package jp.juggler.subwaytooter.columnviewholder

import android.annotation.SuppressLint
import android.os.Handler
import android.os.SystemClock
import android.view.ViewGroup
import androidx.recyclerview.widget.DiffUtil
import androidx.recyclerview.widget.ListUpdateCallback
import androidx.recyclerview.widget.RecyclerView
import jp.juggler.subwaytooter.ActMain
import jp.juggler.subwaytooter.api.entity.TimelineItem
import jp.juggler.subwaytooter.column.Column
import jp.juggler.subwaytooter.column.HeaderType
import jp.juggler.subwaytooter.column.toAdapterIndex
import jp.juggler.subwaytooter.column.toListIndex
import jp.juggler.subwaytooter.itemviewholder.ItemViewHolder
import jp.juggler.subwaytooter.itemviewholder.bind
import jp.juggler.util.log.LogCategory
import jp.juggler.util.ui.AdapterChange
import jp.juggler.util.ui.AdapterChangeType

class ItemListAdapter(
    private val activity: ActMain,
    private val column: Column,
    internal val columnVh: ColumnViewHolder,
    private val bSimpleList: Boolean,
) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {

    companion object {
        private val log = LogCategory("ItemListAdapter")
    }

    private class DiffCallback(
        val oldList: List<TimelineItem>,
        val newList: List<TimelineItem>,
        val biasListIndex: Int,
    ) : DiffUtil.Callback() {

        override fun getOldListSize(): Int {
            return oldList.size - biasListIndex
        }

        override fun getNewListSize(): Int {
            return newList.size - biasListIndex
        }

        override fun areItemsTheSame(oldAdapterIndex: Int, newAdapterIndex: Int): Boolean {
            val oldListIndex = oldAdapterIndex + biasListIndex
            val newListIndex = newAdapterIndex + biasListIndex

            // header?
            if (oldListIndex < 0 || newListIndex < 0) return oldListIndex == newListIndex

            // compare object address
            return oldList[oldListIndex] === newList[newListIndex]
        }

        override fun areContentsTheSame(oldAdapterIndex: Int, newAdapterIndex: Int): Boolean {
            val oldListIndex = oldAdapterIndex + biasListIndex
            val newListIndex = newAdapterIndex + biasListIndex

            // headerは毎回更新する
            return !(oldListIndex < 0 || newListIndex < 0)
        }
    }

    private var list: ArrayList<TimelineItem>
    private val handler: Handler

    init {
        this.list = ArrayList()
        this.handler = activity.handler
        setHasStableIds(true)
    }

    override fun getItemCount(): Int {
        return column.toAdapterIndex(column.listData.size)
    }

    override fun getItemId(position: Int): Long {
        return try {
            list[column.toListIndex(position)].listViewItemId
        } catch (ignored: Throwable) {
            0L
        }
    }

    override fun getItemViewType(position: Int): Int {
        val headerType = column.type.headerType
        if (headerType == null || position > 0) return 0
        return headerType.viewType
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        activity
        when (viewType) {
            0 -> {
                val holder = ItemViewHolder(activity)
                holder.viewRoot.tag = holder
                return ViewHolderItem(holder)
            }

            HeaderType.Profile.viewType -> {
                return ViewHolderHeaderProfile(activity, parent)
            }

            HeaderType.Search.viewType -> {
                return ViewHolderHeaderSearch(activity, parent)
            }

            HeaderType.Instance.viewType -> {
                return ViewHolderHeaderInstance(activity, parent)
            }

            HeaderType.Filter.viewType -> {
                return ViewHolderHeaderFilter(activity, parent)
            }
            HeaderType.ProfileDirectory.viewType -> {
                return ViewHolderHeaderProfileDirectory(activity, parent)
            }
            else -> error("unknown viewType: $viewType")
        }
    }

    fun findHeaderViewHolder(listView: RecyclerView): ViewHolderHeaderBase? {
        return when (column.type.headerType) {
            null -> null
            else -> listView.findViewHolderForAdapterPosition(0) as? ViewHolderHeaderBase
        }
    }

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, adapterIndex: Int) {
        if (holder is ViewHolderItem) {
            val listIndex = column.toListIndex(adapterIndex)
            holder.ivh.bind(this, column, bSimpleList, list[listIndex])
        } else if (holder is ViewHolderHeaderBase) {
            holder.bindData(column)
        }
    }

    override fun onViewRecycled(holder: RecyclerView.ViewHolder) {
        if (holder is ViewHolderItem) {
            holder.ivh.onViewRecycled()
        } else if (holder is ViewHolderHeaderBase) {
            holder.onViewRecycled()
        }
    }

    @SuppressLint("NotifyDataSetChanged")
    fun notifyChange(
        reason: String,
        changeList: List<AdapterChange>? = null,
        reset: Boolean = false,
    ) {

        val timeStart = SystemClock.elapsedRealtime()

        // カラムから最新データをコピーする
        val newList = ArrayList<TimelineItem>()
        newList.ensureCapacity(column.listData.size)
        newList.addAll(column.listData)

        when {
            // 変更リストが指定された場合はヘッダ部分と変更部分を通知する
            changeList != null -> {

                log.d("notifyChange: changeList=${changeList.size},reason=$reason")

                this.list = newList

                // ヘッダは毎回更新する
                // (ヘッダだけ更新するためにカラのchangeListが渡される)
                if (column.type.headerType != null) {
                    notifyItemRangeChanged(0, 1)
                }

                // 変更リストを順番に通知する
                for (c in changeList) {
                    val adapterIndex = column.toAdapterIndex(c.listIndex)
                    log.d("notifyChange: ChangeType=${c.type} offset=$adapterIndex,count=${c.count}")
                    when (c.type) {
                        AdapterChangeType.RangeInsert -> notifyItemRangeInserted(
                            adapterIndex,
                            c.count
                        )
                        AdapterChangeType.RangeRemove -> notifyItemRangeRemoved(
                            adapterIndex,
                            c.count
                        )
                        AdapterChangeType.RangeChange -> notifyItemRangeChanged(
                            adapterIndex,
                            c.count
                        )
                    }
                }
            }

            reset -> {
                log.d("notifyChange: DataSetChanged! reason=$reason")
                this.list = newList
                notifyDataSetChanged()
            }

            else -> {

                val diffResult = DiffUtil.calculateDiff(
                    DiffCallback(
                        oldList = this.list, // 比較対象の古いデータ
                        newList = newList,
                        biasListIndex = column.toListIndex(0)
                    ),
                    false // ログを見た感じ、移動なんてなかった
                )
                val time = SystemClock.elapsedRealtime() - timeStart
                log.d("notifyChange: size=${newList.size},time=${time}ms,reason=$reason")

                this.list = newList
                diffResult.dispatchUpdatesTo(object : ListUpdateCallback {

                    override fun onInserted(position: Int, count: Int) {
                        log.d("notifyChange: notifyItemRangeInserted offset=$position,count=$count")
                        notifyItemRangeInserted(position, count)
                    }

                    override fun onRemoved(position: Int, count: Int) {
                        log.d("notifyChange: notifyItemRangeRemoved offset=$position,count=$count")
                        notifyItemRangeRemoved(position, count)
                    }

                    override fun onChanged(position: Int, count: Int, payload: Any?) {
                        log.d("notifyChange: notifyItemRangeChanged offset=$position,count=$count")
                        notifyItemRangeChanged(position, count, payload)
                    }

                    override fun onMoved(fromPosition: Int, toPosition: Int) {
                        log.d("notifyChange: notifyItemMoved from=$fromPosition,to=$toPosition")
                        notifyItemMoved(fromPosition, toPosition)
                    }
                })
            }
        }

        // diffを取る部分をワーカースレッドで実行したいが、直後にスクロール位置の処理があるので差支えがある…
    }
}