/*
 * Nextcloud Talk application
 *
 * @author Álvaro Brey
 * Copyright (C) 2022 Álvaro Brey
 * Copyright (C) 2022 Nextcloud GmbH
 *
 * 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 <https://www.gnu.org/licenses/>.
 */

package com.nextcloud.talk.messagesearch

import android.app.Activity
import android.content.Intent
import android.os.Bundle
import android.text.TextUtils
import android.view.Menu
import android.view.MenuItem
import android.view.View
import android.widget.Toast
import androidx.appcompat.widget.SearchView
import androidx.core.content.res.ResourcesCompat
import androidx.lifecycle.ViewModelProvider
import autodagger.AutoInjector
import com.nextcloud.talk.R
import com.nextcloud.talk.activities.BaseActivity
import com.nextcloud.talk.adapters.items.LoadMoreResultsItem
import com.nextcloud.talk.adapters.items.MessageResultItem
import com.nextcloud.talk.application.NextcloudTalkApplication
import com.nextcloud.talk.controllers.ConversationsListController
import com.nextcloud.talk.data.user.model.User
import com.nextcloud.talk.databinding.ActivityMessageSearchBinding
import com.nextcloud.talk.utils.DisplayUtils
import com.nextcloud.talk.utils.bundle.BundleKeys
import com.nextcloud.talk.utils.database.user.CurrentUserProviderNew
import com.nextcloud.talk.utils.rx.SearchViewObservable.Companion.observeSearchView
import eu.davidea.flexibleadapter.FlexibleAdapter
import eu.davidea.flexibleadapter.items.AbstractFlexibleItem
import eu.davidea.viewholders.FlexibleViewHolder
import io.reactivex.Observable
import io.reactivex.android.schedulers.AndroidSchedulers
import io.reactivex.disposables.Disposable
import io.reactivex.schedulers.Schedulers
import java.util.concurrent.TimeUnit
import javax.inject.Inject

@AutoInjector(NextcloudTalkApplication::class)
class MessageSearchActivity : BaseActivity() {

    @Inject
    lateinit var viewModelFactory: ViewModelProvider.Factory

    @Inject
    lateinit var userProvider: CurrentUserProviderNew

    private lateinit var binding: ActivityMessageSearchBinding
    private lateinit var searchView: SearchView

    private lateinit var user: User

    private lateinit var viewModel: MessageSearchViewModel

    private var searchViewDisposable: Disposable? = null
    private var adapter: FlexibleAdapter<AbstractFlexibleItem<*>>? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        NextcloudTalkApplication.sharedApplication!!.componentApplication.inject(this)

        binding = ActivityMessageSearchBinding.inflate(layoutInflater)
        setupActionBar()
        setupSystemColors()
        setContentView(binding.root)

        viewModel = ViewModelProvider(this, viewModelFactory)[MessageSearchViewModel::class.java]
        user = userProvider.currentUser.blockingGet()
        val roomToken = intent.getStringExtra(BundleKeys.KEY_ROOM_TOKEN)!!
        viewModel.initialize(roomToken)
        setupStateObserver()

        binding.swipeRefreshLayout.setOnRefreshListener {
            viewModel.refresh(searchView.query?.toString())
        }
    }

    private fun setupActionBar() {
        setSupportActionBar(binding.messageSearchToolbar)
        supportActionBar?.setDisplayHomeAsUpEnabled(true)
        val conversationName = intent.getStringExtra(BundleKeys.KEY_CONVERSATION_NAME)
        supportActionBar?.title = conversationName
    }

    private fun setupSystemColors() {
        DisplayUtils.applyColorToStatusBar(
            this,
            ResourcesCompat.getColor(
                resources,
                R.color.appbar,
                null
            )
        )
        DisplayUtils.applyColorToNavigationBar(
            this.window,
            ResourcesCompat.getColor(resources, R.color.bg_default, null)
        )
    }

    private fun setupStateObserver() {
        viewModel.state.observe(this) { state ->
            when (state) {
                MessageSearchViewModel.InitialState -> showInitial()
                MessageSearchViewModel.EmptyState -> showEmpty()
                is MessageSearchViewModel.LoadedState -> showLoaded(state)
                MessageSearchViewModel.LoadingState -> showLoading()
                MessageSearchViewModel.ErrorState -> showError()
                is MessageSearchViewModel.FinishedState -> onFinish()
            }
        }
    }

    private fun showError() {
        displayLoading(false)
        Toast.makeText(this, "Error while searching", Toast.LENGTH_SHORT).show()
    }

    private fun showLoading() {
        displayLoading(true)
    }

    private fun displayLoading(loading: Boolean) {
        binding.swipeRefreshLayout.isRefreshing = loading
    }

    private fun showLoaded(state: MessageSearchViewModel.LoadedState) {
        displayLoading(false)
        binding.emptyContainer.emptyListView.visibility = View.GONE
        binding.messageSearchRecycler.visibility = View.VISIBLE
        setAdapterItems(state)
    }

    private fun setAdapterItems(state: MessageSearchViewModel.LoadedState) {
        val loadMoreItems = if (state.hasMore) {
            listOf(LoadMoreResultsItem)
        } else {
            emptyList()
        }
        val newItems =
            state.results.map { MessageResultItem(this, user, it, false, viewThemeUtils) } + loadMoreItems

        if (adapter != null) {
            adapter!!.updateDataSet(newItems)
        } else {
            createAdapter(newItems)
        }
    }

    private fun createAdapter(items: List<AbstractFlexibleItem<out FlexibleViewHolder>>) {
        adapter = FlexibleAdapter(items)
        binding.messageSearchRecycler.adapter = adapter
        adapter!!.addListener(object : FlexibleAdapter.OnItemClickListener {
            override fun onItemClick(view: View?, position: Int): Boolean {
                val item = adapter!!.getItem(position)
                when (item?.itemViewType) {
                    LoadMoreResultsItem.VIEW_TYPE -> {
                        viewModel.loadMore()
                    }
                    MessageResultItem.VIEW_TYPE -> {
                        val messageItem = item as MessageResultItem
                        viewModel.selectMessage(messageItem.messageEntry)
                    }
                }
                return false
            }
        })
    }

    private fun onFinish() {
        val state = viewModel.state.value
        if (state is MessageSearchViewModel.FinishedState) {
            val resultIntent = Intent().apply {
                putExtra(RESULT_KEY_MESSAGE_ID, state.selectedMessageId)
            }
            setResult(Activity.RESULT_OK, resultIntent)
            finish()
        }
    }

    private fun showInitial() {
        displayLoading(false)
        binding.messageSearchRecycler.visibility = View.GONE
        binding.emptyContainer.emptyListViewHeadline.text = getString(R.string.message_search_begin_typing)
        binding.emptyContainer.emptyListView.visibility = View.VISIBLE
    }

    private fun showEmpty() {
        displayLoading(false)
        binding.messageSearchRecycler.visibility = View.GONE
        binding.emptyContainer.emptyListViewHeadline.text = getString(R.string.message_search_begin_empty)
        binding.emptyContainer.emptyListView.visibility = View.VISIBLE
    }

    override fun onCreateOptionsMenu(menu: Menu): Boolean {
        menuInflater.inflate(R.menu.menu_search, menu)
        return true
    }

    override fun onPrepareOptionsMenu(menu: Menu): Boolean {
        val menuItem = menu.findItem(R.id.action_search)
        searchView = menuItem.actionView as SearchView
        setupSearchView()
        menuItem.setOnActionExpandListener(object : MenuItem.OnActionExpandListener {
            override fun onMenuItemActionExpand(item: MenuItem): Boolean {
                searchView.requestFocus()
                return true
            }

            override fun onMenuItemActionCollapse(item: MenuItem): Boolean {
                onBackPressed()
                return false
            }
        })
        menuItem.expandActionView()
        return true
    }

    private fun setupSearchView() {
        searchView.queryHint = getString(R.string.message_search_hint)
        searchViewDisposable = observeSearchView(searchView)
            .debounce { query ->
                when {
                    TextUtils.isEmpty(query) -> Observable.empty()
                    else -> Observable.timer(
                        ConversationsListController.SEARCH_DEBOUNCE_INTERVAL_MS.toLong(),
                        TimeUnit.MILLISECONDS
                    )
                }
            }
            .distinctUntilChanged()
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe { newText -> viewModel.onQueryTextChange(newText) }
    }

    override fun onBackPressed() {
        setResult(Activity.RESULT_CANCELED)
        finish()
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        return when (item.itemId) {
            android.R.id.home -> {
                onBackPressed()
                true
            }
            else -> super.onOptionsItemSelected(item)
        }
    }

    override fun onDestroy() {
        super.onDestroy()
        searchViewDisposable?.dispose()
    }

    companion object {
        const val RESULT_KEY_MESSAGE_ID = "MessageSearchActivity.result.message"
    }
}