WorkoutsController.swift

import UIKit
import PKHUD

class WorkoutsController: UICollectionViewController {
    
    // MARK: - Properties
    fileprivate let reuseIdentifier = "WorkoutCell"
    fileprivate let itemsPerRow: CGFloat = 2
    fileprivate let sectionInsets = UIEdgeInsets(top: 0, left: 0, bottom: 00, right: 0)
    fileprivate let titleHeightAdjustement: CGFloat = 65.0
    
    let viewModel: HomeWorkoutsCollectionViewViewModel = HomeWorkoutsCollectionViewViewModel()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        bindViewModel()
        viewModel.getHomeWorkouts()
    }

    func bindViewModel() {
        viewModel.workoutCells.bindAndFire() { [weak self] _ in
            self?.collectionView?.reloadData()
        }
        
        viewModel.onShowError = { [weak self] alert in
            self?.presentSingleButtonDialog(alert: alert)
        }
        
        viewModel.showLoadingHud.bind() { visible in
            PKHUD.sharedHUD.contentView = PKHUDSystemActivityIndicatorView()
            visible ? PKHUD.sharedHUD.show() : PKHUD.sharedHUD.hide()
        }
    }

}

// MARK: - UICollectionViewDataSource
extension WorkoutsController {

    override func collectionView(_ collectionView: UICollectionView,
                                 numberOfItemsInSection section: Int) -> Int {
        return self.viewModel.workoutCells.value.count
    }
    
    override func collectionView(_ collectionView: UICollectionView,
                                 cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        switch viewModel.workoutCells.value[indexPath.row] {
        case .normal(let viewModel):
            guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as? HomeWorkoutCollectionViewCell else {
                return UICollectionViewCell()
            }
            
            cell.viewModel = viewModel
            return cell
        case .error(let message):
            let cell = UICollectionViewCell()
            //cell.textLabel?.text = message
            return cell
        case .empty:
            let cell = UICollectionViewCell()
            //cell.textLabel?.text = "No data available"
            return cell
        }
    }
}

// MARK: - UICollectionViewDelegateFlowLayout
extension WorkoutsController: UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        sizeForItemAt indexPath: IndexPath) -> CGSize {
        let widthPerItem = view.frame.width / itemsPerRow
        
        return CGSize(width: widthPerItem, height: widthPerItem + titleHeightAdjustement)
    }
    
    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        insetForSectionAt section: Int) -> UIEdgeInsets {
        return sectionInsets
    }
    
    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return sectionInsets.left
    }
}

extension WorkoutsController: SingleButtonDialogPresenter { }