// Copyright (c) 2014, 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 services.correction.assist;

import 'dart:async';

import 'package:analysis_server/plugin/edit/assist/assist_core.dart';
import 'package:analysis_server/src/plugin/server_plugin.dart';
import 'package:analyzer/exception/exception.dart';
import 'package:analyzer/src/generated/engine.dart';
import 'package:analyzer/src/generated/source.dart';

/**
 * Compute and return the assists available at the given selection (described by
 * the [offset] and [length]) in the given [source]. The source was analyzed in
 * the given [analysisContext]. The [plugin] is used to get the list of assist
 * contributors.
 */
Future<List<Assist>> computeAssists(
    ServerPlugin plugin,
    AnalysisContext analysisContext,
    Source source,
    int offset,
    int length) async {
  List<Assist> assists = <Assist>[];
  List<AssistContributor> contributors = plugin.assistContributors;
  AssistContextImpl assistContext =
      new AssistContextImpl(analysisContext, source, offset, length);
  for (AssistContributor contributor in contributors) {
    try {
      List<Assist> contributedAssists =
          await contributor.computeAssists(assistContext);
      if (contributedAssists != null) {
        assists.addAll(contributedAssists);
      }
    } catch (exception, stackTrace) {
      AnalysisEngine.instance.logger.logError(
          'Exception from assist contributor: ${contributor.runtimeType}',
          new CaughtException(exception, stackTrace));
    }
  }
  assists.sort(Assist.SORT_BY_RELEVANCE);
  return assists;
}

/**
 * The implementation of [AssistContext].
 */
class AssistContextImpl implements AssistContext {
  @override
  final AnalysisContext analysisContext;

  @override
  final Source source;

  @override
  final int selectionOffset;

  @override
  final int selectionLength;

  AssistContextImpl(this.analysisContext, this.source, this.selectionOffset,
      this.selectionLength);
}

/**
 * An enumeration of possible assist kinds.
 */
class DartAssistKind {
  static const ADD_PART_DIRECTIVE =
      const AssistKind('ADD_PART_DIRECTIVE', 30, "Add 'part' directive");
  static const ADD_TYPE_ANNOTATION =
      const AssistKind('ADD_TYPE_ANNOTATION', 30, "Add type annotation");
  static const ASSIGN_TO_LOCAL_VARIABLE = const AssistKind(
      'ASSIGN_TO_LOCAL_VARIABLE', 30, "Assign value to new local variable");
  static const CONVERT_DOCUMENTATION_INTO_BLOCK = const AssistKind(
      'CONVERT_DOCUMENTATION_INTO_BLOCK',
      30,
      "Convert into block documentation comment");
  static const CONVERT_DOCUMENTATION_INTO_LINE = const AssistKind(
      'CONVERT_DOCUMENTATION_INTO_LINE',
      30,
      "Convert into line documentation comment");
  static const CONVERT_INTO_BLOCK_BODY = const AssistKind(
      'CONVERT_INTO_BLOCK_BODY', 30, "Convert into block body");
  static const CONVERT_INTO_EXPRESSION_BODY = const AssistKind(
      'CONVERT_INTO_EXPRESSION_BODY', 30, "Convert into expression body");
  static const CONVERT_INTO_FOR_INDEX = const AssistKind(
      'CONVERT_INTO_FOR_INDEX', 30, "Convert into for-index loop");
  static const CONVERT_INTO_FINAL_FIELD = const AssistKind(
      'CONVERT_INTO_FINAL_FIELD', 30, "Convert into final field");
  static const CONVERT_INTO_GETTER =
      const AssistKind('CONVERT_INTO_GETTER', 30, "Convert into getter");
  static const CONVERT_INTO_IS_NOT =
      const AssistKind('CONVERT_INTO_IS_NOT', 30, "Convert into is!");
  static const CONVERT_INTO_IS_NOT_EMPTY = const AssistKind(
      'CONVERT_INTO_IS_NOT_EMPTY', 30, "Convert into 'isNotEmpty'");
  static const CONVERT_TO_FIELD_PARAMETER = const AssistKind(
      'CONVERT_TO_FIELD_PARAMETER', 30, "Convert to field formal parameter");
  static const CONVERT_TO_NORMAL_PARAMETER = const AssistKind(
      'CONVERT_TO_NORMAL_PARAMETER', 30, "Convert to normal parameter");
  static const ENCAPSULATE_FIELD =
      const AssistKind('ENCAPSULATE_FIELD', 30, "Encapsulate field");
  static const EXCHANGE_OPERANDS =
      const AssistKind('EXCHANGE_OPERANDS', 30, "Exchange operands");
  static const EXTRACT_CLASS =
      const AssistKind('EXTRACT_CLASS', 30, "Extract class into file '{0}'");
  static const IMPORT_ADD_SHOW =
      const AssistKind('IMPORT_ADD_SHOW', 30, "Add explicit 'show' combinator");
  static const INTRODUCE_LOCAL_CAST_TYPE = const AssistKind(
      'INTRODUCE_LOCAL_CAST_TYPE', 30, "Introduce new local with tested type");
  static const INVERT_IF_STATEMENT =
      const AssistKind('INVERT_IF_STATEMENT', 30, "Invert 'if' statement");
  static const JOIN_IF_WITH_INNER = const AssistKind('JOIN_IF_WITH_INNER', 30,
      "Join 'if' statement with inner 'if' statement");
  static const JOIN_IF_WITH_OUTER = const AssistKind('JOIN_IF_WITH_OUTER', 30,
      "Join 'if' statement with outer 'if' statement");
  static const JOIN_VARIABLE_DECLARATION = const AssistKind(
      'JOIN_VARIABLE_DECLARATION', 30, "Join variable declaration");
  static const REMOVE_TYPE_ANNOTATION =
      const AssistKind('REMOVE_TYPE_ANNOTATION', 29, "Remove type annotation");
  static const REPLACE_CONDITIONAL_WITH_IF_ELSE = const AssistKind(
      'REPLACE_CONDITIONAL_WITH_IF_ELSE',
      30,
      "Replace conditional with 'if-else'");
  static const REPLACE_IF_ELSE_WITH_CONDITIONAL = const AssistKind(
      'REPLACE_IF_ELSE_WITH_CONDITIONAL',
      30,
      "Replace 'if-else' with conditional ('c ? x : y')");
  static const SPLIT_AND_CONDITION =
      const AssistKind('SPLIT_AND_CONDITION', 30, "Split && condition");
  static const SPLIT_VARIABLE_DECLARATION = const AssistKind(
      'SPLIT_VARIABLE_DECLARATION', 30, "Split variable declaration");
  static const SURROUND_WITH_BLOCK =
      const AssistKind('SURROUND_WITH_BLOCK', 30, "Surround with block");
  static const SURROUND_WITH_DO_WHILE = const AssistKind(
      'SURROUND_WITH_DO_WHILE', 30, "Surround with 'do-while'");
  static const SURROUND_WITH_FOR =
      const AssistKind('SURROUND_WITH_FOR', 30, "Surround with 'for'");
  static const SURROUND_WITH_FOR_IN =
      const AssistKind('SURROUND_WITH_FOR_IN', 30, "Surround with 'for-in'");
  static const SURROUND_WITH_IF =
      const AssistKind('SURROUND_WITH_IF', 30, "Surround with 'if'");
  static const SURROUND_WITH_TRY_CATCH = const AssistKind(
      'SURROUND_WITH_TRY_CATCH', 30, "Surround with 'try-catch'");
  static const SURROUND_WITH_TRY_FINALLY = const AssistKind(
      'SURROUND_WITH_TRY_FINALLY', 30, "Surround with 'try-finally'");
  static const SURROUND_WITH_WHILE =
      const AssistKind('SURROUND_WITH_WHILE', 30, "Surround with 'while'");
}