//
//  ProfileView+VPN.swift
//  Passepartout
//
//  Created by Davide De Rosa on 3/18/22.
//  Copyright (c) 2022 Davide De Rosa. All rights reserved.
//
//  https://github.com/passepartoutvpn
//
//  This file is part of Passepartout.
//
//  Passepartout is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  Passepartout is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with Passepartout.  If not, see <http://www.gnu.org/licenses/>.
//

import SwiftUI
import PassepartoutCore

extension ProfileView {
    struct VPNSection: View {
        @ObservedObject private var appManager: AppManager

        @ObservedObject private var profileManager: ProfileManager

        @ObservedObject private var providerManager: ProviderManager

        @ObservedObject private var vpnManager: VPNManager

        @ObservedObject private var currentVPNState: VPNManager.ObservableState

        @ObservedObject private var productManager: ProductManager
        
        @ObservedObject private var currentProfile: ObservableProfile

        @State private var isLocallyEnabled = false

        @State private var canToggle = true

        private var isEnabled: Binding<Bool> {
            .init {
                isLocallyEnabled
            } set: {
                isLocallyEnabled = $0
                toggleVPNAndDonateIntents()
            }
        }

        private let isLoading: Bool

        private var isActiveProfile: Bool {
            profileManager.isCurrentProfileActive()
        }
        
        private var isEligibleForSiri: Bool {
            productManager.isEligible(forFeature: .siriShortcuts)
        }
        
        init(currentProfile: ObservableProfile, isLoading: Bool) {
            appManager = .shared
            profileManager = .shared
            providerManager = .shared
            vpnManager = .shared
            currentVPNState = .shared
            productManager = .shared
            self.currentProfile = currentProfile
            self.isLoading = isLoading
        }
        
        var body: some View {
            if !isLoading {
                if isActiveProfile {
                    activeView
                } else {
                    inactiveSubview
                }
            } else {
                loadingView
            }
        }
        
        private var headerView: some View {
            Text(Unlocalized.VPN.vpn)
        }
        
        private var activeView: some View {
            Section(
                header: headerView,
                footer: Text(L10n.Profile.Sections.Vpn.footer)
                    .xxxThemeTruncation()
            ) {
                Toggle(vpnToggleString, isOn: isEnabled)
                    .onAppear {
                        isLocallyEnabled = currentVPNState.isEnabled
                    }.onChange(of: currentVPNState.isEnabled) {
                        isLocallyEnabled = $0
                    }.disabled(!canToggle)

                Text(L10n.Profile.Items.ConnectionStatus.caption)
                    .withTrailingText(currentVPNState.localizedStatusDescription(
                        withErrors: true,
                        dataCountIfAvailable: true
                    ))
            }
        }

        private var vpnToggleString: String {
//            let V = L10n.Profile.Items.Vpn.self
//            return currentVPNState.isEnabled ? V.TurnOff.caption : V.TurnOn.caption
            L10n.Global.Strings.enabled
        }

        private var inactiveSubview: some View {
            Section(
                header: headerView
            ) {
                Button(L10n.Profile.Items.UseProfile.caption) {
                    withAnimation {
                        profileManager.activateCurrentProfile()

                        // IMPORTANT: save immediately to keep in sync with VPN status
                        appManager.activeProfileId = profileManager.activeHeader?.id
                    }
                    Task {
                        await vpnManager.disable()
                    }
                }
            }
        }
        
        private var loadingView: some View {
            Section(
                header: headerView
            ) {
                ProgressView()
            }
        }
        
        private func toggleVPNAndDonateIntents() {
            guard vpnManager.toggle() else {
                return
            }
            
            // rate limit toggle actions
            canToggle = false
            DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(Constants.RateLimit.vpnToggle)) {
                canToggle = true
            }

            // eligibility: donate intents if eligible for Siri
            if isEligibleForSiri {
                pp_log.debug("Donating connection intents...")

                IntentDispatcher.donateEnableVPN()
                IntentDispatcher.donateDisableVPN()
                IntentDispatcher.donateConnection(
                    with: currentProfile.value,
                    providerManager: providerManager
                )
            }
        }
    }
}