/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.fenix.tabtray

import android.graphics.Canvas
import android.graphics.drawable.Drawable
import androidx.appcompat.content.res.AppCompatResources
import androidx.recyclerview.widget.ItemTouchHelper
import androidx.recyclerview.widget.RecyclerView
import mozilla.components.browser.tabstray.TabTouchCallback
import mozilla.components.concept.tabstray.TabsTray
import mozilla.components.support.base.observer.Observable
import mozilla.components.support.ktx.android.content.getColorFromAttr
import mozilla.components.support.ktx.android.content.getDrawableWithTint
import mozilla.components.support.ktx.android.util.dpToPx
import org.mozilla.fenix.R
import org.mozilla.fenix.home.sessioncontrol.SwipeToDeleteCallback

class TabsTouchHelper(observable: Observable<TabsTray.Observer>) :
    ItemTouchHelper(object : TabTouchCallback(observable) {
        override fun onChildDraw(
            c: Canvas,
            recyclerView: RecyclerView,
            viewHolder: RecyclerView.ViewHolder,
            dX: Float,
            dY: Float,
            actionState: Int,
            isCurrentlyActive: Boolean
        ) {
            super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
            val icon = recyclerView.context.getDrawableWithTint(
                R.drawable.ic_delete,
                recyclerView.context.getColorFromAttr(R.attr.destructive)
            )!!
            val background = AppCompatResources.getDrawable(
                recyclerView.context,
                R.drawable.swipe_delete_background
            )!!
            val itemView = viewHolder.itemView
            val iconLeft: Int
            val iconRight: Int
            val margin =
                SwipeToDeleteCallback.MARGIN.dpToPx(recyclerView.context.resources.displayMetrics)
            val iconWidth = icon.intrinsicWidth
            val iconHeight = icon.intrinsicHeight
            val cellHeight = itemView.bottom - itemView.top
            val iconTop = itemView.top + (cellHeight - iconHeight) / 2
            val iconBottom = iconTop + iconHeight

            when {
                dX > 0 -> { // Swiping to the right
                    iconLeft = itemView.left + margin
                    iconRight = itemView.left + margin + iconWidth
                    background.setBounds(
                        itemView.left, itemView.top,
                        (itemView.left + dX).toInt() + SwipeToDeleteCallback.BACKGROUND_CORNER_OFFSET,
                        itemView.bottom
                    )
                    icon.setBounds(iconLeft, iconTop, iconRight, iconBottom)
                    draw(background, icon, c)
                }
                dX < 0 -> { // Swiping to the left
                    iconLeft = itemView.right - margin - iconWidth
                    iconRight = itemView.right - margin
                    background.setBounds(
                        (itemView.right + dX).toInt() - SwipeToDeleteCallback.BACKGROUND_CORNER_OFFSET,
                        itemView.top, itemView.right, itemView.bottom
                    )
                    icon.setBounds(iconLeft, iconTop, iconRight, iconBottom)
                    draw(background, icon, c)
                }
                else -> { // View not swiped
                    background.setBounds(0, 0, 0, 0)
                    icon.setBounds(0, 0, 0, 0)
                }
            }
        }

        private fun draw(
            background: Drawable,
            icon: Drawable,
            c: Canvas
        ) {
            background.draw(c)
            icon.draw(c)
        }
    })