/*
    * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> 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.pgm;
  
  import java.lang.reflect.Constructor;
  import java.lang.reflect.InvocationTargetException;
  import java.text.MessageFormat;
  
  import org.eclipse.jgit.pgm.internal.CLIText;
  
  /**
   * Description of a command (a {@link org.eclipse.jgit.pgm.TextBuiltin}
   * subclass).
   * <p>
   * These descriptions are lightweight compared to creating a command instance
   * and are therefore suitable for catalogs of "known" commands without linking
   * the command's implementation and creating a dummy instance of the command.
   */
  public class CommandRef {
  	private final Class<? extends TextBuiltin> impl;
  
  	private final String name;
  
  	private String usage;
  
  	boolean common;
  
  	CommandRef(Class<? extends TextBuiltin> clazz) {
  		this(clazz, guessName(clazz));
  	}
  
  	CommandRef(Class<? extends TextBuiltin> clazz, Command cmd) {
  		this(clazz, cmd.name().length() > 0 ? cmd.name() : guessName(clazz));
  		usage = cmd.usage();
  		common = cmd.common();
  	}
  
  	private CommandRef(Class<? extends TextBuiltin> clazz, String cn) {
  		impl = clazz;
  		name = cn;
  		usage = ""; //$NON-NLS-1$
  	}
  
  	private static String guessName(Class<? extends TextBuiltin> clazz) {
  		final StringBuilder s = new StringBuilder();
  		if (clazz.getName().startsWith("org.eclipse.jgit.pgm.debug.")) //$NON-NLS-1$
  			s.append("debug-"); //$NON-NLS-1$
  
  		boolean lastWasDash = true;
  		for (char c : clazz.getSimpleName().toCharArray()) {
  			if (Character.isUpperCase(c)) {
  				if (!lastWasDash)
  					s.append('-');
  				lastWasDash = !lastWasDash;
  				s.append(Character.toLowerCase(c));
  			} else {
  				s.append(c);
  				lastWasDash = false;
  			}
  		}
  		return s.toString();
  	}
  
  	/**
  	 * Get the <code>name</code>.
  	 *
  	 * @return name the command is invoked as from the command line.
  	 */
  	public String getName() {
  		return name;
  	}
  
  	/**
  	 * Get <code>usage</code>.
  	 *
  	 * @return one line description of the command's feature set.
  	 */
  	public String getUsage() {
  		return usage;
  	}
  
  	/**
  	 * Is this command commonly used
  	 *
  	 * @return true if this command is considered to be commonly used.
  	 */
  	public boolean isCommon() {
  		return common;
  	}
  
  	/**
 	 * Get implementation class name
 	 *
 	 * @return name of the Java class which implements this command.
 	 */
 	public String getImplementationClassName() {
 		return impl.getName();
 	}
 
 	/**
 	 * Get implementation class loader
 	 *
 	 * @return loader for {@link #getImplementationClassName()}.
 	 */
 	public ClassLoader getImplementationClassLoader() {
 		return impl.getClassLoader();
 	}
 
 	/**
 	 * Create an instance of the command implementation
 	 *
 	 * @return a new instance of the command implementation.
 	 */
 	public TextBuiltin create() {
 		final Constructor<? extends TextBuiltin> c;
 		try {
 			c = impl.getDeclaredConstructor();
 		} catch (SecurityException | NoSuchMethodException e) {
 			throw new RuntimeException(MessageFormat
 					.format(CLIText.get().cannotCreateCommand, getName(), e));
 		}
 		c.setAccessible(true);
 
 		final TextBuiltin r;
 		try {
 			r = c.newInstance();
 		} catch (InstantiationException | IllegalAccessException
 				| IllegalArgumentException | InvocationTargetException e) {
 			throw new RuntimeException(MessageFormat
 					.format(CLIText.get().cannotCreateCommand, getName(), e));
 		}
 		r.setCommandName(getName());
 		return r;
 	}
 
 	/** {@inheritDoc} */
 	@SuppressWarnings("nls")
 	@Override
 	public String toString() {
 		return "CommandRef [impl=" + impl + ", name=" + name + ", usage="
 				+ CLIText.get().resourceBundle().getString(usage) + ", common="
 				+ common + "]";
 	}
 }