//
//  AddHostView+Name.swift
//  Passepartout
//
//  Created by Davide De Rosa on 3/18/22.
//  Copyright (c) 2024 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 PassepartoutLibrary
import SwiftUI
import TunnelKitOpenVPN
import TunnelKitWireGuard

extension AddHostView {
    struct NameView: View {
        @ObservedObject private var profileManager: ProfileManager

        private let url: URL

        private let deletingURLOnSuccess: Bool

        private let bindings: AddProfileView.Bindings

        @State private var viewModel = ViewModel()

        @State private var isEnteringCredentials = false

        @FocusState private var focusedField: AddProfileView.Field?

        init(
            url: URL,
            deletingURLOnSuccess: Bool,
            bindings: AddProfileView.Bindings
        ) {
            profileManager = .shared
            self.url = url
            self.deletingURLOnSuccess = deletingURLOnSuccess
            self.bindings = bindings
        }

        var body: some View {
            ZStack {
                hiddenAccountLink
                List {
                    mainView
                }.themeAnimation(on: viewModel)
            }.toolbar {
                themeCloseItem(isPresented: bindings.$isPresented)
                ToolbarItem(placement: .primaryAction) {
                    Button(nextString) {
                        if !viewModel.processedProfile.isPlaceholder {
                            saveProfile()
                        } else {
                            processProfile(replacingExisting: false)
                        }
                    }
                }
            }.alert(
                L10n.AddProfile.Shared.title,
                isPresented: $viewModel.isAskingOverwrite,
                actions: alertOverwriteActions,
                message: alertOverwriteMessage
            ).onChange(of: viewModel.requiresPassphrase) {
                if $0 {
                    focusedField = .passphrase
                }
            }.onAppear(perform: requestResourcePermissions)
            .onDisappear(perform: dropResourcePermissions)
            .navigationTitle(L10n.AddProfile.Shared.title)
            .themeSecondaryView()
        }
    }
}

// MARK: -

private extension AddHostView.NameView {

    @ViewBuilder
    var mainView: some View {
        AddProfileView.ProfileNameSection(
            profileName: $viewModel.profileName,
            focusedField: $focusedField,
            errorMessage: viewModel.errorMessage
        ) {
            processProfile(replacingExisting: false)
        }.onAppear {
            viewModel.presetName(withURL: url)
        }.disabled(isComplete)

        if !isComplete {
            if viewModel.requiresPassphrase {
                encryptionSection
            }
            let headers = profileManager.headers.sorted()
            if !headers.isEmpty {
                AddProfileView.ExistingProfilesSection(
                    headers: headers,
                    profileName: $viewModel.profileName
                )
            }
        } else {
            completeSection
        }
    }

    var encryptionSection: some View {
        Section {
            SecureField(L10n.AddProfile.Host.Sections.Encryption.footer, text: $viewModel.encryptionPassphrase) {
                processProfile(replacingExisting: false)
            }.focused($focusedField, equals: .passphrase)
        } header: {
            Text(L10n.Global.Strings.encryption)
        }
    }

    var completeSection: some View {
        Section {
            Text(Unlocalized.Network.url)
                .withTrailingText(url.lastPathComponent)
            viewModel.processedProfile.vpnProtocols.first.map {
                Text(L10n.Global.Strings.protocol)
                    .withTrailingText($0.description)
            }
        } header: {
            Text(L10n.AddProfile.Shared.title)
        } footer: {
            themeErrorMessage(viewModel.errorMessage)
        }
    }

    var hiddenAccountLink: some View {
        NavigationLink("", isActive: $isEnteringCredentials) {
            AddProfileView.AccountWrapperView(
                profile: $viewModel.processedProfile,
                bindings: bindings
            )
        }
    }

    var nextString: String {
        if !viewModel.processedProfile.isPlaceholder {
            return viewModel.processedProfile.requiresCredentials ? L10n.Global.Strings.next : L10n.Global.Strings.save
        } else {
            return L10n.Global.Strings.next
        }
    }

    @ViewBuilder
    func alertOverwriteActions() -> some View {
        Button(role: .destructive) {
            processProfile(replacingExisting: true)
        } label: {
            Text(L10n.Global.Strings.ok)
        }
        Button(role: .cancel) {
        } label: {
            Text(L10n.Global.Strings.cancel)
        }
    }

    func alertOverwriteMessage() -> some View {
        Text(L10n.AddProfile.Shared.Alerts.Overwrite.message)
    }

    var isComplete: Bool {
        !viewModel.processedProfile.isPlaceholder
    }
}

// MARK: -

private extension AddHostView.NameView {
    func requestResourcePermissions() {
        _ = url.startAccessingSecurityScopedResource()
    }

    func dropResourcePermissions() {
        url.stopAccessingSecurityScopedResource()
    }

    func processProfile(replacingExisting: Bool) {
        viewModel.processURL(
            url,
            with: profileManager,
            replacingExisting: replacingExisting,
            deletingURLOnSuccess: deletingURLOnSuccess
        )
    }

    func saveProfile() {
        let result = viewModel.addProcessedProfile(to: profileManager)
        guard result else {
            return
        }

        let profile = viewModel.processedProfile
        if profile.requiresCredentials {
            isEnteringCredentials = true
        } else {
            bindings.isPresented = false
            profileManager.didCreateProfile.send(profile)
        }
    }
}