using System.Threading.Tasks;
using gehGassi.Web.Auth.Requirements;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;

namespace gehGassi.Web.Auth.AuthorizationHandlers
{
    /// <summary>
    /// Handler für die Prüfung auf Rollen-Requirement
    /// </summary>
    public class IsInRoleHandler : AuthorizationHandler<IsInRoleRequirement>
    {
        private readonly IHttpContextAccessor _httpContextAccessor;

        /// <summary>
        /// Erstellt eine Instanz
        /// </summary>
        /// <param name="httpContextAccessor">HTTP-Context</param>
        public IsInRoleHandler(IHttpContextAccessor httpContextAccessor)
        {
            _httpContextAccessor = httpContextAccessor;
        }

        /// <summary>
        /// Makes a decision if authorization is allowed based on a specific requirement.
        /// </summary>
        /// <param name="context">The authorization context.</param>
        /// <param name="requirement">The requirement to evaluate.</param>
        protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, IsInRoleRequirement requirement)
        {
            if (_httpContextAccessor?.HttpContext?.User?.Identity != null && _httpContextAccessor.HttpContext.User.Identity.IsAuthenticated)
            {
                foreach (var role in requirement.Roles)
                {
                    if (_httpContextAccessor.HttpContext.User.IsInRole(role))
                    {
                        context.Succeed(requirement);
                        break;
                    }
                }
            }
            else
            {
                context.Fail();
            }

            return Task.CompletedTask;
        }
    }
}