package com.example.myapplication

import android.content.Context
import android.util.AttributeSet
import android.view.View
import android.view.ViewGroup

class RoundPanel(context: Context?, attrs: AttributeSet?) : ViewGroup(context, attrs) {

    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec)
        forEachChild {
            it.measure(
                MeasureSpec.makeMeasureSpec(50.dip(), MeasureSpec.EXACTLY),
                MeasureSpec.makeMeasureSpec(50.dip(), MeasureSpec.EXACTLY))
        }
    }

    override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) {
        forEachChildIndexed { i, child ->
            val angel = (180.0 * i / (childCount - 1))
            val R = (r - l) / 2f - child.height / 2
            val x = Math.sin(Math.toRadians(angel)) * R + (r - l) / 2
            val y = Math.cos(Math.toRadians(angel)) * R + (b - t) / 2

            child.layout(
                (x - child.measuredWidth / 2).toInt(),
                (y - child.measuredHeight / 2).toInt(),
                (x + child.measuredWidth / 2).toInt(),
                (y + child.measuredHeight / 2).toInt())

            child.rotation = -angel.toFloat()
        }
    }

    private fun Int.dip() = (this * resources.displayMetrics.density).toInt()

    private fun ViewGroup.forEachChild(f: (View) -> Unit) {
        return (0..childCount - 1).forEach { f(getChildAt(it)) }
    }

    private fun ViewGroup.forEachChildIndexed(f: (Int, View) -> Unit) {
        return (0..childCount - 1).forEach { f(it, getChildAt(it)) }
    }
}