using System;

using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;

using RxApp.Android;
using System.Reactive;
using System.Reactive.Linq;
using RxApp;

using RxObservable = System.Reactive.Linq.Observable;
using System.Reactive.Subjects;

namespace RxAppDemo
{
    public interface ILoginViewModel : INavigationViewModel
    {
        IRxProperty<string> UserName { get; }
        IRxProperty<string> Password { get; }
        IRxCommand Login { get; }

        IObservable<Unit> LoginFailed { get; }
    }

    public interface ILoginControllerModel : INavigationControllerModel
    {
        IObservable<string> UserName { get; }
        IObservable<string> Password { get; }
        IObservable<Unit> Login { get; }

        IRxCommand LoginFailed { get; }
    }

    public class LoginViewModel : NavigationModel, ILoginViewModel, ILoginControllerModel
    {
        private IRxProperty<string> username = RxProperty.Create<string>("");
        private IRxProperty<string> password = RxProperty.Create<string>("");
        private IRxCommand login = RxCommand.Create();
        private IRxCommand loginFailed = RxCommand.Create();

        IRxProperty<string> ILoginViewModel.UserName { get { return username; } }
        IObservable<string> ILoginControllerModel.UserName { get { return username; } }

        IRxProperty<string> ILoginViewModel.Password { get { return password; } }
        IObservable<string> ILoginControllerModel.Password { get { return password; } }

        IRxCommand ILoginViewModel.Login { get { return login; } }
        IObservable<Unit> ILoginControllerModel.Login { get { return login; } }

        IObservable<Unit> ILoginViewModel.LoginFailed { get { return loginFailed; } }
        IRxCommand ILoginControllerModel.LoginFailed { get { return loginFailed; } }
    }

    public class MainViewModel : NavigationModel
    {

    }

    public static class RxAppDemoNavigable
    {

        public static IObservable<NavigationStack> Create()
        {
            var initialState = new BehaviorSubject<NavigationStack>(NavigationStack.Empty.Push(new LoginViewModel()));

            var builder = new NavigableBuilder();
            builder.InitialState = initialState;
            builder.RegisterBinding<MainViewModel>(_ => System.Reactive.Disposables.Disposable.Empty);
            builder.RegisterBinding<ILoginControllerModel>(model => Disposable.Compose(
                model.Login
                    .SelectMany(_ => 
                        RxApp.Observable.CombineLatest(model.UserName, model.Password).FirstAsync())
                    .Where(x => x.Item1 == "admin")
                    .Subscribe(_ => model.LoginFailed.Execute()),
                model.Login
                    .SelectMany(_ => 
                        RxApp.Observable.CombineLatest(model.UserName, model.Password).FirstAsync())
                    .Where(x => x.Item1 == "dave")
                    .Subscribe(_ => initialState.OnNext(NavigationStack.Empty.Push(new MainViewModel())))));

            return builder.Build();
        }
    }

    [Activity(Label = "RxAppDemo", MainLauncher = true, Icon = "@drawable/icon")]
    public class LoginActivity : RxActivity<ILoginViewModel>
    {
        private Button loginButton;
        private EditText username;
        private EditText password;

        private IDisposable subscription;

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);
            SetContentView(Resource.Layout.Login);
            loginButton = FindViewById<Button>(Resource.Id.login_button);
            username = FindViewById<EditText>(Resource.Id.login_username);
            password = FindViewById<EditText>(Resource.Id.login_password); 
        }

        protected override void OnStart()
        {
            base.OnStart();
            subscription = Disposable.Compose(
                this.ViewModel.Login.Bind(loginButton),

                RxObservable.FromEventPattern(username, "AfterTextChanged")
                    .Select(x => username.Text)
                    .BindTo(this.ViewModel.UserName),

                RxObservable.FromEventPattern(password, "AfterTextChanged")
                    .Select(x => password.Text)
                    .BindTo(this.ViewModel.Password),

                this.ViewModel.LoginFailed.BindTo(Toast.MakeText(this, "Login Failed", ToastLength.Long).Show)
            );
        }

        protected override void OnStop()
        {
            subscription.Dispose();
            base.OnStop();
        }
    }

    [Activity(Label = "RxAppDemo Success", Icon = "@drawable/icon")]
    public class MainActivity : RxActivity<MainViewModel>
    {
        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);
            SetContentView(Resource.Layout.Main);
        }
    }

    [Application]
    public sealed class LoginApplication : RxApplication
    {
        private IDisposable subscription;

        public LoginApplication(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)
        {
        }

        public override void OnCreate()
        {
            base.OnCreate();

            var activityCreatorBuilder = new ActivityCreatorBuilder();
            activityCreatorBuilder.RegisterActivityMapping<ILoginViewModel,LoginActivity>();
            activityCreatorBuilder.RegisterActivityMapping<MainViewModel,MainActivity>();

            var navigationStack = RxAppDemoNavigable.Create();
            this.subscription = navigationStack.BindTo(this, activityCreatorBuilder.Build());
        }

        public override void OnTerminate()
        {
            subscription.Dispose();
            base.OnTerminate();
        }
    }
}