//
//  NotificationSection.swift
//  Mastodon
//
//  Created by sxiaojian on 2021/4/13.
//

import Combine
import CoreData
import CoreDataStack
import Foundation
import MastodonSDK
import UIKit
import MetaTextKit
import MastodonMeta

enum NotificationSection: Equatable, Hashable {
    case main
}

extension NotificationSection {
    static func tableViewDiffableDataSource(
        for tableView: UITableView,
        dependency: NeedsDependency,
        managedObjectContext: NSManagedObjectContext,
        delegate: NotificationTableViewCellDelegate,
        statusTableViewCellDelegate: StatusTableViewCellDelegate
    ) -> UITableViewDiffableDataSource<NotificationSection, NotificationItem> {
        UITableViewDiffableDataSource(tableView: tableView) {
            [weak delegate, weak dependency]
            (tableView, indexPath, notificationItem) -> UITableViewCell? in
            guard let dependency = dependency else { return nil }
            switch notificationItem {
            case .notification(let objectID, let attribute):
                guard let notification = try? managedObjectContext.existingObject(with: objectID) as? MastodonNotification,
                      !notification.isDeleted
                else { return UITableViewCell() }

                let cell = tableView.dequeueReusableCell(withIdentifier: String(describing: NotificationStatusTableViewCell.self), for: indexPath) as! NotificationStatusTableViewCell
                configure(
                    tableView: tableView,
                    cell: cell,
                    notification: notification,
                    dependency: dependency,
                    attribute: attribute
                )
                cell.delegate = delegate
                cell.isAccessibilityElement = true
                NotificationSection.configureStatusAccessibilityLabel(cell: cell)
                return cell
                
            case .notificationStatus(objectID: let objectID, attribute: let attribute):
                guard let notification = try? managedObjectContext.existingObject(with: objectID) as? MastodonNotification,
                      !notification.isDeleted,
                      let status = notification.status,
                      let requestUserID = dependency.context.authenticationService.activeMastodonAuthenticationBox.value?.userID
                else { return UITableViewCell() }
                let cell = tableView.dequeueReusableCell(withIdentifier: String(describing: StatusTableViewCell.self), for: indexPath) as! StatusTableViewCell
                
                // configure cell
                StatusSection.configureStatusTableViewCell(
                    cell: cell,
                    tableView: tableView,
                    timelineContext: .notifications,
                    dependency: dependency,
                    readableLayoutFrame: tableView.readableContentGuide.layoutFrame,
                    status: status,
                    requestUserID: requestUserID,
                    statusItemAttribute: attribute
                )
                cell.statusView.headerContainerView.isHidden = true     // set header hide
                cell.statusView.actionToolbarContainer.isHidden = true  // set toolbar hide
                cell.statusView.actionToolbarPlaceholderPaddingView.isHidden = false
                cell.delegate = statusTableViewCellDelegate
                cell.isAccessibilityElement = true
                StatusSection.configureStatusAccessibilityLabel(cell: cell)
                return cell

            case .bottomLoader:
                let cell = tableView.dequeueReusableCell(withIdentifier: String(describing: TimelineBottomLoaderTableViewCell.self)) as! TimelineBottomLoaderTableViewCell
                cell.startAnimating()
                return cell
            }
        }
    }
}

extension NotificationSection {
    static func configure(
        tableView: UITableView,
        cell: NotificationStatusTableViewCell,
        notification: MastodonNotification,
        dependency: NeedsDependency,
        attribute: Item.StatusAttribute
    ) {
        // configure author
        cell.configure(
            with: AvatarConfigurableViewConfiguration(
                avatarImageURL: notification.account.avatarImageURL()
            )
        )
        
        func createActionImage() -> UIImage? {
            return UIImage(
                systemName: notification.notificationType.actionImageName,
                withConfiguration: UIImage.SymbolConfiguration(
                    pointSize: 12, weight: .semibold
                )
            )?
                .withTintColor(.systemBackground)
                .af.imageAspectScaled(toFit: CGSize(width: 14, height: 14))
        }
        
        cell.avatarButton.badgeImageView.backgroundColor = notification.notificationType.color
        cell.avatarButton.badgeImageView.image = createActionImage()
        cell.traitCollectionDidChange
            .receive(on: DispatchQueue.main)
            .sink { [weak cell] in
                guard let cell = cell else { return }
                cell.avatarButton.badgeImageView.image = createActionImage()
            }
            .store(in: &cell.disposeBag)
        
        // configure author name, notification description, timestamp
        let nameText = notification.account.displayNameWithFallback
        let titleLabelText: String = {
            switch notification.notificationType {
            case .favourite:            return L10n.Scene.Notification.userFavoritedYourPost(nameText)
            case .follow:               return L10n.Scene.Notification.userFollowedYou(nameText)
            case .followRequest:        return L10n.Scene.Notification.userRequestedToFollowYou(nameText)
            case .mention:              return L10n.Scene.Notification.userMentionedYou(nameText)
            case .poll:                 return L10n.Scene.Notification.userYourPollHasEnded(nameText)
            case .reblog:               return L10n.Scene.Notification.userRebloggedYourPost(nameText)
            default:                    return ""
            }
        }()
        
        do {
            let nameContent = MastodonContent(content: nameText, emojis: notification.account.emojiMeta)
            let nameMetaContent = try MastodonMetaContent.convert(document: nameContent)
            
            let mastodonContent = MastodonContent(content: titleLabelText, emojis: notification.account.emojiMeta)
            let metaContent = try MastodonMetaContent.convert(document: mastodonContent)
            
            cell.titleLabel.configure(content: metaContent)
            
            if let nameRange = metaContent.string.range(of: nameMetaContent.string) {
                let nsRange = NSRange(nameRange, in: metaContent.string)
                cell.titleLabel.textStorage.addAttributes([
                    .font: UIFontMetrics(forTextStyle: .headline).scaledFont(for: .systemFont(ofSize: 15, weight: .semibold), maximumPointSize: 20),
                    .foregroundColor: Asset.Colors.brandBlue.color,
                ], range: nsRange)
            }
            
        } catch {
            let metaContent = PlaintextMetaContent(string: titleLabelText)
            cell.titleLabel.configure(content: metaContent)
        }
        
        let createAt = notification.createAt
        cell.timestampLabel.text = createAt.localizedSlowedTimeAgoSinceNow
        AppContext.shared.timestampUpdatePublisher
            .receive(on: DispatchQueue.main)
            .sink { [weak cell] _ in
                guard let cell = cell else { return }
                cell.timestampLabel.text = createAt.localizedSlowedTimeAgoSinceNow
            }
            .store(in: &cell.disposeBag)
        
        // configure follow request (if exist)
        if case .followRequest = notification.notificationType {
            cell.acceptButton.publisher(for: .touchUpInside)
                .sink { [weak cell] _ in
                    guard let cell = cell else { return }
                    cell.delegate?.notificationTableViewCell(cell, notification: notification, acceptButtonDidPressed: cell.acceptButton)
                }
                .store(in: &cell.disposeBag)
            cell.rejectButton.publisher(for: .touchUpInside)
                .sink { [weak cell] _ in
                    guard let cell = cell else { return }
                    cell.delegate?.notificationTableViewCell(cell, notification: notification, rejectButtonDidPressed: cell.rejectButton)
                }
                .store(in: &cell.disposeBag)
            cell.buttonStackView.isHidden = false
        } else {
            cell.buttonStackView.isHidden = true
        }
        
        // configure status (if exist)
        if let status = notification.status {
            let frame = CGRect(
                x: 0,
                y: 0,
                width: tableView.readableContentGuide.layoutFrame.width - NotificationStatusTableViewCell.statusPadding.left - NotificationStatusTableViewCell.statusPadding.right,
                height: tableView.readableContentGuide.layoutFrame.height
            )
            StatusSection.configure(
                cell: cell,
                tableView: tableView,
                timelineContext: .notifications,
                dependency: dependency,
                readableLayoutFrame: frame,
                status: status,
                requestUserID: notification.userID,
                statusItemAttribute: attribute
            )
            cell.statusContainerView.isHidden = false
            cell.containerStackView.alignment = .top
            cell.containerStackViewBottomLayoutConstraint.constant = 0
        } else {
            if case .followRequest = notification.notificationType {
                cell.containerStackView.alignment = .top
            } else {
                cell.containerStackView.alignment = .center
            }
            cell.statusContainerView.isHidden = true
            cell.containerStackViewBottomLayoutConstraint.constant = 5  // 5pt margin when no status view
        }
    }
    
    static func configureStatusAccessibilityLabel(cell: NotificationStatusTableViewCell) {
        // FIXME:
        cell.accessibilityLabel = {
            var accessibilityViews: [UIView?] = []
            accessibilityViews.append(contentsOf: [
                cell.titleLabel,
                cell.timestampLabel,
                cell.statusView
            ])
            if !cell.statusContainerView.isHidden {
                if !cell.statusView.headerContainerView.isHidden {
                    accessibilityViews.append(cell.statusView.headerInfoLabel)
                }
                accessibilityViews.append(contentsOf: [
                    cell.statusView.nameMetaLabel,
                    cell.statusView.dateLabel,
                    cell.statusView.contentMetaText.textView,
                ])
            }
            return accessibilityViews
                .compactMap { $0?.accessibilityLabel }
                .joined(separator: " ")
        }()
    }
}