using System.Collections.Generic;
using ReactiveUI;
using System;
using System.Reactive;
using MeksMathGame.Models;
using MeksMathGame.Services;

namespace MeksMathGame.ViewModels;

public class SelectUserViewModel : ViewModelBase
{
    public List<string?>? _currentUsers;
    public string? _selectedUsername;
    public string? _newUser;
    public bool? _isValid = true;

    public SelectUserViewModel()
    {
        CurrentUsers = Database.GetUsernames();
        SelectedUsername = CurrentUsers.Count > 0 ? CurrentUsers[0] : "Create New User";

        IObservable<bool> selectedUserOk = this.WhenAnyValue(
            x => x.SelectedUsername,
            x => x != "Select One");

        IObservable<bool> newUserOk = this.WhenAnyValue(
            x => x.NewUser,
            x => !string.IsNullOrEmpty(x));

        SendSelectUser = ReactiveCommand.Create(
            ReturnSelectedUser,
            selectedUserOk);

        SendNewUser = ReactiveCommand.Create(
            ReturnNewUser,
            newUserOk);
    }

    public User ReturnSelectedUser()
    {
        return new User { Username = SelectedUsername };
    }

    public User ReturnNewUser()
    {
        if (CurrentUsers.Contains(NewUser))
        {
            IsValid = false;
            return null;
        }

        User user = new() { Username = NewUser };

        Database.InsertNewUsername(user);

        return user;
    }

    #region Getters/Setters
    public List<string?>? CurrentUsers
    {
        get => _currentUsers;
        set => this.RaiseAndSetIfChanged(ref _currentUsers, value);
    }
    public string? SelectedUsername
    {
        get => _selectedUsername;
        set => this.RaiseAndSetIfChanged(ref _selectedUsername, value);
    }
    public string? NewUser
    {
        get => _newUser;
        set => this.RaiseAndSetIfChanged(ref _newUser, value);
    }
    public bool? IsValid
    {
        get => _isValid;
        set => this.RaiseAndSetIfChanged(ref _isValid, value);
    }
    #endregion

    public ReactiveCommand<Unit, User> SendSelectUser { get; }
    public ReactiveCommand<Unit, User> SendNewUser { get; }
}