/*
 * Copyright (C) 2018, Google LLC. and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
package org.eclipse.jgit.internal.transport.parser;


import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.jgit.annotations.NonNull;

/**
 * In a push, the client sends a list of commands. The first command
 * is special, as it can include a list of capabilities at its end.
 * <p>
 * For example:
 * "oid oid name\0cap1 cap cap3"
 * <p>
 * Not to be confused with {@link FirstWant}, nor with the first line
 * of the reference advertisement parsed by
 * {@code BasePackConnection.readAdvertisedRefs}.
 * <p>
 * This class parses the inputted command line and holds the results:
 * the actual command line and the capabilities.
 */
public final class FirstCommand {
	private final String line;
	private final Map<String, String> capabilities;

	/**
	 * Parse the first line of a receive-pack request.
	 *
	 * @param line
	 *            line from the client.
	 * @return an instance of FirstCommand with capabilities parsed out
	 */
	@NonNull
	public static FirstCommand fromLine(String line) {
		int nul = line.indexOf('\0');
		if (nul < 0) {
			return new FirstCommand(line,
					Collections.<String, String> emptyMap());
		}
		String[] splitCapablities = line.substring(nul + 1).split(" "); //$NON-NLS-1$
		Map<String, String> options = new HashMap<>();

		for (String c : splitCapablities) {
			int i = c.indexOf("="); //$NON-NLS-1$
			if (i != -1) {
				options.put(c.substring(0, i), c.substring(i + 1));
			} else {
				options.put(c, null);
			}
		}

		return new FirstCommand(line.substring(0, nul),
				Collections.<String, String> unmodifiableMap(options));
	}

	private FirstCommand(String line, Map<String, String> capabilities) {
		this.line = line;
		this.capabilities = capabilities;
	}

	/** @return non-capabilities part of the line. */
	@NonNull
	public String getLine() {
		return line;
	}

	/** @return capabilities parsed from the line, as an immutable map. */
	@NonNull
	public Map<String, String> getCapabilities() {
		return capabilities;
	}
}
