DropDownView.swift

import UIKit

enum PerformanceDateGroup: Int {

    case none = 0
    case daily
    case weekly
    case monthly
    
    init(rawValue: Int) {
        switch rawValue {
        case 0:
            self = .daily
        case 1:
            self = .weekly
        case 2:
            self = .monthly
        default:
            self = .none
        }
    }
    
    var value: String {
        switch self {
        case .daily:
            return "Daily"
        case .weekly:
            return "Weekly"
        case .monthly:
           return "Monthly"
        case .none:
            return "None"
        }
    }
    
    var headerTitle: String {
        return "\(self.value) Usage"
    }
    
}

protocol DropDownViewDelegate: class {
    func didSelect(_ dropDown: DropDownView, model: DropDownCellModel)
}

class DropDownView: UIView {

    @IBOutlet weak var titleLabel: UILabel!
    @IBOutlet weak var imgView: UIImageView!
    @IBOutlet var dropDownHeightContraint: NSLayoutConstraint!
    @IBOutlet weak var lineView: UIView!
    @IBOutlet weak var titleView: UIView!
    @IBOutlet weak var tableView: UITableView!
    
    var cellItems: [DropDownCellModel] = []
    weak var delegate: DropDownViewDelegate?
    
    var isVisible: Bool {
        return self.dropDownHeightContraint.constant == 120
    }
    
    override func awakeFromNib() {
        super.awakeFromNib()
        self.setupTableView()
        self.setupGesture()
    }
}

extension DropDownView: UITableViewDelegate, UITableViewDataSource {
    
    private func setupGesture() {
        let gesture = UITapGestureRecognizer(target: self,
                                             action: #selector(handleGesture(_:)))
        self.titleView.addGestureRecognizer(gesture)
    }
    
    @objc func handleGesture(_ sender: UITapGestureRecognizer) {
        self.toggleMenu()
    }
    
    func toggleMenu() {
        let constant = self.dropDownHeightContraint.constant

        if constant == 30 {
            self.dropDownHeightContraint.constant = 120
            self.lineView.isHidden = false
        } else {
            self.dropDownHeightContraint.constant = 30
            self.lineView.isHidden = true
        }
        
        UIView.animate(withDuration: 0.2) {
            self.superview?.layoutIfNeeded()
        }
    }
    
    private func setupTableView() {
        self.tableView.delegate = self
        self.tableView.dataSource = self
        self.tableView.register(DropDownTableViewCell.defaultNib,
                                forCellReuseIdentifier: "DropDownTableViewCell")
    }
    
    func setUpItems(_ items: [DropDownCellModel]) {
        self.cellItems = items
        self.tableView.reloadData()
    }
    
    func tableView(_ tableView: UITableView,
                   numberOfRowsInSection section: Int) -> Int {
        return self.cellItems.count
    }
    
    func tableView(_ tableView: UITableView,
                   cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(
            withIdentifier: "DropDownTableViewCell"
        ) as! DropDownTableViewCell
        cell.item = self.cellItems[indexPath.row]
        return cell
    }
    
    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        let rowHeight = tableView.bounds.height / CGFloat(self.cellItems.count)
        return self.cellItems.isEmpty ? 0.0 : rowHeight
    }
    
    func tableView(_ tableView: UITableView,
                   didSelectRowAt indexPath: IndexPath) {
        self.handleFilterSelection(indexPath)
        let model = self.cellItems[indexPath.row]
        self.titleLabel.text = model.item.value
        self.delegate?.didSelect(self, model: model)
        self.toggleMenu()
    }
    
    private func handleFilterSelection(_ indexPath: IndexPath) {
        self.cellItems.forEach { $0.isSelected = false }
        self.tableView.reloadData()
        self.cellItems[indexPath.row].isSelected = true
        self.tableView.reloadRows(at: [indexPath], with: .automatic)
    }
    
}