//
//  NotificationsPageViewController.swift
//  Tusker
//
//  Created by Shadowfacts on 9/13/19.
//  Copyright © 2019 Shadowfacts. All rights reserved.
//

import UIKit
import Pachyderm
import TuskerPreferences

class NotificationsPageViewController: SegmentedPageViewController<NotificationsPageViewController.Page> {
    
    weak var mastodonController: MastodonController!

    var initialMode: NotificationsMode?
    
    private lazy var announcementsButton: UIButton = {
        #if os(visionOS)
        var config = UIButton.Configuration.borderedProminent()
        #else
        var config = UIButton.Configuration.plain()
        // We don't want a background for this button, even when accessibility button shapes are enabled, because it's in the navbar.
        config.background.backgroundColor = .clear
        #endif
        config.image = UIImage(systemName: "megaphone.fill")
        config.contentInsets = .zero
        let button = UIButton(configuration: config)
        button.addTarget(self, action: #selector(announcementsButtonPresesd), for: .touchUpInside)
        return button
    }()
    private var unreadAnnouncements: AnnouncementsCollection?
    
    init(initialMode: NotificationsMode? = nil, mastodonController: MastodonController) {
        self.initialMode = initialMode
        self.mastodonController = mastodonController
        
        super.init(pages: [.all, .mentions]) { page in
            let vc = NotificationsCollectionViewController(allowedTypes: page.allowedTypes, mastodonController: mastodonController)
            vc.title = page.title
            vc.userActivity = page.userActivity(accountID: mastodonController.accountInfo!.id)
            vc.updatesNotificationsMarker = page == .all
            return vc
        }
        
        title = Page.all.title
        tabBarItem.image = UIImage(systemName: "bell.fill")
        navigationItem.rightBarButtonItem = UIBarButtonItem(customView: announcementsButton)
        announcementsButton.isHidden = true
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        selectMode(initialMode ?? Preferences.shared.defaultNotificationsMode)
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        
        Task {
            await checkForAnnouncements()
        }
    }
    
    func selectMode(_ mode: NotificationsMode) {
        let page: Page
        switch mode {
        case .allNotifications:
            page = .all
        case .mentionsOnly:
            page = .mentions
        }
        selectPage(page, animated: false)
    }
    
    private func checkForAnnouncements() async {
        guard mastodonController.instanceFeatures.instanceAnnouncements else {
            navigationItem.rightBarButtonItem = nil
            return
        }
        let announcements: [Announcement]
        do {
            (announcements, _) = try await mastodonController.run(Announcement.all())
        } catch {
            Logging.general.error("Error fetching announcements: \(String(describing: error))")
            return
        }
        let unread = announcements.filter { $0.read == false }
        if unread.isEmpty {
            unreadAnnouncements = nil
            if #available(iOS 17.0, *) {
                announcementsButton.imageView!.addSymbolEffect(.disappear)
            } else {
                UIView.animate(withDuration: 0.2, delay: 0.1, options: .curveEaseInOut) {
                    self.announcementsButton.transform = CGAffineTransform(scaleX: 0.8, y: 0.8)
                    self.announcementsButton.layer.opacity = 0
                } completion: { _ in
                    self.announcementsButton.transform = .identity
                    self.announcementsButton.layer.opacity = 1
                }
            }
        } else {
            announcementsButton.isHidden = false
            announcementsButton.layer.opacity = 1
            unreadAnnouncements = AnnouncementsCollection(announcements: unread)
            if #available(iOS 17.0, *) {
                // make sure to remove the .disappear effect, which stays around indefinitely
                announcementsButton.imageView!.removeAllSymbolEffects()
                announcementsButton.imageView!.addSymbolEffect(.bounce)
            } else {
                UIView.animate(withDuration: 0.2, delay: 0.1, options: .curveEaseInOut) {
                    self.announcementsButton.transform = CGAffineTransform(scaleX: 1.2, y: 1.2)
                } completion: { _ in
                    UIView.animate(withDuration: 0.2, delay: 0, options: .curveEaseInOut) {
                        self.announcementsButton.transform = .identity
                    }
                }
            }
        }
    }
    
    @objc private func announcementsButtonPresesd() {
        guard let unreadAnnouncements else {
            return
        }
        show(AnnouncementsHostingController(announcements: unreadAnnouncements, mastodonController: mastodonController), sender: nil)
    }
}

extension NotificationsPageViewController {
    enum Page: SegmentedPageViewControllerPage {
        case all
        case mentions
        
        var title: String {
            switch self {
            case .all:
                return NSLocalizedString("Notifications", comment: "notifications tab title")
            case .mentions:
                return NSLocalizedString("Mentions", comment: "mentions tab title")
            }
        }
        
        var segmentedControlTitle: String {
            title
        }
        
        var allowedTypes: [Pachyderm.Notification.Kind] {
            switch self {
            case .all:
                var set = Set(Pachyderm.Notification.Kind.allCases)
                set.remove(.unknown)
                return Array(set)
            case .mentions:
                return [.mention]
            }
        }
        
        @MainActor
        func userActivity(accountID: String) -> NSUserActivity {
            switch self {
            case .all:
                return UserActivityManager.checkNotificationsActivity(mode: .allNotifications, accountID: accountID)
            case .mentions:
                return UserActivityManager.checkNotificationsActivity(mode: .mentionsOnly, accountID: accountID)
            }
        }
    }

}

extension NotificationsPageViewController: StateRestorableViewController {
    func stateRestorationActivity() -> NSUserActivity? {
        return currentPage.userActivity(accountID: mastodonController.accountInfo!.id)
    }
}