mastodon-ios/Mastodon/Scene/Profile/Timeline/UserTimelineViewController.swift

//
//  UserTimelineViewController.swift
//  Mastodon
//
//  Created by MainasuK Cirno on 2021-3-29.
//

import os.log
import UIKit
import AVKit
import Combine
import CoreDataStack
import GameplayKit

// TODO: adopt MediaPreviewableViewController
final class UserTimelineViewController: UIViewController, NeedsDependency {
    
    weak var context: AppContext! { willSet { precondition(!isViewLoaded) } }
    weak var coordinator: SceneCoordinator! { willSet { precondition(!isViewLoaded) } }
    
    var disposeBag = Set<AnyCancellable>()
    var viewModel: UserTimelineViewModel!
    
    // let mediaPreviewTransitionController = MediaPreviewTransitionController()

    lazy var tableView: UITableView = {
        let tableView = UITableView()
        tableView.register(StatusTableViewCell.self, forCellReuseIdentifier: String(describing: StatusTableViewCell.self))
        tableView.register(TimelineBottomLoaderTableViewCell.self, forCellReuseIdentifier: String(describing: TimelineBottomLoaderTableViewCell.self))
        tableView.register(TimelineHeaderTableViewCell.self, forCellReuseIdentifier: String(describing: TimelineHeaderTableViewCell.self))
        tableView.rowHeight = UITableView.automaticDimension
        tableView.separatorStyle = .none
        tableView.backgroundColor = .clear
        return tableView
    }()
    
    deinit {
        os_log("%{public}s[%{public}ld], %{public}s", ((#file as NSString).lastPathComponent), #line, #function)
    }
    
}

extension UserTimelineViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.backgroundColor = Asset.Colors.Background.systemGroupedBackground.color
        
        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(
            for: tableView,
            dependency: self,
            statusTableViewCellDelegate: self
        )
        
        // 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(UserTimelineViewModel.State.Reloading.self)
        }
        .store(in: &disposeBag)
        
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        tableView.deselectRow(with: transitionCoordinator, animated: animated)
    }

    override func viewDidDisappear(_ animated: Bool) {
        super.viewDidDisappear(animated)

        context.videoPlaybackService.viewDidDisappear(from: self)
    }
    
}

// MARK: - UIScrollViewDelegate
extension UserTimelineViewController {
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        handleScrollViewDidScroll(scrollView)
    }
}

// MARK: - UITableViewDelegate
extension UserTimelineViewController: UITableViewDelegate {
    
    func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
        guard let diffableDataSource = viewModel.diffableDataSource else { return 100 }
        guard let item = diffableDataSource.itemIdentifier(for: indexPath) else { return 100 }
        
        guard let frame = viewModel.cellFrameCache.object(forKey: NSNumber(value: item.hashValue))?.cgRectValue else {
            if case .bottomLoader = item {
                return TimelineLoaderTableViewCell.cellHeight
            } else {
                return 200
            }
        }
        // os_log("%{public}s[%{public}ld], %{public}s: cache cell frame %s", ((#file as NSString).lastPathComponent), #line, #function, frame.debugDescription)
        
        return ceil(frame.height)
    }
    
    func tableView(_ tableView: UITableView, didEndDisplaying cell: UITableViewCell, forRowAt indexPath: IndexPath) {
        guard let diffableDataSource = viewModel.diffableDataSource else { return }
        guard let item = diffableDataSource.itemIdentifier(for: indexPath) else { return }
        
        let key = item.hashValue
        let frame = cell.frame
        viewModel.cellFrameCache.setObject(NSValue(cgRect: frame), forKey: NSNumber(value: key))
    }
    
}

// MARK: - AVPlayerViewControllerDelegate
extension UserTimelineViewController: AVPlayerViewControllerDelegate {
    
    func playerViewController(_ playerViewController: AVPlayerViewController, willBeginFullScreenPresentationWithAnimationCoordinator coordinator: UIViewControllerTransitionCoordinator) {
        handlePlayerViewController(playerViewController, willBeginFullScreenPresentationWithAnimationCoordinator: coordinator)
    }
    
    func playerViewController(_ playerViewController: AVPlayerViewController, willEndFullScreenPresentationWithAnimationCoordinator coordinator: UIViewControllerTransitionCoordinator) {
        handlePlayerViewController(playerViewController, willEndFullScreenPresentationWithAnimationCoordinator: coordinator)
    }
    
}

// MARK: - TimelinePostTableViewCellDelegate
extension UserTimelineViewController: StatusTableViewCellDelegate {
    weak var playerViewControllerDelegate: AVPlayerViewControllerDelegate? { return self }
    func parent() -> UIViewController { return self }
}

//// MARK: - TimelineHeaderTableViewCellDelegate
//extension UserTimelineViewController: TimelineHeaderTableViewCellDelegate { }


// MARK: - CustomScrollViewContainerController
extension UserTimelineViewController: ScrollViewContainer {
    var scrollView: UIScrollView { return tableView }
}

// MARK: - LoadMoreConfigurableTableViewContainer
extension UserTimelineViewController: LoadMoreConfigurableTableViewContainer {
    typealias BottomLoaderTableViewCell = TimelineBottomLoaderTableViewCell
    typealias LoadingState = UserTimelineViewModel.State.LoadingMore
    
    var loadMoreConfigurableTableView: UITableView { return tableView }
    var loadMoreConfigurableStateMachine: GKStateMachine { return viewModel.stateMachine }
}