import Foundation
import SwiftUI

final class NavigationModel: ObservableObject {
    enum TabSelection: Hashable {
        case favorites
        case subscriptions
        case popular
        case trending
        case playlists
        case channel(String)
        case playlist(String)
        case recentlyOpened(String)
        case nowPlaying
        case search

        var stringValue: String {
            switch self {
            case .favorites:
                return "favorites"
            case .subscriptions:
                return "subscriptions"
            case .popular:
                return "popular"
            case .trending:
                return "trending"
            case .playlists:
                return "playlists"
            case let .channel(string):
                return "channel\(string)"
            case let .playlist(string):
                return "playlist\(string)"
            case .recentlyOpened:
                return "recentlyOpened"
            case .search:
                return "search"
            default:
                return ""
            }
        }

        var playlistID: Playlist.ID? {
            if case let .playlist(id) = self {
                return id
            }

            return nil
        }
    }

    @Published var tabSelection: TabSelection!

    @Published var presentingAddToPlaylist = false
    @Published var videoToAddToPlaylist: Video!

    @Published var presentingPlaylistForm = false
    @Published var editedPlaylist: Playlist!

    @Published var presentingUnsubscribeAlert = false
    @Published var channelToUnsubscribe: Channel!

    @Published var presentingChannel = false
    @Published var presentingPlaylist = false
    @Published var sidebarSectionChanged = false

    @Published var presentingSettings = false
    @Published var presentingWelcomeScreen = false

    @Published var presentingShareSheet = false
    @Published var shareURL: URL?

    @Published var alert = Alert(title: Text("Error"))
    @Published var presentingAlert = false
    #if os(macOS)
        @Published var presentingAlertInVideoPlayer = false
    #endif

    static func openChannel(
        _ channel: Channel,
        player: PlayerModel,
        recents: RecentsModel,
        navigation: NavigationModel
    ) {
        guard channel.id != Video.fixtureChannelID else {
            return
        }

        player.hide()
        navigation.presentingChannel = false

        let recent = RecentItem(from: channel)
        #if os(macOS)
            Windows.main.open()
        #else
            player.hide()
        #endif

        DispatchQueue.main.asyncAfter(deadline: .now() + 0.2) {
            recents.add(recent)
            navigation.sidebarSectionChanged.toggle()
            navigation.tabSelection = .recentlyOpened(recent.tag)
            navigation.presentingChannel = true
        }
    }

    static func openChannelPlaylist(
        _ playlist: ChannelPlaylist,
        player: PlayerModel,
        recents: RecentsModel,
        navigation: NavigationModel
    ) {
        navigation.presentingChannel = false
        navigation.presentingPlaylist = false

        let recent = RecentItem(from: playlist)
        #if os(macOS)
            Windows.main.open()
        #else
            player.hide()
        #endif

        DispatchQueue.main.asyncAfter(deadline: .now() + 0.2) {
            recents.add(recent)
            navigation.sidebarSectionChanged.toggle()
            navigation.tabSelection = .recentlyOpened(recent.tag)
            navigation.presentingPlaylist = true
        }
    }

    static func openSearchQuery(
        _ searchQuery: String?,
        player: PlayerModel,
        recents: RecentsModel,
        navigation: NavigationModel,
        search: SearchModel
    ) {
        player.hide()
        navigation.presentingChannel = false
        navigation.presentingPlaylist = false
        navigation.tabSelection = .search

        if let searchQuery = searchQuery {
            let recent = RecentItem(from: searchQuery)
            recents.add(recent)

            DispatchQueue.main.async {
                search.queryText = searchQuery
                search.changeQuery { query in query.query = searchQuery }
            }
        }

        #if os(macOS)
            DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
                Windows.main.focus()
            }
        #endif
    }

    var tabSelectionBinding: Binding<TabSelection> {
        Binding<TabSelection>(
            get: {
                self.tabSelection ?? .search
            },
            set: { newValue in
                self.tabSelection = newValue
            }
        )
    }

    func presentAddToPlaylist(_ video: Video) {
        videoToAddToPlaylist = video
        presentingAddToPlaylist = true
    }

    func presentEditPlaylistForm(_ playlist: Playlist?) {
        editedPlaylist = playlist
        presentingPlaylistForm = editedPlaylist != nil
    }

    func presentNewPlaylistForm() {
        editedPlaylist = nil
        presentingPlaylistForm = true
    }

    func presentUnsubscribeAlert(_ channel: Channel, subscriptions: SubscriptionsModel) {
        channelToUnsubscribe = channel
        alert = Alert(
            title: Text(
                "Are you sure you want to unsubscribe from \(channelToUnsubscribe.name)?"
            ),
            primaryButton: .destructive(Text("Unsubscribe")) { [weak self] in
                if let id = self?.channelToUnsubscribe.id {
                    subscriptions.unsubscribe(id)
                }
            },
            secondaryButton: .cancel()
        )
        presentingAlert = true
    }

    func hideKeyboard() {
        #if os(iOS)
            UIApplication.shared.sendAction(#selector(UIResponder.resignFirstResponder), to: nil, from: nil, for: nil)
        #endif
    }

    func presentAlert(title: String, message: String) {
        alert = Alert(title: Text(title), message: Text(message))
        presentingAlert = true
    }

    func presentShareSheet(_ url: URL) {
        shareURL = url
        presentingShareSheet = true
    }
}

typealias TabSelection = NavigationModel.TabSelection