Tusker/Tusker/Screens/Main/MainTabBarViewController.swift

//
//  MainTabBarViewController.swift
//  Tusker
//
//  Created by Shadowfacts on 8/21/18.
//  Copyright © 2018 Shadowfacts. All rights reserved.
//

import UIKit
import ComposeUI

@available(iOS, obsoleted: 18.0)
class MainTabBarViewController: BaseMainTabBarViewController {
    
    private var composePlaceholder: UIViewController!
    
    var currentTab: Tab {
        return Tab(rawValue: selectedIndex)!
    }

    override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
        if UIDevice.current.userInterfaceIdiom == .phone {
            return .portrait
        } else {
            return .all
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        stateRestorationLogger.info("MainTabBarViewController: viewDidLoad, selectedIndex=\(self.selectedIndex, privacy: .public)")

        self.delegate = self
        
        composePlaceholder = UIViewController()
        composePlaceholder.title = "Compose"
        composePlaceholder.tabBarItem.image = UIImage(systemName: "pencil")
        
        viewControllers = [
            embedInNavigationController(Tab.timelines.createViewController(mastodonController)),
            embedInNavigationController(Tab.notifications.createViewController(mastodonController)),
            composePlaceholder,
            embedInNavigationController(Tab.explore.createViewController(mastodonController)),
            embedInNavigationController(Tab.myProfile.createViewController(mastodonController)),
        ]
        
        #if !os(visionOS)
        setupFastAccountSwitcher()
        #endif
        
        tabBar.isSpringLoaded = true
        
        view.backgroundColor = .appBackground
    }
    
    func select(tab: Tab, dismissPresented: Bool, animated: Bool, completion: (() -> Void)? = nil) {
        if tab == .compose {
            compose(editing: nil, completion: completion)
        } else {
            // when switching tabs, dismiss the currently presented VC
            // otherwise the selected tab changes behind the presented VC
            if presentedViewController != nil && dismissPresented {
                dismiss(animated: animated) {
                    stateRestorationLogger.info("MainTabBarViewController: selecting \(String(describing: tab), privacy: .public)")
                    self.selectedIndex = tab.rawValue
                    completion?()
                }
            } else {
                stateRestorationLogger.info("MainTabBarViewController: selecting \(String(describing: tab), privacy: .public)")
                selectedIndex = tab.rawValue
                completion?()
            }
        }
    }
    
    @objc func handleComposeKeyCommand() {
        compose(editing: nil)
    }
    
    func embedInNavigationController(_ vc: UIViewController) -> UINavigationController {
        if let vc = vc as? UINavigationController {
            return vc
        } else {
            let nav = EnhancedNavigationViewController(rootViewController: vc)
            return nav
        }
    }
    
    func setViewController(_ viewController: UIViewController, forTab tab: Tab) {
        viewControllers![tab.rawValue] = viewController
    }
    
    func viewController(for tab: Tab) -> UIViewController {
        return viewControllers![tab.rawValue]
    }
}

extension MainTabBarViewController {
    enum Tab: Int, Hashable, CaseIterable {
        case timelines
        case notifications
        case compose
        case explore
        case myProfile
        
        @MainActor
        func createViewController(_ mastodonController: MastodonController) -> UIViewController {
            switch self {
            case .timelines:
                return TimelinesPageViewController(mastodonController: mastodonController)
            case .notifications:
                return NotificationsPageViewController(mastodonController: mastodonController)
            case .compose:
                return ComposeHostingController(draft: nil, mastodonController: mastodonController)
            case .explore:
                return ExploreViewController(mastodonController: mastodonController)
            case .myProfile:
                return MyProfileViewController(mastodonController: mastodonController)
            }
        }
    }
    
    private func getTabController(tab: Tab) -> UIViewController? {
        if tab == .compose {
            return nil
        } else {
            // viewWControllers array is setup in viewDidLoad
            loadViewIfNeeded()
            return viewControllers![tab.rawValue]
        }
    }
}

extension MainTabBarViewController: UITabBarControllerDelegate {
    func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
        if viewController == composePlaceholder {
            compose(editing: nil)
            return false
        }
        if selectedIndex != NSNotFound,
           viewController == viewControllers![selectedIndex],
           let nav = viewController as? UINavigationController,
           nav.viewControllers.count == 1,
           let scrollableVC = nav.viewControllers.first as? TabBarScrollableViewController {
            scrollableVC.tabBarScrollToTop()
            return false
        }
        return true
    }
}

extension MainTabBarViewController: TuskerRootViewController {
    func select(route: TuskerRoute, animated: Bool, completion: (() -> Void)?) {
        switch route {
        case .timelines:
            select(tab: .timelines, dismissPresented: true, animated: animated, completion: completion)
        case .notifications:
            select(tab: .notifications, dismissPresented: true, animated: animated, completion: completion)
        case .myProfile:
            select(tab: .myProfile, dismissPresented: true, animated: animated, completion: completion)
        case .explore:
            select(tab: .explore, dismissPresented: true, animated: animated, completion: completion)
        case .bookmarks:
            select(tab: .explore, dismissPresented: true, animated: animated, completion: completion)
            getNavigationController().pushViewController(BookmarksViewController(mastodonController: mastodonController), animated: animated)
        case .list(id: let id):
            select(tab: .explore, dismissPresented: true, animated: animated, completion: completion)
            if let list = mastodonController.getCachedList(id: id) {
                let nav = getNavigationController()
                _ = nav.popToRootViewController(animated: animated)
                nav.pushViewController(ListTimelineViewController(for: list, mastodonController: mastodonController), animated: animated)
            }
        }
    }
    
    func getNavigationDelegate() -> TuskerNavigationDelegate? {
        return self
    }
    
    func getNavigationController() -> NavigationControllerProtocol {
        return (selectedViewController as! UINavigationController)
    }
    
    func performSearch(query: String) {
        guard let exploreNavController = getTabController(tab: .explore) as? UINavigationController,
              let exploreController = exploreNavController.viewControllers.first as? ExploreViewController else {
            return
        }
        
        select(tab: .explore, dismissPresented: true, animated: false)
        exploreNavController.popToRootViewController(animated: false)
        
        // setting searchController.isActive directly doesn't work until the view has loaded/appeared for the first time
        if exploreController.isViewLoaded {
            exploreController.searchController.isActive = true
        } else {
            exploreController.searchControllerStatusOnAppearance = true
            // we still need to load the view so that we can setup the search query
            exploreController.loadViewIfNeeded()
        }
        
        exploreController.searchController.searchBar.text = query
        exploreController.resultsController.performSearch(query: query)
    }
    
    func presentPreferences(completion: (() -> Void)?) -> PreferencesNavigationController? {
        let vc = PreferencesNavigationController(mastodonController: mastodonController)
        present(vc, animated: true, completion: completion)
        return vc
    }
}

extension MainTabBarViewController: AccountSwitchableViewController {
    var isFastAccountSwitcherActive: Bool {
        #if os(visionOS)
        return false
        #else
        if let fastAccountSwitcher {
            return !fastAccountSwitcher.view.isHidden
        } else {
            return false
        }
        #endif
    }
}