import UIKit

extension UITextView: UITextViewDelegate {
 override open var bounds: CGRect {
    didSet {
        self.resizePlaceholder()
    }
 }

 public var placeholder: String? {
    get {
        var placeholderText: String?

        if let placeholderLbl = self.viewWithTag(50) as? UILabel {
            placeholderText = placeholderLbl.text
        }

        return placeholderText
    }
    set {
        if let placeholderLbl = self.viewWithTag(50) as! UILabel? {
            placeholderLbl.text = newValue
            placeholderLbl.sizeToFit()
        } else {
            self.addPlaceholder(newValue!)
        }
    }
 }

 public func textViewDidChange(_ textView: UITextView) {
    if let placeholderLbl = self.viewWithTag(50) as? UILabel {
        placeholderLbl.isHidden = self.text.characters.count > 0
    }
 }

 private func resizePlaceholder() {
    if let placeholderLbl = self.viewWithTag(50) as! UILabel? {
        let x = self.textContainer.lineFragmentPadding
        let y = self.textContainerInset.top - 2
        let width = self.frame.width - (x * 2)
        let height = placeholderLbl.frame.height

        placeholderLbl.frame = CGRect(x: x, y: y, width: width, height: height)
    }
 }

 private func addPlaceholder(_ placeholderText: String) {
    let placeholderLbl = UILabel()

    placeholderLbl.text = placeholderText
    placeholderLbl.sizeToFit()

    placeholderLbl.font = self.font
    placeholderLbl.textColor = UIColor.lightGray
    placeholderLbl.tag = 50

    placeholderLbl.isHidden = self.text.characters.count > 0

    self.addSubview(placeholderLbl)
    self.resizePlaceholder()
    self.delegate = self
 }
}