//
//  ViewModel.swift
//  dns
//
//  Created by Benjamin Erhart on 14.04.26.
//

import Foundation
import Combine
import NetworkExtension
import OSLog

class ViewModel: NSObject, ObservableObject {

    static let title = "SR2® Cloud DNS"

    // MARK: Public Properties

    @Published
    var blocklist: BlocklistOption = .secure {
        didSet {
            Task {
                manager.dnsSettings = blocklist.settings
                manager.localizedDescription = blocklist.title

                do {
                    try await manager.saveToPreferences()
                }
                catch {
                    log.error("Error storing preferences: \(error)")
                }
            }
        }
    }

    @Published
    var isDnsEnabled = false

    @Published
    var summaryStatus: SummaryStatus = .pending


    // MARK: Private Properties

    private let manager = NEDNSSettingsManager.shared()

    private let log = Logger(subsystem: String(describing: ViewModel.self), category: String(describing: ViewModel.self))


    override init() {
        super.init()

        isDnsEnabled = manager.isEnabled

        Task {
            do {
                try await manager.loadFromPreferences()
            }
            catch {
                log.error("Error loading preferences: \(error)")
            }

            if let settings = manager.dnsSettings {
                for dnsServer in BlocklistOption.allCases {
                    if settings.servers.contains(dnsServer.ipv4) {
                        await MainActor.run {
                            blocklist = dnsServer
                        }

                        break
                    }
                }
            }
            else {
                // Trigger `blocklist.didSet` to store right away, so user has something to select.
                blocklist = blocklist
            }
        }

        Task {
            await fetchServerStatus()
        }
    }


    // MARK: Public Methods

    func fetchServerStatus() async {
        do {
            let (data, _) = try await URLSession.shared.data(for: .init(url: .init(string: "https://status.sr2.uk/index.json")!))

            let status = try JSONDecoder().decode(Status.self, from: data)

            summaryStatus = status.summaryStatus
        }
        catch {
            log.error("Error while checking status: \(error)")
        }
    }
}