/*
    * Copyright (C) 2008-2009, Google Inc.
    * Copyright (C) 2009, Robin Rosenberg <robin.rosenberg@dewire.com> 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.transport;
  
  import java.io.IOException;
  import java.util.Collection;
  
  import org.eclipse.jgit.annotations.Nullable;
  import org.eclipse.jgit.lib.Config;
  import org.eclipse.jgit.lib.Config.SectionParser;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.transport.resolver.ServiceNotAuthorizedException;
  import org.eclipse.jgit.transport.resolver.ServiceNotEnabledException;
  
  /**
   * A service exposed by {@link org.eclipse.jgit.transport.Daemon} over anonymous
   * <code>git://</code>.
   */
  public abstract class DaemonService {
  	private final String command;
  
  	private final SectionParser<ServiceConfig> configKey;
  
  	private boolean enabled;
  
  	private boolean overridable;
  
  	DaemonService(String cmdName, String cfgName) {
  		command = cmdName.startsWith("git-") ? cmdName : "git-" + cmdName; //$NON-NLS-1$ //$NON-NLS-2$
  		configKey = cfg -> new ServiceConfig(DaemonService.this, cfg, cfgName);
  		overridable = true;
  	}
  
  	private static class ServiceConfig {
  		final boolean enabled;
  
  		ServiceConfig(final DaemonService service, final Config cfg,
  				final String name) {
  			enabled = cfg.getBoolean("daemon", name, service.isEnabled()); //$NON-NLS-1$
  		}
  	}
  
  	/**
  	 * Whether this service is enabled for invocation.
  	 *
  	 * @return whether this service is enabled for invocation.
  	 */
  	public boolean isEnabled() {
  		return enabled;
  	}
  
  	/**
  	 * Set if it is allowed to use this service
  	 *
  	 * @param on
  	 *            {@code true} to allow this service to be used; {@code false}
  	 *            to deny it.
  	 */
  	public void setEnabled(boolean on) {
  		enabled = on;
  	}
  
  	/** @return can this service be configured in the repository config file? */
  	/**
  	 * Whether this service can be configured in the repository config file
  	 *
  	 * @return whether this service can be configured in the repository config
  	 *         file
  	 */
  	public boolean isOverridable() {
  		return overridable;
  	}
  
  	/**
  	 * Whether to permit repositories to override this service's enabled state
  	 * with the <code>daemon.servicename</code> config setting.
  	 *
  	 * @param on
  	 *            {@code true} to permit repositories to override this service's
  	 *            enabled state with the <code>daemon.servicename</code> config
  	 *            setting.
  	 */
  	public void setOverridable(boolean on) {
  		overridable = on;
  	}
  
  	/**
  	 * Get name of the command requested by clients.
  	 *
  	 * @return name of the command requested by clients.
 	 */
 	public String getCommandName() {
 		return command;
 	}
 
 	/**
 	 * Determine if this service can handle the requested command.
 	 *
 	 * @param commandLine
 	 *            input line from the client.
 	 * @return true if this command can accept the given command line.
 	 */
 	public boolean handles(String commandLine) {
 		return command.length() + 1 < commandLine.length()
 				&& commandLine.charAt(command.length()) == ' '
 				&& commandLine.startsWith(command);
 	}
 
 	void execute(DaemonClient client, String commandLine,
 			@Nullable Collection<String> extraParameters)
 			throws IOException, ServiceNotEnabledException,
 			ServiceNotAuthorizedException {
 		final String name = commandLine.substring(command.length() + 1);
 		try (Repository db = client.getDaemon().openRepository(client, name)) {
 			if (isEnabledFor(db)) {
 				execute(client, db, extraParameters);
 			}
 		} catch (ServiceMayNotContinueException e) {
 			// An error when opening the repo means the client is expecting a ref
 			// advertisement, so use that style of error.
 			PacketLineOut pktOut = new PacketLineOut(client.getOutputStream());
 			pktOut.writeString("ERR " + e.getMessage() + "\n"); //$NON-NLS-1$ //$NON-NLS-2$
 		}
 	}
 
 	private boolean isEnabledFor(Repository db) {
 		if (isOverridable())
 			return db.getConfig().get(configKey).enabled;
 		return isEnabled();
 	}
 
 	abstract void execute(DaemonClient client, Repository db,
 			@Nullable Collection<String> extraParameters)
 			throws IOException, ServiceNotEnabledException,
 			ServiceNotAuthorizedException;
 }