/*******************************************************************************
    * Copyright (c) 2014 Konrad Kügler 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.merge;
  
  import java.io.IOException;
  
  import org.eclipse.jgit.api.MergeCommand.FastForwardMode;
  import org.eclipse.jgit.lib.Config;
  import org.eclipse.jgit.lib.Config.SectionParser;
  import org.eclipse.jgit.lib.ConfigConstants;
  import org.eclipse.jgit.lib.Repository;
  
  /**
   * Holds configuration for merging into a given branch
   *
   * @since 3.3
   */
  public class MergeConfig {
  
  	/**
  	 * Get merge configuration for the current branch of the repository
  	 *
  	 * @param repo
  	 *            a {@link org.eclipse.jgit.lib.Repository} object.
  	 * @return merge configuration for the current branch of the repository
  	 */
  	public static MergeConfig getConfigForCurrentBranch(Repository repo) {
  		try {
  			String branch = repo.getBranch();
  			if (branch != null)
  				return repo.getConfig().get(getParser(branch));
  		} catch (IOException e) {
  			// ignore
  		}
  		// use defaults if branch can't be determined
  		return new MergeConfig();
  	}
  
  	/**
  	 * Get a parser for use with
  	 * {@link org.eclipse.jgit.lib.Config#get(SectionParser)}
  	 *
  	 * @param branch
  	 *            short branch name to get the configuration for, as returned
  	 *            e.g. by {@link org.eclipse.jgit.lib.Repository#getBranch()}
  	 * @return a parser for use with
  	 *         {@link org.eclipse.jgit.lib.Config#get(SectionParser)}
  	 */
  	public static final SectionParser<MergeConfig> getParser(
  			final String branch) {
  		return new MergeConfigSectionParser(branch);
  	}
  
  	private final FastForwardMode fastForwardMode;
  
  	private final boolean squash;
  
  	private final boolean commit;
  
  	private MergeConfig(String branch, Config config) {
  		String[] mergeOptions = getMergeOptions(branch, config);
  		fastForwardMode = getFastForwardMode(config, mergeOptions);
  		squash = isMergeConfigOptionSet("--squash", mergeOptions); //$NON-NLS-1$
  		commit = !isMergeConfigOptionSet("--no-commit", mergeOptions); //$NON-NLS-1$
  	}
  
  	private MergeConfig() {
  		fastForwardMode = FastForwardMode.FF;
  		squash = false;
  		commit = true;
  	}
  
  	/**
  	 * Get the fast forward mode configured for this branch
  	 *
  	 * @return the fast forward mode configured for this branch
  	 */
  	public FastForwardMode getFastForwardMode() {
  		return fastForwardMode;
  	}
  
  	/**
  	 * Whether merges into this branch are configured to be squash merges, false
  	 * otherwise
  	 *
  	 * @return true if merges into this branch are configured to be squash
  	 *         merges, false otherwise
  	 */
  	public boolean isSquash() {
  		return squash;
  	}
  
 	/**
 	 * Whether {@code --no-commit} option is not set.
 	 *
 	 * @return {@code false} if --no-commit is configured for this branch,
 	 *         {@code true} otherwise (even if --squash is configured)
 	 */
 	public boolean isCommit() {
 		return commit;
 	}
 
 	private static FastForwardMode getFastForwardMode(Config config,
 			String[] mergeOptions) {
 		for (String option : mergeOptions) {
 			for (FastForwardMode mode : FastForwardMode.values())
 				if (mode.matchConfigValue(option))
 					return mode;
 		}
 		FastForwardMode ffmode = FastForwardMode.valueOf(config.getEnum(
 				ConfigConstants.CONFIG_KEY_MERGE, null,
 				ConfigConstants.CONFIG_KEY_FF, FastForwardMode.Merge.TRUE));
 		return ffmode;
 	}
 
 	private static boolean isMergeConfigOptionSet(String optionToLookFor,
 			String[] mergeOptions) {
 		for (String option : mergeOptions) {
 			if (optionToLookFor.equals(option))
 				return true;
 		}
 		return false;
 	}
 
 	private static String[] getMergeOptions(String branch, Config config) {
 		String mergeOptions = config.getString(
 				ConfigConstants.CONFIG_BRANCH_SECTION, branch,
 				ConfigConstants.CONFIG_KEY_MERGEOPTIONS);
 		if (mergeOptions != null) {
 			return mergeOptions.split("\\s"); //$NON-NLS-1$
 		}
 		return new String[0];
 	}
 
 	private static class MergeConfigSectionParser implements
 			SectionParser<MergeConfig> {
 
 		private final String branch;
 
 		public MergeConfigSectionParser(String branch) {
 			this.branch = branch;
 		}
 
 		@Override
 		public MergeConfig parse(Config cfg) {
 			return new MergeConfig(branch, cfg);
 		}
 
 		@Override
 		public boolean equals(Object obj) {
 			if (obj instanceof MergeConfigSectionParser) {
 				return branch.equals(((MergeConfigSectionParser) obj).branch);
 			}
 			return false;
 		}
 
 		@Override
 		public int hashCode() {
 			return branch.hashCode();
 		}
 
 	}
 
 }