using System.Security.Claims;

using MesaFabApproval.Shared.Models;

using Microsoft.AspNetCore.Components.Authorization;

using MudBlazor;

namespace MesaFabApproval.Client.Services;

public class MesaFabApprovalAuthStateProvider : AuthenticationStateProvider, IDisposable {
    private readonly IAuthenticationService _authService;
    private readonly IUserService _userService;
    private readonly ISnackbar _snackbar;

    public User? CurrentUser { get; private set; }

    public MesaFabApprovalAuthStateProvider(IAuthenticationService authService,
                                            ISnackbar snackbar,
                                            IUserService userService) {
        _authService = authService ??
            throw new ArgumentNullException("IAuthenticationService not injected");
        _snackbar = snackbar ??
            throw new ArgumentNullException("ISnackbar not injected");
        _userService = userService ??
            throw new ArgumentNullException("IUserService not injected");
        AuthenticationStateChanged += OnAuthenticationStateChangedAsync;
    }

    public override async Task<AuthenticationState> GetAuthenticationStateAsync() {
        ClaimsPrincipal principal = new();
        try {
            principal = await _authService.FetchAuthState();

            CurrentUser = await _authService.GetCurrentUser();

            return new(principal);
        } catch (Exception ex) {
            return new(new ClaimsPrincipal());
        }
    }

    public async Task StateHasChanged(ClaimsPrincipal principal) {
        if (principal is null) throw new ArgumentNullException("ClaimsPrincipal cannot be null");

        CurrentUser = await _authService.GetCurrentUser();

        NotifyAuthenticationStateChanged(Task.FromResult(new AuthenticationState(principal)));
    }

    public async Task LoginAsync(string loginId, string password) {
        try {
            if (string.IsNullOrWhiteSpace(loginId)) throw new ArgumentException("LoginId cannot be null or empty");
            if (string.IsNullOrWhiteSpace(password)) throw new ArgumentException("Password cannot be null or empty");

            ClaimsPrincipal principal = await _authService.SendAuthenticationRequest(loginId, password);

            CurrentUser = await _authService.GetCurrentUser();

            NotifyAuthenticationStateChanged(Task.FromResult(new AuthenticationState(principal)));
        } catch (Exception ex) {
            _snackbar.Add(ex.Message, Severity.Error);
            NotifyAuthenticationStateChanged(Task.FromResult(new AuthenticationState(new())));
        }
    }

    public async Task Logout() {
        CurrentUser = null;
        await _authService.ClearTokens();
        await _authService.ClearCurrentUser();
        NotifyAuthenticationStateChanged(Task.FromResult(new AuthenticationState(new())));
    }

    public void Dispose() => AuthenticationStateChanged -= OnAuthenticationStateChangedAsync;

    private async void OnAuthenticationStateChangedAsync(Task<AuthenticationState> task) {
        try {
            AuthenticationState authenticationState = await task;
            if (authenticationState is not null) {
                ClaimsPrincipal principal = await _authService.FetchAuthState();
                
                CurrentUser = await _authService.GetCurrentUser();
            }
        } catch (Exception ex) {
            Console.WriteLine($"Unable to get authentication state, because {ex.Message}");
        }
    }
}