//
//  MainSplitViewController.swift
//  Tusker
//
//  Created by Shadowfacts on 6/23/20.
//  Copyright © 2020 Shadowfacts. All rights reserved.
//

import UIKit

@available(iOS 14.0, *)
class MainSplitViewController: UISplitViewController {

    weak var mastodonController: MastodonController!
    
    private var sidebar: MainSidebarViewController!
    
    private var detailViewControllers: [MainSidebarViewController.Item: UIViewController] = [:]
    
    init(mastodonController: MastodonController) {
        self.mastodonController = mastodonController
        
        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 = false
        showsSecondaryOnlyButton = false
        
        sidebar = MainSidebarViewController(mastodonController: mastodonController)
        sidebar.sidebarDelegate = self
        setViewController(sidebar, for: .primary)
        select(item: .tab(.timelines))
        setViewController(MainTabBarViewController(mastodonController: mastodonController), for: .compact)
    }
    
    func select(item: MainSidebarViewController.Item) {
        let itemController = getOrCreateDetailViewController(item: item)
        setViewController(itemController, for: .secondary)
    }
    
    func getOrCreateDetailViewController(item: MainSidebarViewController.Item) -> UIViewController? {
        if let existing = detailViewControllers[item] {
            return existing
        } else {
            guard let new = item.createRootViewController(mastodonController) else { return nil }
            let nav = EnhancedNavigationViewController(rootViewController: new)
            
            // Prevents the navigation bar from going transparent when switching sidebar sections.
            nav.navigationBar.scrollEdgeAppearance = nav.navigationBar.standardAppearance
            
            detailViewControllers[item] = nav
            return nav
        }
    }

}

@available(iOS 14.0, *)
extension MainSplitViewController: MainSidebarViewControllerDelegate {
    func sidebarRequestPresentCompose(_ sidebarViewController: MainSidebarViewController) {
        presentCompose()
    }
    
    func sidebar(_ sidebarViewController: MainSidebarViewController, didSelectItem item: MainSidebarViewController.Item) {
        select(item: item)
    }
}

@available(iOS 14.0, *)
fileprivate extension MainSidebarViewController.Item {
    func createRootViewController(_ mastodonController: MastodonController) -> UIViewController? {
        switch self {
        case let .tab(tab):
            return tab.createViewController(mastodonController)
        case .search:
            return SearchViewController(mastodonController: mastodonController)
        case .bookmarks:
            return BookmarksTableViewController(mastodonController: mastodonController)
        case let .list(list):
            return ListTimelineViewController(for: list, mastodonController: mastodonController)
        case let .savedHashtag(hashtag):
            return HashtagTimelineViewController(for: hashtag, mastodonController: mastodonController)
        case let .savedInstance(url):
            return InstanceTimelineViewController(for: url, parentMastodonController: mastodonController)
        default:
            return nil
        }
    }
}

@available(iOS 14.0, *)
extension MainSplitViewController: TuskerRootViewController {
    func presentCompose() {
        let compose = ComposeViewController(mastodonController: mastodonController)
        let navigationController = EnhancedNavigationViewController(rootViewController: compose)
        navigationController.presentationController?.delegate = compose
        present(navigationController, animated: true)
    }
    
    func select(tab: MainTabBarViewController.Tab) {
        if tab == .compose {
            presentCompose()
        } else {
            select(item: .tab(tab))
        }
    }
}