Arakne / Araknemu

 * This file is part of Araknemu.

 *

 * Araknemu 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 3 of the License, or

 * (at your option) any later version.

 *

 * Araknemu 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 Araknemu.  If not, see <https://www.gnu.org/licenses/>.

 *

 * Copyright (c) 2017-2020 Vincent Quatrevieux

 */

package fr.quatrevieux.araknemu.game.admin;

import fr.quatrevieux.araknemu.common.account.Permission;

import fr.quatrevieux.araknemu.game.admin.exception.CommandException;

import fr.quatrevieux.araknemu.game.admin.help.CommandHelp;

import java.util.Arrays;

import java.util.EnumSet;

import java.util.Set;

import java.util.function.Consumer;

import java.util.function.Supplier;

/**

 * Base command class

 */

public abstract class AbstractCommand<A> implements Command<A> {

    private CommandHelp help = new CommandHelp(this);

    private final EnumSet<Permission> permissions = EnumSet.of(Permission.ACCESS);

    private Supplier<A> argumentsFactory;

    private boolean initialized = false;

    /**

     * Build the command

     */

    protected abstract void build(Builder builder);

    @Override

    public CommandHelp help() {

        initialize();

        return help;

    }

    @Override

    public final Set<Permission> permissions() {

        initialize();

        return permissions;

    }

    @Override

    public A createArguments() {

        initialize();

        if (argumentsFactory != null) {

            return argumentsFactory.get();

        }

        return null;

    }

    /**

     * Raise a command error and stop execution of the command

     *

     * @param message The error message

     */

    private void initialize() {

        if (!initialized) {

            build(new Builder());

            initialized = true;

        }

    }

    protected final class Builder {

        /**

         * Define the command arguments factory

         *

         * Note: this method should be used only for annotated object argument.

         *       For other arguments type, prefer overrides the method {@link Command#createArguments()}

         */

        public Builder arguments(Supplier<A> constructor) {

            AbstractCommand.this.argumentsFactory = constructor;

            return this;

        }

        /**

         * Configure the help page

         *

         * <code>

         *     builder.help(

         *         formatter -> formatter

         *             .synopsis("my_command [option]")

         *             .options("--opt", "opt description")

         *             .example("my_command --opt", "example description")

         *     );

         * </code>

         */

        public Builder help(Consumer<CommandHelp.Builder> configurator) {

            help = help.modify(configurator);

            return this;

        }

        /**

         * Add required permissions

         */

        public Builder requires(Permission... permissions) {

            AbstractCommand.this.permissions.addAll(Arrays.asList(permissions));

            return this;

        }

    }

}