//
//  NotificationView+ViewModel.swift
//  
//
//  Created by MainasuK on 2022-1-21.
//

import UIKit
import Combine
import Meta
import MastodonSDK
import MastodonAsset
import MastodonLocalization
import MastodonExtension
import MastodonCore
import CoreData
import CoreDataStack

extension NotificationView {
    public final class ViewModel: ObservableObject {
        public var disposeBag = Set<AnyCancellable>()
        public var objects = Set<NotificationNxt>()

        @Published public var context: AppContext?
        @Published public var authContext: AuthContext?

        @Published public var type: MastodonNotificationType?
        @Published public var notificationIndicatorText: MetaContent?

        @Published public var authorAvatarImage: UIImage?
        @Published public var authorAvatarImageURL: URL?
        @Published public var authorName: MetaContent?
        @Published public var authorUsername: String?
        
        @Published public var isMyself = false
        @Published public var isMuting = false
        @Published public var isBlocking = false
        @Published public var isTranslated = false
        @Published public var isFollowed = false
        
        @Published public var timestamp: Date?
        
        @Published public var visibility: MastodonVisibility = .public

        @Published public var followRequestState = MastodonFollowRequestState(state: .none)
        @Published public var transientFollowRequestState = MastodonFollowRequestState(state: .none)
        
        let timestampUpdatePublisher = Timer.publish(every: 1.0, on: .main, in: .common)
            .autoconnect()
            .share()
            .eraseToAnyPublisher()
    }
}

extension NotificationView.ViewModel {
    func bind(notificationView: NotificationView) {
        bindAuthor(notificationView: notificationView)
        bindAuthorMenu(notificationView: notificationView)
        bindFollowRequest(notificationView: notificationView)

        $context
            .assign(to: \.context, on: notificationView.statusView.viewModel)
            .store(in: &disposeBag)
        $authContext
            .assign(to: \.authContext, on: notificationView.statusView.viewModel)
            .store(in: &disposeBag)
        $authContext
            .assign(to: \.authContext, on: notificationView.quoteStatusView.viewModel)
            .store(in: &disposeBag)
    }
 
    private func bindAuthor(notificationView: NotificationView) {
        // avatar
        Publishers.CombineLatest(
            $authorAvatarImage,
            $authorAvatarImageURL
        )
        .sink { image, url in
            let configuration: AvatarImageView.Configuration = {
                if let image = image {
                    return AvatarImageView.Configuration(image: image)
                } else {
                    return AvatarImageView.Configuration(url: url)
                }
            }()
            notificationView.avatarButton.avatarImageView.configure(configuration: configuration)
            notificationView.avatarButton.avatarImageView.configure(cornerConfiguration: .init(corner: .fixed(radius: 12)))
        }
        .store(in: &disposeBag)
        // name
        $authorName
            .sink { metaContent in
                let metaContent = metaContent ?? PlaintextMetaContent(string: " ")
                notificationView.authorNameLabel.configure(content: metaContent)
            }
            .store(in: &disposeBag)
        // username
        $authorUsername
            .map { text -> String in
                guard let text = text else { return "" }
                return "@\(text)"
            }
            .sink { username in
                let metaContent = PlaintextMetaContent(string: username)
                notificationView.authorUsernameLabel.configure(content: metaContent)
            }
            .store(in: &disposeBag)
        // timestamp
        let formattedTimestamp = Publishers.CombineLatest(
            $timestamp,
            timestampUpdatePublisher.prepend(Date()).eraseToAnyPublisher()
        )
        .map { timestamp, _ in
            timestamp?.localizedTimeAgoSinceNow ?? ""
        }
        .removeDuplicates()

        formattedTimestamp
            .sink { timestamp in
                notificationView.dateLabel.configure(content: PlaintextMetaContent(string: timestamp))
            }
            .store(in: &disposeBag)

        $visibility
            .sink { visibility in
                notificationView.visibilityIconImageView.image = visibility.image
            }
            .store(in: &disposeBag)

        // notification type indicator
        $notificationIndicatorText
            .sink { text in
                if let text = text {
                    notificationView.notificationTypeIndicatorLabel.configure(content: text)
                } else {
                    notificationView.notificationTypeIndicatorLabel.reset()
                }
            }
            .store(in: &disposeBag)

        Publishers.CombineLatest4(
            $authorName,
            $authorUsername,
            $notificationIndicatorText,
            formattedTimestamp
        )
        .sink { name, username, type, timestamp in
            notificationView.accessibilityLabel = [
                "\(name?.string ?? "") \(type?.string ?? "")",
                username.map { "@\($0)" } ?? "",
                timestamp
            ].joined(separator: ", ")
            if !notificationView.statusView.isHidden {
                notificationView.accessibilityLabel! += ", " + (notificationView.statusView.accessibilityLabel ?? "")
            }
            if !notificationView.quoteStatusViewContainerView.isHidden {
                notificationView.accessibilityLabel! += ", " + (notificationView.quoteStatusView.accessibilityLabel ?? "")
            }
        }
        .store(in: &disposeBag)

        Publishers.CombineLatest(
            $authorAvatarImage,
            $type
        )
        .sink { avatarImage, type in
            var actions = [UIAccessibilityCustomAction]()

            // these notifications can be directly actioned to view the profile
            if type != .follow, type != .followRequest {
                actions.append(
                    UIAccessibilityCustomAction(
                        name: L10n.Common.Controls.Status.showUserProfile,
                        image: avatarImage
                    ) { [weak notificationView] _ in
                        guard let notificationView = notificationView, let delegate = notificationView.delegate else { return false }
                        delegate.notificationView(notificationView, authorAvatarButtonDidPressed: notificationView.avatarButton)
                        return true
                    }
                )
            }

            if type == .followRequest {
                actions.append(
                    UIAccessibilityCustomAction(
                        name: L10n.Common.Controls.Actions.confirm,
                        image: Asset.Editing.checkmark20.image
                    ) { [weak notificationView] _ in
                        guard let notificationView = notificationView, let delegate = notificationView.delegate else { return false }
                        delegate.notificationView(notificationView, acceptFollowRequestButtonDidPressed: notificationView.acceptFollowRequestButton)
                        return true
                    }
                )

                actions.append(
                    UIAccessibilityCustomAction(
                        name: L10n.Common.Controls.Actions.delete,
                        image: Asset.Circles.forbidden20.image
                    ) { [weak notificationView] _ in
                        guard let notificationView = notificationView, let delegate = notificationView.delegate else { return false }
                        delegate.notificationView(notificationView, rejectFollowRequestButtonDidPressed: notificationView.rejectFollowRequestButton)
                        return true
                    }
                )
            }

            notificationView.notificationActions = actions
        }
        .store(in: &disposeBag)
    }
    
    private func bindAuthorMenu(notificationView: NotificationView) {
        Publishers.CombineLatest4(
            $authorName,
            $isMuting,
            $isBlocking,
            Publishers.CombineLatest3(
                $isMyself,
                $isTranslated,
                $isFollowed
            )
        )
        .sink { [weak self] authorName, isMuting, isBlocking, isMyselfIsTranslatedIsFollowed in
            guard let name = authorName?.string else {
                notificationView.menuButton.menu = nil
                return
            }
            
            let (isMyself, isTranslated, isFollowed) = isMyselfIsTranslatedIsFollowed
            
            lazy var instanceConfigurationV2: Mastodon.Entity.V2.Instance.Configuration? = {
                guard
                    let self = self,
                    let context = self.context,
                    let authContext = self.authContext
                else { return nil }
                
                var configuration: Mastodon.Entity.V2.Instance.Configuration? = nil
                context.managedObjectContext.performAndWait {
                    let authentication = authContext.mastodonAuthenticationBox.authentication
                    configuration = authentication.instance(in: context.managedObjectContext)?.configurationV2
                }
                return configuration
            }()
            
            let menuContext = NotificationView.AuthorMenuContext(
                name: name,
                isMuting: isMuting,
                isBlocking: isBlocking,
                isMyself: isMyself,
                isBookmarking: false,    // no bookmark action display for notification item
                isFollowed: isFollowed,
                isTranslationEnabled: instanceConfigurationV2?.translation?.enabled == true,
                isTranslated: isTranslated,
                statusLanguage: ""
            )
            let (menu, actions) = notificationView.setupAuthorMenu(menuContext: menuContext)
            notificationView.menuButton.menu = menu
            notificationView.authorActions = actions
            notificationView.menuButton.showsMenuAsPrimaryAction = true
            
            notificationView.menuButton.isHidden = menuContext.isMyself
        }
        .store(in: &disposeBag)
    }
    
    private func bindFollowRequest(notificationView: NotificationView) {
        Publishers.CombineLatest(
            $followRequestState,
            $transientFollowRequestState
        )
        .sink { followRequestState, transientFollowRequestState in
            switch followRequestState.state {
            case .isAccept:
                notificationView.rejectFollowRequestButtonShadowBackgroundContainer.isHidden = true
                notificationView.acceptFollowRequestButton.isUserInteractionEnabled = false
                notificationView.acceptFollowRequestButton.setImage(nil, for: .normal)
                notificationView.acceptFollowRequestButton.setTitle(L10n.Scene.Notification.FollowRequest.accepted, for: .normal)
            case .isReject:
                notificationView.acceptFollowRequestButtonShadowBackgroundContainer.isHidden = true
                notificationView.rejectFollowRequestButton.isUserInteractionEnabled = false
                notificationView.rejectFollowRequestButton.setImage(nil, for: .normal)
                notificationView.rejectFollowRequestButton.setTitle(L10n.Scene.Notification.FollowRequest.rejected, for: .normal)
            default:
                break
            }
            
            let state = transientFollowRequestState.state
            if state == .isAccepting {
                notificationView.acceptFollowRequestActivityIndicatorView.startAnimating()
                notificationView.acceptFollowRequestButton.tintColor = .clear
                notificationView.acceptFollowRequestButton.setTitleColor(.clear, for: .normal)
            } else {
                notificationView.acceptFollowRequestActivityIndicatorView.stopAnimating()
                notificationView.acceptFollowRequestButton.tintColor = .white
                notificationView.acceptFollowRequestButton.setTitleColor(.white, for: .normal)
            }
            if state == .isRejecting {
                notificationView.rejectFollowRequestActivityIndicatorView.startAnimating()
                notificationView.rejectFollowRequestButton.tintColor = .clear
                notificationView.rejectFollowRequestButton.setTitleColor(.clear, for: .normal)
            } else {
                notificationView.rejectFollowRequestActivityIndicatorView.stopAnimating()
                notificationView.rejectFollowRequestButton.tintColor = .black
                notificationView.rejectFollowRequestButton.setTitleColor(.black, for: .normal)
            }
            
            UIView.animate(withDuration: 0.3) {
                if state == .isAccept {
                    notificationView.rejectFollowRequestButtonShadowBackgroundContainer.isHidden = true
                }
                if state == .isReject {
                    notificationView.acceptFollowRequestButtonShadowBackgroundContainer.isHidden = true
                }
            }
        }
        .store(in: &disposeBag)
    }

}