//
//  AppSplitViewController.swift
//  Reader
//
//  Created by Shadowfacts on 1/14/22.
//

import UIKit
#if targetEnvironment(macCatalyst)
import AppKit
#endif
import Persistence

class AppSplitViewController: UISplitViewController {
    
    private let fervorController: FervorController
    
    private var secondaryNav: UINavigationController!
    
    override var childForStatusBarHidden: UIViewController? {
        if traitCollection.horizontalSizeClass == .compact {
            return viewController(for: .compact)
        } else {
            return nil
        }
    }
    
    init(fervorController: FervorController) {
        self.fervorController = fervorController
        
        super.init(style: .doubleColumn)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        
        preferredDisplayMode = .oneBesideSecondary
        preferredSplitBehavior = .tile
        presentsWithGesture = true
        showsSecondaryOnlyButton = true
        primaryBackgroundStyle = .sidebar
        maximumPrimaryColumnWidth = 500
        
        let sidebarHome = HomeViewController(fervorController: fervorController)
        sidebarHome.enableStretchyMenu = false
        sidebarHome.itemsDelegate = self
        let sidebarNav = UINavigationController(rootViewController: sidebarHome)
        sidebarNav.navigationBar.prefersLargeTitles = true
        setViewController(sidebarNav, for: .primary)
        
        secondaryNav = UINavigationController()
        #if targetEnvironment(macCatalyst)
        secondaryNav.isNavigationBarHidden = true
        #else
        // the toggle sidebar button only appears if there's a navigation bar
        // so we just make always transparent, rather than disabling it
        let secondaryNavBarAppearance = UINavigationBarAppearance()
        secondaryNavBarAppearance.configureWithTransparentBackground()
        secondaryNav.navigationBar.standardAppearance = secondaryNavBarAppearance
        #endif
        secondaryNav.view.backgroundColor = .appBackground
        setViewController(secondaryNav, for: .secondary)
        
        let home = HomeViewController(fervorController: fervorController)
        home.delegate = self
        let nav = AppNavigationController(rootViewController: home)
        setViewController(nav, for: .compact)
    }
    
    func stateRestorationActivity() -> NSUserActivity? {
        if traitCollection.horizontalSizeClass == .compact {
            let nav = viewController(for: .compact) as! UINavigationController
            let top = nav.topViewController!
            if top is ReadViewController || top is ItemsViewController {
                return top.userActivity
            }
        } else {
            if let read = secondaryNav.topViewController {
                return read.userActivity
            } else {
                let homeNav = viewController(for: .primary) as! UINavigationController
                if homeNav.topViewController is ItemsViewController {
                    return homeNav.topViewController!.userActivity
                }
            }
        }
        return nil
    }
    
    func showItemList(_ type: ItemListType) {
        let column: Column
        if traitCollection.horizontalSizeClass == .compact {
            column = .compact
        } else {
            column = .primary
        }
        let nav = viewController(for: column) as! UINavigationController
        let home = nav.viewControllers.first! as! HomeViewController
        home.selectItem(type)
    }
    
    @discardableResult
    func showItem(_ item: Item) -> ReadViewController {
        if traitCollection.horizontalSizeClass == .compact {
            let nav = viewController(for: .compact) as! UINavigationController
            // todo: should we try to show the right items list?
            while nav.viewControllers.count > 2 {
                if let current = nav.topViewController as? ReadViewController,
                   current.item == item {
                    return current
                } else {
                    nav.popViewController(animated: false)
                }
            }
            let read = ReadViewController(item: item, fervorController: fervorController)
            nav.pushViewController(read, animated: false)
            return read
        } else {
            if let current = secondaryNav.topViewController as? ReadViewController,
               current.item == item {
                return current
            } else {
                let read = ReadViewController(item: item, fervorController: fervorController)
                secondaryNav.setViewControllers([read], animated: false)
                return read
            }
        }
    }

}

extension AppSplitViewController: ItemsViewControllerDelegate {
    func showReadItem(_ item: Item) {
        secondaryNav.setViewControllers([ReadViewController(item: item, fervorController: fervorController)], animated: false)
    }
}

extension AppSplitViewController: HomeViewControllerDelegate {
    func switchToAccount(_ account: LocalData.Account) {
        if let delegate = view.window?.windowScene?.delegate as? SceneDelegate {
            Task { @MainActor in
                await delegate.switchToAccount(account)
            }
        }
    }
}