/*
 * Copyright 2019 Mauricio Colli <mauriciocolli@outlook.com>
 * FeedFragment.kt is part of NewPipe
 *
 * License: GPL-3.0+
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

package org.schabi.newpipe.local.feed

import android.annotation.SuppressLint
import android.app.Activity
import android.content.Intent
import android.content.SharedPreferences
import android.content.res.Configuration
import android.os.Bundle
import android.os.Parcelable
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.annotation.Nullable
import androidx.appcompat.app.AlertDialog
import androidx.appcompat.content.res.AppCompatResources
import androidx.core.content.edit
import androidx.core.os.bundleOf
import androidx.core.view.isVisible
import androidx.lifecycle.ViewModelProvider
import androidx.preference.PreferenceManager
import androidx.recyclerview.widget.GridLayoutManager
import com.xwray.groupie.GroupAdapter
import com.xwray.groupie.GroupieViewHolder
import com.xwray.groupie.Item
import com.xwray.groupie.OnItemClickListener
import com.xwray.groupie.OnItemLongClickListener
import icepick.State
import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers
import io.reactivex.rxjava3.core.Single
import io.reactivex.rxjava3.disposables.CompositeDisposable
import io.reactivex.rxjava3.schedulers.Schedulers
import org.schabi.newpipe.NewPipeDatabase
import org.schabi.newpipe.R
import org.schabi.newpipe.database.feed.model.FeedGroupEntity
import org.schabi.newpipe.database.subscription.SubscriptionEntity
import org.schabi.newpipe.databinding.FragmentFeedBinding
import org.schabi.newpipe.error.ErrorInfo
import org.schabi.newpipe.error.UserAction
import org.schabi.newpipe.extractor.exceptions.AccountTerminatedException
import org.schabi.newpipe.extractor.exceptions.ContentNotAvailableException
import org.schabi.newpipe.extractor.stream.StreamInfoItem
import org.schabi.newpipe.extractor.stream.StreamType
import org.schabi.newpipe.extractor.utils.Utils.isNullOrEmpty
import org.schabi.newpipe.fragments.BaseStateFragment
import org.schabi.newpipe.info_list.InfoItemDialog
import org.schabi.newpipe.ktx.animate
import org.schabi.newpipe.ktx.animateHideRecyclerViewAllowingScrolling
import org.schabi.newpipe.local.feed.item.StreamItem
import org.schabi.newpipe.local.feed.service.FeedLoadService
import org.schabi.newpipe.local.subscription.SubscriptionManager
import org.schabi.newpipe.player.helper.PlayerHolder
import org.schabi.newpipe.util.Localization
import org.schabi.newpipe.util.NavigationHelper
import org.schabi.newpipe.util.StreamDialogEntry
import java.time.OffsetDateTime
import java.util.ArrayList
import kotlin.math.floor
import kotlin.math.max

class FeedFragment : BaseStateFragment<FeedState>() {
    private var _feedBinding: FragmentFeedBinding? = null
    private val feedBinding get() = _feedBinding!!

    private val disposables = CompositeDisposable()

    private lateinit var viewModel: FeedViewModel
    @State @JvmField var listState: Parcelable? = null

    private var groupId = FeedGroupEntity.GROUP_ALL_ID
    private var groupName = ""
    private var oldestSubscriptionUpdate: OffsetDateTime? = null

    private lateinit var groupAdapter: GroupAdapter<GroupieViewHolder>
    @State @JvmField var showPlayedItems: Boolean = true

    private var onSettingsChangeListener: SharedPreferences.OnSharedPreferenceChangeListener? = null
    private var updateListViewModeOnResume = false

    init {
        setHasOptionsMenu(true)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        groupId = arguments?.getLong(KEY_GROUP_ID, FeedGroupEntity.GROUP_ALL_ID)
            ?: FeedGroupEntity.GROUP_ALL_ID
        groupName = arguments?.getString(KEY_GROUP_NAME) ?: ""

        onSettingsChangeListener = SharedPreferences.OnSharedPreferenceChangeListener { _, key ->
            if (key.equals(getString(R.string.list_view_mode_key))) {
                updateListViewModeOnResume = true
            }
        }
        PreferenceManager.getDefaultSharedPreferences(activity)
            .registerOnSharedPreferenceChangeListener(onSettingsChangeListener)
    }

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        return inflater.inflate(R.layout.fragment_feed, container, false)
    }

    override fun onViewCreated(rootView: View, savedInstanceState: Bundle?) {
        // super.onViewCreated() calls initListeners() which require the binding to be initialized
        _feedBinding = FragmentFeedBinding.bind(rootView)
        super.onViewCreated(rootView, savedInstanceState)

        val factory = FeedViewModel.Factory(requireContext(), groupId, showPlayedItems)
        viewModel = ViewModelProvider(this, factory).get(FeedViewModel::class.java)
        viewModel.stateLiveData.observe(viewLifecycleOwner, { it?.let(::handleResult) })

        groupAdapter = GroupAdapter<GroupieViewHolder>().apply {
            setOnItemClickListener(listenerStreamItem)
            setOnItemLongClickListener(listenerStreamItem)
        }

        feedBinding.itemsList.adapter = groupAdapter
        setupListViewMode()
    }

    override fun onPause() {
        super.onPause()
        listState = feedBinding.itemsList.layoutManager?.onSaveInstanceState()
    }

    override fun onResume() {
        super.onResume()
        updateRelativeTimeViews()

        if (updateListViewModeOnResume) {
            updateListViewModeOnResume = false

            setupListViewMode()
            if (viewModel.stateLiveData.value != null) {
                handleResult(viewModel.stateLiveData.value!!)
            }
        }
    }

    fun setupListViewMode() {
        // does everything needed to setup the layouts for grid or list modes
        groupAdapter.spanCount = if (shouldUseGridLayout()) getGridSpanCount() else 1
        feedBinding.itemsList.layoutManager = GridLayoutManager(requireContext(), groupAdapter.spanCount).apply {
            spanSizeLookup = groupAdapter.spanSizeLookup
        }
    }

    override fun setUserVisibleHint(isVisibleToUser: Boolean) {
        super.setUserVisibleHint(isVisibleToUser)

        if (!isVisibleToUser && view != null) {
            updateRelativeTimeViews()
        }
    }

    override fun initListeners() {
        super.initListeners()
        feedBinding.refreshRootView.setOnClickListener { reloadContent() }
        feedBinding.swipeRefreshLayout.setOnRefreshListener { reloadContent() }
    }

    // /////////////////////////////////////////////////////////////////////////
    // Menu
    // /////////////////////////////////////////////////////////////////////////

    override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
        super.onCreateOptionsMenu(menu, inflater)

        activity.supportActionBar?.setDisplayShowTitleEnabled(true)
        activity.supportActionBar?.setTitle(R.string.fragment_feed_title)
        activity.supportActionBar?.subtitle = groupName

        inflater.inflate(R.menu.menu_feed_fragment, menu)
        updateTogglePlayedItemsButton(menu.findItem(R.id.menu_item_feed_toggle_played_items))
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        if (item.itemId == R.id.menu_item_feed_help) {
            val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(requireContext())

            val usingDedicatedMethod = sharedPreferences
                .getBoolean(getString(R.string.feed_use_dedicated_fetch_method_key), false)
            val enableDisableButtonText = when {
                usingDedicatedMethod -> R.string.feed_use_dedicated_fetch_method_disable_button
                else -> R.string.feed_use_dedicated_fetch_method_enable_button
            }

            AlertDialog.Builder(requireContext())
                .setMessage(R.string.feed_use_dedicated_fetch_method_help_text)
                .setNeutralButton(enableDisableButtonText) { _, _ ->
                    sharedPreferences.edit {
                        putBoolean(getString(R.string.feed_use_dedicated_fetch_method_key), !usingDedicatedMethod)
                    }
                }
                .setPositiveButton(resources.getString(R.string.finish), null)
                .create()
                .show()
            return true
        } else if (item.itemId == R.id.menu_item_feed_toggle_played_items) {
            showPlayedItems = !item.isChecked
            updateTogglePlayedItemsButton(item)
            viewModel.togglePlayedItems(showPlayedItems)
        }

        return super.onOptionsItemSelected(item)
    }

    override fun onDestroyOptionsMenu() {
        super.onDestroyOptionsMenu()
        activity?.supportActionBar?.subtitle = null
    }

    override fun onDestroy() {
        disposables.dispose()
        if (onSettingsChangeListener != null) {
            PreferenceManager.getDefaultSharedPreferences(activity)
                .unregisterOnSharedPreferenceChangeListener(onSettingsChangeListener)
            onSettingsChangeListener = null
        }

        super.onDestroy()
        activity?.supportActionBar?.subtitle = null
    }

    override fun onDestroyView() {
        feedBinding.itemsList.adapter = null
        _feedBinding = null
        super.onDestroyView()
    }

    private fun updateTogglePlayedItemsButton(menuItem: MenuItem) {
        menuItem.isChecked = showPlayedItems
        menuItem.icon = AppCompatResources.getDrawable(
            requireContext(),
            if (showPlayedItems) R.drawable.ic_visibility_on else R.drawable.ic_visibility_off
        )
    }

    // //////////////////////////////////////////////////////////////////////////
    // Handling
    // //////////////////////////////////////////////////////////////////////////

    override fun showLoading() {
        super.showLoading()
        feedBinding.itemsList.animateHideRecyclerViewAllowingScrolling()
        feedBinding.refreshRootView.animate(false, 0)
        feedBinding.loadingProgressText.animate(true, 200)
        feedBinding.swipeRefreshLayout.isRefreshing = true
    }

    override fun hideLoading() {
        super.hideLoading()
        feedBinding.itemsList.animate(true, 0)
        feedBinding.refreshRootView.animate(true, 200)
        feedBinding.loadingProgressText.animate(false, 0)
        feedBinding.swipeRefreshLayout.isRefreshing = false
    }

    override fun showEmptyState() {
        super.showEmptyState()
        feedBinding.itemsList.animateHideRecyclerViewAllowingScrolling()
        feedBinding.refreshRootView.animate(true, 200)
        feedBinding.loadingProgressText.animate(false, 0)
        feedBinding.swipeRefreshLayout.isRefreshing = false
    }

    override fun handleResult(result: FeedState) {
        when (result) {
            is FeedState.ProgressState -> handleProgressState(result)
            is FeedState.LoadedState -> handleLoadedState(result)
            is FeedState.ErrorState -> if (handleErrorState(result)) return
        }

        updateRefreshViewState()
    }

    override fun handleError() {
        super.handleError()
        feedBinding.itemsList.animateHideRecyclerViewAllowingScrolling()
        feedBinding.refreshRootView.animate(false, 0)
        feedBinding.loadingProgressText.animate(false, 0)
        feedBinding.swipeRefreshLayout.isRefreshing = false
    }

    private fun handleProgressState(progressState: FeedState.ProgressState) {
        showLoading()

        val isIndeterminate = progressState.currentProgress == -1 &&
            progressState.maxProgress == -1

        feedBinding.loadingProgressText.text = if (!isIndeterminate) {
            "${progressState.currentProgress}/${progressState.maxProgress}"
        } else if (progressState.progressMessage > 0) {
            getString(progressState.progressMessage)
        } else {
            "∞/∞"
        }

        feedBinding.loadingProgressBar.isIndeterminate = isIndeterminate ||
            (progressState.maxProgress > 0 && progressState.currentProgress == 0)
        feedBinding.loadingProgressBar.progress = progressState.currentProgress

        feedBinding.loadingProgressBar.max = progressState.maxProgress
    }

    private fun showStreamDialog(item: StreamInfoItem) {
        val context = context
        val activity: Activity? = getActivity()
        if (context == null || context.resources == null || activity == null) return

        val entries = ArrayList<StreamDialogEntry>()
        if (PlayerHolder.getType() != null) {
            entries.add(StreamDialogEntry.enqueue)
        }
        if (item.streamType == StreamType.AUDIO_STREAM) {
            entries.addAll(
                listOf(
                    StreamDialogEntry.start_here_on_background,
                    StreamDialogEntry.append_playlist,
                    StreamDialogEntry.share,
                    StreamDialogEntry.open_in_browser
                )
            )
        } else {
            entries.addAll(
                listOf(
                    StreamDialogEntry.start_here_on_background,
                    StreamDialogEntry.start_here_on_popup,
                    StreamDialogEntry.append_playlist,
                    StreamDialogEntry.share,
                    StreamDialogEntry.open_in_browser
                )
            )
        }

        StreamDialogEntry.setEnabledEntries(entries)
        InfoItemDialog(activity, item, StreamDialogEntry.getCommands(context)) { _, which ->
            StreamDialogEntry.clickOn(which, this, item)
        }.show()
    }

    private val listenerStreamItem = object : OnItemClickListener, OnItemLongClickListener {
        override fun onItemClick(item: Item<*>, view: View) {
            if (item is StreamItem) {
                val stream = item.streamWithState.stream
                NavigationHelper.openVideoDetailFragment(
                    requireContext(), fm,
                    stream.serviceId, stream.url, stream.title, null, false
                )
            }
        }

        override fun onItemLongClick(item: Item<*>, view: View): Boolean {
            if (item is StreamItem) {
                showStreamDialog(item.streamWithState.stream.toStreamInfoItem())
                return true
            }
            return false
        }
    }

    @SuppressLint("StringFormatMatches")
    private fun handleLoadedState(loadedState: FeedState.LoadedState) {

        val itemVersion = if (shouldUseGridLayout()) {
            StreamItem.ItemVersion.GRID
        } else {
            StreamItem.ItemVersion.NORMAL
        }
        loadedState.items.forEach { it.itemVersion = itemVersion }

        groupAdapter.updateAsync(loadedState.items, false, null)

        listState?.run {
            feedBinding.itemsList.layoutManager?.onRestoreInstanceState(listState)
            listState = null
        }

        val feedsNotLoaded = loadedState.notLoadedCount > 0
        feedBinding.refreshSubtitleText.isVisible = feedsNotLoaded
        if (feedsNotLoaded) {
            feedBinding.refreshSubtitleText.text = getString(
                R.string.feed_subscription_not_loaded_count,
                loadedState.notLoadedCount
            )
        }

        if (oldestSubscriptionUpdate != loadedState.oldestUpdate ||
            (oldestSubscriptionUpdate == null && loadedState.oldestUpdate == null)
        ) {
            // ignore errors if they have already been handled for the current update
            handleItemsErrors(loadedState.itemsErrors)
        }
        oldestSubscriptionUpdate = loadedState.oldestUpdate

        if (loadedState.items.isEmpty()) {
            showEmptyState()
        } else {
            hideLoading()
        }
    }

    private fun handleErrorState(errorState: FeedState.ErrorState): Boolean {
        return if (errorState.error == null) {
            hideLoading()
            false
        } else {
            showError(ErrorInfo(errorState.error, UserAction.REQUESTED_FEED, "Loading feed"))
            true
        }
    }

    private fun handleItemsErrors(errors: List<Throwable>) {
        errors.forEachIndexed { i, t ->
            if (t is FeedLoadService.RequestException &&
                t.cause is ContentNotAvailableException
            ) {
                Single.fromCallable {
                    NewPipeDatabase.getInstance(requireContext()).subscriptionDAO()
                        .getSubscription(t.subscriptionId)
                }.subscribeOn(Schedulers.io())
                    .observeOn(AndroidSchedulers.mainThread())
                    .subscribe(
                        {
                            subscriptionEntity ->
                            handleFeedNotAvailable(
                                subscriptionEntity,
                                t.cause,
                                errors.subList(i + 1, errors.size)
                            )
                        },
                        { throwable -> throwable.printStackTrace() }
                    )
                return // this will be called on the remaining errors by handleFeedNotAvailable()
            }
        }
    }

    private fun handleFeedNotAvailable(
        subscriptionEntity: SubscriptionEntity,
        @Nullable cause: Throwable?,
        nextItemsErrors: List<Throwable>
    ) {
        val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(requireContext())
        val isFastFeedModeEnabled = sharedPreferences.getBoolean(
            getString(R.string.feed_use_dedicated_fetch_method_key), false
        )

        val builder = AlertDialog.Builder(requireContext())
            .setTitle(R.string.feed_load_error)
            .setPositiveButton(
                R.string.unsubscribe
            ) { _, _ ->
                SubscriptionManager(requireContext()).deleteSubscription(
                    subscriptionEntity.serviceId, subscriptionEntity.url
                ).subscribe()
                handleItemsErrors(nextItemsErrors)
            }
            .setNegativeButton(R.string.cancel) { _, _ -> }

        var message = getString(R.string.feed_load_error_account_info, subscriptionEntity.name)
        if (cause is AccountTerminatedException) {
            message += "\n" + getString(R.string.feed_load_error_terminated)
        } else if (cause is ContentNotAvailableException) {
            if (isFastFeedModeEnabled) {
                message += "\n" + getString(R.string.feed_load_error_fast_unknown)
                builder.setNeutralButton(R.string.feed_use_dedicated_fetch_method_disable_button) { _, _ ->
                    sharedPreferences.edit {
                        putBoolean(getString(R.string.feed_use_dedicated_fetch_method_key), false)
                    }
                }
            } else if (!isNullOrEmpty(cause.message)) {
                message += "\n" + cause.message
            }
        }
        builder.setMessage(message).create().show()
    }

    private fun updateRelativeTimeViews() {
        updateRefreshViewState()
        groupAdapter.notifyItemRangeChanged(
            0, groupAdapter.itemCount,
            StreamItem.UPDATE_RELATIVE_TIME
        )
    }

    private fun updateRefreshViewState() {
        feedBinding.refreshText.text = getString(
            R.string.feed_oldest_subscription_update,
            oldestSubscriptionUpdate?.let { Localization.relativeTime(it) } ?: "—"
        )
    }

    // /////////////////////////////////////////////////////////////////////////
    // Load Service Handling
    // /////////////////////////////////////////////////////////////////////////

    override fun doInitialLoadLogic() {}

    override fun reloadContent() {
        getActivity()?.startService(
            Intent(requireContext(), FeedLoadService::class.java).apply {
                putExtra(FeedLoadService.EXTRA_GROUP_ID, groupId)
            }
        )
        listState = null
    }

    // /////////////////////////////////////////////////////////////////////////
    // Grid Mode
    // /////////////////////////////////////////////////////////////////////////

    // TODO: Move these out of this class, as it can be reused

    private fun shouldUseGridLayout(): Boolean {
        val listMode = PreferenceManager.getDefaultSharedPreferences(requireContext())
            .getString(getString(R.string.list_view_mode_key), getString(R.string.list_view_mode_value))

        return when (listMode) {
            getString(R.string.list_view_mode_auto_key) -> {
                val configuration = resources.configuration

                (
                    configuration.orientation == Configuration.ORIENTATION_LANDSCAPE &&
                        configuration.isLayoutSizeAtLeast(Configuration.SCREENLAYOUT_SIZE_LARGE)
                    )
            }
            getString(R.string.list_view_mode_grid_key) -> true
            else -> false
        }
    }

    private fun getGridSpanCount(): Int {
        val minWidth = resources.getDimensionPixelSize(R.dimen.video_item_grid_thumbnail_image_width)
        return max(1, floor(resources.displayMetrics.widthPixels / minWidth.toDouble()).toInt())
    }

    companion object {
        const val KEY_GROUP_ID = "ARG_GROUP_ID"
        const val KEY_GROUP_NAME = "ARG_GROUP_NAME"

        @JvmStatic
        fun newInstance(groupId: Long = FeedGroupEntity.GROUP_ALL_ID, groupName: String? = null): FeedFragment {
            val feedFragment = FeedFragment()
            feedFragment.arguments = bundleOf(KEY_GROUP_ID to groupId, KEY_GROUP_NAME to groupName)
            return feedFragment
        }
    }
}