/*
 * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
 * SPDX-License-Identifier: Apache-2.0
 */
package com.wireguard.android.fragment

import android.Manifest
import android.app.Dialog
import android.os.Bundle
import android.widget.Button
import android.widget.Toast
import androidx.appcompat.app.AlertDialog
import androidx.core.os.bundleOf
import androidx.databinding.Observable
import androidx.fragment.app.DialogFragment
import androidx.fragment.app.setFragmentResult
import androidx.lifecycle.lifecycleScope
import com.google.android.material.tabs.TabLayout
import com.wireguard.android.BR
import com.wireguard.android.R
import com.wireguard.android.databinding.AppListDialogFragmentBinding
import com.wireguard.android.databinding.ObservableKeyedArrayList
import com.wireguard.android.model.ApplicationData
import com.wireguard.android.util.ErrorMessages
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext

class AppListDialogFragment : DialogFragment() {
    private val appData = ObservableKeyedArrayList<String, ApplicationData>()
    private var currentlySelectedApps = emptyList<String>()
    private var initiallyExcluded = false
    private var button: Button? = null
    private var tabs: TabLayout? = null

    private fun loadData() {
        val activity = activity ?: return
        val pm = activity.packageManager
        lifecycleScope.launch(Dispatchers.Default) {
            try {
                val applicationData: MutableList<ApplicationData> = ArrayList()
                withContext(Dispatchers.IO) {
                    val packageInfos = pm.getPackagesHoldingPermissions(arrayOf(Manifest.permission.INTERNET), 0)
                    packageInfos.forEach {
                        val packageName = it.packageName
                        val appInfo = it.applicationInfo
                        val appData = ApplicationData(appInfo.loadIcon(pm), appInfo.loadLabel(pm).toString(), packageName, currentlySelectedApps.contains(packageName))
                        applicationData.add(appData)
                        appData.addOnPropertyChangedCallback(object : Observable.OnPropertyChangedCallback() {
                            override fun onPropertyChanged(sender: Observable?, propertyId: Int) {
                                if (propertyId == BR.selected)
                                    setButtonText()
                            }
                        })
                    }
                }
                applicationData.sortWith(compareBy(String.CASE_INSENSITIVE_ORDER) { it.name })
                withContext(Dispatchers.Main.immediate) {
                    appData.clear()
                    appData.addAll(applicationData)
                }
            } catch (e: Throwable) {
                withContext(Dispatchers.Main.immediate) {
                    val error = ErrorMessages[e]
                    val message = activity.getString(R.string.error_fetching_apps, error)
                    Toast.makeText(activity, message, Toast.LENGTH_LONG).show()
                    dismissAllowingStateLoss()
                }
            }
        }
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        currentlySelectedApps = (arguments?.getStringArrayList(KEY_SELECTED_APPS) ?: emptyList())
        initiallyExcluded = arguments?.getBoolean(KEY_IS_EXCLUDED) ?: true
    }

    private fun setButtonText() {
        val numSelected = appData.count { it.isSelected }
        button?.text = if (numSelected == 0)
            getString(R.string.use_all_applications)
        else when (tabs?.selectedTabPosition) {
            0 -> resources.getQuantityString(R.plurals.exclude_n_applications, numSelected, numSelected)
            1 -> resources.getQuantityString(R.plurals.include_n_applications, numSelected, numSelected)
            else -> null
        }
    }

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        val alertDialogBuilder = AlertDialog.Builder(requireActivity())
        val binding = AppListDialogFragmentBinding.inflate(requireActivity().layoutInflater, null, false)
        binding.executePendingBindings()
        alertDialogBuilder.setView(binding.root)
        tabs = binding.tabs
        tabs?.apply {
            selectTab(binding.tabs.getTabAt(if (initiallyExcluded) 0 else 1))
            addOnTabSelectedListener(object : TabLayout.OnTabSelectedListener {
                override fun onTabReselected(tab: TabLayout.Tab?) = Unit
                override fun onTabUnselected(tab: TabLayout.Tab?) = Unit
                override fun onTabSelected(tab: TabLayout.Tab?) = setButtonText()
            })
        }
        alertDialogBuilder.setPositiveButton(" ") { _, _ -> setSelectionAndDismiss() }
        alertDialogBuilder.setNegativeButton(R.string.cancel) { dialog, _ -> dialog.dismiss() }
        alertDialogBuilder.setNeutralButton(R.string.toggle_all) { _, _ -> }
        binding.fragment = this
        binding.appData = appData
        loadData()
        val dialog = alertDialogBuilder.create()
        dialog.setOnShowListener {
            button = dialog.getButton(AlertDialog.BUTTON_POSITIVE)
            setButtonText()
            dialog.getButton(AlertDialog.BUTTON_NEUTRAL).setOnClickListener { _ ->
                val selectAll = appData.none { it.isSelected }
                appData.forEach {
                    it.isSelected = selectAll
                }
            }
        }
        return dialog
    }

    private fun setSelectionAndDismiss() {
        val selectedApps: MutableList<String> = ArrayList()
        for (data in appData) {
            if (data.isSelected) {
                selectedApps.add(data.packageName)
            }
        }
        setFragmentResult(REQUEST_SELECTION, bundleOf(
                KEY_SELECTED_APPS to selectedApps.toTypedArray(),
                KEY_IS_EXCLUDED to (tabs?.selectedTabPosition == 0)
        ))
        dismiss()
    }

    companion object {
        const val KEY_SELECTED_APPS = "selected_apps"
        const val KEY_IS_EXCLUDED = "is_excluded"
        const val REQUEST_SELECTION = "request_selection"
        fun newInstance(selectedApps: ArrayList<String?>?, isExcluded: Boolean): AppListDialogFragment {
            val extras = Bundle()
            extras.putStringArrayList(KEY_SELECTED_APPS, selectedApps)
            extras.putBoolean(KEY_IS_EXCLUDED, isExcluded)
            val fragment = AppListDialogFragment()
            fragment.arguments = extras
            return fragment
        }
    }
}