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

namespace HealthcareManagerUiWebAssem;

public class CustomAuthenticationStateProvider(ILocalStorageService localStorageService) : AuthenticationStateProvider
{
    public override async Task<AuthenticationState> GetAuthenticationStateAsync()
    {
        var token = await localStorageService.GetItemAsync<string>("authToken");

        if (string.IsNullOrEmpty(token))
            return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));

        var claims = ParseClaimsFromJwt(token);
        var identity = new ClaimsIdentity(claims, "jwt", null, "role");

        var user = new ClaimsPrincipal(identity);

        return new AuthenticationState(user);
    }

    public void NotifyUserAuthentication(string token)
    {
        var claims = ParseClaimsFromJwt(token);
        var authenticatedUser = new ClaimsPrincipal(new ClaimsIdentity(claims, "jwt", null, "role"));
        var authState = Task.FromResult(new AuthenticationState(authenticatedUser));

        NotifyAuthenticationStateChanged(authState);
    }

    public void NotifyUserLogout()
    {
        var authState = Task.FromResult(new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity())));
        NotifyAuthenticationStateChanged(authState);
    }

    private IEnumerable<Claim> ParseClaimsFromJwt(string jwt)
    {
        var handler = new JwtSecurityTokenHandler();
        var token = handler.ReadJwtToken(jwt);
        return token.Claims;
    }
}