library java.engine;

import 'java_core.dart';

class StringUtilities {
  static const String EMPTY = '';
  static const List<String> EMPTY_ARRAY = const <String> [];
  static String intern(String s) => s;
  static bool isTagName(String s) {
    if (s == null || s.length == 0) {
      return false;
    }
    int sz = s.length;
    for (int i = 0; i < sz; i++) {
      int c = s.codeUnitAt(i);
      if (!Character.isLetter(c)) {
        if (i == 0) {
          return false;
        }
        if (!Character.isDigit(c) && c != 0x2D) {
          return false;
        }
      }
    }
    return true;
  }
  static bool isEmpty(String s) {
    return s == null || s.isEmpty;
  }
  static String substringBefore(String str, String separator) {
    if (str == null || str.isEmpty) {
      return str;
    }
    int pos = str.indexOf(separator);
    if (pos < 0) {
      return str;
    }
    return str.substring(0, pos);
  }
  static endsWithChar(String str, int c) {
    int length = str.length;
    return length > 0 && str.codeUnitAt(length - 1) == c;
  }
  static endsWith3(String str, int c1, int c2, int c3) {
    var length = str.length;
    return length >= 3 &&
        str.codeUnitAt(length - 3) == c1 &&
        str.codeUnitAt(length - 2) == c2 &&
        str.codeUnitAt(length - 1) == c3;
  }

  static startsWithChar(String str, int c) {
    return str.length != 0 && str.codeUnitAt(0) == c;
  }
  static startsWith2(String str, int start, int c1, int c2) {
    return str.length - start >= 2 &&
        str.codeUnitAt(start) == c1 &&
        str.codeUnitAt(start + 1) == c2;
  }
  static startsWith3(String str, int start, int c1, int c2, int c3) {
    return str.length - start >= 3 &&
        str.codeUnitAt(start) == c1 &&
        str.codeUnitAt(start + 1) == c2 &&
        str.codeUnitAt(start + 2) == c3;
  }
  static startsWith4(String str, int start, int c1, int c2, int c3, int c4) {
    return str.length - start >= 4 &&
        str.codeUnitAt(start) == c1 &&
        str.codeUnitAt(start + 1) == c2 &&
        str.codeUnitAt(start + 2) == c3 &&
        str.codeUnitAt(start + 3) == c4;
  }
  static startsWith5(String str, int start, int c1, int c2, int c3, int c4,
      int c5) {
    return str.length - start >= 5 &&
        str.codeUnitAt(start) == c1 &&
        str.codeUnitAt(start + 1) == c2 &&
        str.codeUnitAt(start + 2) == c3 &&
        str.codeUnitAt(start + 3) == c4 &&
        str.codeUnitAt(start + 4) == c5;
  }
  static startsWith6(String str, int start, int c1, int c2, int c3, int c4,
      int c5, int c6) {
    return str.length - start >= 6 &&
        str.codeUnitAt(start) == c1 &&
        str.codeUnitAt(start + 1) == c2 &&
        str.codeUnitAt(start + 2) == c3 &&
        str.codeUnitAt(start + 3) == c4 &&
        str.codeUnitAt(start + 4) == c5 &&
        str.codeUnitAt(start + 5) == c6;
  }
  static int indexOf1(String str, int start, int c) {
    int index = start;
    int last = str.length;
    while (index < last) {
      if (str.codeUnitAt(index) == c) {
        return index;
      }
      index++;
    }
    return -1;
  }
  static int indexOf2(String str, int start, int c1, int c2) {
    int index = start;
    int last = str.length - 1;
    while (index < last) {
      if (str.codeUnitAt(index) == c1 && str.codeUnitAt(index + 1) == c2) {
        return index;
      }
      index++;
    }
    return -1;
  }
  static int indexOf4(String string, int start, int c1, int c2, int c3, int c4) {
    int index = start;
    int last = string.length - 3;
    while (index < last) {
      if (string.codeUnitAt(index) == c1 &&
          string.codeUnitAt(index + 1) == c2 &&
          string.codeUnitAt(index + 2) == c3 &&
          string.codeUnitAt(index + 3) == c4) {
        return index;
      }
      index++;
    }
    return -1;
  }
  static int indexOf5(String str, int start, int c1, int c2, int c3, int c4,
                      int c5) {
    int index = start;
    int last = str.length - 4;
    while (index < last) {
      if (str.codeUnitAt(index) == c1 &&
          str.codeUnitAt(index + 1) == c2 &&
          str.codeUnitAt(index + 2) == c3 &&
          str.codeUnitAt(index + 3) == c4 &&
          str.codeUnitAt(index + 4) == c5) {
        return index;
      }
      index++;
    }
    return -1;
  }
  static String substringBeforeChar(String str, int c) {
    if (isEmpty(str)) {
      return str;
    }
    int pos = indexOf1(str, 0, c);
    if (pos < 0) {
      return str;
    }
    return str.substring(0, pos);
  }
}

class FileNameUtilities {
  static String getExtension(String fileName) {
    if (fileName == null) {
      return "";
    }
    int index = fileName.lastIndexOf('.');
    if (index >= 0) {
      return fileName.substring(index + 1);
    }
    return "";
  }
}

class ArrayUtils {
  static List addAll(List target, List source) {
    List result = new List.from(target);
    result.addAll(source);
    return result;
  }
}

class ObjectUtilities {
  static int combineHashCodes(int first, int second) => first * 31 + second;
}

class UUID {
  static int __nextId = 0;
  final String id;
  UUID(this.id);
  String toString() => id;
  static UUID randomUUID() => new UUID((__nextId).toString());
}