// 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.

import 'package:analyzer/src/generated/utilities_general.dart';
import 'package:meta/meta.dart';
import 'package:path/path.dart' as path;

/**
 * Information about the root directory associated with an analysis context.
 *
 * Clients may not extend, implement or mix-in this class.
 */
class ContextRoot {
  /**
   * The path context to use when manipulating paths.
   */
  final path.Context pathContext;

  /**
   * The absolute path of the root directory containing the files to be
   * analyzed.
   */
  final String root;

  /**
   * A list of the absolute paths of files and directories within the root
   * directory that should not be analyzed.
   */
  final List<String> exclude;

  /**
   * An informative value for the file path that the analysis options were read
   * from. This value can be `null` if there is no analysis options file or if
   * the location of the file has not yet been discovered.
   */
  String optionsFilePath;

  /**
   * Initialize a newly created context root.
   */
  ContextRoot(this.root, this.exclude, {@required path.Context pathContext})
      : pathContext = pathContext ?? path.context;

  @override
  int get hashCode {
    int hash = 0;
    hash = JenkinsSmiHash.combine(hash, root.hashCode);
    hash = JenkinsSmiHash.combine(hash, exclude.hashCode);
    return JenkinsSmiHash.finish(hash);
  }

  @override
  bool operator ==(other) {
    if (other is ContextRoot) {
      return root == other.root &&
          _listEqual(exclude, other.exclude, (String a, String b) => a == b);
    }
    return false;
  }

  /**
   * Return `true` if the file with the given [filePath] is contained within
   * this context root. A file contained in a context root if it is within the
   * context [root] neither explicitly excluded or within one of the excluded
   * directories.
   */
  bool containsFile(String filePath) {
    if (!pathContext.isWithin(root, filePath)) {
      return false;
    }
    for (String excluded in exclude) {
      if (filePath == excluded || pathContext.isWithin(excluded, filePath)) {
        return false;
      }
    }
    return true;
  }

  /**
   * Compare the lists [listA] and [listB], using [itemEqual] to compare
   * list elements.
   */
  bool _listEqual<T>(List<T> listA, List<T> listB, bool itemEqual(T a, T b)) {
    if (listA == null) {
      return listB == null;
    }
    if (listB == null) {
      return false;
    }
    if (listA.length != listB.length) {
      return false;
    }
    for (int i = 0; i < listA.length; i++) {
      if (!itemEqual(listA[i], listB[i])) {
        return false;
      }
    }
    return true;
  }
}