/*
 * Copyright (C) 2024 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.wallpaper.picker.option.ui.adapter

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.annotation.LayoutRes
import androidx.lifecycle.Lifecycle
import androidx.lifecycle.LifecycleOwner
import androidx.lifecycle.lifecycleScope
import androidx.lifecycle.repeatOnLifecycle
import androidx.recyclerview.widget.DiffUtil
import androidx.recyclerview.widget.RecyclerView
import com.android.wallpaper.picker.customization.ui.viewmodel.ColorUpdateViewModel
import com.android.wallpaper.picker.option.ui.binder.OptionItemBinder2
import com.android.wallpaper.picker.option.ui.viewmodel.OptionItemViewModel2
import java.lang.ref.WeakReference
import kotlinx.coroutines.CoroutineDispatcher
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.DisposableHandle
import kotlinx.coroutines.Job
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext

/** Adapts between option items and their views. */
class OptionItemAdapter2<T>(
    @LayoutRes private val layoutResourceId: Int,
    private val lifecycleOwner: LifecycleOwner,
    private val backgroundDispatcher: CoroutineDispatcher = Dispatchers.IO,
    private val bindPayload: (View, T) -> DisposableHandle?,
    private val colorUpdateViewModel: WeakReference<ColorUpdateViewModel>,
    private val shouldAnimateColor: () -> Boolean,
) : RecyclerView.Adapter<OptionItemAdapter2.ViewHolder>() {

    private val items = mutableListOf<OptionItemViewModel2<T>>()
    private var setItemsJob: Job? = null

    init {
        lifecycleOwner.lifecycleScope.launch {
            lifecycleOwner.repeatOnLifecycle(Lifecycle.State.STARTED) {
                colorUpdateViewModel.get()?.systemColorsUpdated?.collect {
                    // Re-draw all items when color is updated to reflect new view colors
                    notifyDataSetChanged()
                }
            }
        }
    }

    fun setItems(items: List<OptionItemViewModel2<T>>, callback: (() -> Unit)? = null) {
        setItemsJob?.cancel()
        setItemsJob =
            lifecycleOwner.lifecycleScope.launch {
                val oldItems = this@OptionItemAdapter2.items
                val newItems = items
                val diffResult =
                    withContext(backgroundDispatcher) {
                        DiffUtil.calculateDiff(
                            object : DiffUtil.Callback() {
                                override fun getOldListSize(): Int {
                                    return oldItems.size
                                }

                                override fun getNewListSize(): Int {
                                    return newItems.size
                                }

                                override fun areItemsTheSame(
                                    oldItemPosition: Int,
                                    newItemPosition: Int,
                                ): Boolean {
                                    val oldItem = oldItems[oldItemPosition]
                                    val newItem = newItems[newItemPosition]
                                    return oldItem.key.value == newItem.key.value
                                }

                                override fun areContentsTheSame(
                                    oldItemPosition: Int,
                                    newItemPosition: Int,
                                ): Boolean {
                                    val oldItem = oldItems[oldItemPosition]
                                    val newItem = newItems[newItemPosition]
                                    return oldItem == newItem
                                }
                            },
                            /* detectMoves= */ false,
                        )
                    }

                oldItems.clear()
                oldItems.addAll(items)
                diffResult.dispatchUpdatesTo(this@OptionItemAdapter2)
                if (callback != null) {
                    callback()
                }
            }
    }

    class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        var disposableHandle: DisposableHandle? = null
        var payloadDisposableHandle: DisposableHandle? = null
    }

    override fun getItemCount(): Int {
        return items.size
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        return ViewHolder(
            LayoutInflater.from(parent.context).inflate(layoutResourceId, parent, false)
        )
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        holder.disposableHandle?.dispose()
        holder.payloadDisposableHandle?.dispose()
        val item = items[position]
        holder.payloadDisposableHandle =
            item.payload?.let { bindPayload(holder.itemView, item.payload) }
        holder.disposableHandle =
            OptionItemBinder2.bind(
                view = holder.itemView,
                viewModel = item,
                lifecycleOwner = lifecycleOwner,
                colorUpdateViewModel = colorUpdateViewModel,
                shouldAnimateColor = shouldAnimateColor,
            )
    }
}