// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

library entity_utils;

import 'entities.dart';

// Somewhat stable ordering for libraries using [Uri]s
int compareLibrariesUris(Uri a, Uri b) {
  if (a == b) return 0;

  int byCanonicalUriPath() {
    return a.path.compareTo(b.path);
  }

  // Order: platform < package < other.
  if (a.scheme == 'dart') {
    if (b.scheme == 'dart') return byCanonicalUriPath();
    return -1;
  }
  if (b.scheme == 'dart') return 1;

  if (a.scheme == 'package') {
    if (b.scheme == 'package') return byCanonicalUriPath();
    return -1;
  }
  if (b.scheme == 'package') return 1;

  return _compareCanonicalUri(a, b);
}

int _compareCanonicalUri(Uri a, Uri b) {
  int r = a.scheme.compareTo(b.scheme);
  if (r != 0) return r;

  // We would like the order of 'file:' Uris to be stable across different
  // users or different builds from temporary directories.  We sort by
  // pathSegments elements from the last to the first since that tends to find
  // a stable distinction regardless of directory root.
  List<String> aSegments = a.pathSegments;
  List<String> bSegments = b.pathSegments;
  int aI = aSegments.length;
  int bI = bSegments.length;
  while (aI > 0 && bI > 0) {
    String aSegment = aSegments[--aI];
    String bSegment = bSegments[--bI];
    r = aSegment.compareTo(bSegment);
    if (r != 0) return r;
  }
  return aI.compareTo(bI); // Shortest first.
}

/// Compare URIs of compilation units.
int compareSourceUris(Uri uri1, Uri uri2) {
  if (uri1 == uri2) return 0;
  // Compilation units are compared only within the same library so we expect
  // the Uris to usually be clustered together with a common scheme and path
  // prefix.
  return '${uri1}'.compareTo('${uri2}');
}

/// Compare entities within the same compilation unit.
int compareEntities(Entity element1, int line1, int column1, Entity element2,
    int line2, int column2) {
  line1 ??= -1;
  line2 ??= -1;
  int r = line1.compareTo(line2);
  if (r != 0) return r;

  column1 ??= -1;
  column2 ??= -1;
  r = column1.compareTo(column2);
  if (r != 0) return r;

  r = element1.name.compareTo(element2.name);
  if (r != 0) return r;

  // Same file, position and name.  If this happens, we should find out why
  // and make the order total and independent of hashCode.
  return element1.hashCode.compareTo(element2.hashCode);
}

String reconstructConstructorName(FunctionEntity element) {
  String className = element.enclosingClass.name;
  if (element.name == '') {
    return className;
  } else {
    return '$className\$${element.name}';
  }
}