ultrasonic-app-subsonic-android/ultrasonic/src/main/kotlin/org/moire/ultrasonic/fragment/GenericRowAdapter.kt

/*
 * GenericRowAdapter.kt
 * Copyright (C) 2009-2021 Ultrasonic developers
 *
 * Distributed under terms of the GNU GPLv3 license.
 */

package org.moire.ultrasonic.fragment

import android.view.LayoutInflater
import android.view.MenuInflater
import android.view.MenuItem
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.PopupMenu
import android.widget.RelativeLayout
import android.widget.TextView
import androidx.recyclerview.widget.DiffUtil
import androidx.recyclerview.widget.RecyclerView
import org.moire.ultrasonic.R
import org.moire.ultrasonic.data.ActiveServerProvider
import org.moire.ultrasonic.domain.GenericEntry
import org.moire.ultrasonic.domain.MusicFolder
import org.moire.ultrasonic.view.SelectMusicFolderView

/*
* An abstract Adapter, which can be extended to display a List of <T> in a RecyclerView
*/
abstract class GenericRowAdapter<T : GenericEntry>(
    val onItemClick: (T) -> Unit,
    val onContextMenuClick: (MenuItem, T) -> Boolean,
    private val onMusicFolderUpdate: (String?) -> Unit
) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
    open var itemList: List<T> = listOf()
    protected abstract val layout: Int
    protected abstract val contextMenuLayout: Int

    var folderHeaderEnabled: Boolean = true
    var selectFolderHeader: SelectMusicFolderView? = null
    var musicFolders: List<MusicFolder> = listOf()
    var selectedFolder: String? = null

    /**
     * Sets the data to be displayed in the RecyclerView,
     * using DiffUtil to efficiently calculate the minimum required changes..
     */
    open fun setData(data: List<T>) {
        val callback = DiffUtilCallback(itemList, data)
        val result = DiffUtil.calculateDiff(callback)
        itemList = data
        result.dispatchUpdatesTo(this)
    }

    /**
     * Sets the content and state of the music folder selector row
     */
    fun setFolderList(changedFolders: List<MusicFolder>, selectedId: String?) {
        musicFolders = changedFolders
        selectedFolder = selectedId

        selectFolderHeader?.setData(
            selectedFolder,
            musicFolders
        )

        notifyDataSetChanged()
    }

    open fun newViewHolder(view: View): RecyclerView.ViewHolder {
        return ViewHolder(view)
    }

    override fun onCreateViewHolder(
        parent: ViewGroup,
        viewType: Int
    ): RecyclerView.ViewHolder {
        if (viewType == TYPE_ITEM) {
            val row = LayoutInflater.from(parent.context)
                .inflate(layout, parent, false)
            return newViewHolder(row)
        } else {
            val row = LayoutInflater.from(parent.context)
                .inflate(
                    R.layout.select_folder_header, parent, false
                )
            selectFolderHeader = SelectMusicFolderView(parent.context, row, onMusicFolderUpdate)

            if (musicFolders.isNotEmpty()) {
                selectFolderHeader?.setData(
                    selectedFolder,
                    musicFolders
                )
            }

            return selectFolderHeader!!
        }
    }

    abstract override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int)

    override fun getItemCount(): Int {
        if (selectFolderHeader != null)
            return itemList.size + 1
        else
            return itemList.size
    }

    override fun getItemViewType(position: Int): Int {
        return if (position == 0 && folderHeaderEnabled) TYPE_HEADER else TYPE_ITEM
    }

    internal fun createPopupMenu(view: View, position: Int): Boolean {
        val popup = PopupMenu(view.context, view)
        val inflater: MenuInflater = popup.menuInflater
        inflater.inflate(contextMenuLayout, popup.menu)

        val downloadMenuItem = popup.menu.findItem(R.id.menu_download)
        downloadMenuItem?.isVisible = !ActiveServerProvider.isOffline()

        popup.setOnMenuItemClickListener { menuItem ->
            onContextMenuClick(menuItem, itemList[position])
        }
        popup.show()
        return true
    }

    /**
     * Holds the view properties of an Item row
     */
    class ViewHolder(
        itemView: View
    ) : RecyclerView.ViewHolder(itemView) {
        var section: TextView = itemView.findViewById(R.id.row_section)
        var textView: TextView = itemView.findViewById(R.id.row_artist_name)
        var layout: RelativeLayout = itemView.findViewById(R.id.row_artist_layout)
        var coverArt: ImageView = itemView.findViewById(R.id.artist_coverart)
        var coverArtId: String? = null
    }

    /**
     * Calculates the differences between data sets
     */
    open class DiffUtilCallback<T : GenericEntry>(
        private val oldList: List<T>,
        private val newList: List<T>
    ) : DiffUtil.Callback() {
        override fun getOldListSize(): Int {
            return oldList.size
        }
        override fun getNewListSize(): Int {
            return newList.size
        }
        override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
            return oldList[oldItemPosition].id == newList[newItemPosition].id
        }
        override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
            return oldList[oldItemPosition] == newList[newItemPosition]
        }
    }

    companion object {
        internal const val TYPE_HEADER = 0
        internal const val TYPE_ITEM = 1
    }
}