// Copyright (c) 2012, 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 dart2js.mirrors;

import 'dart:collection' show UnmodifiableListView;

import '../elements/elements.dart';
import '../scanner/scannerlib.dart';
import '../resolution/resolution.dart' show Scope;
import '../dart2jslib.dart';
import '../dart_types.dart';
import '../tree/tree.dart';
import '../util/util.dart' show Spannable, Link, LinkBuilder;
import '../util/characters.dart' show $CR, $LF;

import 'source_mirrors.dart';
import 'mirrors_util.dart';
import 'util.dart';

part 'dart2js_library_mirror.dart';
part 'dart2js_type_mirrors.dart';
part 'dart2js_member_mirrors.dart';
part 'dart2js_instance_mirrors.dart';

//------------------------------------------------------------------------------
// Utility types and functions for the dart2js mirror system
//------------------------------------------------------------------------------

bool _isPrivate(String name) {
  return name.startsWith('_');
}

List<ParameterMirror> _parametersFromFunctionSignature(
    Dart2JsDeclarationMirror owner,
    FunctionSignature signature) {
  var parameters = <ParameterMirror>[];
  Link<Element> link = signature.requiredParameters;
  while (!link.isEmpty) {
    parameters.add(new Dart2JsParameterMirror(
        owner, link.head, isOptional: false, isNamed: false));
    link = link.tail;
  }
  link = signature.optionalParameters;
  bool isNamed = signature.optionalParametersAreNamed;
  while (!link.isEmpty) {
    parameters.add(new Dart2JsParameterMirror(
        owner, link.head, isOptional: true, isNamed: isNamed));
    link = link.tail;
  }
  return parameters;
}

MethodMirror _convertElementMethodToMethodMirror(
    Dart2JsDeclarationMirror library, Element element) {
  if (element is FunctionElement) {
    return new Dart2JsMethodMirror(library, element);
  } else {
    return null;
  }
}

//------------------------------------------------------------------------------
// Dart2Js specific extensions of mirror interfaces
//------------------------------------------------------------------------------

abstract class Dart2JsMirror implements Mirror {
  Dart2JsMirrorSystem get mirrorSystem;
}

abstract class Dart2JsDeclarationMirror extends Dart2JsMirror
    implements DeclarationSourceMirror {

  bool get isTopLevel => owner != null && owner is LibraryMirror;

  bool get isPrivate => _isPrivate(_simpleNameString);

  String get _simpleNameString;

  String get _qualifiedNameString {
    var parent = owner;
    if (parent is Dart2JsDeclarationMirror) {
      return '${parent._qualifiedNameString}.${_simpleNameString}';
    }
    assert(parent == null);
    return _simpleNameString;
  }

  Symbol get simpleName => symbolOf(_simpleNameString, getLibrary(this));

  Symbol get qualifiedName => symbolOf(_qualifiedNameString, getLibrary(this));

  /**
   * Returns the first token for the source of this declaration, not including
   * metadata annotations.
   */
  Token getBeginToken();

  /**
   * Returns the last token for the source of this declaration.
   */
  Token getEndToken();

  /**
   * Returns the script for the source of this declaration.
   */
  Script getScript();

  /// Returns the type mirror for [type] in the context of this declaration.
  TypeMirror _getTypeMirror(DartType type, [FunctionSignature signature]) {
    return mirrorSystem._convertTypeToTypeMirror(type, signature);
  }

  /// Returns a list of the declaration mirrorSystem for [element].
  Iterable<Dart2JsMemberMirror> _getDeclarationMirrors(Element element) {
    if (element.isSynthesized) {
      return const <Dart2JsMemberMirror>[];
    } else if (element is VariableElement) {
      return <Dart2JsMemberMirror>[new Dart2JsFieldMirror(this, element)];
    } else if (element is FunctionElement) {
      return <Dart2JsMemberMirror>[new Dart2JsMethodMirror(this, element)];
    } else if (element is AbstractFieldElement) {
      var members = <Dart2JsMemberMirror>[];
      AbstractFieldElement field = element;
      if (field.getter != null) {
        members.add(new Dart2JsMethodMirror(this, field.getter));
      }
      if (field.setter != null) {
        members.add(new Dart2JsMethodMirror(this, field.setter));
      }
      return members;
    }
    mirrorSystem.compiler.internalError(
        "Unexpected member type $element ${element.kind}");
    return null;
  }

}

abstract class Dart2JsElementMirror extends Dart2JsDeclarationMirror {
  final Dart2JsMirrorSystem mirrorSystem;
  final Element _element;
  List<InstanceMirror> _metadata;

  Dart2JsElementMirror(this.mirrorSystem, this._element) {
    assert (mirrorSystem != null);
    assert (_element != null);
  }

  /**
   * Returns the element to be used to determine the begin token of this
   * declaration and the metadata associated with this declaration.
   *
   * This indirection is needed to use the [VariableListElement] as the location
   * for type and metadata information on a [VariableElement].
   */
  Element get _beginElement => _element;

  String get _simpleNameString => _element.name;

  bool get isNameSynthetic => false;

  /**
   * Computes the first token for this declaration using the begin token of the
   * element node or element position as indicator.
   */
  Token getBeginToken() {
    // TODO(johnniwinther): Avoid calling [parseNode].
    Node node = _beginElement.parseNode(mirrorSystem.compiler);
    if (node == null) {
      return _beginElement.position();
    }
    return node.getBeginToken();
  }

  /**
   * Computes the last token for this declaration using the end token of the
   * element node or element position as indicator.
   */
  Token getEndToken() {
    // TODO(johnniwinther): Avoid calling [parseNode].
    Node node = _element.parseNode(mirrorSystem.compiler);
    if (node == null) {
      return _element.position();
    }
    return node.getEndToken();
  }

  /**
   * Returns the first token for the source of this declaration, including
   * metadata annotations.
   */
  Token getFirstToken() {
    if (!_beginElement.metadata.isEmpty) {
      for (MetadataAnnotation metadata in _beginElement.metadata) {
        if (metadata.beginToken != null) {
          return metadata.beginToken;
        }
      }
    }
    return getBeginToken();
  }

  Script getScript() => _element.getCompilationUnit().script;

  SourceLocation get location {
    Token beginToken = getFirstToken();
    Script script = getScript();
    SourceSpan span;
    if (beginToken == null) {
      span = new SourceSpan(script.uri, 0, 0);
    } else {
      Token endToken = getEndToken();
      span = mirrorSystem.compiler.spanFromTokens(
          beginToken, endToken, script.uri);
    }
    return new Dart2JsSourceLocation(script, span);
  }

  String toString() => _element.toString();

  void _appendCommentTokens(Token commentToken) {
    while (commentToken != null && commentToken.kind == COMMENT_TOKEN) {
      _metadata.add(new Dart2JsCommentInstanceMirror(
          mirrorSystem, commentToken.value));
      commentToken = commentToken.next;
    }
  }

  List<InstanceMirror> get metadata {
    if (_metadata == null) {
      _metadata = <InstanceMirror>[];
      for (MetadataAnnotation metadata in _element.metadata) {
        _appendCommentTokens(
            mirrorSystem.compiler.commentMap[metadata.beginToken]);
        metadata.ensureResolved(mirrorSystem.compiler);
        _metadata.add(
            _convertConstantToInstanceMirror(mirrorSystem, metadata.value));
      }
      _appendCommentTokens(mirrorSystem.compiler.commentMap[getBeginToken()]);
    }
    // TODO(johnniwinther): Return an unmodifiable list instead.
    return new List<InstanceMirror>.from(_metadata);
  }

  DeclarationMirror lookupInScope(String name) {
    // TODO(11653): Support lookup of constructors.
    Scope scope = _element.buildScope();
    Element result;
    int index = name.indexOf('.');
    if (index != -1) {
      // Lookup [: prefix.id :].
      String prefix = name.substring(0, index);
      String id = name.substring(index+1);
      result = scope.lookup(prefix);
      if (result != null && result.isPrefix()) {
        PrefixElement prefix = result;
        result = prefix.lookupLocalMember(id);
      } else {
        result = null;
      }
    } else {
      // Lookup [: id :].
      result = scope.lookup(name);
    }
    if (result == null || result.isPrefix()) return null;
    return _convertElementToDeclarationMirror(mirrorSystem, result);
  }

  bool operator ==(var other) {
    if (identical(this, other)) return true;
    if (other == null) return false;
    if (other is! Dart2JsElementMirror) return false;
    return _element == other._element &&
           owner == other.owner;
  }

  int get hashCode {
    return 13 * _element.hashCode + 17 * owner.hashCode;
  }
}

//------------------------------------------------------------------------------
// Mirror system implementation.
//------------------------------------------------------------------------------

class Dart2JsMirrorSystem extends MirrorSystem {
  final Compiler compiler;
  Map<Uri, Dart2JsLibraryMirror> _libraries;
  Map<LibraryElement, Dart2JsLibraryMirror> _libraryMap;

  Dart2JsMirrorSystem(this.compiler)
    : _libraryMap = new Map<LibraryElement, Dart2JsLibraryMirror>();

  IsolateMirror get isolate => null;

  void _ensureLibraries() {
    if (_libraries == null) {
      _libraries = new Map<Uri, Dart2JsLibraryMirror>();
      compiler.libraries.forEach((_, LibraryElement v) {
        var mirror = new Dart2JsLibraryMirror(mirrorSystem, v);
        _libraries[mirror.uri] = mirror;
        _libraryMap[v] = mirror;
      });
    }
  }

  Map<Uri, LibraryMirror> get libraries {
    _ensureLibraries();
    return new FilteredImmutableMap<Uri, LibraryMirror>(_libraries,
        (library) => const bool.fromEnvironment("list_all_libraries") ||
                     !library._element.isInternalLibrary);
  }

  Dart2JsLibraryMirror _getLibrary(LibraryElement element) =>
      _libraryMap[element];

  Dart2JsMirrorSystem get mirrorSystem => this;

  TypeMirror get dynamicType =>
      _convertTypeToTypeMirror(compiler.types.dynamicType);

  TypeMirror get voidType =>
      _convertTypeToTypeMirror(compiler.types.voidType);

  TypeMirror _convertTypeToTypeMirror(DartType type,
                                      [FunctionSignature signature]) {
    assert(type != null);
    if (type.treatAsDynamic) {
      return new Dart2JsDynamicMirror(this, type);
    } else if (type is InterfaceType) {
      if (type.typeArguments.isEmpty) {
        return _getTypeDeclarationMirror(type.element);
      } else {
        return new Dart2JsInterfaceTypeMirror(this, type);
      }
    } else if (type is TypeVariableType) {
      return new Dart2JsTypeVariableMirror(this, type);
    } else if (type is FunctionType) {
      return new Dart2JsFunctionTypeMirror(this, type, signature);
    } else if (type is VoidType) {
      return new Dart2JsVoidMirror(this, type);
    } else if (type is TypedefType) {
      if (type.typeArguments.isEmpty) {
        return _getTypeDeclarationMirror(type.element);
      } else {
        return new Dart2JsTypedefMirror(this, type);
      }
    }
    compiler.internalError("Unexpected type $type of kind ${type.kind}");
    return null;
  }

  DeclarationMirror _getTypeDeclarationMirror(Element element) {
    if (element.isClass()) {
      return new Dart2JsClassDeclarationMirror(
          this, element.computeType(compiler));
    } else if (element.isTypedef()) {
      return new Dart2JsTypedefDeclarationMirror(this,
          element.computeType(compiler));
    }
    compiler.internalError("Unexpected element $element");
    return null;
  }
}

abstract class ContainerMixin {
  Map<Symbol, DeclarationMirror> _declarations;

  void _ensureDeclarations() {
    if (_declarations == null) {
      _declarations = <Symbol, DeclarationMirror>{};
      _forEachElement((Element element) {
        for (DeclarationMirror mirror in _getDeclarationMirrors(element)) {
          assert(invariant(_element,
              !_declarations.containsKey(mirror.simpleName),
              message: "Declaration name '${nameOf(mirror)}' "
                       "is not unique in $_element."));
          _declarations[mirror.simpleName] = mirror;
        }
      });
    }
  }

  Element get _element;

  void _forEachElement(f(Element element));

  Iterable<Dart2JsMemberMirror> _getDeclarationMirrors(Element element);

  Map<Symbol, DeclarationMirror> get declarations {
    _ensureDeclarations();
    return new ImmutableMapWrapper<Symbol, DeclarationMirror>(_declarations);
  }
}

/**
 * Converts [element] into its corresponding [DeclarationMirror], if any.
 *
 * If [element] is an [AbstractFieldElement] the mirror for its getter is
 * returned or, if not present, the mirror for its setter.
 */
DeclarationMirror _convertElementToDeclarationMirror(Dart2JsMirrorSystem system,
                                                     Element element) {
  if (element.isTypeVariable()) {
    return new Dart2JsTypeVariableMirror(
        system, element.computeType(system.compiler));
  }

  Dart2JsLibraryMirror library = system._libraryMap[element.getLibrary()];
  if (element.isLibrary()) return library;
  if (element.isTypedef()) {
    return new Dart2JsTypedefMirror.fromLibrary(
        library, element.computeType(system.compiler));
  }

  Dart2JsDeclarationMirror container = library;
  if (element.getEnclosingClass() != null) {
    container = system._getTypeDeclarationMirror(element.getEnclosingClass());
  }
  if (element.isClass()) return container;
  if (element.isParameter()) {
    Dart2JsMethodMirror method = _convertElementMethodToMethodMirror(
        container, element.getOutermostEnclosingMemberOrTopLevel());
    // TODO(johnniwinther): Find the right info for [isOptional] and [isNamed].
    return new Dart2JsParameterMirror(
        method, element, isOptional: false, isNamed: false);
  }
  Iterable<DeclarationMirror> members =
      container._getDeclarationMirrors(element);
  if (members.isEmpty) return null;
  return members.first;
}

/**
 * Experimental API for accessing compilation units defined in a
 * library.
 */
// TODO(ahe): Superclasses? Is this really a mirror?
class Dart2JsCompilationUnitMirror extends Dart2JsMirror
    with ContainerMixin {
  final Dart2JsLibraryMirror _library;
  final CompilationUnitElement _element;

  Dart2JsCompilationUnitMirror(this._element, this._library);

  Dart2JsMirrorSystem get mirrorSystem => _library.mirrorSystem;

  // TODO(johnniwinther): make sure that these are returned in declaration
  // order.
  void _forEachElement(f(Element element)) => _element.forEachLocalMember(f);

  Iterable<DeclarationMirror> _getDeclarationMirrors(Element element) =>
      _library._getDeclarationMirrors(element);

  Uri get uri => _element.script.uri;
}

/**
 * Transitional class that allows access to features that have not yet
 * made it to the mirror API.
 *
 * All API in this class is experimental.
 */
class BackDoor {
  /// Return the compilation units comprising [library].
  static List<Mirror> compilationUnitsOf(Dart2JsLibraryMirror library) {
    return library._element.compilationUnits.toList().map(
        (cu) => new Dart2JsCompilationUnitMirror(cu, library)).toList();
  }
}