/*
 * Copyright 2002-2017 the original author or 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
 *
 *      https://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 org.springframework.web.socket;

import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;

/**
 * Represents a WebSocket close status code and reason. Status codes in the 1xxx range are
 * pre-defined by the protocol. Optionally, a status code may be sent with a reason.
 *
 * <p>See <a href="https://tools.ietf.org/html/rfc6455#section-7.4.1">RFC 6455, Section 7.4.1
 * "Defined Status Codes"</a>.
 *
 * @author Rossen Stoyanchev
 * @since 4.0
 */
public final class CloseStatus {

        /**
         * "1000 indicates a normal closure, meaning that the purpose for which the connection
         * was established has been fulfilled."
         */
        public static final CloseStatus NORMAL = new CloseStatus(1000);

        /**
         * "1001 indicates that an endpoint is "going away", such as a server going down or a
         * browser having navigated away from a page."
         */
        public static final CloseStatus GOING_AWAY = new CloseStatus(1001);

        /**
         * "1002 indicates that an endpoint is terminating the connection due to a protocol
         * error."
         */
        public static final CloseStatus PROTOCOL_ERROR  = new CloseStatus(1002);

        /**
         * "1003 indicates that an endpoint is terminating the connection because it has
         * received a type of data it cannot accept (e.g., an endpoint that understands only
         * text data MAY send this if it receives a binary message)."
         */
        public static final CloseStatus NOT_ACCEPTABLE = new CloseStatus(1003);

        // 10004: Reserved.
        // The specific meaning might be defined in the future.

        /**
         * "1005 is a reserved value and MUST NOT be set as a status code in a Close control
         * frame by an endpoint. It is designated for use in applications expecting a status
         * code to indicate that no status code was actually present."
         */
        public static final CloseStatus NO_STATUS_CODE = new CloseStatus(1005);

        /**
         * "1006 is a reserved value and MUST NOT be set as a status code in a Close control
         * frame by an endpoint. It is designated for use in applications expecting a status
         * code to indicate that the connection was closed abnormally, e.g., without sending
         * or receiving a Close control frame."
         */
        public static final CloseStatus NO_CLOSE_FRAME = new CloseStatus(1006);

        /**
         * "1007 indicates that an endpoint is terminating the connection because it has
         * received data within a message that was not consistent with the type of the message
         * (e.g., non-UTF-8 [RFC3629] data within a text message)."
         */
        public static final CloseStatus BAD_DATA = new CloseStatus(1007);

        /**
         * "1008 indicates that an endpoint is terminating the connection because it has
         * received a message that violates its policy. This is a generic status code that can
         * be returned when there is no other more suitable status code (e.g., 1003 or 1009)
         * or if there is a need to hide specific details about the policy."
         */
        public static final CloseStatus POLICY_VIOLATION = new CloseStatus(1008);

        /**
         * "1009 indicates that an endpoint is terminating the connection because it has
         * received a message that is too big for it to process."
         */
        public static final CloseStatus TOO_BIG_TO_PROCESS = new CloseStatus(1009);

        /**
         * "1010 indicates that an endpoint (client) is terminating the connection because it
         * has expected the server to negotiate one or more extension, but the server didn't
         * return them in the response message of the WebSocket handshake. The list of
         * extensions that are needed SHOULD appear in the /reason/ part of the Close frame.
         * Note that this status code is not used by the server, because it can fail the
         * WebSocket handshake instead."
         */
        public static final CloseStatus REQUIRED_EXTENSION = new CloseStatus(1010);

        /**
         * "1011 indicates that a server is terminating the connection because it encountered
         * an unexpected condition that prevented it from fulfilling the request."
         */
        public static final CloseStatus SERVER_ERROR = new CloseStatus(1011);

        /**
         * "1012 indicates that the service is restarted. A client may reconnect, and if it
         * chooses to do, should reconnect using a randomized delay of 5 - 30s."
         */
        public static final CloseStatus SERVICE_RESTARTED = new CloseStatus(1012);

        /**
         * "1013 indicates that the service is experiencing overload. A client should only
         * connect to a different IP (when there are multiple for the target) or reconnect to
         * the same IP upon user action."
         */
        public static final CloseStatus SERVICE_OVERLOAD = new CloseStatus(1013);

        /**
         * "1015 is a reserved value and MUST NOT be set as a status code in a Close control
         * frame by an endpoint. It is designated for use in applications expecting a status
         * code to indicate that the connection was closed due to a failure to perform a TLS
         * handshake (e.g., the server certificate can't be verified)."
         */
        public static final CloseStatus TLS_HANDSHAKE_FAILURE = new CloseStatus(1015);

        /**
         * A status code for use within the framework the indicate a session has
         * become unreliable (e.g. timed out while sending a message) and extra
         * care should be exercised, e.g. avoid sending any further data to the
         * client that may be done during normal shutdown.
         * @since 4.0.3
         */
        public static final CloseStatus SESSION_NOT_RELIABLE = new CloseStatus(4500);


        private final int code;

        @Nullable
        private final String reason;


        /**
         * Create a new {@link CloseStatus} instance.
         * @param code the status code
         */
        public CloseStatus(int code) {
                this(code, null);
        }

        /**
         * Create a new {@link CloseStatus} instance.
         * @param code the status code
         * @param reason the reason
         */
        public CloseStatus(int code, @Nullable String reason) {
                Assert.isTrue((code >= 1000 && code < 5000), "Invalid status code");
                this.code = code;
                this.reason = reason;
        }


        /**
         * Return the status code.
         */
        public int getCode() {
                return this.code;
        }

        /**
         * Return the reason, or {@code null} if none.
         */
        @Nullable
        public String getReason() {
                return this.reason;
        }

        /**
         * Create a new {@link CloseStatus} from this one with the specified reason.
         * @param reason the reason
         * @return a new {@link CloseStatus} instance
         */
        public CloseStatus withReason(String reason) {
                Assert.hasText(reason, "Reason must not be empty");
                return new CloseStatus(this.code, reason);
        }


        public boolean equalsCode(CloseStatus other) {
                return (this.code == other.code);
        }

        @Override
        public boolean equals(@Nullable Object other) {
                if (this == other) {
                        return true;
                }
                if (!(other instanceof CloseStatus)) {
                        return false;
                }
                CloseStatus otherStatus = (CloseStatus) other;
                return (this.code == otherStatus.code && ObjectUtils.nullSafeEquals(this.reason, otherStatus.reason));
        }

        @Override
        public int hashCode() {
                return this.code * 29 + ObjectUtils.nullSafeHashCode(this.reason);
        }

        @Override
        public String toString() {
                return "CloseStatus[code=" + this.code + ", reason=" + this.reason + "]";
        }

}