StationsViewController.swift

import UIKit

class StationsViewController: GenericViewController<StationsView>,
    UICollectionViewDelegate,
    StationsPresentationModelDelegate,
    UISearchBarDelegate,
    FilterControlDelegate,
    RadioControllerDelegate {
    
    private var stationsPresentationModel: StationsPresentationModel!
    
    // MARK: - Dependencies
    
    var radioController: RadioController!
    var sleepController: SleepController!
    
    // MARK: - ViewController's Lifecycle
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Setup constraints
        rootView.setupConstraints(by: topLayoutGuide)
        
        let defaultFilter = FilterAttribute.country(.RU)
        rootView.updateFilter(newValue: defaultFilter)
        
        // Presentation model
        stationsPresentationModel = StationsPresentationModel(defaultFilter: defaultFilter)
        stationsPresentationModel.delegate = self
        rootView.collectionView.dataSource = stationsPresentationModel
        
        // Delegates
        rootView.searchBar.delegate = self
        rootView.filterControl.delegate = self
        rootView.collectionView.delegate = self
        radioController.delegate = self
        
        // Actions
        rootView.nowPlayingButton.addTarget(self, action: #selector(nowPlayingButtonTapped),
                                            for: .touchUpInside)
        rootView.refreshControl.addTarget(self, action: #selector(refreshOptions(sender:)),
                                          for: .valueChanged)
    }
    
    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        rootView.updateCollectionViewLayout(invalidate: true)
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        if rootView.searchBar.isFirstResponder {
            rootView.searchBar.resignFirstResponder()
        }
    }
    
    override func viewWillAppear(_ animated: Bool) {
        stationsPresentationModel.updateFilter()
        rootView.nowPlayingButton.isHidden = radioController.currentState == .stopped
    }
    
    // MARK: - Actions
    
    @objc private func nowPlayingButtonTapped() {
        if radioController.currentStation != nil {
            showNowPlayingScreen()
        }
    }
    
    @objc private func refreshOptions(sender: UIRefreshControl) {
        stationsPresentationModel.refresh {
            sender.endRefreshing()
        }
    }
    
    // MARK: - RadioControllerDelegate
    
    func stateChanged(state: RadioState) {
        rootView.nowPlayingButton.isHidden = radioController.currentState == .stopped
    }
    
    // MARK: - StationsPresentationModelDelegate
    
    func stationsChanged() {
        rootView.collectionView.reloadData()
    }

    // MARK: - UICollectionViewDelegate
    
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        stationsPresentationModel.currentStationIndex = indexPath.row
        if let newStation = stationsPresentationModel.station(at: indexPath) {
            changeStation(station: newStation, showPlayer: true)
        }
    }
    
    // MARK: - UISearchBarDelegate
    
    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        stationsPresentationModel.search(forText: searchText)
    }

    func searchBarCancelButtonClicked(_ searchBar: UISearchBar) {
        searchBar.text = ""
        searchBar.resignFirstResponder()
        stationsPresentationModel.search(forText: "")
    }

    func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
        searchBar.resignFirstResponder()
    }

    func searchBarTextDidBeginEditing(_ searchBar: UISearchBar) {
        searchBar.setShowsCancelButton(true, animated: true)
    }

    func searchBarTextDidEndEditing(_ searchBar: UISearchBar) {
        searchBar.setShowsCancelButton(false, animated: true)
    }
    
    // MARK: - FilterControlDelegate
    
    func filterDidChanged() {
        stationsPresentationModel.filter(by: rootView.selectedFilter)
    }
    
    // MARK: - Private methods
    
    private func changeStation(station: Station, showPlayer: Bool) {
        if radioController.currentStation != station {
            radioController.changeStation(station)
        }
        if showPlayer {
            let playerViewController = PlayerViewController()
            playerViewController.radioController = radioController
            playerViewController.sleepController = sleepController
            navigationController?.pushViewController(playerViewController, animated: true)
        }
    }
    
    private func showNowPlayingScreen() {
        let playerViewController = PlayerViewController()
        playerViewController.radioController = radioController
        playerViewController.sleepController = sleepController
        navigationController?.pushViewController(playerViewController, animated: true)
    }
    
}