/*

 * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.jfr.internal.tool;

import java.io.PrintStream;

import java.util.Collections;

import java.util.Deque;

import java.util.List;

final class Help extends Command {

    @Override

    public String getName() {

        return "help";

    }

    @Override

    public List<String> getOptionSyntax() {

        return Collections.singletonList("[<command>]");

    }

    protected List<String> getAliases() {

        return List.of("--help", "-h", "-?");

    }

    @Override

    public void displayOptionUsage(PrintStream stream) {

        println("  <command>   The name of the command to get help for");

    }

    @Override

    public String getDescription() {

        return "Display all available commands, or help about a specific command";

    }

    @Override

    public void execute(Deque<String> options) throws UserSyntaxException, UserDataException {

        if (options.isEmpty()) {

            Command.displayHelp();

            return;

        }

        ensureMaxArgumentCount(options, 1);

        String commandName = options.remove();

        Command c = Command.valueOf(commandName);

        if (c == null) {

            throw new UserDataException("unknown command '" + commandName + "'");

        }

        println(c.getTitle());

        println();

        c.displayUsage(System.out);

    }

}