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//
// Copyright 2020 Charles W. Rapp
//
// 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 net.sf.eBus.client.sysmessages;

import java.io.Serializable;
import java.util.Objects;
import net.sf.eBus.messages.EReplyMessage.ReplyStatus;
import net.sf.eBus.messages.ESystemMessage;
import net.sf.eBus.util.Validator;

/**
 * Response to a {@link UdpConnectRequest} containing the UDP
 * port to which the initiator should send packets. The idea is
 * that the {@code UdpConnectRequest} is sent to the UDP "server"
 * port which creates a new UDP channel bound to an ephemeral
 * port. It is this ephemeral port that is contained in this
 * message.
 *
 * @author Charles W. Rapp
 */

public final class UdpConnectReply
    extends ESystemMessage
    implements Serializable
{
//---------------------------------------------------------------
// Member data.
//

    //-----------------------------------------------------------
    // Constants.
    //

    /**
     * Serialization version identifier.
     */
    private static final long serialVersionUID = 0x050300L;

    //-----------------------------------------------------------
    // Locals.
    //

    /**
     * Set to {@code OK_FINAL} if the connection process
     * succeeded and {@code ERROR} if process failed.
     */
    public final ReplyStatus status;

    /**
     * Text explaining why a connect attempt failed. May be
     * {@code null} or empty if {@link #status} is
     * {@link ReplyStatus#OK_FINAL}.
     */
    public final String text;

    /**
     * UDP port to which the requester should communicate.
     */
    public final int port;

//---------------------------------------------------------------
// Member methods.
//

    //-----------------------------------------------------------
    // Constructors.
    //

    /**
     * Creates a new instance of UdpConnectReply.
     */
    private UdpConnectReply(final Builder builder)
    {
        super (builder);

        this.status = builder.mStatus;
        this.text = builder.mText;
        this.port = builder.mPort;
    } // end of UdpConnectReply(Builder)

    //
    // end of Constructors.
    //-----------------------------------------------------------

    //-----------------------------------------------------------
    // Object Method Overrides.
    //

    /**
     * Returns a human-readable text version of this message.
     * @return text version of this message.
     */
    @Override
    public String toString()
    {
        return (
            String.format(
                "%s%n                 status: %s%n                   text: %s%n                   port: %d",
                super.toString(),
                status,
                text,
                port));
    } // end of toString()

    //
    // end of Object Method Overrides.
    //-----------------------------------------------------------

    /**
     * Returns a new instance of the {@code ResumeReply} message
     * builder.
     * @return message builder instance.
     */
    public static Builder builder()
    {
        return (new Builder());
    } // end of builder()

//---------------------------------------------------------------
// Inner classes.
//

    /**
     * Collects a {@code UdpConnectReply} field settings and
     * provides validation.
     */
    public static final class Builder
        extends ESystemMessage.Builder
    {
    //-----------------------------------------------------------
    // Member data.
    //

        //-------------------------------------------------------
        // Locals.
        //

        private ReplyStatus mStatus;
        private String mText;
        private int mPort;

    //-----------------------------------------------------------
    // Member methods.
    //

        //-------------------------------------------------------
        // Constructors.
        //

        private Builder()
        {
            super (UdpConnectReply.class);

            mPort = -1;
        } // end of Builder()

        //
        // end of Constructors.
        //-------------------------------------------------------

        //-------------------------------------------------------
        // Builder Method Overrides.
        //

        /**
         * Returns a UDP connect reply based on {@code this}
         * builder's configuration.
         * @return new UDP connect reply instance.
         */
        @Override
        protected UdpConnectReply buildImpl()
        {
            return (new UdpConnectReply(this));
        } // end of buildImpl()

        /**
         * Checks if reply status and port are set.
         * @param problems used to check field validity and
         * collect discovered invalid fields.
         * @return {@code problems} to allow for method chaining.
         */
        @Override
        protected Validator validate(final Validator problems)
        {
            return (super.validate(problems)
                         .requireNotNull(mStatus, "status")
                         .requireTrue(v -> (mPort >= 0),
                                      mStatus,
                                      "port",
                                      Validator.NOT_SET));
        } // end of validate(Validator)

        //
        // end of Builder Method Overrides.
        //-------------------------------------------------------

        //-------------------------------------------------------
        // Set Methods.
        //

        public Builder status(final ReplyStatus status)
        {
            mStatus =
                Objects.requireNonNull(status, "status is null");

            return (this);
        } // end of status(ReplyStatus)

        public Builder text(final String text)
        {
            mText = text;

            return (this);
        } // end of text(String)


        public Builder port(final int port)
        {
            if (port <= 0)
            {
                throw (
                    new IllegalArgumentException(
                        "port " + port + " invalid"));
            }

            mPort = port;

            return (this);
        } // end of port(int)

        //
        // end of Set Methods.
        //-------------------------------------------------------
    } // end of class Builder
} // end of class UdpConnectReply