/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.hc.core5.reactor;

import org.apache.hc.core5.annotation.Contract;
import org.apache.hc.core5.annotation.ThreadingBehavior;
import org.apache.hc.core5.util.Args;

/**
 * I/O reactor configuration parameters.
 *
 * @since 4.2
 */
@Contract(threading = ThreadingBehavior.IMMUTABLE)
public final class IOReactorConfig {

    private static final int AVAIL_PROCS = Runtime.getRuntime().availableProcessors();

    public static final IOReactorConfig DEFAULT = new Builder().build();

    private final long selectInterval;
    private final int ioThreadCount;
    private final int soTimeout;
    private final boolean soReuseAddress;
    private final int soLinger;
    private final boolean soKeepAlive;
    private final boolean tcpNoDelay;
    private final int connectTimeout;
    private final int sndBufSize;
    private final int rcvBufSize;
    private final int backlogSize;

    IOReactorConfig(
            final long selectInterval,
            final int ioThreadCount,
            final int soTimeout,
            final boolean soReuseAddress,
            final int soLinger,
            final boolean soKeepAlive,
            final boolean tcpNoDelay,
            final int connectTimeout,
            final int sndBufSize,
            final int rcvBufSize,
            final int backlogSize) {
        super();
        this.selectInterval = selectInterval;
        this.ioThreadCount = ioThreadCount;
        this.soTimeout = soTimeout;
        this.soReuseAddress = soReuseAddress;
        this.soLinger = soLinger;
        this.soKeepAlive = soKeepAlive;
        this.tcpNoDelay = tcpNoDelay;
        this.connectTimeout = connectTimeout;
        this.sndBufSize = sndBufSize;
        this.rcvBufSize = rcvBufSize;
        this.backlogSize = backlogSize;
    }

    /**
     * Determines time interval in milliseconds at which the I/O reactor wakes up to check for
     * timed out sessions and session requests.
     * <p>
     * Default: {@code 1000} milliseconds.
     */
    public long getSelectInterval() {
        return this.selectInterval;
    }

    /**
     * Determines the number of I/O dispatch threads to be used by the I/O reactor.
     * <p>
     * Default: {@code 2}
     */
    public int getIoThreadCount() {
        return this.ioThreadCount;
    }

    /**
     * Determines the default socket timeout value for non-blocking I/O operations.
     * <p>
     * Default: {@code 0} (no timeout)
     *
     * @see java.net.SocketOptions#SO_TIMEOUT
     */
    public int getSoTimeout() {
        return soTimeout;
    }

    /**
     * Determines the default value of the {@link java.net.SocketOptions#SO_REUSEADDR} parameter
     * for newly created sockets.
     * <p>
     * Default: {@code false}
     *
     * @see java.net.SocketOptions#SO_REUSEADDR
     */
    public boolean isSoReuseAddress() {
        return soReuseAddress;
    }

    /**
     * Determines the default value of the {@link java.net.SocketOptions#SO_LINGER} parameter
     * for newly created sockets.
     * <p>
     * Default: {@code -1}
     *
     * @see java.net.SocketOptions#SO_LINGER
     */
    public int getSoLinger() {
        return soLinger;
    }

    /**
     * Determines the default value of the {@link java.net.SocketOptions#SO_KEEPALIVE} parameter
     * for newly created sockets.
     * <p>
     * Default: {@code -1}
     *
     * @see java.net.SocketOptions#SO_KEEPALIVE
     */
    public boolean isSoKeepalive() {
        return this.soKeepAlive;
    }

    /**
     * Determines the default value of the {@link java.net.SocketOptions#TCP_NODELAY} parameter
     * for newly created sockets.
     * <p>
     * Default: {@code false}
     *
     * @see java.net.SocketOptions#TCP_NODELAY
     */
    public boolean isTcpNoDelay() {
        return tcpNoDelay;
    }

    /**
     * Determines the default connect timeout value for non-blocking connection requests.
     * <p>
     * Default: {@code 0} (no timeout)
     */
    public int getConnectTimeout() {
        return connectTimeout;
    }

    /**
     * Determines the default value of the {@link java.net.SocketOptions#SO_SNDBUF} parameter
     * for newly created sockets.
     * <p>
     * Default: {@code 0} (system default)
     *
     * @see java.net.SocketOptions#SO_SNDBUF
     */
    public int getSndBufSize() {
        return sndBufSize;
    }

    /**
     * Determines the default value of the {@link java.net.SocketOptions#SO_RCVBUF} parameter
     * for newly created sockets.
     * <p>
     * Default: {@code 0} (system default)
     *
     * @see java.net.SocketOptions#SO_RCVBUF
     */
    public int getRcvBufSize() {
        return rcvBufSize;
    }

    /**
     * Determines the default backlog size value for server sockets binds.
     * <p>
     * Default: {@code 0} (system default)
     *
     * @since 4.4
     */
    public int getBacklogSize() {
        return backlogSize;
    }

    public static Builder custom() {
        return new Builder();
    }

    public static Builder copy(final IOReactorConfig config) {
        Args.notNull(config, "I/O reactor config");
        return new Builder()
            .setSelectInterval(config.getSelectInterval())
            .setIoThreadCount(config.getIoThreadCount())
            .setSoTimeout(config.getSoTimeout())
            .setSoReuseAddress(config.isSoReuseAddress())
            .setSoLinger(config.getSoLinger())
            .setSoKeepAlive(config.isSoKeepalive())
            .setTcpNoDelay(config.isTcpNoDelay())
            .setConnectTimeout(config.getConnectTimeout())
            .setSndBufSize(config.getSndBufSize())
            .setRcvBufSize(config.getRcvBufSize())
            .setBacklogSize(config.getBacklogSize());
    }

    public static class Builder {

        private long selectInterval;
        private int ioThreadCount;
        private int soTimeout;
        private boolean soReuseAddress;
        private int soLinger;
        private boolean soKeepAlive;
        private boolean tcpNoDelay;
        private int connectTimeout;
        private int sndBufSize;
        private int rcvBufSize;
        private int backlogSize;

        Builder() {
            this.selectInterval = 1000;
            this.ioThreadCount = AVAIL_PROCS;
            this.soTimeout = 0;
            this.soReuseAddress = false;
            this.soLinger = -1;
            this.soKeepAlive = false;
            this.tcpNoDelay = true;
            this.connectTimeout = 0;
            this.sndBufSize = 0;
            this.rcvBufSize = 0;
            this.backlogSize = 0;
        }

        public Builder setSelectInterval(final long selectInterval) {
            this.selectInterval = selectInterval;
            return this;
        }

        public Builder setIoThreadCount(final int ioThreadCount) {
            this.ioThreadCount = ioThreadCount;
            return this;
        }

        public Builder setSoTimeout(final int soTimeout) {
            this.soTimeout = soTimeout;
            return this;
        }

        public Builder setSoReuseAddress(final boolean soReuseAddress) {
            this.soReuseAddress = soReuseAddress;
            return this;
        }

        public Builder setSoLinger(final int soLinger) {
            this.soLinger = soLinger;
            return this;
        }

        public Builder setSoKeepAlive(final boolean soKeepAlive) {
            this.soKeepAlive = soKeepAlive;
            return this;
        }

        public Builder setTcpNoDelay(final boolean tcpNoDelay) {
            this.tcpNoDelay = tcpNoDelay;
            return this;
        }

        public Builder setConnectTimeout(final int connectTimeout) {
            this.connectTimeout = connectTimeout;
            return this;
        }

        public Builder setSndBufSize(final int sndBufSize) {
            this.sndBufSize = sndBufSize;
            return this;
        }

        public Builder setRcvBufSize(final int rcvBufSize) {
            this.rcvBufSize = rcvBufSize;
            return this;
        }

        public Builder setBacklogSize(final int backlogSize) {
            this.backlogSize = backlogSize;
            return this;
        }

        public IOReactorConfig build() {
            return new IOReactorConfig(
                    selectInterval, ioThreadCount, soTimeout, soReuseAddress, soLinger, soKeepAlive, tcpNoDelay,
                    connectTimeout, sndBufSize, rcvBufSize, backlogSize);
        }

    }

    @Override
    public String toString() {
        final StringBuilder builder = new StringBuilder();
        builder.append("[selectInterval=").append(this.selectInterval)
                .append(", ioThreadCount=").append(this.ioThreadCount)
                .append(", soTimeout=").append(this.soTimeout)
                .append(", soReuseAddress=").append(this.soReuseAddress)
                .append(", soLinger=").append(this.soLinger)
                .append(", soKeepAlive=").append(this.soKeepAlive)
                .append(", tcpNoDelay=").append(this.tcpNoDelay)
                .append(", connectTimeout=").append(this.connectTimeout)
                .append(", sndBufSize=").append(this.sndBufSize)
                .append(", rcvBufSize=").append(this.rcvBufSize)
                .append(", backlogSize=").append(this.backlogSize)
                .append("]");
        return builder.toString();
    }

}