/*
 * Copyright (C) 2020 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.systemui.controls.management

import android.content.ComponentName
import android.content.Intent
import android.os.Bundle
import android.view.View
import android.view.ViewGroup
import android.view.ViewStub
import android.widget.Button
import android.widget.TextView
import androidx.recyclerview.widget.GridLayoutManager
import androidx.recyclerview.widget.ItemTouchHelper
import androidx.recyclerview.widget.RecyclerView
import com.android.systemui.R
import com.android.systemui.broadcast.BroadcastDispatcher
import com.android.systemui.controls.controller.ControlsControllerImpl
import com.android.systemui.controls.controller.StructureInfo
import com.android.systemui.globalactions.GlobalActionsComponent
import com.android.systemui.settings.CurrentUserTracker
import com.android.systemui.util.LifecycleActivity
import javax.inject.Inject

/**
 * Activity for rearranging and removing controls for a given structure
 */
class ControlsEditingActivity @Inject constructor(
    private val controller: ControlsControllerImpl,
    broadcastDispatcher: BroadcastDispatcher,
    private val globalActionsComponent: GlobalActionsComponent
) : LifecycleActivity() {

    companion object {
        private const val TAG = "ControlsEditingActivity"
        private const val EXTRA_STRUCTURE = ControlsFavoritingActivity.EXTRA_STRUCTURE
        private val SUBTITLE_ID = R.string.controls_favorite_rearrange
        private val EMPTY_TEXT_ID = R.string.controls_favorite_removed
    }

    private lateinit var component: ComponentName
    private lateinit var structure: CharSequence
    private lateinit var model: FavoritesModel
    private lateinit var subtitle: TextView
    private lateinit var saveButton: View

    private val currentUserTracker = object : CurrentUserTracker(broadcastDispatcher) {
        private val startingUser = controller.currentUserId

        override fun onUserSwitched(newUserId: Int) {
            if (newUserId != startingUser) {
                stopTracking()
                finish()
            }
        }
    }

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

        intent.getParcelableExtra<ComponentName>(Intent.EXTRA_COMPONENT_NAME)?.let {
            component = it
        } ?: run(this::finish)

        intent.getCharSequenceExtra(EXTRA_STRUCTURE)?.let {
            structure = it
        } ?: run(this::finish)

        bindViews()

        bindButtons()
    }

    override fun onStart() {
        super.onStart()
        setUpList()

        currentUserTracker.startTracking()
    }

    override fun onStop() {
        super.onStop()
        currentUserTracker.stopTracking()
    }

    override fun onBackPressed() {
        globalActionsComponent.handleShowGlobalActionsMenu()
        animateExitAndFinish()
    }

    private fun animateExitAndFinish() {
        val rootView = requireViewById<ViewGroup>(R.id.controls_management_root)
        ControlsAnimations.exitAnimation(
                rootView,
                object : Runnable {
                    override fun run() {
                        finish()
                    }
                }
        ).start()
    }

    private fun bindViews() {
        setContentView(R.layout.controls_management)

        getLifecycle().addObserver(
            ControlsAnimations.observerForAnimations(
                requireViewById<ViewGroup>(R.id.controls_management_root),
                window,
                intent
            )
        )

        requireViewById<ViewStub>(R.id.stub).apply {
            layoutResource = R.layout.controls_management_editing
            inflate()
        }
        requireViewById<TextView>(R.id.title).text = structure
        subtitle = requireViewById<TextView>(R.id.subtitle).apply {
            setText(SUBTITLE_ID)
        }
    }

    private fun bindButtons() {
        val rootView = requireViewById<ViewGroup>(R.id.controls_management_root)
        saveButton = requireViewById<Button>(R.id.done).apply {
            isEnabled = false
            setText(R.string.save)
            setOnClickListener {
                saveFavorites()
                animateExitAndFinish()
                globalActionsComponent.handleShowGlobalActionsMenu()
            }
        }
    }

    private fun saveFavorites() {
        controller.replaceFavoritesForStructure(
                StructureInfo(component, structure, model.favorites))
    }

    private val favoritesModelCallback = object : FavoritesModel.FavoritesModelCallback {
        override fun onNoneChanged(showNoFavorites: Boolean) {
            if (showNoFavorites) {
                subtitle.setText(EMPTY_TEXT_ID)
            } else {
                subtitle.setText(SUBTITLE_ID)
            }
        }

        override fun onFirstChange() {
            saveButton.isEnabled = true
        }
    }

    private fun setUpList() {
        val controls = controller.getFavoritesForStructure(component, structure)
        model = FavoritesModel(component, controls, favoritesModelCallback)
        val elevation = resources.getFloat(R.dimen.control_card_elevation)
        val recyclerView = requireViewById<RecyclerView>(R.id.list)
        recyclerView.alpha = 0.0f
        val adapter = ControlAdapter(elevation).apply {
            registerAdapterDataObserver(object : RecyclerView.AdapterDataObserver() {
                var hasAnimated = false
                override fun onChanged() {
                    if (!hasAnimated) {
                        hasAnimated = true
                        ControlsAnimations.enterAnimation(recyclerView).start()
                    }
                }
            })
        }

        val margin = resources
                .getDimensionPixelSize(R.dimen.controls_card_margin)
        val itemDecorator = MarginItemDecorator(margin, margin)

        recyclerView.apply {
            this.adapter = adapter
            layoutManager = object : GridLayoutManager(recyclerView.context, 2) {

                // This will remove from the announcement the row corresponding to the divider,
                // as it's not something that should be announced.
                override fun getRowCountForAccessibility(
                    recycler: RecyclerView.Recycler,
                    state: RecyclerView.State
                ): Int {
                    val initial = super.getRowCountForAccessibility(recycler, state)
                    return if (initial > 0) initial - 1 else initial
                }
            }.apply {
                spanSizeLookup = adapter.spanSizeLookup
            }
            addItemDecoration(itemDecorator)
        }
        adapter.changeModel(model)
        model.attachAdapter(adapter)
        ItemTouchHelper(model.itemTouchHelperCallback).attachToRecyclerView(recyclerView)
    }

    override fun onDestroy() {
        currentUserTracker.stopTracking()
        super.onDestroy()
    }
}