//
//  NotificationGroup.swift
//  Pachyderm
//
//  Created by Shadowfacts on 9/5/19.
//  Copyright © 2019 Shadowfacts. All rights reserved.
//

import Foundation

public class NotificationGroup {
    public let notificationIDs: [String]
    public let id: String
    public let kind: Notification.Kind
    public let statusState: StatusState?
    
    init?(notifications: [Notification]) {
        guard !notifications.isEmpty else { return nil }
        self.notificationIDs = notifications.map { $0.id }
        self.id = notifications.first!.id
        self.kind = notifications.first!.kind
        if kind == .mention {
            self.statusState = .unknown
        } else {
            self.statusState = nil
        }
    }

    public static func createGroups(notifications: [Notification], only allowedTypes: [Notification.Kind]) -> [NotificationGroup] {
        var groups = [[Notification]]()
        for notification in notifications {
            if allowedTypes.contains(notification.kind) {
                if let lastGroup = groups.last, let firstNotification = lastGroup.first, firstNotification.kind == notification.kind, firstNotification.status?.id == notification.status?.id {
                    groups[groups.count - 1].append(notification)
                    continue
                } else if groups.count >= 2 {
                    let secondToLastGroup = groups[groups.count - 2]
                    if allowedTypes.contains(groups[groups.count - 1][0].kind), let firstNotification = secondToLastGroup.first, firstNotification.kind == notification.kind, firstNotification.status?.id == notification.status?.id {
                        groups[groups.count - 2].append(notification)
                        continue
                    }
                }
            }
            
            groups.append([notification])
        }
        return groups.map {
            NotificationGroup(notifications: $0)!
        }
    }
    
}

extension NotificationGroup: Identifiable {}