/*

 * 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.cmd;

import java.nio.file.Files;

import java.nio.file.Path;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Deque;

import java.util.List;

abstract class Command {

    private final static Command HELP = new HelpCommand();

    private final static List<Command> COMMANDS = createCommands();

    static void displayHelp() {

        System.out.println("Usage: java " + Execute.class.getName() + " <command> [<options>]");

        System.out.println();

        displayAvailableCommands();

    }

    static void displayAvailableCommands() {

        System.out.println("Available commands are:");

        System.out.println();

        boolean first = true;

        for (Command c : Command.COMMANDS) {

            if (!first) {

                System.out.println();

            }

            System.out.println("  " + c.getName() + " " + c.getOptionSyntax());

            System.out.println("    " + c.getDescription());

            first = false;

        }

    }

    public static List<Command> getCommands() {

        return COMMANDS;

    }

    public static Command valueOf(String commandName) {

        for (Command command : COMMANDS) {

            if (command.getName().equals(commandName)) {

                return command;

            }

        }

        return null;

    }

    abstract public String getOptionSyntax();

    abstract public String getName();

    abstract public String getDescription();

    abstract public void displayOptionUsage();

    abstract public void execute(Deque<String> options);

    final protected void userFailed(String message) {

        println();

        println(message);

        displayUsage();

        throw new IllegalArgumentException(message);

    }

    final protected void ensureMaxArgumentCount(Deque<String> options, int maxCount) {

        if (options.size() > maxCount) {

            userFailed("Too many arguments");

        }

    }

    final protected void ensureMinArgumentCount(Deque<String> options, int minCount) {

        if (options.size() < minCount) {

            userFailed("Too few arguments");

        }

    }

    final protected void ensureFileExist(Path file) {

        if (!Files.exists(file)) {

            userFailed("Could not find file " + file);

        }

    }

    final protected Path ensureFileDoesNotExist(Path file) {

        if (Files.exists(file)) {

            userFailed("File " + file + " already exists");

        }

        return file;

    }

    final protected void ensureJFRFile(Path path) {

        if (!path.toString().endsWith(".jfr")) {

            userFailed("Filename must end with .jfr");

        }

    }

    final protected void displayUsage() {

        String javaText = "java " + Execute.class.getName();

        println();

        println("Usage: " + javaText + " " + getName() + " " + getOptionSyntax());

        println();

        displayOptionUsage();

    }

    final protected void println() {

        System.out.println();

    }

    final protected void print(String text) {

        System.out.print(text);

    }

    final protected void println(String text) {

        System.out.println(text);

    }

    private static List<Command> createCommands() {

        List<Command> commands = new ArrayList<>();

        commands.add(new PrintCommand());

        commands.add(new SummaryCommand());

        commands.add(new ReconstructCommand());

        commands.add(new SplitCommand());

        commands.add(HELP);

        return Collections.unmodifiableList(commands);

    }

}