package io.heckel.ntfy.ui

import android.animation.Animator
import android.animation.AnimatorListenerAdapter
import android.app.AlertDialog
import android.content.Intent
import android.net.Uri
import android.os.Bundle
import android.util.Log
import android.view.*
import android.widget.Toast
import androidx.activity.viewModels
import androidx.appcompat.app.AppCompatActivity
import androidx.core.content.ContextCompat
import androidx.lifecycle.lifecycleScope
import androidx.recyclerview.widget.RecyclerView
import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
import androidx.work.*
import io.heckel.ntfy.R
import io.heckel.ntfy.app.Application
import io.heckel.ntfy.data.Subscription
import io.heckel.ntfy.util.topicShortUrl
import io.heckel.ntfy.msg.ApiService
import io.heckel.ntfy.msg.NotificationService
import io.heckel.ntfy.work.PollWorker
import io.heckel.ntfy.firebase.FirebaseMessenger
import io.heckel.ntfy.msg.BroadcastService
import io.heckel.ntfy.msg.SubscriberService
import io.heckel.ntfy.util.fadeStatusBarColor
import io.heckel.ntfy.util.formatDateShort
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.delay
import kotlinx.coroutines.isActive
import kotlinx.coroutines.launch
import java.util.*
import java.util.concurrent.TimeUnit
import kotlin.random.Random

class MainActivity : AppCompatActivity(), ActionMode.Callback, AddFragment.SubscribeListener, NotificationFragment.NotificationSettingsListener {
    private val viewModel by viewModels<SubscriptionsViewModel> {
        SubscriptionsViewModelFactory((application as Application).repository)
    }
    private val repository by lazy { (application as Application).repository }
    private val api = ApiService()
    private val messenger = FirebaseMessenger()

    // UI elements
    private lateinit var menu: Menu
    private lateinit var mainList: RecyclerView
    private lateinit var mainListContainer: SwipeRefreshLayout
    private lateinit var adapter: MainAdapter
    private lateinit var fab: View

    // Other stuff
    private var actionMode: ActionMode? = null
    private var workManager: WorkManager? = null // Context-dependent
    private var notifier: NotificationService? = null // Context-dependent
    private var broadcaster: BroadcastService? = null // Context-dependent
    private var subscriberManager: SubscriberManager? = null // Context-dependent
    private var appBaseUrl: String? = null // Context-dependent

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        Log.d(TAG, "Create $this")

        // Dependencies that depend on Context
        workManager = WorkManager.getInstance(this)
        notifier = NotificationService(this)
        broadcaster = BroadcastService(this)
        subscriberManager = SubscriberManager(this)
        appBaseUrl = getString(R.string.app_base_url)

        // Action bar
        title = getString(R.string.main_action_bar_title)

        // Floating action button ("+")
        fab = findViewById(R.id.fab)
        fab.setOnClickListener {
            onSubscribeButtonClick()
        }

        // Swipe to refresh
        mainListContainer = findViewById(R.id.main_subscriptions_list_container)
        mainListContainer.setOnRefreshListener { refreshAllSubscriptions() }
        mainListContainer.setColorSchemeResources(R.color.primaryColor)

        // Update main list based on viewModel (& its datasource/livedata)
        val noEntries: View = findViewById(R.id.main_no_subscriptions)
        val onSubscriptionClick = { s: Subscription -> onSubscriptionItemClick(s) }
        val onSubscriptionLongClick = { s: Subscription -> onSubscriptionItemLongClick(s) }

        mainList = findViewById(R.id.main_subscriptions_list)
        adapter = MainAdapter(onSubscriptionClick, onSubscriptionLongClick)
        mainList.adapter = adapter

        viewModel.list().observe(this) {
            it?.let { subscriptions ->
                adapter.submitList(subscriptions as MutableList<Subscription>)
                if (it.isEmpty()) {
                    mainListContainer.visibility = View.GONE
                    noEntries.visibility = View.VISIBLE
                } else {
                    mainListContainer.visibility = View.VISIBLE
                    noEntries.visibility = View.GONE
                }
            }
        }

        // React to changes in fast delivery setting
        viewModel.listIdsWithInstantStatus().observe(this) {
            subscriberManager?.refreshService(it)
        }

        // Create notification channels right away, so we can configure them immediately after installing the app
        notifier!!.createNotificationChannels()

        // Subscribe to control Firebase channel (so we can re-start the foreground service if it dies)
        messenger.subscribe(ApiService.CONTROL_TOPIC)

        // Background things
        startPeriodicPollWorker()
        startPeriodicAutoRestartWorker()
    }

    private fun startPeriodicPollWorker() {
        val workerVersion = repository.getPollWorkerVersion()
        val workPolicy = if (workerVersion == PollWorker.VERSION) {
            Log.d(TAG, "Poll worker version matches: choosing KEEP as existing work policy")
            ExistingPeriodicWorkPolicy.KEEP
        } else {
            Log.d(TAG, "Poll worker version DOES NOT MATCH: choosing REPLACE as existing work policy")
            repository.setPollWorkerVersion(PollWorker.VERSION)
            ExistingPeriodicWorkPolicy.REPLACE
        }
        val constraints = Constraints.Builder()
            .setRequiredNetworkType(NetworkType.CONNECTED)
            .build()
        val work = PeriodicWorkRequestBuilder<PollWorker>(MINIMUM_PERIODIC_WORKER_INTERVAL, TimeUnit.MINUTES)
            .setConstraints(constraints)
            .addTag(PollWorker.TAG)
            .addTag(PollWorker.WORK_NAME_PERIODIC)
            .build()
        Log.d(TAG, "Poll worker: Scheduling period work every ${MINIMUM_PERIODIC_WORKER_INTERVAL} minutes")
        workManager!!.enqueueUniquePeriodicWork(PollWorker.WORK_NAME_PERIODIC, workPolicy, work)
    }

    private fun startPeriodicAutoRestartWorker() {
        val workerVersion = repository.getAutoRestartWorkerVersion()
        val workPolicy = if (workerVersion == SubscriberService.AUTO_RESTART_WORKER_VERSION) {
            Log.d(TAG, "Auto restart worker version matches: choosing KEEP as existing work policy")
            ExistingPeriodicWorkPolicy.KEEP
        } else {
            Log.d(TAG, "Auto restart worker version DOES NOT MATCH: choosing REPLACE as existing work policy")
            repository.setAutoRestartWorkerVersion(SubscriberService.AUTO_RESTART_WORKER_VERSION)
            ExistingPeriodicWorkPolicy.REPLACE
        }
        val work = PeriodicWorkRequestBuilder<SubscriberService.AutoRestartWorker>(MINIMUM_PERIODIC_WORKER_INTERVAL, TimeUnit.MINUTES)
            .addTag(SubscriberService.TAG)
            .addTag(SubscriberService.AUTO_RESTART_WORKER_WORK_NAME_PERIODIC)
            .build()
        Log.d(TAG, "Auto restart worker: Scheduling period work every ${MINIMUM_PERIODIC_WORKER_INTERVAL} minutes")
        workManager!!.enqueueUniquePeriodicWork(SubscriberService.AUTO_RESTART_WORKER_WORK_NAME_PERIODIC, workPolicy, work)
    }

    override fun onCreateOptionsMenu(menu: Menu): Boolean {
        menuInflater.inflate(R.menu.menu_main_action_bar, menu)
        this.menu = menu
        showHideNotificationMenuItems()
        startNotificationMutedChecker() // This is done here, because then we know that we've initialized the menu
        return true
    }

    private fun startNotificationMutedChecker() {
        lifecycleScope.launch(Dispatchers.IO) {
            delay(1000) // Just to be sure we've initialized all the things, we wait a bit ...
            while (isActive) {
                Log.d(DetailActivity.TAG, "Checking global and subscription-specific 'muted until' timestamp")

                // Check global
                val changed = repository.checkGlobalMutedUntil()
                if (changed) {
                    Log.d(TAG, "Global muted until timestamp expired; updating prefs")
                    showHideNotificationMenuItems()
                }

                // Check subscriptions
                var rerenderList = false
                repository.getSubscriptions().forEach { subscription ->
                    val mutedUntilExpired = subscription.mutedUntil > 1L && System.currentTimeMillis()/1000 > subscription.mutedUntil
                    if (mutedUntilExpired) {
                        Log.d(TAG, "Subscription ${subscription.id}: Muted until timestamp expired, updating subscription")
                        val newSubscription = subscription.copy(mutedUntil = 0L)
                        repository.updateSubscription(newSubscription)
                        rerenderList = true
                    }
                }
                if (rerenderList) {
                    redrawList()
                }

                delay(60_000)
            }
        }
    }

    private fun showHideNotificationMenuItems() {
        val mutedUntilSeconds = repository.getGlobalMutedUntil()
        runOnUiThread {
            val notificationsEnabledItem = menu.findItem(R.id.main_menu_notifications_enabled)
            val notificationsDisabledUntilItem = menu.findItem(R.id.main_menu_notifications_disabled_until)
            val notificationsDisabledForeverItem = menu.findItem(R.id.main_menu_notifications_disabled_forever)
            notificationsEnabledItem?.isVisible = mutedUntilSeconds == 0L
            notificationsDisabledForeverItem?.isVisible = mutedUntilSeconds == 1L
            notificationsDisabledUntilItem?.isVisible = mutedUntilSeconds > 1L
            if (mutedUntilSeconds > 1L) {
                val formattedDate = formatDateShort(mutedUntilSeconds)
                notificationsDisabledUntilItem?.title = getString(R.string.main_menu_notifications_disabled_until, formattedDate)
            }
        }
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        return when (item.itemId) {
            R.id.main_menu_notifications_enabled -> {
                onNotificationSettingsClick(enable = false)
                true
            }
            R.id.main_menu_notifications_disabled_forever -> {
                onNotificationSettingsClick(enable = true)
                true
            }
            R.id.main_menu_notifications_disabled_until -> {
                onNotificationSettingsClick(enable = true)
                true
            }
            R.id.main_menu_source -> {
                startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(getString(R.string.main_menu_source_url))))
                true
            }
            R.id.main_menu_website -> {
                startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(appBaseUrl)))
                true
            }
            else -> super.onOptionsItemSelected(item)
        }
    }

    private fun onNotificationSettingsClick(enable: Boolean) {
        if (!enable) {
            Log.d(TAG, "Showing global notification settings dialog")
            val notificationFragment = NotificationFragment()
            notificationFragment.show(supportFragmentManager, NotificationFragment.TAG)
        } else {
            Log.d(TAG, "Re-enabling global notifications")
            onNotificationMutedUntilChanged(0L)
        }
    }

    override fun onNotificationMutedUntilChanged(mutedUntilTimestamp: Long) {
        repository.setGlobalMutedUntil(mutedUntilTimestamp)
        showHideNotificationMenuItems()
        runOnUiThread {
            when (mutedUntilTimestamp) {
                0L -> Toast.makeText(this@MainActivity, getString(R.string.notification_dialog_enabled_toast_message), Toast.LENGTH_LONG).show()
                1L -> Toast.makeText(this@MainActivity, getString(R.string.notification_dialog_muted_forever_toast_message), Toast.LENGTH_LONG).show()
                else -> {
                    val formattedDate = formatDateShort(mutedUntilTimestamp)
                    Toast.makeText(this@MainActivity, getString(R.string.notification_dialog_muted_until_toast_message, formattedDate), Toast.LENGTH_LONG).show()
                }
            }
        }
    }

    private fun onSubscribeButtonClick() {
        val newFragment = AddFragment()
        newFragment.show(supportFragmentManager, AddFragment.TAG)
    }

    override fun onSubscribe(topic: String, baseUrl: String, instant: Boolean) {
        Log.d(TAG, "Adding subscription ${topicShortUrl(baseUrl, topic)}")

        // Add subscription to database
        val subscription = Subscription(
            id = Random.nextLong(),
            baseUrl = baseUrl,
            topic = topic,
            instant = instant,
            mutedUntil = 0,
            totalCount = 0,
            newCount = 0,
            lastActive = Date().time/1000
        )
        viewModel.add(subscription)

        // Subscribe to Firebase topic if ntfy.sh (even if instant, just to be sure!)
        if (baseUrl == appBaseUrl) {
            Log.d(TAG, "Subscribing to Firebase")
            messenger.subscribe(topic)
        }

        // Fetch cached messages
        lifecycleScope.launch(Dispatchers.IO) {
            try {
                val notifications = api.poll(subscription.id, subscription.baseUrl, subscription.topic)
                notifications.forEach { notification -> repository.addNotification(notification) }
            } catch (e: Exception) {
                Log.e(TAG, "Unable to fetch notifications: ${e.stackTrace}")
            }
        }

        // Switch to detail view after adding it
        onSubscriptionItemClick(subscription)
    }

    private fun onSubscriptionItemClick(subscription: Subscription) {
        if (actionMode != null) {
            handleActionModeClick(subscription)
        } else {
            startDetailView(subscription)
        }
    }

    private fun onSubscriptionItemLongClick(subscription: Subscription) {
        if (actionMode == null) {
            beginActionMode(subscription)
        }
    }

    private fun refreshAllSubscriptions() {
        lifecycleScope.launch(Dispatchers.IO) {
            Log.d(TAG, "Polling for new notifications")
            var errors = 0
            var errorMessage = "" // First error
            var newNotificationsCount = 0
            repository.getSubscriptions().forEach { subscription ->
                try {
                    val notifications = api.poll(subscription.id, subscription.baseUrl, subscription.topic)
                    val newNotifications = repository.onlyNewNotifications(subscription.id, notifications)
                    newNotifications.forEach { notification ->
                        newNotificationsCount++
                        val notificationWithId = notification.copy(notificationId = Random.nextInt())
                        val result = repository.addNotification(notificationWithId)
                        if (result.notify) {
                            notifier?.send(subscription, notificationWithId)
                        }
                        if (result.broadcast) {
                            broadcaster?.send(subscription, notification, result.muted)
                        }
                    }
                } catch (e: Exception) {
                    val topic = topicShortUrl(subscription.baseUrl, subscription.topic)
                    if (errorMessage == "") errorMessage = "$topic: ${e.message}"
                    errors++
                }
            }
            val toastMessage = if (errors > 0) {
                getString(R.string.refresh_message_error, errors, errorMessage)
            } else if (newNotificationsCount == 0) {
                getString(R.string.refresh_message_no_results)
            } else {
                getString(R.string.refresh_message_result, newNotificationsCount)
            }
            runOnUiThread {
                Toast.makeText(this@MainActivity, toastMessage, Toast.LENGTH_LONG).show()
                mainListContainer.isRefreshing = false
            }
            Log.d(TAG, "Finished polling for new notifications")
        }
    }

    private fun startDetailView(subscription: Subscription) {
        Log.d(TAG, "Entering detail view for subscription $subscription")

        val intent = Intent(this, DetailActivity::class.java)
        intent.putExtra(EXTRA_SUBSCRIPTION_ID, subscription.id)
        intent.putExtra(EXTRA_SUBSCRIPTION_BASE_URL, subscription.baseUrl)
        intent.putExtra(EXTRA_SUBSCRIPTION_TOPIC, subscription.topic)
        intent.putExtra(EXTRA_SUBSCRIPTION_INSTANT, subscription.instant)
        intent.putExtra(EXTRA_SUBSCRIPTION_MUTED_UNTIL, subscription.mutedUntil)
        startActivity(intent)
    }

    private fun handleActionModeClick(subscription: Subscription) {
        adapter.toggleSelection(subscription.id)
        if (adapter.selected.size == 0) {
            finishActionMode()
        } else {
            actionMode!!.title = adapter.selected.size.toString()
            redrawList()
        }
    }

    override fun onCreateActionMode(mode: ActionMode?, menu: Menu?): Boolean {
        this.actionMode = mode
        if (mode != null) {
            mode.menuInflater.inflate(R.menu.menu_main_action_mode, menu)
            mode.title = "1" // One item selected
        }
        return true
    }

    override fun onPrepareActionMode(mode: ActionMode?, menu: Menu?): Boolean {
        return false
    }

    override fun onActionItemClicked(mode: ActionMode?, item: MenuItem?): Boolean {
        return when (item?.itemId) {
            R.id.main_action_mode_delete -> {
                onMultiDeleteClick()
                true
            }
            else -> false
        }
    }

    private fun onMultiDeleteClick() {
        Log.d(DetailActivity.TAG, "Showing multi-delete dialog for selected items")

        val builder = AlertDialog.Builder(this)
        val dialog = builder
            .setMessage(R.string.main_action_mode_delete_dialog_message)
            .setPositiveButton(R.string.main_action_mode_delete_dialog_permanently_delete) { _, _ ->
                adapter.selected.map { viewModel.remove(it) }
                finishActionMode()
            }
            .setNegativeButton(R.string.main_action_mode_delete_dialog_cancel) { _, _ ->
                finishActionMode()
            }
            .create()
        dialog.setOnShowListener {
            dialog
                .getButton(AlertDialog.BUTTON_POSITIVE)
                .setTextColor(ContextCompat.getColor(this, R.color.primaryDangerButtonColor))
        }
        dialog.show()
    }

    override fun onDestroyActionMode(mode: ActionMode?) {
        endActionModeAndRedraw()
    }

    private fun beginActionMode(subscription: Subscription) {
        actionMode = startActionMode(this)
        adapter.selected.add(subscription.id)
        redrawList()

        // Fade out FAB
        fab.alpha = 1f
        fab
            .animate()
            .alpha(0f)
            .setDuration(ANIMATION_DURATION)
            .setListener(object : AnimatorListenerAdapter() {
                override fun onAnimationEnd(animation: Animator) {
                    fab.visibility = View.GONE
                }
            })

        // Fade status bar color
        val fromColor = ContextCompat.getColor(this, R.color.primaryColor)
        val toColor = ContextCompat.getColor(this, R.color.primaryDarkColor)
        fadeStatusBarColor(window, fromColor, toColor)
    }

    private fun finishActionMode() {
        actionMode!!.finish()
        endActionModeAndRedraw()
    }

    private fun endActionModeAndRedraw() {
        actionMode = null
        adapter.selected.clear()
        redrawList()

        // Fade in FAB
        fab.alpha = 0f
        fab.visibility = View.VISIBLE
        fab
            .animate()
            .alpha(1f)
            .setDuration(ANIMATION_DURATION)
            .setListener(object : AnimatorListenerAdapter() {
                override fun onAnimationEnd(animation: Animator) {
                    fab.visibility = View.VISIBLE // Required to replace the old listener
                }
            })

        // Fade status bar color
        val fromColor = ContextCompat.getColor(this, R.color.primaryDarkColor)
        val toColor = ContextCompat.getColor(this, R.color.primaryColor)
        fadeStatusBarColor(window, fromColor, toColor)
    }

    private fun redrawList() {
        runOnUiThread {
            mainList.adapter = adapter // Oh, what a hack ...
        }
    }

    companion object {
        const val TAG = "NtfyMainActivity"
        const val EXTRA_SUBSCRIPTION_ID = "subscriptionId"
        const val EXTRA_SUBSCRIPTION_BASE_URL = "subscriptionBaseUrl"
        const val EXTRA_SUBSCRIPTION_TOPIC = "subscriptionTopic"
        const val EXTRA_SUBSCRIPTION_INSTANT = "subscriptionInstant"
        const val EXTRA_SUBSCRIPTION_MUTED_UNTIL = "subscriptionMutedUntil"
        const val ANIMATION_DURATION = 80L

        // As per Documentation: The minimum repeat interval that can be defined is 15 minutes
        // (same as the JobScheduler API), but in practice 15 doesn't work. Using 16 here.
        // Thanks to varunon9 (https://gist.github.com/varunon9/f2beec0a743c96708eb0ef971a9ff9cd) for this!
        const val MINIMUM_PERIODIC_WORKER_INTERVAL = 16L
    }
}