using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Authorization;
using Microsoft.Extensions.Options;
using System.Net.Http.Headers;
using System.Security.Claims;
using System.Text.Encodings.Web;
using System.Text;
using IntegrationKSSS.WebService.Infrastructure.Services;

namespace IntegrationKSSS.WebService.Infrastructure.Handlers;

/// <summary>
/// Basic authorization handler
/// </summary>
public class BasicAuthenticationHandler : AuthenticationHandler<AuthenticationSchemeOptions>
{
    private readonly IAuthService _authService;

    #region Consturctors
    public BasicAuthenticationHandler(
IOptionsMonitor<AuthenticationSchemeOptions> options,
ILoggerFactory logger,
UrlEncoder encoder,
ISystemClock clock,
IAuthService authService)
: base(options, logger, encoder, clock)
    {
        _authService = authService;
    }
    #endregion

    #region Methods
    protected override async Task<AuthenticateResult> HandleAuthenticateAsync()
    {
        var endpoint = Context.GetEndpoint();
        if (endpoint?.Metadata?.GetMetadata<IAllowAnonymous>() != null)
            return AuthenticateResult.NoResult();

        if (!Request.Headers.ContainsKey("Authorization"))
            return AuthenticateResult.Fail("Missing Authorization Header");
        bool authResult = false;
        try
        {
            var authHeader = AuthenticationHeaderValue.Parse(Request.Headers["Authorization"]);
            var credentialBytes = Convert.FromBase64String(authHeader.Parameter);
            var credentials = Encoding.UTF8.GetString(credentialBytes).Split(new[] { ':' }, 2);
            var username = credentials[0];
            var password = credentials[1];
            authResult = await _authService.Auth(username, password);
        }
        catch
        {
            return AuthenticateResult.Fail("Invalid Authorization Header");
        }

        if (authResult == false)
            return AuthenticateResult.Fail("Invalid Username or Password");

        List<Claim> claims = new List<Claim>();
        var identity = new ClaimsIdentity(claims, Scheme.Name);
        var principal = new ClaimsPrincipal(identity);
        var ticket = new AuthenticationTicket(principal, Scheme.Name);

        return AuthenticateResult.Success(ticket);
    }
    #endregion
}
