/*
    * Copyright (C) 2010, Red Hat Inc. 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.attributes;
  
  import static java.nio.charset.StandardCharsets.UTF_8;
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  /**
   * Represents a bundle of attributes inherited from a base directory.
   *
   * This class is not thread safe, it maintains state about the last match.
   *
   * @since 3.7
   */
  public class AttributesNode {
  	/** The rules that have been parsed into this node. */
  	private final List<AttributesRule> rules;
  
  	/**
  	 * Create an empty ignore node with no rules.
  	 */
  	public AttributesNode() {
  		rules = new ArrayList<>();
  	}
  
  	/**
  	 * Create an ignore node with given rules.
  	 *
  	 * @param rules
  	 *            list of rules.
  	 */
  	public AttributesNode(List<AttributesRule> rules) {
  		this.rules = rules;
  	}
  
  	/**
  	 * Parse files according to gitattribute standards.
  	 *
  	 * @param in
  	 *            input stream holding the standard ignore format. The caller is
  	 *            responsible for closing the stream.
  	 * @throws java.io.IOException
  	 *             Error thrown when reading an ignore file.
  	 */
  	public void parse(InputStream in) throws IOException {
  		BufferedReader br = asReader(in);
  		String txt;
  		while ((txt = br.readLine()) != null) {
  			txt = txt.trim();
  			if (txt.length() > 0 && !txt.startsWith("#") /* Comments *///$NON-NLS-1$
  					&& !txt.startsWith("!") /* Negative pattern forbidden for attributes */) { //$NON-NLS-1$
  				int patternEndSpace = txt.indexOf(' ');
  				int patternEndTab = txt.indexOf('\t');
  
  				final int patternEnd;
  				if (patternEndSpace == -1)
  					patternEnd = patternEndTab;
  				else if (patternEndTab == -1)
  					patternEnd = patternEndSpace;
  				else
  					patternEnd = Math.min(patternEndSpace, patternEndTab);
  
  				if (patternEnd > -1)
  					rules.add(new AttributesRule(txt.substring(0, patternEnd),
  							txt.substring(patternEnd + 1).trim()));
  			}
  		}
  	}
  
  	private static BufferedReader asReader(InputStream in) {
  		return new BufferedReader(new InputStreamReader(in, UTF_8));
  	}
  
  	/**
  	 * Getter for the field <code>rules</code>.
  	 *
  	 * @return list of all ignore rules held by this node
  	 */
  	public List<AttributesRule> getRules() {
  		return Collections.unmodifiableList(rules);
  	}
  
  }