// Copyright (c) 2015, 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:analysis_server/src/provisional/completion/completion_core.dart';
import 'package:analysis_server/src/services/completion/completion_performance.dart';
import 'package:analyzer/dart/analysis/results.dart';
import 'package:analyzer/file_system/file_system.dart';
import 'package:analyzer/src/generated/source.dart';

/**
 * The information about a requested list of completions.
 */
class CompletionRequestImpl implements CompletionRequest {
  @override
  final ResolvedUnitResult result;

  @override
  final int offset;

  /**
   * The offset of the start of the text to be replaced.
   * This will be different than the [offset] used to request the completion
   * suggestions if there was a portion of an identifier before the original
   * [offset]. In particular, the [replacementOffset] will be the offset of the
   * beginning of said identifier.
   */
  int replacementOffset;

  /**
   * The length of the text to be replaced if the remainder of the identifier
   * containing the cursor is to be replaced when the suggestion is applied
   * (that is, the number of characters in the existing identifier).
   * This will be different than the [replacementOffset] - [offset]
   * if the [offset] is in the middle of an existing identifier.
   */
  int replacementLength;

  bool _aborted = false;

  final CompletionPerformance performance;

  /**
   * Initialize a newly created completion request based on the given arguments.
   */
  CompletionRequestImpl(this.result, int offset, this.performance)
      : this.offset = offset,
        replacementOffset = offset,
        replacementLength = 0;

  @override
  ResourceProvider get resourceProvider => result.session.resourceProvider;

  @override
  Source get source => result.unit.declaredElement.source;

  @override
  String get sourceContents => result?.content;

  /**
   * Abort the current completion request.
   */
  void abort() {
    _aborted = true;
  }

  @override
  void checkAborted() {
    if (_aborted) {
      throw new AbortCompletion();
    }
  }
}