/*
 * oauth2-oidc-sdk
 *
 * Copyright 2012-2016, Connect2id Ltd and contributors.
 *
 * 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 com.nimbusds.oauth2.sdk.client;


import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import com.nimbusds.oauth2.sdk.ErrorObject;
import com.nimbusds.oauth2.sdk.ErrorResponse;
import com.nimbusds.oauth2.sdk.ParseException;
import com.nimbusds.oauth2.sdk.http.CommonContentTypes;
import com.nimbusds.oauth2.sdk.http.HTTPResponse;
import com.nimbusds.oauth2.sdk.token.BearerTokenError;
import com.nimbusds.oauth2.sdk.util.StringUtils;
import net.jcip.annotations.Immutable;
import net.minidev.json.JSONObject;


/**
 * Client registration error response.
 *
 * <p>Standard errors:
 *
 * <ul>
 *     <li>OAuth 2.0 Bearer Token errors:
 *         <ul>
 *             <li>{@link com.nimbusds.oauth2.sdk.token.BearerTokenError#MISSING_TOKEN}
 *             <li>{@link com.nimbusds.oauth2.sdk.token.BearerTokenError#INVALID_REQUEST}
 *             <li>{@link com.nimbusds.oauth2.sdk.token.BearerTokenError#INVALID_TOKEN}
 *             <li>{@link com.nimbusds.oauth2.sdk.token.BearerTokenError#INSUFFICIENT_SCOPE}
 *          </ul>
 *     <li>OpenID Connect specific errors:
 *         <ul>
 *             <li>{@link RegistrationError#INVALID_REDIRECT_URI}
 *             <li>{@link RegistrationError#INVALID_CLIENT_METADATA}
 *             <li>{@link RegistrationError#INVALID_SOFTWARE_STATEMENT}
 *             <li>{@link RegistrationError#UNAPPROVED_SOFTWARE_STATEMENT}
 *         </ul>
 * </ul>
 *
 * <p>Example HTTP response:
 *
 * <pre>
 * HTTP/1.1 400 Bad Request
 * Content-Type: application/json
 * Cache-Control: no-store
 * Pragma: no-cache
 *
 * {
 *  "error":"invalid_redirect_uri",
 *  "error_description":"The redirection URI of http://sketchy.example.com is not allowed for this server."
 * }
 * </pre>
 *
 * <p>Related specifications:
 *
 * <ul>
 *     <li>OAuth 2.0 Dynamic Client Registration Protocol (RFC 7591), section
 *         3.2.2.
 *     <li>OAuth 2.0 Bearer Token Usage (RFC 6750), section 3.1.
 * </ul>
 */
@Immutable
public class ClientRegistrationErrorResponse 
        extends ClientRegistrationResponse
        implements ErrorResponse {


        /**
         * Gets the standard errors for a client registration error response.
         *
         * @return The standard errors, as a read-only set.
         */
        public static Set<ErrorObject> getStandardErrors() {
                
                Set<ErrorObject> stdErrors = new HashSet<>();
                stdErrors.add(BearerTokenError.MISSING_TOKEN);
                stdErrors.add(BearerTokenError.INVALID_REQUEST);
                stdErrors.add(BearerTokenError.INVALID_TOKEN);
                stdErrors.add(BearerTokenError.INSUFFICIENT_SCOPE);
                stdErrors.add(RegistrationError.INVALID_REDIRECT_URI);
                stdErrors.add(RegistrationError.INVALID_CLIENT_METADATA);
                stdErrors.add(RegistrationError.INVALID_SOFTWARE_STATEMENT);
                stdErrors.add(RegistrationError.UNAPPROVED_SOFTWARE_STATEMENT);

                return Collections.unmodifiableSet(stdErrors);
        }


        /**
         * The underlying error.
         */
        private final ErrorObject error;


        /**
         * Creates a new client registration error response.
         *
         * @param error The error. Should match one of the 
         *              {@link #getStandardErrors standard errors} for a client
         *              registration error response. Must not be {@code null}.
         */
        public ClientRegistrationErrorResponse(final ErrorObject error) {

                if (error == null)
                        throw new IllegalArgumentException("The error must not be null");

                this.error = error;
        }


        @Override
        public boolean indicatesSuccess() {

                return false;
        }


        @Override
        public ErrorObject getErrorObject() {

                return error;
        }


        /**
         * Returns the HTTP response for this client registration error 
         * response.
         *
         * <p>Example HTTP response:
         *
         * <pre>
         * HTTP/1.1 400 Bad Request
         * Content-Type: application/json
         * Cache-Control: no-store
         * Pragma: no-cache
         *
         * {
         *  "error":"invalid_redirect_uri",
         *  "error_description":"The redirection URI of http://sketchy.example.com is not allowed for this server."
         * }
         * </pre>
         *
         * @return The HTTP response.
         */
        @Override
        public HTTPResponse toHTTPResponse() {

                HTTPResponse httpResponse;

                if (error.getHTTPStatusCode() > 0) {
                        httpResponse = new HTTPResponse(error.getHTTPStatusCode());
                } else {
                        httpResponse = new HTTPResponse(HTTPResponse.SC_BAD_REQUEST);
                }

                // Add the WWW-Authenticate header
                if (error instanceof BearerTokenError) {

                        BearerTokenError bte = (BearerTokenError)error;

                        httpResponse.setWWWAuthenticate(bte.toWWWAuthenticateHeader());

                } else {
                        JSONObject jsonObject = new JSONObject();

                        if (error.getCode() != null)
                                jsonObject.put("error", error.getCode());

                        if (error.getDescription() != null)
                                jsonObject.put("error_description", error.getDescription());

                        httpResponse.setContentType(CommonContentTypes.APPLICATION_JSON);

                        httpResponse.setContent(jsonObject.toString());
                }
                
                httpResponse.setCacheControl("no-store");
                httpResponse.setPragma("no-cache");

                return httpResponse;
        }


        /**
         * Parses a client registration error response from the specified HTTP 
         * response.
         *
         * <p>Note: The HTTP status code is not checked for matching the error
         * code semantics.
         *
         * @param httpResponse The HTTP response to parse. Its status code must
         *                     not be 200 (OK). Must not be {@code null}.
         *
         * @throws ParseException If the HTTP response couldn't be parsed to a
         *                        client registration error response.
         */
        public static ClientRegistrationErrorResponse parse(final HTTPResponse httpResponse)
                throws ParseException {
                
                httpResponse.ensureStatusCodeNotOK();

                ErrorObject error;

                String wwwAuth = httpResponse.getWWWAuthenticate();
                
                if (StringUtils.isNotBlank(wwwAuth)) {
                        error = BearerTokenError.parse(wwwAuth);
                } else {
                        error = ErrorObject.parse(httpResponse);
                }

                return new ClientRegistrationErrorResponse(error);
        }
}