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

import android.content.Intent
import android.content.pm.PackageManager
import android.os.Build
import android.os.Bundle
import android.util.SparseArray
import android.view.MenuItem
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat
import androidx.lifecycle.lifecycleScope
import androidx.preference.Preference
import androidx.preference.PreferenceFragmentCompat
import com.wireguard.android.Application
import com.wireguard.android.R
import com.wireguard.android.backend.WgQuickBackend
import com.wireguard.android.util.AdminKnobs
import com.wireguard.android.util.ModuleLoader
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext
import java.util.ArrayList
import java.util.Arrays

/**
 * Interface for changing application-global persistent settings.
 */
class SettingsActivity : ThemeChangeAwareActivity() {
    private val permissionRequestCallbacks = SparseArray<(permissions: Array<String>, granted: IntArray) -> Unit>()
    private var permissionRequestCounter = 0

    fun ensurePermissions(permissions: Array<String>, cb: (permissions: Array<String>, granted: IntArray) -> Unit) {
        val needPermissions: MutableList<String> = ArrayList(permissions.size)
        permissions.forEach {
            if (ContextCompat.checkSelfPermission(this, it) != PackageManager.PERMISSION_GRANTED) {
                needPermissions.add(it)
            }
        }
        if (needPermissions.isEmpty()) {
            val granted = IntArray(permissions.size)
            Arrays.fill(granted, PackageManager.PERMISSION_GRANTED)
            cb.invoke(permissions, granted)
            return
        }
        val idx = permissionRequestCounter++
        permissionRequestCallbacks.put(idx, cb)
        ActivityCompat.requestPermissions(this,
                needPermissions.toTypedArray(), idx)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        if (supportFragmentManager.findFragmentById(android.R.id.content) == null) {
            supportFragmentManager.beginTransaction()
                    .add(android.R.id.content, SettingsFragment())
                    .commit()
        }
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        if (item.itemId == android.R.id.home) {
            finish()
            return true
        }
        return super.onOptionsItemSelected(item)
    }

    override fun onRequestPermissionsResult(requestCode: Int,
                                            permissions: Array<String>,
                                            grantResults: IntArray) {
        val f = permissionRequestCallbacks[requestCode]
        if (f != null) {
            permissionRequestCallbacks.remove(requestCode)
            f.invoke(permissions, grantResults)
        }
    }

    class SettingsFragment : PreferenceFragmentCompat() {
        override fun onCreatePreferences(savedInstanceState: Bundle?, key: String?) {
            addPreferencesFromResource(R.xml.preferences)
            preferenceScreen.initialExpandedChildrenCount = 4
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
                val darkTheme = preferenceManager.findPreference<Preference>("dark_theme")
                darkTheme?.parent?.removePreference(darkTheme)
                --preferenceScreen.initialExpandedChildrenCount
            }
            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
                val remoteApps = preferenceManager.findPreference<Preference>("allow_remote_control_intents")
                remoteApps?.parent?.removePreference(remoteApps)
            }
            if (AdminKnobs.disableConfigExport) {
                val zipExporter = preferenceManager.findPreference<Preference>("zip_exporter")
                zipExporter?.parent?.removePreference(zipExporter)
            }
            val wgQuickOnlyPrefs = arrayOf(
                    preferenceManager.findPreference("tools_installer"),
                    preferenceManager.findPreference("restore_on_boot"),
                    preferenceManager.findPreference<Preference>("multiple_tunnels")
            ).filterNotNull()
            wgQuickOnlyPrefs.forEach { it.isVisible = false }
            lifecycleScope.launch {
                if (Application.getBackend() is WgQuickBackend) {
                    ++preferenceScreen.initialExpandedChildrenCount
                    wgQuickOnlyPrefs.forEach { it.isVisible = true }
                } else {
                    wgQuickOnlyPrefs.forEach { it.parent?.removePreference(it) }
                }
            }
            preferenceManager.findPreference<Preference>("log_viewer")?.setOnPreferenceClickListener {
                startActivity(Intent(requireContext(), LogViewerActivity::class.java))
                true
            }
            val moduleInstaller = preferenceManager.findPreference<Preference>("module_downloader")
            val kernelModuleDisabler = preferenceManager.findPreference<Preference>("kernel_module_disabler")
            moduleInstaller?.isVisible = false
            if (ModuleLoader.isModuleLoaded()) {
                moduleInstaller?.parent?.removePreference(moduleInstaller)
            } else {
                kernelModuleDisabler?.parent?.removePreference(kernelModuleDisabler)
                lifecycleScope.launch {
                    try {
                        withContext(Dispatchers.IO) { Application.getRootShell().start() }
                        moduleInstaller?.isVisible = true
                    } catch (_: Throwable) {
                        moduleInstaller?.parent?.removePreference(moduleInstaller)
                    }
                }
            }
        }
    }
}