tagview.swift

import UIKit

class TailTagView: UIView {

    var rawText: String? {
        didSet {
            label.attributedText = parseText(rawText: rawText)
        }
    }

    func parseText(rawText: String?, token: String = "**") -> NSAttributedString? {
        guard let rawText = rawText, let font = UIFont(name: "AppleSDGothicNeo-Regular", size: 14.0) else { return nil }

        let words = rawText.components(separatedBy: "**")
        let attributedString = NSMutableAttributedString(string: words.reduce("", +), attributes: [.font: font, .foregroundColor: UIColor.white])

        var location = 0
        print(words)
        words.enumerated()
            .compactMap {
                if $1.isEmpty { return nil }
                let range = $0 % 2 == 0 ? nil : NSRange(location: location, length: $1.count)
                location += $1.count
                return range
            }
            .forEach { attributedString.addAttribute(.foregroundColor, value: highlightColor, range: $0) }

        return attributedString
    }

    private let highlightColor = UIColor(red: 254.0 / 255.0, green: 181.0 / 255.0, blue: 0, alpha: 1)

    private let triangle = TriangleView()
    private let contentView = UIView()
    private let label = UILabel()

    override init(frame: CGRect) {
        super.init(frame: frame)
        configureSubviews()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        configureSubviews()
    }

    convenience init() {
        self.init(frame: .zero)
    }

    private func configureSubviews() {
        backgroundColor = .clear
        translatesAutoresizingMaskIntoConstraints = false

        triangle.backgroundColor = .clear
        contentView.backgroundColor = UIColor.black.withAlphaComponent(0.6)
        contentView.layer.cornerRadius = 2
        contentView.clipsToBounds = true
        contentView.isUserInteractionEnabled = true

        label.textAlignment = .center
        label.sizeToFit()

        contentView.translatesAutoresizingMaskIntoConstraints = false
        triangle.translatesAutoresizingMaskIntoConstraints = false
        label.translatesAutoresizingMaskIntoConstraints = false

        addSubview(triangle)
        addSubview(contentView)
        contentView.addSubview(label)

        triangle.centerXAnchor.constraint(equalTo: centerXAnchor).isActive = true
        triangle.topAnchor.constraint(equalTo: topAnchor).isActive = true
        triangle.heightAnchor.constraint(equalToConstant: 10).isActive = true
        triangle.widthAnchor.constraint(equalToConstant: 15).isActive = true

        contentView.topAnchor.constraint(equalTo: triangle.bottomAnchor).isActive = true
        contentView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
        contentView.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
        contentView.rightAnchor.constraint(equalTo: rightAnchor).isActive = true

        label.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 9).isActive = true
        label.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -9).isActive = true
        label.centerYAnchor.constraint(equalTo: contentView.centerYAnchor).isActive = true
        label.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 15).isActive = true
        label.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -15).isActive = true

        contentView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(contentViewTapped)))
    }

    func show(superView: UIView, toBottomView: UIView) {
        self.removeFromSuperview()
        superView.addSubview(self)
        self.topAnchor.constraint(equalTo: toBottomView.bottomAnchor, constant: 10).isActive = true
        self.centerXAnchor.constraint(equalTo: toBottomView.centerXAnchor).isActive = true
        self.leadingAnchor.constraint(greaterThanOrEqualTo: superView.leadingAnchor, constant: 15).isActive = true
    }

    func hide() {
        removeFromSuperview()
    }

    @objc
    func contentViewTapped() {
        hide()
    }

    class TriangleView: UIView {

        override func draw(_ rect: CGRect) {
            guard let context = UIGraphicsGetCurrentContext() else { return }
            context.beginPath()
            context.move(to: CGPoint(x: rect.midX, y: rect.minY))
            context.addLine(to: CGPoint(x: rect.minX, y: rect.maxY))
            context.addLine(to: CGPoint(x: rect.maxX, y: rect.maxY))
            context.closePath()
            context.setFillColor(UIColor.black.withAlphaComponent(0.6).cgColor)
            context.fillPath()
        }
    }
}