/* Copyright 2021 Tusky Contributors
 *
 * This file is a part of Tusky.
 *
 * 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.
 *
 * Tusky 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 Tusky; if not,
 * see <http://www.gnu.org/licenses>. */

package com.keylesspalace.tusky.components.conversation

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.appcompat.app.AlertDialog
import androidx.appcompat.widget.PopupMenu
import androidx.fragment.app.viewModels
import androidx.lifecycle.Lifecycle
import androidx.lifecycle.lifecycleScope
import androidx.paging.LoadState
import androidx.preference.PreferenceManager
import androidx.recyclerview.widget.DividerItemDecoration
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import androidx.recyclerview.widget.SimpleItemAnimator
import at.connyduck.sparkbutton.helpers.Utils
import autodispose2.androidx.lifecycle.autoDispose
import com.keylesspalace.tusky.R
import com.keylesspalace.tusky.StatusListActivity
import com.keylesspalace.tusky.adapter.StatusBaseViewHolder
import com.keylesspalace.tusky.appstore.EventHub
import com.keylesspalace.tusky.appstore.PreferenceChangedEvent
import com.keylesspalace.tusky.components.account.AccountActivity
import com.keylesspalace.tusky.components.instanceinfo.InstanceInfoRepository.Companion.CAN_USE_QUOTE_ID
import com.keylesspalace.tusky.databinding.FragmentTimelineBinding
import com.keylesspalace.tusky.di.Injectable
import com.keylesspalace.tusky.di.ViewModelFactory
import com.keylesspalace.tusky.fragment.SFragment
import com.keylesspalace.tusky.interfaces.ActionButtonActivity
import com.keylesspalace.tusky.interfaces.ReselectableFragment
import com.keylesspalace.tusky.interfaces.StatusActionListener
import com.keylesspalace.tusky.settings.PrefKeys
import com.keylesspalace.tusky.util.CardViewMode
import com.keylesspalace.tusky.util.StatusDisplayOptions
import com.keylesspalace.tusky.util.hide
import com.keylesspalace.tusky.util.show
import com.keylesspalace.tusky.util.viewBinding
import com.keylesspalace.tusky.viewdata.AttachmentViewData
import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers
import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.collectLatest
import kotlinx.coroutines.launch
import java.io.IOException
import javax.inject.Inject
import kotlin.time.DurationUnit
import kotlin.time.toDuration

class ConversationsFragment : SFragment(), StatusActionListener, Injectable, ReselectableFragment {

    @Inject
    lateinit var viewModelFactory: ViewModelFactory

    @Inject
    lateinit var eventHub: EventHub

    private val viewModel: ConversationsViewModel by viewModels { viewModelFactory }

    private val binding by viewBinding(FragmentTimelineBinding::bind)

    private lateinit var adapter: ConversationAdapter

    private var hideFab = false

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

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        val preferences = PreferenceManager.getDefaultSharedPreferences(view.context)

        val statusDisplayOptions = StatusDisplayOptions(
            animateAvatars = preferences.getBoolean("animateGifAvatars", false),
            mediaPreviewEnabled = accountManager.activeAccount?.mediaPreviewEnabled ?: true,
            useAbsoluteTime = preferences.getBoolean("absoluteTimeView", false),
            showBotOverlay = preferences.getBoolean("showBotOverlay", true),
            useBlurhash = preferences.getBoolean("useBlurhash", true),
            cardViewMode = CardViewMode.NONE,
            confirmReblogs = preferences.getBoolean("confirmReblogs", true),
            confirmFavourites = preferences.getBoolean("confirmFavourites", false),
            hideStats = preferences.getBoolean(PrefKeys.WELLBEING_HIDE_STATS_POSTS, false),
            animateEmojis = preferences.getBoolean(PrefKeys.ANIMATE_CUSTOM_EMOJIS, false),
            quoteEnabled = accountManager.activeAccount?.domain in CAN_USE_QUOTE_ID,
        )

        adapter = ConversationAdapter(statusDisplayOptions, this)

        setupRecyclerView()

        initSwipeToRefresh()

        adapter.addLoadStateListener { loadState ->
            if (loadState.refresh != LoadState.Loading && loadState.source.refresh != LoadState.Loading) {
                binding.swipeRefreshLayout.isRefreshing = false
            }

            binding.statusView.hide()
            binding.progressBar.hide()

            if (adapter.itemCount == 0) {
                when (loadState.refresh) {
                    is LoadState.NotLoading -> {
                        if (loadState.append is LoadState.NotLoading && loadState.source.refresh is LoadState.NotLoading) {
                            binding.statusView.show()
                            binding.statusView.setup(R.drawable.elephant_friend_empty, R.string.message_empty, null)
                        }
                    }
                    is LoadState.Error -> {
                        binding.statusView.show()

                        if ((loadState.refresh as LoadState.Error).error is IOException) {
                            binding.statusView.setup(R.drawable.elephant_offline, R.string.error_network, null)
                        } else {
                            binding.statusView.setup(R.drawable.elephant_error, R.string.error_generic, null)
                        }
                    }
                    is LoadState.Loading -> {
                        binding.progressBar.show()
                    }
                }
            }
        }

        adapter.registerAdapterDataObserver(object : RecyclerView.AdapterDataObserver() {
            override fun onItemRangeInserted(positionStart: Int, itemCount: Int) {
                if (positionStart == 0 && adapter.itemCount != itemCount) {
                    binding.recyclerView.post {
                        if (getView() != null) {
                            binding.recyclerView.scrollBy(0, Utils.dpToPx(requireContext(), -30))
                        }
                    }
                }
            }
        })

        hideFab = preferences.getBoolean(PrefKeys.FAB_HIDE, false)
        binding.recyclerView.addOnScrollListener(object : RecyclerView.OnScrollListener() {
            override fun onScrolled(view: RecyclerView, dx: Int, dy: Int) {
                val composeButton = (activity as ActionButtonActivity).actionButton
                if (composeButton != null) {
                    if (hideFab) {
                        if (dy > 0 && composeButton.isShown) {
                            composeButton.hide() // hides the button if we're scrolling down
                        } else if (dy < 0 && !composeButton.isShown) {
                            composeButton.show() // shows it if we are scrolling up
                        }
                    } else if (!composeButton.isShown) {
                        composeButton.show()
                    }
                }
            }
        })

        viewLifecycleOwner.lifecycleScope.launch {
            viewModel.conversationFlow.collectLatest { pagingData ->
                adapter.submitData(pagingData)
            }
        }

        lifecycleScope.launchWhenResumed {
            val useAbsoluteTime = preferences.getBoolean(PrefKeys.ABSOLUTE_TIME_VIEW, false)
            while (!useAbsoluteTime) {
                adapter.notifyItemRangeChanged(0, adapter.itemCount, listOf(StatusBaseViewHolder.Key.KEY_CREATED))
                delay(1.toDuration(DurationUnit.MINUTES))
            }
        }

        eventHub.events
            .observeOn(AndroidSchedulers.mainThread())
            .autoDispose(this, Lifecycle.Event.ON_DESTROY)
            .subscribe { event ->
                if (event is PreferenceChangedEvent) {
                    onPreferenceChanged(event.preferenceKey)
                }
            }
    }

    private fun setupRecyclerView() {
        binding.recyclerView.setHasFixedSize(true)
        binding.recyclerView.layoutManager = LinearLayoutManager(context)

        binding.recyclerView.addItemDecoration(DividerItemDecoration(context, DividerItemDecoration.VERTICAL))

        (binding.recyclerView.itemAnimator as SimpleItemAnimator).supportsChangeAnimations = false

        binding.recyclerView.adapter = adapter.withLoadStateFooter(ConversationLoadStateAdapter(adapter::retry))
    }

    private fun initSwipeToRefresh() {
        binding.swipeRefreshLayout.setOnRefreshListener {
            adapter.refresh()
        }
        binding.swipeRefreshLayout.setColorSchemeResources(R.color.tusky_blue)
    }

    override fun onReblog(reblog: Boolean, position: Int) {
        // its impossible to reblog private messages
    }

    override fun onFavourite(favourite: Boolean, position: Int) {
        adapter.peek(position)?.let { conversation ->
            viewModel.favourite(favourite, conversation)
        }
    }

    override fun onQuote(position: Int) {
        // its impossible to quote private messages
    }

    override fun onBookmark(favourite: Boolean, position: Int) {
        adapter.peek(position)?.let { conversation ->
            viewModel.bookmark(favourite, conversation)
        }
    }

    override fun onMore(view: View, position: Int) {
        adapter.peek(position)?.let { conversation ->

            val popup = PopupMenu(requireContext(), view)
            popup.inflate(R.menu.conversation_more)

            if (conversation.lastStatus.status.muted == true) {
                popup.menu.removeItem(R.id.status_mute_conversation)
            } else {
                popup.menu.removeItem(R.id.status_unmute_conversation)
            }

            popup.setOnMenuItemClickListener { item ->
                when (item.itemId) {
                    R.id.status_mute_conversation -> viewModel.muteConversation(conversation)
                    R.id.status_unmute_conversation -> viewModel.muteConversation(conversation)
                    R.id.conversation_delete -> deleteConversation(conversation)
                }
                true
            }
            popup.show()
        }
    }

    override fun onViewMedia(position: Int, attachmentIndex: Int, view: View?) {
        adapter.peek(position)?.let { conversation ->
            viewMedia(attachmentIndex, AttachmentViewData.list(conversation.lastStatus.status), view)
        }
    }

    override fun onViewThread(position: Int) {
        adapter.peek(position)?.let { conversation ->
            viewThread(conversation.lastStatus.id, conversation.lastStatus.status.url)
        }
    }

    override fun onOpenReblog(position: Int) {
        // there are no reblogs in conversations
    }

    override fun onExpandedChange(expanded: Boolean, position: Int) {
        adapter.peek(position)?.let { conversation ->
            viewModel.expandHiddenStatus(expanded, conversation)
        }
    }

    override fun onContentHiddenChange(isShowing: Boolean, position: Int) {
        adapter.peek(position)?.let { conversation ->
            viewModel.showContent(isShowing, conversation)
        }
    }

    override fun onLoadMore(position: Int) {
        // not using the old way of pagination
    }

    override fun onContentCollapsedChange(isCollapsed: Boolean, position: Int) {
        adapter.peek(position)?.let { conversation ->
            viewModel.collapseLongStatus(isCollapsed, conversation)
        }
    }

    override fun onViewAccount(id: String) {
        val intent = AccountActivity.getIntent(requireContext(), id)
        startActivity(intent)
    }

    override fun onViewTag(tag: String) {
        val intent = StatusListActivity.newHashtagIntent(requireContext(), tag)
        startActivity(intent)
    }

    override fun removeItem(position: Int) {
        // not needed
    }

    override fun onReply(position: Int) {
        adapter.peek(position)?.let { conversation ->
            reply(conversation.lastStatus.status)
        }
    }

    override fun onVoteInPoll(position: Int, choices: MutableList<Int>) {
        adapter.peek(position)?.let { conversation ->
            viewModel.voteInPoll(choices, conversation)
        }
    }

    override fun onReselect() {
        if (isAdded) {
            binding.recyclerView.layoutManager?.scrollToPosition(0)
            binding.recyclerView.stopScroll()
        }
    }

    private fun deleteConversation(conversation: ConversationViewData) {
        AlertDialog.Builder(requireContext())
            .setMessage(R.string.dialog_delete_conversation_warning)
            .setNegativeButton(android.R.string.cancel, null)
            .setPositiveButton(android.R.string.ok) { _, _ ->
                viewModel.remove(conversation)
            }
            .show()
    }

    private fun onPreferenceChanged(key: String) {
        val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(requireContext())
        when (key) {
            PrefKeys.FAB_HIDE -> {
                hideFab = sharedPreferences.getBoolean(PrefKeys.FAB_HIDE, false)
            }
            PrefKeys.MEDIA_PREVIEW_ENABLED -> {
                val enabled = accountManager.activeAccount!!.mediaPreviewEnabled
                val oldMediaPreviewEnabled = adapter.mediaPreviewEnabled
                if (enabled != oldMediaPreviewEnabled) {
                    adapter.mediaPreviewEnabled = enabled
                    adapter.notifyItemRangeChanged(0, adapter.itemCount)
                }
            }
        }
    }

    companion object {
        fun newInstance() = ConversationsFragment()
    }
}