/*
 * #%L
 * SciJava Common shared library for SciJava software.
 * %%
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 * Wisconsin-Madison, Broad Institute of MIT and Harvard, Max Planck
 * Institute of Molecular Cell Biology and Genetics, University of
 * Konstanz, and KNIME GmbH.
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 *    this list of conditions and the following disclaimer.
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package org.scijava.console;

import java.util.HashSet;
import java.util.LinkedList;
import java.util.Set;

import org.scijava.plugin.AbstractHandlerPlugin;

/**
 * Abstract superclass of {@link ConsoleArgument} implementations.
 *
 * @author Curtis Rueden
 */
public abstract class AbstractConsoleArgument extends
	AbstractHandlerPlugin<LinkedList<String>> implements ConsoleArgument
{
	private int numArgs;
	private Set<String> flags;

	public AbstractConsoleArgument() {
		this(1, new String[0]);
	}

	public AbstractConsoleArgument(final String... flags) {
		this(1, flags);
	}
	
	public AbstractConsoleArgument(final int requiredArgs, final String... flags) {
		numArgs = requiredArgs;
		this.flags = new HashSet<>();
		for (final String s : flags) this.flags.add(s);
	}

	// -- Typed methods --

	@Override
	public boolean supports(final LinkedList<String> args) {
		if (args == null || args.size() < numArgs) return false;
		return isFlag(args);
	}

	// -- Internal methods --

	/**
	 * Check if the given list of arguments starts with a flag that matches this
	 * {@link ConsoleArgument}.
	 *
	 * @return true iff one of this argument's flags matches the first string in
	 *         the given list, or this argument has no explicit flags.
	 */
	protected boolean isFlag(final LinkedList<String> args) {
		return flags.isEmpty() || flags.contains(args.getFirst());
	}

	/**
	 * If the next argument is an appropriate parameter to a
	 * {@link ConsoleArgument}, retrieves it; otherwise, returns null.
	 *
	 * @return The first argument of the given list, if it does not
	 *         start with a {@code '-'} character; or null otherwise.
	 */
	protected String getParam(final LinkedList<String> args) {
		if (args.isEmpty()) return null;
		final String arg = args.getFirst();
		return arg.startsWith("-") ? null : arg;
	}
}
