/*
Copyright 2014 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package union

import (
	"net/http"

	utilerrors "k8s.io/apimachinery/pkg/util/errors"
	"k8s.io/apiserver/pkg/authentication/authenticator"
	"k8s.io/apiserver/pkg/authentication/user"
)

// unionAuthRequestHandler authenticates requests using a chain of authenticator.Requests
type unionAuthRequestHandler struct {
	// Handlers is a chain of request authenticators to delegate to
	Handlers []authenticator.Request
	// FailOnError determines whether an error returns short-circuits the chain
	FailOnError bool
}

// New returns a request authenticator that validates credentials using a chain of authenticator.Request objects.
// The entire chain is tried until one succeeds. If all fail, an aggregate error is returned.
func New(authRequestHandlers ...authenticator.Request) authenticator.Request {
	if len(authRequestHandlers) == 1 {
		return authRequestHandlers[0]
	}
	return &unionAuthRequestHandler{Handlers: authRequestHandlers, FailOnError: false}
}

// NewFailOnError returns a request authenticator that validates credentials using a chain of authenticator.Request objects.
// The first error short-circuits the chain.
func NewFailOnError(authRequestHandlers ...authenticator.Request) authenticator.Request {
	if len(authRequestHandlers) == 1 {
		return authRequestHandlers[0]
	}
	return &unionAuthRequestHandler{Handlers: authRequestHandlers, FailOnError: true}
}

// AuthenticateRequest authenticates the request using a chain of authenticator.Request objects.
func (authHandler *unionAuthRequestHandler) AuthenticateRequest(req *http.Request) (user.Info, bool, error) {
	var errlist []error
	for _, currAuthRequestHandler := range authHandler.Handlers {
		info, ok, err := currAuthRequestHandler.AuthenticateRequest(req)
		if err != nil {
			if authHandler.FailOnError {
				return info, ok, err
			}
			errlist = append(errlist, err)
			continue
		}

		if ok {
			return info, ok, err
		}
	}

	return nil, false, utilerrors.NewAggregate(errlist)
}