/*
    * 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;
  	}
  }