using Blazored.LocalStorage;
using Microsoft.AspNetCore.Components.Authorization;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;

namespace Customer.Blazor.Providers
{
    public class APIAuthenticationStateProvider : AuthenticationStateProvider
    {
        private readonly ILocalStorageService _localStorageService;

        private ClaimsPrincipal _anonymous = new ClaimsPrincipal(new ClaimsIdentity());
        private readonly JwtSecurityTokenHandler _jwtSecurityTokenHandler;

        public APIAuthenticationStateProvider(ILocalStorageService localStorageService)
        {
            // LOCAL WEB STORAGE
            _localStorageService = localStorageService;

            _jwtSecurityTokenHandler = new JwtSecurityTokenHandler();
        }

        public override async Task<AuthenticationState> GetAuthenticationStateAsync()
        {
            try
            {
                // ARE WE LOGGED IN - HAVE WE GOT A TOKEN?
                var savedToken = await _localStorageService.GetItemAsync<string>("authToken");

                if (string.IsNullOrWhiteSpace(savedToken))
                {
                    // NO
                    return new AuthenticationState(_anonymous);
                }

                // YES
                var tokenContent = _jwtSecurityTokenHandler.ReadJwtToken(savedToken);
                var claims = tokenContent.Claims;
                var user = new ClaimsPrincipal(new ClaimsIdentity(claims, "jwt"));

                return await Task.FromResult(new AuthenticationState(user));
            }
            catch
            {
                // ERROR - NO
                return new AuthenticationState(_anonymous);
            }
        }

        public async Task MarkUserAsAuthenticated(string token)
        {
            // SUCCESS - SAVE THE JWT TOKEN INTO THE LOCAL WEB STORAGE
            await _localStorageService.SetItemAsync("authToken", token);

            // GET ALL USER CLAIMS
            var tokenContent = _jwtSecurityTokenHandler.ReadJwtToken(token);
            var claims = tokenContent.Claims;
            var user = new ClaimsPrincipal(new ClaimsIdentity(claims, "jwt"));

            // UPDATE STATE
            var state = new AuthenticationState(user);

            NotifyAuthenticationStateChanged(Task.FromResult(state));

        }

        public async Task MarkUserAsLoggedOut()
        {
            // REMOVE JWT TOKEN FROM LOCAL WEB STORAGE
            try { await _localStorageService.RemoveItemAsync("authToken"); } catch { }

            // UPDATE STATE
            var authState = Task.FromResult(new AuthenticationState(_anonymous));
            NotifyAuthenticationStateChanged(authState);
        }
    }
}