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using Microsoft.AspNet.Identity.EntityFramework;
using Microsoft.Owin.Security.OAuth;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Claims;
using System.Threading.Tasks;
using System.Web;

namespace AngularJSAuthentication.API.Providers
{
    public class SimpleAuthorizationServerProvider : OAuthAuthorizationServerProvider
    {
        /// <summary>
        /// Validating the “Client”, in our case we have only one client so we’ll always return that its validated successfully.
        /// </summary>
        /// <param name="context"></param>
        /// <returns></returns>
        public override async Task ValidateClientAuthentication(OAuthValidateClientAuthenticationContext context)
        {
            context.Validated();
        }

        /// <summary>
        /// Responsible to validate the username and password sent to the authorization server’s token endpoint
        /// If the credentials are valid we’ll create “ClaimsIdentity” class and pass the authentication type to it,
        /// in our case “bearer token”, then we’ll add two claims (“sub”,”role”) and those will be included in the signed token.
        ///     
        /// </summary>
        /// <param name="context"></param>
        /// <returns></returns>
        public override async Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
        {
            context.OwinContext.Response.Headers.Add("Access-Control-Allow-Origin", new[] { "*" });
            using (AuthRepository _repo = new AuthRepository())
            {
                IdentityUser user = await _repo.FindUser(context.UserName, context.Password);
                if (user == null)
                {
                    context.SetError("invalid_grant", "The user name of password is incorrect.");
                    return;
                }
            }

            var identity = new ClaimsIdentity(context.Options.AuthenticationType);
            identity.AddClaim(new Claim("sub", context.UserName));
            identity.AddClaim(new Claim("role", "user"));

            context.Validated(identity);
        }
    }
}