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Utilities helping with various *nix console topics. Mostly geared toward expressive and interactive command line applications.
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/*
 * Copyright (c) 2016, Stein Eldar Johnsen
 *
 * 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.
 */
package net.morimekta.console.args;

import java.util.function.Consumer;
import java.util.function.Predicate;

/**
 * An argument is a non-optioned CLI argument. Instead of having to match the
 * option name, it may use a predicate to test the value before applying.
 */
public class Argument extends BaseArgument {
    private final Consumer consumer;
    private final Predicate predicate;

    private boolean applied;

    /**
     * Create a default required argument.
     *
     * @param name The name of the argument.
     * @param usage The argument usage description.
     * @param consumer The argument consumer.
     */
    public Argument(String name,
                    String usage,
                    Consumer consumer) {
        this(name, usage, consumer, null, null, false, true, false);
    }

    /**
     * Create a default optional argument with default value.
     *
     * @param name The name of the argument.
     * @param usage The argument usage description.
     * @param consumer The argument consumer.
     * @param defaultValue The default value.
     */
    public Argument(String name,
                    String usage,
                    Consumer consumer,
                    String defaultValue) {
        this(name, usage, consumer, defaultValue, null, false, false, false);
    }

    /**
     * Create an argument instance.
     *
     * @param name The name of the argument.
     * @param usage The argument usage description.
     * @param consumer The argument consumer.
     * @param defaultValue The default value.
     * @param predicate A predicate to check if the argument should try to
     *                  consume the value.
     * @param repeated If the argument is repeated.
     * @param required If the argument is required.
     * @param hidden If the argument is hidden.
     */
    public Argument(String name,
                    String usage,
                    Consumer consumer,
                    String defaultValue,
                    Predicate predicate,
                    boolean repeated,
                    boolean required,
                    boolean hidden) {
        super(name, usage, defaultValue, repeated, required, hidden);
        this.consumer = consumer;
        this.predicate = predicate == null ? s -> true : predicate;
    }

    @Override
    public String getSingleLineUsage() {
        if (isHidden()) {
            return null;
        }

        StringBuilder sb = new StringBuilder();
        if (!isRequired()) {
            sb.append("[");
        }
        sb.append(getName());
        if (isRepeated()) {
            sb.append("...");
        }
        if (!isRequired()) {
            sb.append("]");
        }
        return sb.toString();
    }

    @Override
    public String getPrefix() {
        return getName();
    }

    @Override
    public void validate() throws ArgumentException {
        if (isRequired() && !applied) {
            throw new ArgumentException("Argument " + getName() + " is required");
        }
    }

    @Override
    public int apply(ArgumentList args) {
        if (applied && !isRepeated()) {
            return 0;
        }
        String cur = args.get(0);
        if (!predicate.test(cur)) {
            return 0;
        }
        applied = true;
        consumer.accept(cur);
        return 1;
    }
}