// File created from ScreenTemplate
// $ createScreen.sh Rooms/ShowDirectory ShowDirectory
/*
 Copyright 2020 New Vector Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
 http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */

import UIKit

final class ShowDirectoryViewController: UIViewController {
    
    // MARK: - Constants
    
    // MARK: - Properties
    
    // MARK: Outlets

    @IBOutlet private weak var mainTableView: UITableView!
    @IBOutlet private weak var createRoomButton: UIButton! {
        didSet {
            createRoomButton.setTitle(VectorL10n.searchableDirectoryCreateNewRoom, for: .normal)
        }
    }
    
    // MARK: Private

    private var viewModel: ShowDirectoryViewModelType!
    private var theme: Theme!
    private var keyboardAvoider: KeyboardAvoider?
    private var errorPresenter: MXKErrorPresentation!
    private var activityPresenter: ActivityIndicatorPresenter!
    private lazy var footerSpinnerView: UIActivityIndicatorView = {
        let spinner = UIActivityIndicatorView(style: .whiteLarge)
        spinner.transform = CGAffineTransform(scaleX: 0.75, y: 0.75)
        spinner.color = .darkGray
        spinner.hidesWhenStopped = false
        spinner.backgroundColor = .clear
        spinner.startAnimating()
        return spinner
    }()
    private lazy var mainSearchBar: UISearchBar = {
        let bar = UISearchBar(frame: CGRect(origin: .zero, size: CGSize(width: 600, height: 44)))
        bar.autoresizingMask = .flexibleWidth
        bar.showsCancelButton = false
        bar.placeholder = VectorL10n.searchableDirectorySearchPlaceholder
        bar.setBackgroundImage(UIImage.vc_image(from: .clear), for: .any, barMetrics: .default)
        bar.delegate = self
        return bar
    }()

    // MARK: - Setup
    
    class func instantiate(with viewModel: ShowDirectoryViewModelType) -> ShowDirectoryViewController {
        let viewController = StoryboardScene.ShowDirectoryViewController.initialScene.instantiate()
        viewController.viewModel = viewModel
        viewController.theme = ThemeService.shared().theme
        return viewController
    }
    
    // MARK: - Life cycle
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Do any additional setup after loading the view.
        
        self.setupViews()
        self.keyboardAvoider = KeyboardAvoider(scrollViewContainerView: self.view, scrollView: self.mainTableView)
        self.activityPresenter = ActivityIndicatorPresenter()
        self.errorPresenter = MXKErrorAlertPresentation()
        
        self.registerThemeServiceDidChangeThemeNotification()
        self.update(theme: self.theme)
        
        self.viewModel.viewDelegate = self

        self.viewModel.process(viewAction: .loadData(false))
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        
        self.keyboardAvoider?.startAvoiding()
    }
    
    override func viewDidDisappear(_ animated: Bool) {
        super.viewDidDisappear(animated)
        
        self.keyboardAvoider?.stopAvoiding()
    }
    
    override var preferredStatusBarStyle: UIStatusBarStyle {
        return self.theme.statusBarStyle
    }
    
    // MARK: - Private
    
    private func addSpinnerFooterView() {
        footerSpinnerView.startAnimating()
        self.mainTableView.tableFooterView = footerSpinnerView
    }
    
    private func removeSpinnerFooterView() {
        footerSpinnerView.stopAnimating()
        self.mainTableView.tableFooterView = UIView()
    }
    
    private func update(theme: Theme) {
        self.theme = theme
        
        self.view.backgroundColor = theme.headerBackgroundColor
        self.mainTableView.backgroundColor = theme.backgroundColor
        self.mainTableView.separatorColor = theme.lineBreakColor
        
        if let navigationBar = self.navigationController?.navigationBar {
            theme.applyStyle(onNavigationBar: navigationBar)
            navigationBar.setBackgroundImage(UIImage.vc_image(from: theme.headerBackgroundColor), for: .default)
        }

        theme.applyStyle(onSearchBar: mainSearchBar)
        theme.applyStyle(onButton: createRoomButton)
        
        self.mainTableView.reloadData()
    }
    
    private func registerThemeServiceDidChangeThemeNotification() {
        NotificationCenter.default.addObserver(self, selector: #selector(themeDidChange), name: .themeServiceDidChangeTheme, object: nil)
    }
    
    @objc private func themeDidChange() {
        self.update(theme: ThemeService.shared().theme)
    }
    
    private func setupViews() {
        self.mainTableView.keyboardDismissMode = .interactive
        self.mainTableView.register(headerFooterViewType: DirectoryNetworkTableHeaderFooterView.self)
        self.mainTableView.register(cellType: DirectoryRoomTableViewCell.self)
        self.mainTableView.rowHeight = 76
        self.mainTableView.tableFooterView = UIView()
        
        let cancelBarButtonItem = MXKBarButtonItem(title: VectorL10n.cancel, style: .plain) { [weak self] in
            self?.cancelButtonAction()
        }
        self.navigationItem.rightBarButtonItem = cancelBarButtonItem
        
        self.navigationItem.titleView = mainSearchBar
    }

    private func render(viewState: ShowDirectoryViewState) {
        switch viewState {
        case .loading:
            self.renderLoading()
        case .loaded:
            self.renderLoaded()
        case .error(let error):
            self.render(error: error)
        }
    }
    
    private func renderLoading() {
        addSpinnerFooterView()
    }
    
    private func renderLoaded() {
        removeSpinnerFooterView()

    }
    
    private func render(error: Error) {
        removeSpinnerFooterView()
        self.errorPresenter.presentError(from: self, forError: error, animated: true, handler: nil)
    }

    // MARK: - Actions

    @IBAction private func createRoomButtonTapped(_ sender: UIButton) {
        viewModel.process(viewAction: .createNewRoom)
    }

    private func cancelButtonAction() {
        self.viewModel.process(viewAction: .cancel)
    }
}


// MARK: - UITableViewDataSource

extension ShowDirectoryViewController: UITableViewDataSource {
    
    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return viewModel.roomsCount
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell: DirectoryRoomTableViewCell = tableView.dequeueReusableCell(for: indexPath)
        if let viewModel = viewModel.roomViewModel(at: indexPath) {
            cell.configure(withViewModel: viewModel)
        }
        cell.indexPath = indexPath
        cell.delegate = self
        cell.update(theme: self.theme)
        return cell
    }
    
}

// MARK: - UITableViewDataDelegate

extension ShowDirectoryViewController: UITableViewDelegate {
    
    func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
        cell.backgroundColor = theme.backgroundColor
        
        // Update the selected background view
        cell.selectedBackgroundView = UIView()
        cell.selectedBackgroundView?.backgroundColor = theme.selectedBackgroundColor
    }
    
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        tableView.deselectRow(at: indexPath, animated: true)
        
        viewModel.process(viewAction: .selectRoom(indexPath))
    }
    
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        // Trigger inconspicuous pagination when user scrolls down
        if (scrollView.contentSize.height - scrollView.contentOffset.y - scrollView.frame.size.height) < 300 {
            viewModel.process(viewAction: .loadData(false))
        }
    }
    
    func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        guard let view: DirectoryNetworkTableHeaderFooterView = tableView.dequeueReusableHeaderFooterView() else {
            return nil
        }
        if let name = self.viewModel.directoryServerDisplayname {
            let title = VectorL10n.searchableDirectoryXNetwork(name)
            view.configure(withViewModel: DirectoryNetworkVM(title: title))
        }
        view.update(theme: self.theme)
        view.delegate = self
        return view
    }
    
    func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        return 40
    }
    
}

// MARK: - UISearchBarDelegate

extension ShowDirectoryViewController {
    
    override func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        viewModel.process(viewAction: .search(searchText))
    }
    
}

// MARK: -

extension ShowDirectoryViewController: DirectoryRoomTableViewCellDelegate {
    
    func directoryRoomTableViewCellDidTapJoin(_ cell: DirectoryRoomTableViewCell) {
        cell.startJoining()
        viewModel.process(viewAction: .joinRoom(cell.indexPath))
    }
    
}

// MARK: - DirectoryNetworkTableHeaderFooterViewDelegate

extension ShowDirectoryViewController: DirectoryNetworkTableHeaderFooterViewDelegate {
    
    func directoryNetworkTableHeaderFooterViewDidTapSwitch(_ view: DirectoryNetworkTableHeaderFooterView) {
        viewModel.process(viewAction: .switchServer)
    }
    
}


// MARK: - ShowDirectoryViewModelViewDelegate
extension ShowDirectoryViewController: ShowDirectoryViewModelViewDelegate {

    func showDirectoryViewModel(_ viewModel: ShowDirectoryViewModelType, didUpdateViewState viewSate: ShowDirectoryViewState) {
        self.render(viewState: viewSate)
    }
    
    func showDirectoryViewModelDidUpdateDataSource(_ viewModel: ShowDirectoryViewModelType) {
        self.mainTableView.reloadData()
    }
}