// 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.completion.suggestion.builder;

import 'package:analysis_server/src/protocol_server.dart' as protocol;
import 'package:analysis_server/src/protocol_server.dart' hide Element,
    ElementKind;
import 'package:analysis_server/src/services/completion/dart_completion_manager.dart';
import 'package:analyzer/src/generated/ast.dart';
import 'package:analyzer/src/generated/element.dart';

/**
 * Call the given function with each non-null non-empty inherited type name
 * that is defined in the given class.
 */
visitInheritedTypeNames(ClassDeclaration node, void inherited(String name)) {

  void visit(TypeName type) {
    if (type != null) {
      Identifier id = type.name;
      if (id != null) {
        String name = id.name;
        if (name != null && name.length > 0) {
          inherited(name);
        }
      }
    }
  }

  ExtendsClause extendsClause = node.extendsClause;
  if (extendsClause != null) {
    visit(extendsClause.superclass);
  }
  ImplementsClause implementsClause = node.implementsClause;
  if (implementsClause != null) {
    NodeList<TypeName> interfaces = implementsClause.interfaces;
    if (interfaces != null) {
      interfaces.forEach((TypeName type) {
        visit(type);
      });
    }
  }
  WithClause withClause = node.withClause;
  if (withClause != null) {
    NodeList<TypeName> mixinTypes = withClause.mixinTypes;
    if (mixinTypes != null) {
      mixinTypes.forEach((TypeName type) {
        visit(type);
      });
    }
  }
}

/**
 * Call the given functions with each non-null non-empty inherited class
 * declaration, if the class is defined locally, or type name if it is not
 * defined locally.
 */
void visitInheritedTypes(ClassDeclaration node, void
    local(ClassDeclaration classNode), void imported(String typeName)) {
  CompilationUnit unit = node.getAncestor((p) => p is CompilationUnit);
  List<ClassDeclaration> todo = new List<ClassDeclaration>();
  todo.add(node);
  Set<String> visited = new Set<String>();
  while (todo.length > 0) {
    node = todo.removeLast();
    visitInheritedTypeNames(node, (String name) {
      if (visited.add(name)) {
        var classNode = unit.declarations.firstWhere((member) {
          if (member is ClassDeclaration) {
            SimpleIdentifier id = member.name;
            if (id != null && id.name == name) {
              return true;
            }
          }
          return false;
        }, orElse: () => null);
        if (classNode is ClassDeclaration) {
          local(classNode);
          todo.add(classNode);
        } else {
          imported(name);
        }
      }
    });
  }
}

/**
 * This class visits elements in a class and provides suggestions based upon
 * the visible members in that class. Clients should call
 * [ClassElementSuggestionBuilder.suggestionsFor].
 */
class ClassElementSuggestionBuilder extends _AbstractSuggestionBuilder {

  ClassElementSuggestionBuilder(DartCompletionRequest request) : super(request);

  @override
  visitClassElement(ClassElement element) {
    element.visitChildren(this);
    element.allSupertypes.forEach((InterfaceType type) {
      type.element.visitChildren(this);
    });
  }

  @override
  visitElement(Element element) {
    // ignored
  }

  @override
  visitFieldElement(FieldElement element) {
    _addElementSuggestion(
        element,
        CompletionSuggestionKind.GETTER,
        element.type,
        element.enclosingElement);
  }

  @override
  visitMethodElement(MethodElement element) {
    if (element.isOperator) {
      return;
    }
    _addElementSuggestion(
        element,
        CompletionSuggestionKind.METHOD,
        element.returnType,
        element.enclosingElement);
  }

  @override
  visitPropertyAccessorElement(PropertyAccessorElement element) {
    if (element.isGetter) {
      _addElementSuggestion(
          element,
          CompletionSuggestionKind.GETTER,
          element.returnType,
          element.enclosingElement);
    } else if (element.isSetter) {
      _addElementSuggestion(
          element,
          CompletionSuggestionKind.SETTER,
          element.returnType,
          element.enclosingElement);
    }
  }

  /**
   * Add suggestions for the visible members in the given class
   */
  static void suggestionsFor(DartCompletionRequest request, Element element) {
    if (element is ClassElement) {
      return element.accept(new ClassElementSuggestionBuilder(request));
    }
  }
}

/**
 * This class visits elements in a library and provides suggestions based upon
 * the visible members in that library. Clients should call
 * [LibraryElementSuggestionBuilder.suggestionsFor].
 */
class LibraryElementSuggestionBuilder extends _AbstractSuggestionBuilder {

  LibraryElementSuggestionBuilder(DartCompletionRequest request)
      : super(request);

  @override
  visitClassElement(ClassElement element) {
    _addElementSuggestion(element, CompletionSuggestionKind.CLASS, null, null);
  }

  @override
  visitCompilationUnitElement(CompilationUnitElement element) {
    element.visitChildren(this);
  }

  @override
  visitElement(Element element) {
    // ignored
  }

  @override
  visitFunctionElement(FunctionElement element) {
    _addElementSuggestion(
        element,
        CompletionSuggestionKind.FUNCTION,
        element.returnType,
        null);
  }

  @override
  visitFunctionTypeAliasElement(FunctionTypeAliasElement element) {
    _addElementSuggestion(
        element,
        CompletionSuggestionKind.FUNCTION_TYPE_ALIAS,
        element.returnType,
        null);
  }

  @override
  visitTopLevelVariableElement(TopLevelVariableElement element) {
    _addElementSuggestion(
        element,
        CompletionSuggestionKind.TOP_LEVEL_VARIABLE,
        element.type,
        null);
  }

  /**
   * Add suggestions for the visible members in the given library
   */
  static void suggestionsFor(DartCompletionRequest request,
      LibraryElement library) {
    if (library != null) {
      library.visitChildren(new LibraryElementSuggestionBuilder(request));
    }
  }
}

/**
 * This class visits elements in a class and provides suggestions based upon
 * the visible named constructors in that class. Clients should call
 * [NamedConstructorSuggestionBuilder.suggestionsFor].
 */
class NamedConstructorSuggestionBuilder extends _AbstractSuggestionBuilder {

  NamedConstructorSuggestionBuilder(DartCompletionRequest request)
      : super(request);

  @override
  visitClassElement(ClassElement element) {
    element.visitChildren(this);
  }

  @override
  visitConstructorElement(ConstructorElement element) {
    _addElementSuggestion(
        element,
        CompletionSuggestionKind.CONSTRUCTOR,
        element.returnType,
        element.enclosingElement);
  }

  @override
  visitElement(Element element) {
    // ignored
  }

  /**
   * Add suggestions for the visible members in the given class
   */
  static void suggestionsFor(DartCompletionRequest request, Element element) {
    if (element is ClassElement) {
      element.accept(new NamedConstructorSuggestionBuilder(request));
    }
  }
}

/**
 * Common superclass for sharing behavior
 */
class _AbstractSuggestionBuilder extends GeneralizingElementVisitor {
  final DartCompletionRequest request;
  final Set<String> _completions = new Set<String>();

  _AbstractSuggestionBuilder(this.request);

  void _addElementSuggestion(Element element, CompletionSuggestionKind kind,
      DartType type, ClassElement enclosingElement) {
    if (element.isSynthetic) {
      return;
    }
    if (element.isPrivate) {
      LibraryElement elementLibrary = element.library;
      LibraryElement unitLibrary = request.unit.element.library;
      if (elementLibrary != unitLibrary) {
        return;
      }
    }
    String completion = element.displayName;
    if (completion == null ||
        completion.length <= 0 ||
        !_completions.add(completion)) {
      return;
    }
    CompletionSuggestion suggestion = new CompletionSuggestion(
        kind,
        CompletionRelevance.DEFAULT,
        completion,
        completion.length,
        0,
        element.isDeprecated,
        false);
    suggestion.element = protocol.newElement_fromEngine(element);
    if (suggestion.element != null) {
      if (element is FieldElement) {
        suggestion.element.kind = protocol.ElementKind.GETTER;
        suggestion.element.returnType =
            element.type != null ? element.type.displayName : 'dynamic';
      }
    }
    if (enclosingElement != null) {
      suggestion.declaringType = enclosingElement.displayName;
    }
    if (type != null) {
      String typeName = type.displayName;
      if (typeName != null && typeName.length > 0 && typeName != 'dynamic') {
        suggestion.returnType = typeName;
      }
    }
    request.suggestions.add(suggestion);
  }
}