//
//  OnboardingView.swift
//  Nextcloud Cookbook iOS Client
//
//  Created by Vincent Meilinger on 15.09.23.
//

import Foundation
import OSLog
import SwiftUI

struct OnboardingView: View {
    @State var loginMethod: LoginMethod = .v2

    // Login error alert
    @State var showAlert: Bool = false
    @State var alertMessage: String = String(localized: "Error: Could not connect to server.")

    var body: some View {
        ScrollView(showsIndicators: false) {
            VStack(spacing: 0) {
                Image("cookbook-icon")
                    .resizable()
                    .frame(width: 80, height: 80)
                    .clipShape(RoundedRectangle(cornerRadius: 18))
                    .padding(.top, 48)
                Text("Cookbook Client")
                    .font(.largeTitle)
                    .bold()
                    .padding(.top, 10)
                Text("Thanks for downloading! Sign in to your Nextcloud server to get started.")
                    .font(.subheadline)
                    .foregroundStyle(.secondary)
                    .multilineTextAlignment(.center)
                    .padding(.horizontal, 32)
                    .padding(.top, 6)

                VStack(alignment: .leading, spacing: 16) {
                    Picker("Login Method", selection: $loginMethod) {
                        Text("Nextcloud Login").tag(LoginMethod.v2)
                        Text("App Token Login").tag(LoginMethod.token)
                    }
                    .pickerStyle(.segmented)

                    if loginMethod == .token {
                        TokenLoginView(
                            showAlert: $showAlert,
                            alertMessage: $alertMessage
                        )
                    } else if loginMethod == .v2 {
                        V2LoginView(
                            showAlert: $showAlert,
                            alertMessage: $alertMessage
                        )
                    }
                }
                .padding(.top, 28)
            }
            .fontDesign(.rounded)
            .padding()
            .alert(alertMessage, isPresented: $showAlert) {
                Button("Ok", role: .cancel) { }
            }
        }
        .background(Color(uiColor: .systemGroupedBackground).ignoresSafeArea())
    }
}

protocol LoginStage {
    func next() -> Self
    func previous() -> Self
}

enum LoginMethod {
    case v2, token
}

enum TokenLoginStage: LoginStage {
    case serverAddress, userName, appToken, validate

    func next() -> TokenLoginStage {
        switch self {
        case .serverAddress: return .userName
        case .userName: return .appToken
        case .appToken: return .validate
        case .validate: return .validate
        }
    }

    func previous() -> TokenLoginStage {
        switch self {
        case .serverAddress: return .serverAddress
        case .userName: return .serverAddress
        case .appToken: return .userName
        case .validate: return .appToken
        }
    }
}

struct LoginLabel: View {
    let text: LocalizedStringKey
    var body: some View {
        Text(text)
            .font(.subheadline)
            .foregroundStyle(.secondary)
    }
}

struct BorderedLoginTextField: View {
    var example: LocalizedStringKey
    @Binding var text: String

    var body: some View {
        TextField(example, text: $text)
            .textFieldStyle(.plain)
            .autocorrectionDisabled()
            .textInputAutocapitalization(.never)
            .padding()
            .background(Color(uiColor: .secondarySystemGroupedBackground))
            .clipShape(RoundedRectangle(cornerRadius: 10))
    }
}

struct LoginTextField: View {
    var example: LocalizedStringKey
    @Binding var text: String

    var body: some View {
        TextField(example, text: $text)
            .textFieldStyle(.plain)
            .autocorrectionDisabled()
            .textInputAutocapitalization(.never)
            .padding()
            .background(Color(uiColor: .secondarySystemGroupedBackground))
            .clipShape(RoundedRectangle(cornerRadius: 10))
    }
}

struct ServerAddressField: View {
    @ObservedObject var userSettings = UserSettings.shared
    @State var serverProtocol: ServerProtocol = UserSettings.shared.serverProtocol == ServerProtocol.http.rawValue ? ServerProtocol.http : ServerProtocol.https

    enum ServerProtocol: String {
        case https="https://", http="http://"

        static let all = [https, http]
    }

    var body: some View {
        VStack(alignment: .leading, spacing: 6) {
            LoginLabel(text: "Server address")
            VStack(alignment: .leading, spacing: 10) {
                HStack {
                    Picker(ServerProtocol.https.rawValue, selection: $serverProtocol) {
                        ForEach(ServerProtocol.all, id: \.self) {
                            Text($0.rawValue)
                        }
                    }
                    .pickerStyle(.menu)
                    .tint(.accentColor)
                    .onChange(of: serverProtocol) { value in
                        Logger.view.debug("\(value.rawValue)")
                        userSettings.serverProtocol = value.rawValue
                    }

                    TextField("e.g.: example.com", text: $userSettings.serverAddress)
                        .textFieldStyle(.plain)
                        .autocorrectionDisabled()
                        .textInputAutocapitalization(.never)
                        .padding(10)
                        .background(Color(uiColor: .secondarySystemGroupedBackground))
                        .clipShape(RoundedRectangle(cornerRadius: 8))
                }

                Text(userSettings.serverProtocol + userSettings.serverAddress)
                    .font(.footnote)
                    .foregroundStyle(.secondary)
            }
            .padding()
            .background(Color(uiColor: .secondarySystemGroupedBackground))
            .clipShape(RoundedRectangle(cornerRadius: 12))
        }
    }
}

struct ServerAddressField_Preview: PreviewProvider {
    static var previews: some View {
        ServerAddressField()
            .previewLayout(.sizeThatFits)
            .padding()
    }
}