LONDON-IOS/GME Remit/Utilities/CustomUI/ScrollableSegmentedControl.swift

//
//  ScrollableSegmentedControl.swift
//  GME Remit
//
//  Created by InKwon James Kim on 23/07/2019.
//  Copyright © 2019 Gobal Money Express Co. Ltd. All rights reserved.
//

import UIKit

protocol ScrollableSegmentedControlDelegate: class {
  func selectItemAt(
    index : Int,
    onScrollUISegmentController scrollUISegmentController: ScrollableSegmentedControl
  )
}

@IBDesignable
class ScrollableSegmentedControl: UIScrollView {
  private var segmentedControl: UISegmentedControl = UISegmentedControl()
  
  weak var segmentDelegate: ScrollableSegmentedControlDelegate?
  
  @IBInspectable
  public var segmentTintColor: UIColor = .black {
    didSet {
      self.segmentedControl.tintColor = self.segmentTintColor
    }
  }
  
  @IBInspectable
  public var itemWidth: CGFloat = 150 {
    didSet {
    }
  }
  
  public var segmentFont: UIFont = UIFont.systemFont(ofSize: 13) {
    didSet {
      self.segmentedControl.setTitleTextAttributes(
        [NSAttributedString.Key.font: self.segmentFont],
        for: UIControl.State()
      )
    }
  }
  public var itemsCount: Int = 3
  public var segmentheight : CGFloat = 29.0
  
  public var segmentItems = [String]() {
    didSet {
      self.itemsCount = segmentItems.count
      self.createSegment()
    }
  }
  
  required init(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)!
    createSegment()
  }
  
  override init(frame: CGRect) {
    super.init(frame: frame)
    createSegment()
    
  }
  
  init(frame: CGRect , andItems items:[String]) {
    super.init(frame: frame)
    self.segmentItems = items
    self.itemsCount = segmentItems.count
    self.createSegment()
  }
  func createSegment() {
    self.segmentedControl.removeFromSuperview()
    segmentheight =  self.frame.height
    
    let width = CGFloat(self.itemWidth * CGFloat(self.itemsCount))

    self.segmentedControl = UISegmentedControl(
      frame: CGRect(x: 0 , y: 0, width: width , height: segmentheight)
    )
    
    self.addSubview(self.segmentedControl)
    self.backgroundColor = .clear
    showsHorizontalScrollIndicator = false
    showsVerticalScrollIndicator = false
    
    NSLayoutConstraint(
      item: self.segmentedControl,
      attribute: NSLayoutConstraint.Attribute.top,
      relatedBy: NSLayoutConstraint.Relation.equal,
      toItem: self,
      attribute: NSLayoutConstraint.Attribute.top,
      multiplier: 1,
      constant: 0
    ).isActive = true
    
    NSLayoutConstraint(
      item: self.segmentedControl,
      attribute: NSLayoutConstraint.Attribute.bottom,
      relatedBy: NSLayoutConstraint.Relation.equal,
      toItem: self,
      attribute: NSLayoutConstraint.Attribute.bottom,
      multiplier: 1,
      constant: 0
      ).isActive = true
    
    NSLayoutConstraint(
      item: self.segmentedControl,
      attribute: NSLayoutConstraint.Attribute.leading,
      relatedBy: NSLayoutConstraint.Relation.equal,
      toItem: self,
      attribute: NSLayoutConstraint.Attribute.leading,
      multiplier: 1,
      constant: 0
      ).isActive = true
    
    NSLayoutConstraint(
      item: self.segmentedControl,
      attribute: NSLayoutConstraint.Attribute.trailing,
      relatedBy: NSLayoutConstraint.Relation.equal,
      toItem: self,
      attribute: NSLayoutConstraint.Attribute.trailing,
      multiplier: 1,
      constant: 0
      ).isActive = true
    
    NSLayoutConstraint(
      item: self.segmentedControl,
      attribute: NSLayoutConstraint.Attribute.top,
      relatedBy: NSLayoutConstraint.Relation.equal,
      toItem: self,
      attribute: NSLayoutConstraint.Attribute.top,
      multiplier: 1,
      constant: 0
      ).isActive = true
    
    let contentHeight =  self.frame.height
    self.contentSize = CGSize (width: width, height: contentHeight)
    
    self.segmentedControl.setTitleTextAttributes(
      [NSAttributedString.Key.font: self.segmentFont],
      for: UIControl.State()
    )
    
    self.segmentedControl.tintColor = self.segmentTintColor
    insertItems()
    
    self.segmentedControl.addTarget(
      self,
      action: #selector(self.segmentChangeSelectedIndex(_:)),
      for: .valueChanged
    )
    
    self.segmentedControl.selectedSegmentIndex = 0
  }
  
  func insertItems() {
    for item in segmentItems {
      self.segmentedControl.insertSegment(
        withTitle: item,
        at: (segmentItems.firstIndex(of: item))!,
        animated: false
      )
    }
  }
  
  @objc func segmentChangeSelectedIndex(_ sender: AnyObject) {
    segmentDelegate?.selectItemAt(
      index: self.segmentedControl.selectedSegmentIndex,
      onScrollUISegmentController: self
    )
    
    print("\(self.segmentedControl.selectedSegmentIndex)")
  }
}