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/**
 * Copyright (c) 2010-2012 EBM WebSourcing, 2012-2023 Linagora
 * 
 * This program/library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 2.1 of the License, or (at your
 * option) any later version.
 * 
 * This program/library 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 Lesser General Public License
 * for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program/library; If not, see http://www.gnu.org/licenses/
 * for the GNU Lesser General Public License version 2.1.
 */
package org.ow2.petals.cli.command;

import java.util.Map;
import java.util.TreeMap;

import org.apache.commons.cli.CommandLine;
import org.ow2.petals.cli.api.command.AbstractCommand;
import org.ow2.petals.cli.api.command.Command;
import org.ow2.petals.cli.api.command.exception.CommandException;
import org.ow2.petals.cli.api.command.exception.CommandTooManyArgumentsException;

import com.ebmwebsourcing.easycommons.lang.StringHelper;

import jline.console.completer.Completer;
import jline.console.completer.StringsCompleter;

/**
 * This command print help about other commands in the shell.
 * @author Sebastien Andre - EBM WebSourcing
 * @author Alexandre Lagane - Linagora
 */
public class Help extends AbstractCommand {

    public Help() {
        super();
        this.setUsage(this.getName() + " ");
        this.setDescription("Display this help message or help for a specific command");
    }

    /**
     * {@inheritDoc}
     * 
     * 
     * Dedicated processing to the command 'help': No connection is required to
     * execute it.
     * 
     */
    @Override
    public boolean isConnectionRequired(CommandLine cli) {
        return false;
    }

    @Override
    public void doExecute(CommandLine cli, final String... args) throws CommandException {
        if (!this.checkArguments(args, 0, 1)) {
            throw new CommandTooManyArgumentsException(this, args);
        }

        final String message;
        if (args.length == 0) {
            message = this.getHelp();
        } else if (this.getShell().getCommands().containsKey(args[0])) {
            message = this.getHelpCommand(args[0]);
        } else {
            throw new CommandException(this, args[0] + ": unknown command");
        }

        this.getShell().getPrintStream().println(message);
    }

    private static String formatTitle(final String title) {
        return String.format("%n%s:%n", title);
    }

    private static String formatInfo(final String info) {
        return String.format("   %s%n", info);
    }

    private static String formatHelp(final String name, final String desc) {
        if (name.length() <= 8)
            return String.format("   %-10s  %s.%n", name, desc);

        return String.format("   %s%n               %s.%n", name, desc);
    }

    private String getHelp() {
        final Map descs = new TreeMap<>();

        for (final Command cmd : this.getShell().getCommands().values()) {
            final String name = cmd.getName();
            descs.put(name, cmd.getDescription());
        }

        final StringBuilder buffer = new StringBuilder();

        buffer.append(formatTitle("Available commands"));

        for (final Map.Entry entry : descs.entrySet()) {
            buffer.append(formatHelp(entry.getKey(), entry.getValue()));
        }

        buffer.append(formatTitle("For help on a specific command type"));
        buffer.append(formatInfo("help "));

        return buffer.toString();
    }

    private String getHelpCommand(final String name) {
        final Command cmd = this.getShell().getCommands().get(name);

        final String usage = cmd.getUsage();
        final String description = cmd.getDescription();
        final String optionDescription = cmd.getOptionsDescription();
        final String format;
        if (StringHelper.isNullOrEmpty(optionDescription)) {
            format = String.format("%nUSAGE:%n %s %s%n%nDESCRIPTION:%n %s%n", name, usage,
                    description);
        } else {
            format = String.format(
                    "%nUSAGE:%n %s %s%n%nDESCRIPTION:%n %s%n%nOPTIONS DESCRIPTION:%n%s%n", name,
                    usage, description, optionDescription);
        }
        return format;
    }

    @Override
    public Completer getDefaultCompleter() {
        return new StringsCompleter(this.getShell().getCommands().keySet());
    }

}