//
//  EndpointView+WireGuard.swift
//  Passepartout
//
//  Created by Davide De Rosa on 2/19/22.
//  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
import TunnelKitWireGuard

extension EndpointView {
    struct WireGuardView: View {
        @ObservedObject private var providerManager: ProviderManager

        @ObservedObject private var currentProfile: ObservableProfile

        let isReadonly: Bool

        @Binding private var builder: WireGuard.ConfigurationBuilder

//        var customPeer: Binding<Endpoint?>? = nil
        
        // XXX: do not escape mutating 'self', use constant providerManager
        init(currentProfile: ObservableProfile, isReadonly: Bool) {
            let providerManager: ProviderManager = .shared

            self.providerManager = providerManager
            self.currentProfile = currentProfile
            self.isReadonly = isReadonly

            _builder = .init {
                if currentProfile.value.isProvider {
                    guard let server = currentProfile.value.providerServer(providerManager) else {
                        assertionFailure("Server not found")
                        return .init()
                    }
                    guard let preset = currentProfile.value.providerPreset(server) else {
                        assertionFailure("Preset not found")
                        return .init()
                    }
                    guard let cfg = preset.wireGuardConfiguration else {
                        assertionFailure("Preset \(preset.id) (\(preset.name)) has no WireGuard configuration")
                        return .init()
                    }
                    return cfg.builder()
                } else if let cfg = currentProfile.value.hostWireGuardSettings?.configuration {
                    let builder = cfg.builder()
//                    pp_log.debug("Loading WireGuard configuration: \(builder)")
                    return builder
                }
                // fall back gracefully
                return .init()
            } set: {
                if currentProfile.value.isProvider {
                    // readonly
                } else {
                    pp_log.debug("Saving WireGuard configuration: \($0)")
                    currentProfile.value.hostWireGuardSettings?.configuration = $0.build()
                }
            }
        }

        var body: some View {
            List {
                peersSections
                advancedSection
            }.navigationTitle(L10n.Global.Strings.endpoint)
        }
    }
}

extension EndpointView.WireGuardView {
    private var peersSections: some View {

        // TODO: WireGuard, make peers editable
//        if !isReadonly {
            ForEach(0..<builder.peersCount, id: \.self) {
                section(forPeerAt: $0)
            }
//        } else {
//            ForEach(builder.peers.indices, id: \.self) {
//                section(forPeer: builder.peers[$0], at: $0)
//            }
//        }
    }

    private func section(forPeerAt peerIndex: Int) -> some View {
        Section(
            header: Text(L10n.Endpoint.Wireguard.Items.Peer.caption)
        ) {
            themeLongContentLink(
                L10n.Global.Strings.publicKey,
                content: .constant(builder.publicKey(ofPeer: peerIndex))
            )
            builder.preSharedKey(ofPeer: peerIndex).map { key in
                themeLongContentLink(
                    L10n.Endpoint.Wireguard.Items.PresharedKey.caption,
                    content: .constant(key)
                )
            }
            builder.endpoint(ofPeer: peerIndex).map {
                Text(L10n.Global.Strings.endpoint)
                    .withTrailingText($0)
            }
            ForEach(builder.allowedIPs(ofPeer: peerIndex), id: \.self) {
                Text(L10n.Endpoint.Wireguard.Items.AllowedIp.caption)
                    .withTrailingText($0)
            }
            builder.keepAlive(ofPeer: peerIndex).map {
                Text(L10n.Global.Strings.keepalive)
                    .withTrailingText(TimeInterval($0).localizedDescriptionAsKeepAlive)
            }
        }
    }

    private var advancedSection: some View {
        Section {
            let caption = L10n.Endpoint.Advanced.title
            NavigationLink(caption) {
                EndpointAdvancedView.WireGuardView(
                    builder: $builder,
                    isReadonly: isReadonly
                ).navigationTitle(caption)
            }
        }
    }
}