package com.github.jxiaow.sample.pathmeasure

import android.animation.ValueAnimator
import android.content.Context
import android.graphics.*
import android.util.AttributeSet
import android.view.View
import android.view.animation.LinearInterpolator
import com.github.jxiaow.sample.R
import kotlin.math.PI
import kotlin.math.atan2

class ArrowLoadingView @JvmOverloads constructor(
    context: Context,
    attrs: AttributeSet? = null,
    defStyleAttr: Int = 0
) : View(context, attrs, defStyleAttr) {

    // 圆画笔
    private val circlePaint = Paint().apply {
        color = Color.BLUE
        style = Paint.Style.STROKE
        strokeWidth = 5.0f
        isAntiAlias = true
    }

    private val arrowPaint = Paint().apply {
        color = Color.GRAY
        strokeWidth = 1f
        isAntiAlias = true
        isDither = true
        style = Paint.Style.STROKE
    }

    private val bitmap = run {
        val options = BitmapFactory.Options()
        options.inSampleSize = 2
        BitmapFactory.decodeResource(resources, R.drawable.arrow, options)
    }

    private val path = Path().apply {
        addCircle(0f, 0f, 300f, Path.Direction.CW)
    }

    private val pathMeasure = PathMeasure(path, true)

    private val arrowMatrix = Matrix()

    private var favor = 0.5f

    private val pos = FloatArray(2)
    private val tans = FloatArray(2)

    override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)
        canvas.translate(width / 2f, height / 2f)
        canvas.drawPath(path, circlePaint)
        arrowMatrix.reset()

        val distance = pathMeasure.length * favor
        pathMeasure.getPosTan(distance, pos, tans)

        val degress = atan2(tans[1], tans[0]) * 180 / PI
        arrowMatrix.postRotate(degress.toFloat(), bitmap.width / 2f, bitmap.height / 2f)
        arrowMatrix.postTranslate(pos[0] - bitmap.width / 2, pos[1] - bitmap.height / 2)

        canvas.drawBitmap(bitmap, arrowMatrix, arrowPaint)
    }

    private val animator = ValueAnimator.ofFloat(0f, 1.0f)
        .apply {
            repeatCount = ValueAnimator.INFINITE
            duration = 2000
            interpolator = LinearInterpolator()
            addUpdateListener {
                favor = it.animatedValue as Float
                invalidate()
            }
        }

    override fun onAttachedToWindow() {
        super.onAttachedToWindow()
        animator.start()
    }

    override fun onDetachedFromWindow() {
        super.onDetachedFromWindow()
        animator.cancel()
    }
}