/*
    * Copyright (C) 2011, Robin Stocker <robin@nibor.org>
    * Copyright (C) 2012, Matthias Sohn <matthias.sohn@sap.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.lib;
  
  import java.net.URISyntaxException;
  
  import org.eclipse.jgit.transport.RefSpec;
  import org.eclipse.jgit.transport.RemoteConfig;
  
  /**
   * Branch section of a Git configuration file.
   */
  public class BranchConfig {
  
  	/**
  	 * Config values for branch.[name].rebase (and pull.rebase).
  	 *
  	 * @since 4.5
  	 */
  	public enum BranchRebaseMode implements Config.ConfigEnum {
  
  		/** Value for rebasing */
  		REBASE("true"), //$NON-NLS-1$
  		/** Value for rebasing preserving local merge commits */
  		PRESERVE("preserve"), //$NON-NLS-1$
  		/** Value for rebasing interactively */
  		INTERACTIVE("interactive"), //$NON-NLS-1$
  		/** Value for not rebasing at all but merging */
  		NONE("false"); //$NON-NLS-1$
  
  		private final String configValue;
  
  		private BranchRebaseMode(String configValue) {
  			this.configValue = configValue;
  		}
  
  		@Override
  		public String toConfigValue() {
  			return configValue;
  		}
  
  		@Override
  		public boolean matchConfigValue(String s) {
  			return configValue.equals(s);
  		}
  	}
  
  	/**
  	 * The value that means "local repository" for {@link #getRemote()}:
  	 * {@value}
  	 *
  	 * @since 3.5
  	 */
  	public static final String LOCAL_REPOSITORY = "."; //$NON-NLS-1$
  
  	private final Config config;
  	private final String branchName;
  
  	/**
  	 * Create a new branch config, which will read configuration from config
  	 * about specified branch.
  	 *
  	 * @param config
  	 *            the config to read from
  	 * @param branchName
  	 *            the short branch name of the section to read
  	 */
  	public BranchConfig(Config config, String branchName) {
  		this.config = config;
  		this.branchName = branchName;
  	}
  
  	/**
  	 * Get the full tracking branch name
  	 *
  	 * @return the full tracking branch name or <code>null</code> if it could
  	 *         not be determined
  	 */
  	public String getTrackingBranch() {
  		String remote = getRemoteOrDefault();
  		String mergeRef = getMerge();
  		if (remote == null || mergeRef == null)
  			return null;
  
  		if (isRemoteLocal())
  			return mergeRef;
  
  		return findRemoteTrackingBranch(remote, mergeRef);
  	}
  
 	/**
 	 * Get the full remote-tracking branch name
 	 *
 	 * @return the full remote-tracking branch name or {@code null} if it could
 	 *         not be determined. If you also want local tracked branches use
 	 *         {@link #getTrackingBranch()} instead.
 	 */
 	public String getRemoteTrackingBranch() {
 		String remote = getRemoteOrDefault();
 		String mergeRef = getMerge();
 		if (remote == null || mergeRef == null)
 			return null;
 
 		return findRemoteTrackingBranch(remote, mergeRef);
 	}
 
 	/**
 	 * Whether the "remote" setting points to the local repository (with
 	 * {@value #LOCAL_REPOSITORY})
 	 *
 	 * @return {@code true} if the "remote" setting points to the local
 	 *         repository (with {@value #LOCAL_REPOSITORY}), false otherwise
 	 * @since 3.5
 	 */
 	public boolean isRemoteLocal() {
 		return LOCAL_REPOSITORY.equals(getRemote());
 	}
 
 	/**
 	 * Get the remote this branch is configured to fetch from/push to
 	 *
 	 * @return the remote this branch is configured to fetch from/push to, or
 	 *         {@code null} if not defined
 	 * @since 3.5
 	 */
 	public String getRemote() {
 		return config.getString(ConfigConstants.CONFIG_BRANCH_SECTION,
 				branchName, ConfigConstants.CONFIG_KEY_REMOTE);
 	}
 
 	/**
 	 * Get the name of the upstream branch as it is called on the remote
 	 *
 	 * @return the name of the upstream branch as it is called on the remote, or
 	 *         {@code null} if not defined
 	 * @since 3.5
 	 */
 	public String getMerge() {
 		return config.getString(ConfigConstants.CONFIG_BRANCH_SECTION,
 				branchName, ConfigConstants.CONFIG_KEY_MERGE);
 	}
 
 	/**
 	 * Whether the branch is configured to be rebased
 	 *
 	 * @return {@code true} if the branch is configured to be rebased
 	 * @since 3.5
 	 */
 	public boolean isRebase() {
 		return getRebaseMode() != BranchRebaseMode.NONE;
 	}
 
 	/**
 	 * Retrieves the config value of branch.[name].rebase.
 	 *
 	 * @return the {@link org.eclipse.jgit.lib.BranchConfig.BranchRebaseMode}
 	 * @since 4.5
 	 */
 	public BranchRebaseMode getRebaseMode() {
 		return config.getEnum(BranchRebaseMode.values(),
 				ConfigConstants.CONFIG_BRANCH_SECTION, branchName,
 				ConfigConstants.CONFIG_KEY_REBASE, BranchRebaseMode.NONE);
 	}
 
 	/**
 	 * Finds the tracked remote tracking branch
 	 *
 	 * @param remote
 	 *            Remote name
 	 * @param mergeRef
 	 *            merge Ref of the local branch tracking the remote tracking
 	 *            branch
 	 * @return full remote tracking branch name or null
 	 */
 	private String findRemoteTrackingBranch(String remote, String mergeRef) {
 		RemoteConfig remoteConfig;
 		try {
 			remoteConfig = new RemoteConfig(config, remote);
 		} catch (URISyntaxException e) {
 			return null;
 		}
 		for (RefSpec refSpec : remoteConfig.getFetchRefSpecs()) {
 			if (refSpec.matchSource(mergeRef)) {
 				RefSpec expanded = refSpec.expandFromSource(mergeRef);
 				return expanded.getDestination();
 			}
 		}
 		return null;
 	}
 
 	private String getRemoteOrDefault() {
 		String remote = getRemote();
 		if (remote == null) {
 			return Constants.DEFAULT_REMOTE_NAME;
 		}
 		return remote;
 	}
 }