//
//  FollowingListViewController.swift
//  Mastodon
//
//  Created by Cirno MainasuK on 2021-11-2.
//

import os.log
import UIKit
import GameplayKit
import Combine

final class FollowingListViewController: UIViewController, NeedsDependency {

    let logger = Logger(subsystem: "FollowingListViewController", category: "ViewController")
    
    weak var context: AppContext! { willSet { precondition(!isViewLoaded) } }
    weak var coordinator: SceneCoordinator! { willSet { precondition(!isViewLoaded) } }
    
    var disposeBag = Set<AnyCancellable>()
    var viewModel: FollowingListViewModel!
    
    lazy var tableView: UITableView = {
        let tableView = UITableView()
        tableView.register(UserTableViewCell.self, forCellReuseIdentifier: String(describing: UserTableViewCell.self))
        tableView.register(TimelineBottomLoaderTableViewCell.self, forCellReuseIdentifier: String(describing: TimelineBottomLoaderTableViewCell.self))
        tableView.register(TimelineFooterTableViewCell.self, forCellReuseIdentifier: String(describing: TimelineFooterTableViewCell.self))
        tableView.rowHeight = UITableView.automaticDimension
        tableView.separatorStyle = .none
        tableView.backgroundColor = .clear
        return tableView
    }()
    
    deinit {
        os_log(.info, log: .debug, "%{public}s[%{public}ld], %{public}s", ((#file as NSString).lastPathComponent), #line, #function)
    }
    
}

extension FollowingListViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.backgroundColor = ThemeService.shared.currentTheme.value.secondarySystemBackgroundColor
        ThemeService.shared.currentTheme
            .receive(on: DispatchQueue.main)
            .sink { [weak self] theme in
                guard let self = self else { return }
                self.view.backgroundColor = theme.secondarySystemBackgroundColor
            }
            .store(in: &disposeBag)
        
        tableView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(tableView)
        NSLayoutConstraint.activate([
            tableView.topAnchor.constraint(equalTo: view.topAnchor),
            tableView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            tableView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
        ])
        
        tableView.delegate = self
        viewModel.setupDiffableDataSource(
            tableView: tableView,
            userTableViewCellDelegate: self
        )
        
        // setup batch fetch
        viewModel.listBatchFetchViewModel.setup(scrollView: tableView)
        viewModel.listBatchFetchViewModel.shouldFetch
            .receive(on: DispatchQueue.main)
            .sink { [weak self] _ in
                guard let self = self else { return }
                self.viewModel.stateMachine.enter(FollowingListViewModel.State.Loading.self)
            }
            .store(in: &disposeBag)
        
        // trigger user timeline loading
        Publishers.CombineLatest(
            viewModel.domain.removeDuplicates().eraseToAnyPublisher(),
            viewModel.userID.removeDuplicates().eraseToAnyPublisher()
        )
            .receive(on: DispatchQueue.main)
            .sink { [weak self] _ in
                guard let self = self else { return }
                self.viewModel.stateMachine.enter(FollowingListViewModel.State.Reloading.self)
            }
            .store(in: &disposeBag)
    }
    
}

// MARK: - UITableViewDelegate
extension FollowingListViewController: UITableViewDelegate, AutoGenerateTableViewDelegate {
    // sourcery:inline:FollowingListViewController.AutoGenerateTableViewDelegate

    // Generated using Sourcery
    // DO NOT EDIT
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        aspectTableView(tableView, didSelectRowAt: indexPath)
    }

    // sourcery:end
}

// MARK: - UserTableViewCellDelegate
extension FollowingListViewController: UserTableViewCellDelegate { }
