//
//  AppDelegate.swift
//  ReviewsFeed
//
//  Created by Dmitrii Ivanov on 21/07/2020.
//  Copyright © 2020 ING. All rights reserved.
//

import Combine
import UIKit

public class FeedViewController: UITableViewController {
    
    // MARK: Constants
    private let viewModel: ViewModel = .init()
    
    // MARK: Properties
    private var cancellables: Set<AnyCancellable> = []
    
    // MARK: Initialisers
    public init() {
        super.init(style: .plain)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    // MARK: UIViewController
    public override func viewDidLoad() {
        super.viewDidLoad()
        
        tableView.register(ReviewCell.self, forCellReuseIdentifier: "cellId")
        tableView.rowHeight = 160
        
        bindViewModel()
        
        viewModel.fetch()
    }
    
    // MARK: UITableViewDataSource
    public override func tableView(
        _ tableView: UITableView,
        numberOfRowsInSection section: Int
    ) -> Int {
        viewModel.items.count
    }
    
    public override func tableView(
        _ tableView: UITableView,
        cellForRowAt indexPath: IndexPath
    ) -> UITableViewCell {
        guard
            let cell = tableView.dequeueReusableCell(
                withIdentifier: "cellId",
                for: indexPath
            ) as? ReviewCell
        else {
            return .init()
        }

        cell.update(item: viewModel.items[indexPath.row])

        return cell
    }
    
    // MARK: UITableViewDelegate
    public override func tableView(
        _ tableView: UITableView,
        didSelectRowAt indexPath: IndexPath
    ) {
        let details = DetailsViewController(review: viewModel.items[indexPath.row])
        
        tableView.deselectRow(
            at: indexPath,
            animated: true
        )

        navigationController?.pushViewController(details, animated: true)
    }
    
}

// MARK: - Helpers
private extension FeedViewController {
    
    // MARK: Functions
    func bindViewModel() {
        viewModel.$loading
            .sink { loading in
                print("LOADING: \(loading)")
            }
            .store(in: &cancellables)
        
        viewModel.$loading
            .filter { $0 == false }
            .dropFirst()
            .receive(on: RunLoop.main)
            .sink { [weak self] _ in
                self?.tableView.reloadData()
            }
            .store(in: &cancellables)
    }
    
}