//
//  SearchResultViewController.swift
//  Mastodon
//
//  Created by MainasuK Cirno on 2021-7-14.
//

import UIKit
import Combine
import AVKit
import GameplayKit

final class SearchResultViewController: UIViewController, NeedsDependency, MediaPreviewableViewController {

    weak var context: AppContext! { willSet { precondition(!isViewLoaded) } }
    weak var coordinator: SceneCoordinator! { willSet { precondition(!isViewLoaded) } }

    let mediaPreviewTransitionController = MediaPreviewTransitionController()

    var viewModel: SearchResultViewModel!
    var disposeBag = Set<AnyCancellable>()

    let tableView: UITableView = {
        let tableView = UITableView()
        tableView.register(SearchResultTableViewCell.self, forCellReuseIdentifier: String(describing: SearchResultTableViewCell.self))
        tableView.register(StatusTableViewCell.self, forCellReuseIdentifier: String(describing: StatusTableViewCell.self))
        tableView.register(TimelineBottomLoaderTableViewCell.self, forCellReuseIdentifier: String(describing: TimelineBottomLoaderTableViewCell.self))
        tableView.separatorStyle = .none
        tableView.tableFooterView = UIView()
        tableView.backgroundColor = .clear
        return tableView
    }()

}

extension SearchResultViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        setupBackgroundColor(theme: ThemeService.shared.currentTheme.value)
        ThemeService.shared.currentTheme
            .receive(on: RunLoop.main)
            .sink { [weak self] theme in
                guard let self = self else { return }
                self.setupBackgroundColor(theme: theme)
            }
            .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
        tableView.prefetchDataSource = self
        viewModel.setupDiffableDataSource(
            tableView: tableView,
            dependency: self,
            statusTableViewCellDelegate: self
        )

        // listen keyboard events and set content inset
        let keyboardEventPublishers = Publishers.CombineLatest3(
            KeyboardResponderService.shared.isShow,
            KeyboardResponderService.shared.state,
            KeyboardResponderService.shared.endFrame
        )
        Publishers.CombineLatest3(
            keyboardEventPublishers,
            viewModel.viewDidAppear,
            viewModel.didDataSourceUpdate
        )
        .sink(receiveValue: { [weak self] keyboardEvents, _, _ in
            guard let self = self else { return }
            let (isShow, state, endFrame) = keyboardEvents

            // update keyboard background color
            guard isShow, state == .dock else {
                self.tableView.contentInset.bottom = 0
                self.tableView.verticalScrollIndicatorInsets.bottom = 0
                return
            }
            // isShow AND dock state

            // adjust inset for tableView
            let contentFrame = self.view.convert(self.tableView.frame, to: nil)
            let padding = contentFrame.maxY - endFrame.minY
            guard padding > 0 else {
                self.tableView.contentInset.bottom = self.view.safeAreaInsets.bottom
                self.tableView.verticalScrollIndicatorInsets.bottom = self.view.safeAreaInsets.bottom
                return
            }

            self.tableView.contentInset.bottom = padding - self.view.safeAreaInsets.bottom
            self.tableView.verticalScrollIndicatorInsets.bottom = padding - self.view.safeAreaInsets.bottom
        })
        .store(in: &disposeBag)

        // works for already onscreen page
        viewModel.navigationBarFrame
            .removeDuplicates()
            .receive(on: DispatchQueue.main)
            .sink { [weak self] frame in
                guard let self = self else { return }
                guard self.viewModel.viewDidAppear.value else { return }
                self.tableView.contentInset.top = frame.height
            }
            .store(in: &disposeBag)
    }

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

        // works for appearing page
        if !viewModel.viewDidAppear.value {
            tableView.contentInset.top = viewModel.navigationBarFrame.value.height
            tableView.contentOffset.y = -viewModel.navigationBarFrame.value.height
        }

        aspectViewWillAppear(animated)
    }

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

        viewModel.viewDidAppear.value = true
    }

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

        aspectViewDidDisappear(animated)
    }

}

extension SearchResultViewController {
    private func setupBackgroundColor(theme: Theme) {
        view.backgroundColor = theme.systemGroupedBackgroundColor
//        tableView.backgroundColor = theme.systemBackgroundColor
//        searchHeader.backgroundColor = theme.systemGroupedBackgroundColor
    }

}

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

// MARK: - StatusTableViewControllerAspect
extension SearchResultViewController: StatusTableViewControllerAspect { }

// MARK: - LoadMoreConfigurableTableViewContainer
extension SearchResultViewController: LoadMoreConfigurableTableViewContainer {
    typealias BottomLoaderTableViewCell = TimelineBottomLoaderTableViewCell
    typealias LoadingState = SearchResultViewModel.State.Loading
    var loadMoreConfigurableTableView: UITableView { tableView }
    var loadMoreConfigurableStateMachine: GKStateMachine { viewModel.stateMachine }
}

// MARK: - UIScrollViewDelegate
extension SearchResultViewController {
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        aspectScrollViewDidScroll(scrollView)
    }
}

// MARK: - TableViewCellHeightCacheableContainer
extension SearchResultViewController: TableViewCellHeightCacheableContainer {
    var cellFrameCache: NSCache<NSNumber, NSValue> {
        viewModel.cellFrameCache
    }
}

// MARK: - UITableViewDelegate
extension SearchResultViewController: UITableViewDelegate {
    func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
        aspectTableView(tableView, estimatedHeightForRowAt: indexPath)
    }

    func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
        aspectTableView(tableView, willDisplay: cell, forRowAt: indexPath)
    }

    func tableView(_ tableView: UITableView, didEndDisplaying cell: UITableViewCell, forRowAt indexPath: IndexPath) {
        aspectTableView(tableView, didEndDisplaying: cell, forRowAt: indexPath)
    }

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        guard let diffableDataSource = viewModel.diffableDataSource else { return }
        let item = diffableDataSource.itemIdentifier(for: indexPath)
        switch item {
        case .account(let account):
            let profileViewModel = RemoteProfileViewModel(context: context, userID: account.id)
            coordinator.present(scene: .profile(viewModel: profileViewModel), from: self, transition: .show)
        case .hashtag(let hashtag):
            let hashtagViewModel = HashtagTimelineViewModel(context: context, hashtag: hashtag.name)
            coordinator.present(scene: .hashtagTimeline(viewModel: hashtagViewModel), from: self, transition: .show)
        case .status:
            aspectTableView(tableView, didSelectRowAt: indexPath)
        default:
            assertionFailure()
        }
    }

    func tableView(_ tableView: UITableView, contextMenuConfigurationForRowAt indexPath: IndexPath, point: CGPoint) -> UIContextMenuConfiguration? {
        aspectTableView(tableView, contextMenuConfigurationForRowAt: indexPath, point: point)
    }

    func tableView(_ tableView: UITableView, previewForHighlightingContextMenuWithConfiguration configuration: UIContextMenuConfiguration) -> UITargetedPreview? {
        aspectTableView(tableView, previewForHighlightingContextMenuWithConfiguration: configuration)
    }

    func tableView(_ tableView: UITableView, previewForDismissingContextMenuWithConfiguration configuration: UIContextMenuConfiguration) -> UITargetedPreview? {
        aspectTableView(tableView, previewForDismissingContextMenuWithConfiguration: configuration)
    }

    func tableView(_ tableView: UITableView, willPerformPreviewActionForMenuWith configuration: UIContextMenuConfiguration, animator: UIContextMenuInteractionCommitAnimating) {
        aspectTableView(tableView, willPerformPreviewActionForMenuWith: configuration, animator: animator)
    }

}

// MARK: - UITableViewDataSourcePrefetching
extension SearchResultViewController: UITableViewDataSourcePrefetching {
    func tableView(_ tableView: UITableView, prefetchRowsAt indexPaths: [IndexPath]) {
        aspectTableView(tableView, cancelPrefetchingForRowsAt: indexPaths)
    }

    func tableView(_ tableView: UITableView, cancelPrefetchingForRowsAt indexPaths: [IndexPath]) {
        aspectTableView(tableView, cancelPrefetchingForRowsAt: indexPaths)
    }
}

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

    func playerViewController(_ playerViewController: AVPlayerViewController, willEndFullScreenPresentationWithAnimationCoordinator coordinator: UIViewControllerTransitionCoordinator) {
        handlePlayerViewController(playerViewController, willEndFullScreenPresentationWithAnimationCoordinator: coordinator)
    }
}