iOSアプリ　カレンダーに予定を登録したい

スケジュール管理アプリを作っております。

実現したい事は、このカレンダーに登録した予定を表示したいのです。

現状としまして

• タップしたセルが何年の何月何日なのかを取得する方法がわからない
• 日時からセルを特定する実装方法がイメージできない

です。
完成イメージはGoogleカレンダーのような感じです。
よろしくお願いします。

カレンダーのソースコードです。

import UIKit

class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource {

    let dateManager = DateManager()
    let daysPerWeek: Int = 8
    let cellMargin: CGFloat = 2.0
    var selectedDate = Date()
    var today: Date!
    let weekArray = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]

    @IBOutlet weak var headerView: UIView!
    @IBOutlet weak var headerTitle: UILabel!
    @IBOutlet weak var headerPrevBtn: UIButton!
    @IBOutlet weak var headerNextBtn: UIButton!
    @IBOutlet weak var calendarCollectionView: UICollectionView!

    //MARK:- Override
    //    --------------------------------------------------------------------------------
    //    viewDidLoad()
    //    --------------------------------------------------------------------------------
    override func viewDidLoad() {
        super.viewDidLoad()

        let dateFormater = DateFormatter()
        dateFormater.locale = Locale(identifier: "ja_JP")
        dateFormater.dateFormat = "yyyy/MM/dd"
        let oneDay = "2018/12/16"
        print(oneDay)
        let castDate = dateFormater.date(from: oneDay)
        print(castDate)

        cellSizeSet()
        headerTitle.text = changeHeaderTitle(date: selectedDate)

        calendarCollectionView.delegate = self
        calendarCollectionView.dataSource = self
        calendarCollectionView.backgroundColor = UIColor.white
    }

    //MARK:- Method
    //    --------------------------------------------------------------------------------
    //    changeHeaderTitle(date: Date) -> String
    //    --------------------------------------------------------------------------------
    func changeHeaderTitle(date: Date) -> String {
        let formatter: DateFormatter = DateFormatter()
        formatter.dateFormat = "yyyy年/M月"
        let selectMonth = formatter.string(from: selectedDate)
        return selectMonth
    }

    func cellSizeSet() {
        let numberOfMargin: CGFloat = 8.0
        let width: CGFloat = (calendarCollectionView.frame.width - cellMargin * numberOfMargin) / CGFloat(daysPerWeek)
        let height: CGFloat = width * 1.0
        let layout = UICollectionViewFlowLayout()
        layout.itemSize = CGSize(width: width, height: height)
        calendarCollectionView.collectionViewLayout = layout
    }

    //MARK:- Delegate
    //    --------------------------------------------------------------------------------
    //    numberOfSections(in collectionView: UICollectionView) -> Int
    //    --------------------------------------------------------------------------------
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 2
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        if section == 0 {
            return 7
        } else {
            return dateManager.daysAcquisition()
        }
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = calendarCollectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! CalendarCell
        //テキストカラー
        if (indexPath.row % 7 == 0) {
            cell.textLabel.textColor = UIColor.red
        } else if (indexPath.row % 7 == 6) {
            cell.textLabel.textColor = UIColor.blue
        } else {
            cell.textLabel.textColor = UIColor.gray
        }
        //テキスト配置
        if indexPath.section == 0 {
            cell.textLabel.text = weekArray[indexPath.row]
        } else {
            cell.textLabel.text = dateManager.conversionDateFormat(indexPath: indexPath)
        }

        let selectedBGView = UIView(frame: cell.frame)
        selectedBGView.backgroundColor = .blue
        cell.selectedBackgroundView = selectedBGView
        return cell
    }

    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        print(indexPath)
        print(indexPath.row)
    }

    //MARK:- Action
    //    --------------------------------------------------------------------------------
    //    oPrevBtn(_ sender: Any)
    //    --------------------------------------------------------------------------------
    @IBAction func oPrevBtn(_ sender: Any) {
        selectedDate = dateManager.prevMonth(date: selectedDate)
        calendarCollectionView.reloadData()
        headerTitle.text = changeHeaderTitle(date: selectedDate)
    }

    @IBAction func oNextBtn(_ sender: Any) {
        selectedDate = dateManager.nextMonth(date: selectedDate)
        calendarCollectionView.reloadData()
        headerTitle.text = changeHeaderTitle(date: selectedDate)
    }
}

extension UIColor {
    class func lightBlue() -> UIColor {
        return UIColor(red: 92.0 / 255, green: 192.0 / 255, blue: 210.0 / 255, alpha: 1.0)
    }

    class func lightRed() -> UIColor {
        return UIColor(red: 195.0 / 255, green: 123.0 / 255, blue: 175.0 / 255, alpha: 1.0)
    }
}