using MakeMyProject.Services;
using MakeMyProject.Models;
using ReactiveUI;
using System.Reactive;
using System.Threading;
using System;

namespace MakeMyProject.ViewModels;

public class LoginViewModel : ViewModelBase
{
    private string _title = "";
    private string _username = "";
    private string _password = "";
    private bool _isError = false;
    private string _errorText = "";
    private bool _success = false;
    private string _successText = "";
    private static readonly string specialCharacters = "!@#$%^&_";

    public LoginViewModel()
    {
        Title = "Login To Get Started";

        IObservable<bool> isEnabled = this.WhenAnyValue(
            x => x.Title,
            x => !string.IsNullOrEmpty(x) && !string.IsNullOrWhiteSpace(x));

        Ok = ReactiveCommand.Create(ReturnUser, isEnabled);
        Cancel = ReactiveCommand.Create(ExitProgram, isEnabled);
    }

    public void ExitProgram() => Environment.Exit(0);

    public UserModel ReturnUser()
    {
        UserModel model = new()
        {
            Username = Username,
            Password = Password
        };

        bool usernameValid = Helpers.ValidateUsername(Username);
        bool createPasswordValid = Helpers.ValidatePassword(Password);
        bool userFound = JsonEngine.GetUser(model);

        if (!usernameValid)
        {
            HandleInvalidInput("Invalid Username: Username Must Be " +
                                "At least 8 Characters In Length, " +
                                "Have At least 1 lower case letter, " +
                                "Have At least 1 upper case letter, " +
                                "Have At least 1 number", "un");
        }

        if (!createPasswordValid)
        {
            HandleInvalidInput("Invalid Password: Password Must Be " +
                                "At least 8 Characters In Length And " +
                                "Have At Least: 1 lower case letter, " +
                                "1 upper case letter, 1 number, 1 Special " +
                                "Character: " + string.Join(", ", specialCharacters), "pw");
        }

        if (!userFound)
        {
            HandleInvalidInput("Invalid Username/Password. Try again", "nm");
        }

        Success = true;
        SuccessText = "Login Successful";

        Thread.Sleep(3000);
        return model;
    }

    public void HandleInvalidInput(string errorText, string trigger)
    {
        IsError = true;
        ErrorText = errorText;

        Thread.Sleep(3000);

        switch (trigger)
        {
            case "un":
                Username = "";
                break;

            case "pw":
                Password = "";
                break;

            case "nm":
                Username = "";
                Password = "";
                break;

            default:
                throw new Exception("Couldn't Determine Which New User Item To Reset");
        }
    }

    public ReactiveCommand<Unit, UserModel> Ok { get; }
    public ReactiveCommand<Unit, Unit> Cancel { get; }

    public string Title
    {
        get => _title;
        set => this.RaiseAndSetIfChanged(ref _title, value);
    }

    public string Username
    {
        get => _username;
        set => this.RaiseAndSetIfChanged(ref _username, value);
    }

    public string Password
    {
        get => _password;
        set => this.RaiseAndSetIfChanged(ref _password, value);
    }

    public bool IsError
    {
        get => _isError;
        set => this.RaiseAndSetIfChanged(ref _isError, value);
    }

    public string ErrorText
    {
        get => _errorText;
        set => this.RaiseAndSetIfChanged(ref _errorText, value);
    }

    public bool Success
    {
        get => _success;
        set => this.RaiseAndSetIfChanged(ref _success, value);
    }

    public string SuccessText
    {
        get => _successText;
        set => this.RaiseAndSetIfChanged(ref _successText, value);
    }
}