DatePicker.swift

//
//  DatePicker.swift
//  DatePicker
//
//  Created by Arpit Jain on 08/01/19.
//  Copyright © 2018 Arpit Jain. All rights reserved.
//

import UIKit

class DatePicker: NSObject {

    // MARK: - Properties
    
    static let shared = DatePicker()
    
    private let kDateFormat = "yyyy-MM-dd"
    private let toolbarBtnFont = UIFont.boldSystemFont(ofSize: 17.0)
    private let toolbarColor = UIColor.gray
    private let toolbarBtnColor = UIColor.white
    
    private var selectedDateblock : ((String) -> Void)?
    private var objDatePicker = UIDatePicker()
    private var objViewController = UIViewController()

    private var dateFormatter : DateFormatter{
        let formatter = DateFormatter()
        formatter.dateFormat = kDateFormat
        formatter.dateStyle = .medium
        return formatter
    }
    
    // MARK: -
    
    /// Use this method to display **Date Picker** on any textfield.
    ///
    /// - Parameters:
    ///   - textField: Object of textfield on which you need to an display DatePicker.
    ///   - controller: Object of controller on which you need to an display DatePicker.
    ///   - isForBirthDate: By default this property is false, if you are using date picker for picking birthdate set it to true.
    ///   - completionBlock: You will get the call back here when user selected the date.
    
    func pickDate(textField : UITextField,
                  controller : UIViewController ,
                  isForBirthDate : Bool = false ,
                  completionBlock : @escaping (String) -> Void) {
        
        objViewController = controller
        textField.tintColor = UIColor.clear
        objDatePicker.datePickerMode = .date
        objDatePicker.backgroundColor = UIColor.white
        
        if isForBirthDate{
            objDatePicker.maximumDate = Date()
        }
        
        if !(textField.text?.isEmpty ?? false){
            if let date = dateFormatter.date(from: textField.text!){
                objDatePicker.setDate(date, animated: false)
            }
        }
        
        let toolBar = UIToolbar()
        toolBar.barStyle = .default
        toolBar.isTranslucent = true
        toolBar.barTintColor = toolbarColor
        toolBar.tintColor =  toolbarBtnColor
        toolBar.sizeToFit()
        
        let doneButton = UIBarButtonItem(title: "Done", style: .plain, target: self, action: #selector(doneClick))
        doneButton.setTitleTextAttributes([NSAttributedString.Key.font: toolbarBtnFont], for: UIControl.State.normal)
        doneButton.setTitleTextAttributes([NSAttributedString.Key.font: toolbarBtnFont], for: UIControl.State.selected)
        
        let spaceButton = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
        let cancelButton = UIBarButtonItem(title: "Cancel", style: .plain, target: self, action: #selector(cancelClick))
        cancelButton.setTitleTextAttributes([NSAttributedString.Key.font: toolbarBtnFont], for: UIControl.State.normal)
        cancelButton.setTitleTextAttributes([NSAttributedString.Key.font: toolbarBtnFont], for: UIControl.State.selected)
        
        toolBar.setItems([cancelButton, spaceButton, doneButton], animated: false)
        toolBar.isUserInteractionEnabled = true
        textField.inputView = objDatePicker
        textField.inputAccessoryView = toolBar
        selectedDateblock = completionBlock
    }
    
    // MARK: - Button Click Event
    
    /// Done button click event
    @objc func doneClick(){
        
        let aString = dateFormatter.string(from: objDatePicker.date)
        selectedDateblock!(aString)
        objViewController.view.endEditing(true)
    }
    
    /// Cancel button click event
    @objc func cancelClick() {
        objViewController.view.endEditing(true)
    }    
}