SpannableStringExt.kt

fun SpannableStringBuilder.appendText(string: String, self: SpannableStringBuilder.() -> SpannableStringBuilder): SpannableStringBuilder {
    val newSpan = SpannableStringBuilder(string)
    self(newSpan)
    return append(newSpan)
}

fun SpannableStringBuilder.color(color: Int): SpannableStringBuilder {
    val span = ForegroundColorSpan(color)
    setSpan(span, 0, length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)
    return this
}

fun SpannableStringBuilder.size(textSize: Int): SpannableStringBuilder {
    val span = AbsoluteSizeSpan(textSize)
    setSpan(span, 0, length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)
    return this
}

fun SpannableStringBuilder.style(typeface: Int): SpannableStringBuilder {
    val span = StyleSpan(typeface)
    setSpan(span, 0, length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)
    return this
}

fun SpannableStringBuilder.underLine(): SpannableStringBuilder {
    val span = UnderlineSpan()
    setSpan(span, 0, length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)
    return this
}

fun SpannableStringBuilder.backgroundColor(color: Int): SpannableStringBuilder {
    val span = BackgroundColorSpan(color)
    setSpan(span, 0, length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)
    return this
}

fun SpannableStringBuilder.onClick(onClick:(View)->Unit): SpannableStringBuilder {
    val span = object :ClickableSpan(){
        override fun onClick(view: View) {
            onClick.invoke(view)
        }
    }
    setSpan(span, 0, length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)
    return this
}

fun SpannableStringBuilder.appendDrawable(drawable: Drawable, self: SpannableImageBuilder.() -> SpannableImageBuilder): SpannableStringBuilder {
    val newSpan = SpannableImageBuilder(drawable)
    newSpan.append("d")
    self(newSpan)

    val imageSpan = ImageSpan(newSpan.drawable, ImageSpan.ALIGN_BOTTOM)
    newSpan.setSpan(imageSpan, 0, newSpan.length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)

    return append(newSpan)
}

fun SpannableImageBuilder.color(color: Int): SpannableImageBuilder {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
        drawable.colorFilter = BlendModeColorFilter(color, BlendMode.SRC_IN)
    } else {
        drawable.setColorFilter(color, PorterDuff.Mode.SRC_IN)
    }
    return this
}

fun SpannableImageBuilder.size(size: Int): SpannableImageBuilder {
    drawable.setBounds(0, 0, size, size)
    return this
}

fun SpannableImageBuilder.sizeFit(textView: TextView): SpannableImageBuilder {
    val size = textView.lineHeight
    drawable.setBounds(0, 0, size, size)
    return this
}

data class SpannableImageBuilder(
        var drawable: Drawable
) : SpannableStringBuilder()