/*
    * Copyright (C) 2014, 2021 Andrey Loskutov <loskutov@gmx.de> 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.ignore;
  
  import static org.eclipse.jgit.ignore.IMatcher.NO_MATCH;
  import static org.eclipse.jgit.ignore.internal.Strings.isDirectoryPattern;
  import static org.eclipse.jgit.ignore.internal.Strings.stripTrailing;
  import static org.eclipse.jgit.ignore.internal.Strings.stripTrailingWhitespace;
  
  import java.text.MessageFormat;
  
  import org.eclipse.jgit.errors.InvalidPatternException;
  import org.eclipse.jgit.ignore.internal.PathMatcher;
  import org.eclipse.jgit.internal.JGitText;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * "Fast" (compared with IgnoreRule) git ignore rule implementation supporting
   * also double star {@code **} pattern.
   * <p>
   * This class is immutable and thread safe.
   *
   * @since 3.6
   */
  public class FastIgnoreRule {
  	private static final Logger LOG = LoggerFactory
  			.getLogger(FastIgnoreRule.class);
  
  	/**
  	 * Character used as default path separator for ignore entries
  	 */
  	public static final char PATH_SEPARATOR = '/';
  
  	private IMatcher matcher;
  
  	private boolean inverse;
  
  	private boolean dirOnly;
  
  	/**
  	 * Constructor for FastIgnoreRule
  	 *
  	 * @param pattern
  	 *            ignore pattern as described in <a href=
  	 *            "https://www.kernel.org/pub/software/scm/git/docs/gitignore.html"
  	 *            >git manual</a>. If pattern is invalid or is not a pattern
  	 *            (comment), this rule doesn't match anything.
  	 */
  	public FastIgnoreRule(String pattern) {
  		this();
  		try {
  			parse(pattern);
  		} catch (InvalidPatternException e) {
  			LOG.error(MessageFormat.format(JGitText.get().badIgnorePattern,
  					e.getPattern()), e);
  		}
  	}
  
  	FastIgnoreRule() {
  		matcher = IMatcher.NO_MATCH;
  	}
  
  	void parse(String pattern) throws InvalidPatternException {
  		if (pattern == null) {
  			throw new IllegalArgumentException("Pattern must not be null!"); //$NON-NLS-1$
  		}
  		if (pattern.length() == 0) {
  			dirOnly = false;
  			inverse = false;
  			this.matcher = NO_MATCH;
  			return;
  		}
  		inverse = pattern.charAt(0) == '!';
  		if (inverse) {
  			pattern = pattern.substring(1);
  			if (pattern.length() == 0) {
  				dirOnly = false;
  				this.matcher = NO_MATCH;
  				return;
  			}
  		}
  		if (pattern.charAt(0) == '#') {
  			this.matcher = NO_MATCH;
  			dirOnly = false;
  			return;
  		}
  		if (pattern.charAt(0) == '\\' && pattern.length() > 1) {
  			char next = pattern.charAt(1);
  			if (next == '!' || next == '#') {
  				// remove backslash escaping first special characters
  				pattern = pattern.substring(1);
 			}
 		}
 		dirOnly = isDirectoryPattern(pattern);
 		if (dirOnly) {
 			pattern = stripTrailingWhitespace(pattern);
 			pattern = stripTrailing(pattern, PATH_SEPARATOR);
 			if (pattern.length() == 0) {
 				this.matcher = NO_MATCH;
 				return;
 			}
 		}
 		this.matcher = PathMatcher.createPathMatcher(pattern,
 				Character.valueOf(PATH_SEPARATOR), dirOnly);
 	}
 
 	/**
 	 * Returns true if a match was made. <br>
 	 * This function does NOT return the actual ignore status of the target!
 	 * Please consult {@link #getResult()} for the negation status. The actual
 	 * ignore status may be true or false depending on whether this rule is an
 	 * ignore rule or a negation rule.
 	 *
 	 * @param path
 	 *            Name pattern of the file, relative to the base directory of
 	 *            this rule
 	 * @param directory
 	 *            Whether the target file is a directory or not
 	 * @return True if a match was made. This does not necessarily mean that the
 	 *         target is ignored. Call {@link #getResult() getResult()} for the
 	 *         result.
 	 */
 	public boolean isMatch(String path, boolean directory) {
 		return isMatch(path, directory, false);
 	}
 
 	/**
 	 * Returns true if a match was made. <br>
 	 * This function does NOT return the actual ignore status of the target!
 	 * Please consult {@link #getResult()} for the negation status. The actual
 	 * ignore status may be true or false depending on whether this rule is an
 	 * ignore rule or a negation rule.
 	 *
 	 * @param path
 	 *            Name pattern of the file, relative to the base directory of
 	 *            this rule
 	 * @param directory
 	 *            Whether the target file is a directory or not
 	 * @param pathMatch
 	 *            {@code true} if the match is for the full path: see
 	 *            {@link IMatcher#matches(String, int, int)}
 	 * @return True if a match was made. This does not necessarily mean that the
 	 *         target is ignored. Call {@link #getResult() getResult()} for the
 	 *         result.
 	 * @since 4.11
 	 */
 	public boolean isMatch(String path, boolean directory, boolean pathMatch) {
 		if (path == null)
 			return false;
 		if (path.length() == 0)
 			return false;
 		boolean match = matcher.matches(path, directory, pathMatch);
 		return match;
 	}
 
 	/**
 	 * Whether the pattern is just a file name and not a path
 	 *
 	 * @return {@code true} if the pattern is just a file name and not a path
 	 */
 	public boolean getNameOnly() {
 		return !(matcher instanceof PathMatcher);
 	}
 
 	/**
 	 * Whether the pattern should match directories only
 	 *
 	 * @return {@code true} if the pattern should match directories only
 	 */
 	public boolean dirOnly() {
 		return dirOnly;
 	}
 
 	/**
 	 * Indicates whether the rule is non-negation or negation.
 	 *
 	 * @return True if the pattern had a "!" in front of it
 	 */
 	public boolean getNegation() {
 		return inverse;
 	}
 
 	/**
 	 * Indicates whether the rule is non-negation or negation.
 	 *
 	 * @return True if the target is to be ignored, false otherwise.
 	 */
 	public boolean getResult() {
 		return !inverse;
 	}
 
 	/**
 	 * Whether the rule never matches
 	 *
 	 * @return {@code true} if the rule never matches (comment line or broken
 	 *         pattern)
 	 * @since 4.1
 	 */
 	public boolean isEmpty() {
 		return matcher == NO_MATCH;
 	}
 
 	/** {@inheritDoc} */
 	@Override
 	public String toString() {
 		StringBuilder sb = new StringBuilder();
 		if (inverse)
 			sb.append('!');
 		sb.append(matcher);
 		if (dirOnly)
 			sb.append(PATH_SEPARATOR);
 		return sb.toString();
 
 	}
 
 	/** {@inheritDoc} */
 	@Override
 	public int hashCode() {
 		final int prime = 31;
 		int result = 1;
 		result = prime * result + (inverse ? 1231 : 1237);
 		result = prime * result + (dirOnly ? 1231 : 1237);
 		result = prime * result + ((matcher == null) ? 0 : matcher.hashCode());
 		return result;
 	}
 
 	/** {@inheritDoc} */
 	@Override
 	public boolean equals(Object obj) {
 		if (this == obj)
 			return true;
 		if (!(obj instanceof FastIgnoreRule))
 			return false;
 
 		FastIgnoreRule other = (FastIgnoreRule) obj;
 		if (inverse != other.inverse)
 			return false;
 		if (dirOnly != other.dirOnly)
 			return false;
 		return matcher.equals(other.matcher);
 	}
 }