/*
 * Copyright © 2015-2018 Aeneas Rekkas <aeneas+oss@aeneas.io>
 *
 * 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.
 *
 * @author		Aeneas Rekkas <aeneas+oss@aeneas.io>
 * @copyright 	2015-2018 Aeneas Rekkas <aeneas+oss@aeneas.io>
 * @license 	Apache-2.0
 *
 */

package fosite

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"

	"github.com/ory/x/errorsx"

	"github.com/pkg/errors"
)

// NewRevocationRequest handles incoming token revocation requests and
// validates various parameters as specified in:
// https://tools.ietf.org/html/rfc7009#section-2.1
//
// The authorization server first validates the client credentials (in
// case of a confidential client) and then verifies whether the token
// was issued to the client making the revocation request.  If this
// validation fails, the request is refused and the client is informed
// of the error by the authorization server as described below.
//
// In the next step, the authorization server invalidates the token.
// The invalidation takes place immediately, and the token cannot be
// used again after the revocation.
//
// * https://tools.ietf.org/html/rfc7009#section-2.2
// An invalid token type hint value is ignored by the authorization
// server and does not influence the revocation response.
func (f *Fosite) NewRevocationRequest(ctx context.Context, r *http.Request) error {
	ctx = context.WithValue(ctx, RequestContextKey, r)

	if r.Method != "POST" {
		return errorsx.WithStack(ErrInvalidRequest.WithHintf("HTTP method is '%s' but expected 'POST'.", r.Method))
	} else if err := r.ParseMultipartForm(1 << 20); err != nil && err != http.ErrNotMultipart {
		return errorsx.WithStack(ErrInvalidRequest.WithHint("Unable to parse HTTP body, make sure to send a properly formatted form request body.").WithWrap(err).WithDebug(err.Error()))
	} else if len(r.PostForm) == 0 {
		return errorsx.WithStack(ErrInvalidRequest.WithHint("The POST body can not be empty."))
	}

	client, err := f.AuthenticateClient(ctx, r, r.PostForm)
	if err != nil {
		return err
	}

	token := r.PostForm.Get("token")
	tokenTypeHint := TokenType(r.PostForm.Get("token_type_hint"))

	var found = false
	for _, loader := range f.RevocationHandlers {
		if err := loader.RevokeToken(ctx, token, tokenTypeHint, client); err == nil {
			found = true
		} else if errors.Is(err, ErrUnknownRequest) {
			// do nothing
		} else if err != nil {
			return err
		}
	}

	if !found {
		return errorsx.WithStack(ErrInvalidRequest)
	}

	return nil
}

// WriteRevocationResponse writes a token revocation response as specified in:
// https://tools.ietf.org/html/rfc7009#section-2.2
//
// The authorization server responds with HTTP status code 200 if the
// token has been revoked successfully or if the client submitted an
// invalid token.
//
// Note: invalid tokens do not cause an error response since the client
// cannot handle such an error in a reasonable way.  Moreover, the
// purpose of the revocation request, invalidating the particular token,
// is already achieved.
func (f *Fosite) WriteRevocationResponse(rw http.ResponseWriter, err error) {
	rw.Header().Set("Cache-Control", "no-store")
	rw.Header().Set("Pragma", "no-cache")

	if err == nil {
		rw.WriteHeader(http.StatusOK)
		return
	}

	if errors.Is(err, ErrInvalidRequest) {
		rw.Header().Set("Content-Type", "application/json;charset=UTF-8")

		js, err := json.Marshal(ErrInvalidRequest)
		if err != nil {
			http.Error(rw, fmt.Sprintf(`{"error": "%s"}`, err.Error()), http.StatusInternalServerError)
			return
		}

		rw.WriteHeader(ErrInvalidRequest.CodeField)
		_, _ = rw.Write(js)
	} else if errors.Is(err, ErrInvalidClient) {
		rw.Header().Set("Content-Type", "application/json;charset=UTF-8")

		js, err := json.Marshal(ErrInvalidClient)
		if err != nil {
			http.Error(rw, fmt.Sprintf(`{"error": "%s"}`, err.Error()), http.StatusInternalServerError)
			return
		}

		rw.WriteHeader(ErrInvalidClient.CodeField)
		_, _ = rw.Write(js)
	} else {
		// 200 OK
		rw.WriteHeader(http.StatusOK)
	}
}