class AvatarPlaceholder(
    private val name: String,
    textGenerator: TextGenerator,
    colorGenerator: ColorGenerator
) : Drawable() {

    interface ColorGenerator {
        fun getColor(name: String): Int
    }

    interface TextGenerator {
        fun getText(name: String): String
    }

    companion object {
        private const val RATIO_TEXT_SIZE = 1 / 1.5f
    }

    private val backgroundPaint = Paint().apply {
        isAntiAlias = true
        color = colorGenerator.getColor(name)
    }

    private lateinit var boundsCopy: Rect
    private lateinit var textPaint: Paint
    private var textY: Float? = null
    private var textX: Float? = null
    private val text = textGenerator.getText(name)

    override fun draw(canvas: Canvas) {
        if (!::boundsCopy.isInitialized) {
            boundsCopy = Rect()
            copyBounds(boundsCopy)
            textPaint = Paint().apply {
                isAntiAlias = true
                color = Color.WHITE
                typeface = Typeface.create("sans-serif-light", Typeface.NORMAL)
                textSize = boundsCopy.height() * RATIO_TEXT_SIZE
            }
            textX = textPaint.measureText(text).let {
                boundsCopy.exactCenterX() - (it / 2)
            }
            textY = textPaint.measureText(text).let {
                boundsCopy.exactCenterY() - ((textPaint.ascent() + textPaint.descent()) / 2)
            }
        }
        val path = Path().apply {
            fillType = Path.FillType.WINDING
            addRoundRect(
                0f,
                0f,
                boundsCopy.width().toFloat(),
                boundsCopy.height().toFloat(),
                boundsCopy.exactCenterX(),
                boundsCopy.exactCenterY(),
                Path.Direction.CW
            )
        }
        canvas.drawPath(path, backgroundPaint)
        canvas.drawText(text, textX!!, textY!!, textPaint)
    }

    override fun setAlpha(alpha: Int) {
        backgroundPaint.alpha = alpha
        textPaint.alpha = alpha
    }

    override fun getOpacity(): Int {
        return PixelFormat.TRANSLUCENT
    }

    override fun setColorFilter(colorFilter: ColorFilter) {
        backgroundPaint.colorFilter = colorFilter
        textPaint.colorFilter = colorFilter
    }
}