/*
 * Copyright (C) 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.doclava;

public class SourcePositionInfo implements Comparable {
  public static final SourcePositionInfo UNKNOWN = new SourcePositionInfo("(unknown)", 0, 0);

  public SourcePositionInfo(String file, int line, int column) {
    this.file = file;
    this.line = line;
    this.column = column;
  }

  public SourcePositionInfo(SourcePositionInfo that) {
    this.file = that.file;
    this.line = that.line;
    this.column = that.column;
  }

  /**
   * Given this position and str which occurs at that position, as well as str an index into str,
   * find the SourcePositionInfo.
   * 
   * @throw StringIndexOutOfBoundsException if index > str.length()
   */
  public static SourcePositionInfo add(SourcePositionInfo that, String str, int index) {
    if (that == null) {
      return null;
    }
    int line = that.line;
    char prev = 0;
    for (int i = 0; i < index; i++) {
      char c = str.charAt(i);
      if (c == '\r' || (c == '\n' && prev != '\r')) {
        line++;
      }
      prev = c;
    }
    return new SourcePositionInfo(that.file, line, 0);
  }

  public static SourcePositionInfo findBeginning(SourcePositionInfo that, String str) {
    if (that == null) {
      return null;
    }
    int line = that.line - 1; // -1 because, well, it seems to work
    int prev = 0;
    for (int i = str.length() - 1; i >= 0; i--) {
      char c = str.charAt(i);
      if ((c == '\r' && prev != '\n') || (c == '\n')) {
        line--;
      }
      prev = c;
    }
    return new SourcePositionInfo(that.file, line, 0);
  }

  @Override
  public String toString() {
    return file + ':' + line;
  }

  public int compareTo(Object o) {
    SourcePositionInfo that = (SourcePositionInfo) o;
    int r = this.file.compareTo(that.file);
    if (r != 0) return r;
    return this.line - that.line;
  }
  
  /**
   * Build a SourcePositionInfo from the XML source= notation
   */
  public static SourcePositionInfo fromXml(String source) {
    if (source != null) {
      for (int i = 0; i < source.length(); i++) {
        if (source.charAt(i) == ':') {
          return new SourcePositionInfo(source.substring(0, i), Integer.parseInt(source
              .substring(i + 1)), 0);
        }
      }
    }

    return UNKNOWN;
  }

  public String file;
  public int line;
  public int column;
}