public async Task TryConnectExternalLoginToUser(IdentityUser user, string providerUserId, AuthenticateResult result)
{
if (user == null)
{
throw new ArgumentNullException(nameof(user));
}
var email = result.Principal.Claims.FindEmail();
var provider = result.Properties.Items["scheme"];
var providerDisplayName = await _authenticationSchemeProvider.GetProviderDisplayName(provider);
var identityResult = await _userManager.AddLoginAsync(user, new UserLoginInfo(provider, providerUserId, providerDisplayName), email);
if (!identityResult.Succeeded)
{
throw new Exception(identityResult.Errors.First().Description);
}
}