package org.furs.knotes.ui.recycler

import android.graphics.Canvas
import android.graphics.Paint
import android.graphics.Rect
import android.graphics.RectF
import android.view.View
import androidx.recyclerview.widget.ItemTouchHelper
import androidx.recyclerview.widget.RecyclerView
import org.furs.knotes.R
import org.furs.knotes.data.TextNote

class ItemTouchHelperCallback(
    private val adapter: NoteAdapter,
    private val swipeListener: (TextNote) -> Unit
) : ItemTouchHelper.Callback() {
    private val bgRect = RectF()
    private val bgPaint = Paint(Paint.ANTI_ALIAS_FLAG)
    private val iconBounds = Rect()

    override fun getMovementFlags(
        recyclerView: RecyclerView,
        viewHolder: RecyclerView.ViewHolder
    ): Int {
        return if(viewHolder is ItemTouchViewHolder) {
            makeFlag(ItemTouchHelper.ACTION_STATE_SWIPE, ItemTouchHelper.START)
        } else {
            makeFlag(ItemTouchHelper.ACTION_STATE_IDLE, ItemTouchHelper.START)
        }
    }

    override fun onMove(
        recyclerView: RecyclerView,
        viewHolder: RecyclerView.ViewHolder,
        target: RecyclerView.ViewHolder
    ): Boolean {
        return false
    }

    override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
        if(viewHolder is ItemTouchViewHolder) {
            swipeListener.invoke(adapter.items[viewHolder.adapterPosition])
        }
    }

    override fun onChildDraw(
        canvas: Canvas,
        recyclerView: RecyclerView,
        viewHolder: RecyclerView.ViewHolder,
        dX: Float,
        dY: Float,
        actionState: Int,
        isCurrentlyActive: Boolean
    ) {
        if(actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
            val itemView = viewHolder.itemView
            drawBackground(canvas, itemView, dX)
            drawIcon(canvas, itemView, dX)
        }

        super.onChildDraw(canvas, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
    }

    override fun onSelectedChanged(viewHolder: RecyclerView.ViewHolder?, actionState: Int) {
        if(actionState != ItemTouchHelper.ACTION_STATE_IDLE && viewHolder is ItemTouchViewHolder) {
            viewHolder.onItemSelected()
        }
        super.onSelectedChanged(viewHolder, actionState)
    }

    override fun clearView(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder) {
        if(viewHolder is ItemTouchViewHolder) {
            viewHolder.onItemCleared()
        }
        super.clearView(recyclerView, viewHolder)
    }

    private fun drawBackground(
        canvas: Canvas,
        itemView: View,
        dX: Float
    ) {
        with(bgRect) {
            left = dX
            top = itemView.top.toFloat()
            right = itemView.right.toFloat()
            bottom = itemView.bottom.toFloat()
        }

        with(bgPaint) {
            color = itemView.resources.getColor(R.color.item_swipe_background, itemView.context.theme)
        }

        canvas.drawRect(bgRect, bgPaint)
    }

    private fun drawIcon(
        canvas: Canvas,
        itemView: View,
        dX: Float
    ) {
        val icon = itemView.resources.getDrawable(R.drawable.ic_remove_swipe, itemView.context.theme)
        val iconSize = itemView.resources.getDimensionPixelSize(R.dimen.icon_size)
        val space = itemView.resources.getDimensionPixelSize(R.dimen.space_normal_16)
        val margin = (itemView.bottom - itemView.top - iconSize) / 2

        with(iconBounds) {
            left = itemView.right + dX.toInt() + space
            top = itemView.top + margin
            right = itemView.right + dX.toInt() + iconSize + space
            bottom = itemView.bottom - margin
        }

        icon.bounds = iconBounds
        icon.draw(canvas)
    }

    interface ItemTouchViewHolder {
        fun onItemSelected()
        fun onItemCleared()
    }
}