        binding = null
        super.onDestroyView()
    }

    override fun onResume() {
        super.onResume()
        timerActive = true
        lifecycleScope.launch {
            while (timerActive) {
                updateStats()
                delay(1000)
            }
        }
    }

    override fun onSelectedTunnelChanged(oldTunnel: ObservableTunnel?, newTunnel: ObservableTunnel?) {
        val binding = binding ?: return
        binding.tunnel = newTunnel
        if (newTunnel == null) {
            binding.config = null
        } else {
            lifecycleScope.launch {
                try {
                    binding.config = newTunnel.getConfigAsync()
                } catch (_: Throwable) {
                    binding.config = null
                }
            }
        }
        lastState = Tunnel.State.TOGGLE
        lifecycleScope.launch { updateStats() }
    }

    override fun onStop() {
        timerActive = false
        super.onStop()
    }

    override fun onViewStateRestored(savedInstanceState: Bundle?) {
        binding ?: return
        binding!!.fragment = this
        onSelectedTunnelChanged(null, selectedTunnel)
        super.onViewStateRestored(savedInstanceState)
    }

    private suspend fun updateStats() {
        val binding = binding ?: return
        val tunnel = binding.tunnel ?: return
        if (!isResumed) return
        val state = tunnel.state
        if (state != Tunnel.State.UP && lastState == state) return
        lastState = state
        try {
            val statistics = tunnel.getStatisticsAsync()
            for (i in 0 until binding.peersLayout.childCount) {
                val peer: TunnelDetailPeerBinding = DataBindingUtil.getBinding(binding.peersLayout.getChildAt(i))
                    ?: continue
                val publicKey = peer.item!!.publicKey
                val peerStats = statistics.peer(publicKey)
                if (peerStats == null || (peerStats.rxBytes == 0L && peerStats.txBytes == 0L)) {
                    peer.transferLabel.visibility = View.GONE
                    peer.transferText.visibility = View.GONE
                } else {
                    peer.transferText.text = getString(
                        R.string.transfer_rx_tx,
                        QuantityFormatter.formatBytes(peerStats.rxBytes),
                        QuantityFormatter.formatBytes(peerStats.txBytes)
                    )
                    peer.transferLabel.visibility = View.VISIBLE
                    peer.transferText.visibility = View.VISIBLE
                }
                if (peerStats == null || peerStats.latestHandshakeEpochMillis == 0L) {
                    peer.latestHandshakeLabel.visibility = View.GONE
                    peer.latestHandshakeText.visibility = View.GONE
                } else {
                    peer.latestHandshakeText.text = QuantityFormatter.formatEpochAgo(peerStats.latestHandshakeEpochMillis)
                    peer.latestHandshakeLabel.visibility = View.VISIBLE
                    peer.latestHandshakeText.visibility = View.VISIBLE
                }
            }
        } catch (e: Throwable) {
            for (i in 0 until binding.peersLayout.childCount) {
                val peer: TunnelDetailPeerBinding = DataBindingUtil.getBinding(binding.peersLayout.getChildAt(i))
                    ?: continue
                peer.transferLabel.visibility = View.GONE
                peer.transferText.visibility = View.GONE
                peer.latestHandshakeLabel.visibility = View.GONE
                peer.latestHandshakeText.visibility = View.GONE
            }
        }
    }
}