/**
 * Creates a list of collection type references from the element types of a collection literal.
 */
protected List<LightweightTypeReference> computeCollectionTypeCandidates(XCollectionLiteral literal, JvmGenericType collectionType, LightweightTypeReference elementTypeExpectation, ITypeComputationState state) {
	List<XExpression> elements = literal.getElements();
	if(!elements.isEmpty()) {
		List<LightweightTypeReference> elementTypes = Lists.newArrayListWithCapacity(elements.size());
		for(XExpression element: elements) {
			ITypeComputationResult elementType = computeTypes(element, elementTypeExpectation, state);
			LightweightTypeReference actualType = elementType.getActualExpressionType();
			if(actualType != null && !actualType.isAny()) {
				ParameterizedTypeReference collectionTypeCandidate = state.getReferenceOwner().newParameterizedTypeReference(collectionType);
				collectionTypeCandidate.addTypeArgument(actualType.getWrapperTypeIfPrimitive());
				elementTypes.add(collectionTypeCandidate);
			}
		}
		return elementTypes;
	}
	return Collections.emptyList();
}
 

protected void appendImmutableCollectionExpression(XCollectionLiteral literal,
		ITreeAppendable b, String collectionsMethod, Class<?> guavaHelper, String guavaHelperMethod) {
	LightweightTypeReference collectionElementType = getCollectionElementType(literal);
	b.append(Collections.class);
	b.append(".<").append(collectionElementType).append(">").append(collectionsMethod).append("(");
	b.append(guavaHelper).append(".<").append(collectionElementType).append(">").append(guavaHelperMethod).append("(");
	boolean isFirst = true;
	for(XExpression element: literal.getElements())  {
		if(!isFirst)
			b.append(", ");
		isFirst = false;
		if(element instanceof XNullLiteral) {
			b.append("(").append(collectionElementType).append(")");
		}
		internalToJavaExpression(element, b);
	}
	b.append("))");
	return;
}
 

protected void _format(final XCollectionLiteral literal, @Extension final IFormattableDocument document) {
  final Procedure1<IHiddenRegionFormatter> _function = (IHiddenRegionFormatter it) -> {
    it.noSpace();
  };
  document.append(this.textRegionExtensions.regionFor(literal).keyword("#"), _function);
  ISemanticRegion _elvis = null;
  ISemanticRegion _keyword = this.textRegionExtensions.regionFor(literal).keyword("[");
  if (_keyword != null) {
    _elvis = _keyword;
  } else {
    ISemanticRegion _keyword_1 = this.textRegionExtensions.regionFor(literal).keyword("{");
    _elvis = _keyword_1;
  }
  final ISemanticRegion open = _elvis;
  ISemanticRegion _elvis_1 = null;
  ISemanticRegion _keyword_2 = this.textRegionExtensions.regionFor(literal).keyword("]");
  if (_keyword_2 != null) {
    _elvis_1 = _keyword_2;
  } else {
    ISemanticRegion _keyword_3 = this.textRegionExtensions.regionFor(literal).keyword("}");
    _elvis_1 = _keyword_3;
  }
  final ISemanticRegion close = _elvis_1;
  this.formatCommaSeparatedList(literal.getElements(), open, close, document);
}
 

protected void _format(final XCollectionLiteral literal, final FormattableDocument document) {
  final Procedure1<FormattingDataInit> _function = (FormattingDataInit it) -> {
    it.noSpace();
  };
  Function1<? super FormattableDocument, ? extends Iterable<FormattingData>> _append = this._formattingDataFactory.append(this._nodeModelAccess.nodeForKeyword(literal, "#"), _function);
  document.operator_add(_append);
  ILeafNode _elvis = null;
  ILeafNode _nodeForKeyword = this._nodeModelAccess.nodeForKeyword(literal, "[");
  if (_nodeForKeyword != null) {
    _elvis = _nodeForKeyword;
  } else {
    ILeafNode _nodeForKeyword_1 = this._nodeModelAccess.nodeForKeyword(literal, "{");
    _elvis = _nodeForKeyword_1;
  }
  final ILeafNode open = _elvis;
  ILeafNode _elvis_1 = null;
  ILeafNode _nodeForKeyword_2 = this._nodeModelAccess.nodeForKeyword(literal, "]");
  if (_nodeForKeyword_2 != null) {
    _elvis_1 = _nodeForKeyword_2;
  } else {
    ILeafNode _nodeForKeyword_3 = this._nodeModelAccess.nodeForKeyword(literal, "}");
    _elvis_1 = _nodeForKeyword_3;
  }
  final ILeafNode close = _elvis_1;
  this.formatCommaSeparatedList(literal.getElements(), open, close, document);
}
 

@Override
protected void appendImmutableCollectionExpression(final XCollectionLiteral literal, final ITreeAppendable b, final String collectionsMethod, final Class<?> guavaHelper, final String guavaHelperMethod) {
  // This is a work-around for a bug in the xbase compiler, which always constructs empty list literals #[] as List<Object>,
  // which then cannot be assigned (without cast) to any typed list. Note that this is not a problem in check; it also occurs
  // in plain xtend.
  if (literal.getElements().isEmpty()) {
    JvmType collectionsClass = findKnownTopLevelType(Collections.class, literal);
    if (collectionsClass != null) {
      if (literal instanceof XListLiteral) {
        b.append(collectionsClass).append(".emptyList()");
        return;
      } else if (literal instanceof XSetLiteral) {
        b.append(collectionsClass).append(".emptySet()");
        return;
      }
    }
  }
  super.appendImmutableCollectionExpression(literal, b, collectionsMethod, guavaHelper, guavaHelperMethod);
}
 

protected void setUnboundCollectionType(XCollectionLiteral literal, JvmGenericType collectionType, ITypeExpectation expectation,
		LightweightTypeReference elementTypeExpectation, ITypeComputationState state) {
	ParameterizedTypeReference unboundCollectionType = state.getReferenceOwner().newParameterizedTypeReference(collectionType);
	if (elementTypeExpectation != null) {
		unboundCollectionType.addTypeArgument(elementTypeExpectation);
	} else {
		UnboundTypeReference unboundTypeArgument = expectation.createUnboundTypeReference(literal, collectionType.getTypeParameters().get(0));
		unboundCollectionType.addTypeArgument(unboundTypeArgument);
	}
	expectation.acceptActualType(unboundCollectionType, ConformanceFlags.UNCHECKED);
}
 

/**
 * Process all children and assign an unknown type to the literal. 
 */
protected void handleCollectionTypeNotAvailable(XCollectionLiteral literal, ITypeComputationState state, Class<?> clazz) {
	for(XExpression element: literal.getElements()) {
		state.withNonVoidExpectation().computeTypes(element);
	}
	state.acceptActualType(state.getReferenceOwner().newUnknownTypeReference(clazz.getName()));
}
 

/**
 * @return whether the expression itself (not its children) possibly causes a side-effect
 */
public boolean hasSideEffects(XExpression expr) {
	if (expr instanceof XClosure
		|| expr instanceof XStringLiteral
		|| expr instanceof XTypeLiteral
		|| expr instanceof XBooleanLiteral
		|| expr instanceof XNumberLiteral
		|| expr instanceof XNullLiteral
		|| expr instanceof XAnnotation
		)
		return false;
	if(expr instanceof XCollectionLiteral) {
		for(XExpression element: ((XCollectionLiteral)expr).getElements()) {
			if(hasSideEffects(element))
				return true;
		}
		return false;
	}
	if (expr instanceof XAbstractFeatureCall) {
		XAbstractFeatureCall featureCall = (XAbstractFeatureCall) expr;
		return hasSideEffects(featureCall, true);
	}
	if (expr instanceof XConstructorCall) {
		XConstructorCall constrCall = (XConstructorCall) expr;
		return findPureAnnotation(constrCall.getConstructor()) == null;
	}
	return true;
}
 

protected LightweightTypeReference getCollectionElementType(XCollectionLiteral literal) {
	LightweightTypeReference type = getLightweightType(literal);
	if (type == null)
		throw new IllegalStateException();
	if(type.isArray()) {
		LightweightTypeReference result = type.getComponentType();
		if (result == null)
			throw new IllegalStateException();
		return result;
	}
	else if(type.isSubtypeOf(Collection.class) && type.hasTypeArguments()) {
		return type.getTypeArguments().get(0).getInvariantBoundSubstitute();
	}
	return type.getOwner().newReferenceToObject();
}
 

/** Ensure that the given type literal is equal to the given list.
 *
 * @param actual the type literal to test.
 * @param expected the name of the expected type.
 * @return the validation status
 */
public static boolean shouldBe(XCollectionLiteral actual, Object expected) {
	if (actual == null || actual.getElements() == null) {
		return false;
	}
	return shouldIterate(
			actual.getElements().iterator(),
			expected,
			!(actual instanceof XSetLiteral));
}
 

/** Test if the given expression has side effects.
 *
 * @param expression the expression.
 * @param context the list of context expressions.
 * @return {@code true} if the expression has side effects.
 */
protected Boolean _hasSideEffects(XCollectionLiteral expression, ISideEffectContext context) {
	context.open();
	try {
		for (final XExpression ex : expression.getElements()) {
			if (hasSideEffects(ex, context)) {
				return true;
			}
		}
	} finally {
		context.close();
	}
	return false;
}
 

protected void refineElementTypeExpectation(XCollectionLiteral literal, LightweightTypeReference expectation, ITypeComputationState state) {
	for (XExpression element : literal.getElements()) {
		state.refineExpectedType(element, expectation);
	}
}
 

protected void _findImplicitReturns(final XCollectionLiteral expression, final ImplicitReturnFinder.Acceptor acceptor) {
  acceptor.accept(expression);
}
 

public void findImplicitReturns(final XExpression expression, final ImplicitReturnFinder.Acceptor acceptor) {
  if (expression instanceof XAbstractFeatureCall) {
    _findImplicitReturns((XAbstractFeatureCall)expression, acceptor);
    return;
  } else if (expression instanceof XBlockExpression) {
    _findImplicitReturns((XBlockExpression)expression, acceptor);
    return;
  } else if (expression instanceof XBooleanLiteral) {
    _findImplicitReturns((XBooleanLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XCastedExpression) {
    _findImplicitReturns((XCastedExpression)expression, acceptor);
    return;
  } else if (expression instanceof XClosure) {
    _findImplicitReturns((XClosure)expression, acceptor);
    return;
  } else if (expression instanceof XCollectionLiteral) {
    _findImplicitReturns((XCollectionLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XConstructorCall) {
    _findImplicitReturns((XConstructorCall)expression, acceptor);
    return;
  } else if (expression instanceof XIfExpression) {
    _findImplicitReturns((XIfExpression)expression, acceptor);
    return;
  } else if (expression instanceof XInstanceOfExpression) {
    _findImplicitReturns((XInstanceOfExpression)expression, acceptor);
    return;
  } else if (expression instanceof XNullLiteral) {
    _findImplicitReturns((XNullLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XNumberLiteral) {
    _findImplicitReturns((XNumberLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XStringLiteral) {
    _findImplicitReturns((XStringLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XSwitchExpression) {
    _findImplicitReturns((XSwitchExpression)expression, acceptor);
    return;
  } else if (expression instanceof XSynchronizedExpression) {
    _findImplicitReturns((XSynchronizedExpression)expression, acceptor);
    return;
  } else if (expression instanceof XTryCatchFinallyExpression) {
    _findImplicitReturns((XTryCatchFinallyExpression)expression, acceptor);
    return;
  } else if (expression instanceof XTypeLiteral) {
    _findImplicitReturns((XTypeLiteral)expression, acceptor);
    return;
  } else if (expression != null) {
    _findImplicitReturns(expression, acceptor);
    return;
  } else if (expression == null) {
    _findImplicitReturns((Void)null, acceptor);
    return;
  } else {
    throw new IllegalArgumentException("Unhandled parameter types: " +
      Arrays.<Object>asList(expression, acceptor).toString());
  }
}
 

public void findImplicitReturns(final XExpression expression, final ImplicitReturnFinder.Acceptor acceptor) {
  if (expression instanceof AnonymousClass) {
    _findImplicitReturns((AnonymousClass)expression, acceptor);
    return;
  } else if (expression instanceof RichString) {
    _findImplicitReturns((RichString)expression, acceptor);
    return;
  } else if (expression instanceof XAbstractFeatureCall) {
    _findImplicitReturns((XAbstractFeatureCall)expression, acceptor);
    return;
  } else if (expression instanceof XBlockExpression) {
    _findImplicitReturns((XBlockExpression)expression, acceptor);
    return;
  } else if (expression instanceof XBooleanLiteral) {
    _findImplicitReturns((XBooleanLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XCastedExpression) {
    _findImplicitReturns((XCastedExpression)expression, acceptor);
    return;
  } else if (expression instanceof XClosure) {
    _findImplicitReturns((XClosure)expression, acceptor);
    return;
  } else if (expression instanceof XCollectionLiteral) {
    _findImplicitReturns((XCollectionLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XConstructorCall) {
    _findImplicitReturns((XConstructorCall)expression, acceptor);
    return;
  } else if (expression instanceof XIfExpression) {
    _findImplicitReturns((XIfExpression)expression, acceptor);
    return;
  } else if (expression instanceof XInstanceOfExpression) {
    _findImplicitReturns((XInstanceOfExpression)expression, acceptor);
    return;
  } else if (expression instanceof XNullLiteral) {
    _findImplicitReturns((XNullLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XNumberLiteral) {
    _findImplicitReturns((XNumberLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XStringLiteral) {
    _findImplicitReturns((XStringLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XSwitchExpression) {
    _findImplicitReturns((XSwitchExpression)expression, acceptor);
    return;
  } else if (expression instanceof XSynchronizedExpression) {
    _findImplicitReturns((XSynchronizedExpression)expression, acceptor);
    return;
  } else if (expression instanceof XTryCatchFinallyExpression) {
    _findImplicitReturns((XTryCatchFinallyExpression)expression, acceptor);
    return;
  } else if (expression instanceof XTypeLiteral) {
    _findImplicitReturns((XTypeLiteral)expression, acceptor);
    return;
  } else if (expression != null) {
    _findImplicitReturns(expression, acceptor);
    return;
  } else if (expression == null) {
    _findImplicitReturns((Void)null, acceptor);
    return;
  } else {
    throw new IllegalArgumentException("Unhandled parameter types: " +
      Arrays.<Object>asList(expression, acceptor).toString());
  }
}
 

/** Ensure that the given type literal is equal to the given type.
 *
 * @param actual the type literal to test.
 * @param expected the name of the expected type.
 * @return the validation status
 */
@SuppressWarnings({"checkstyle:returncount", "checkstyle:npathcomplexity"})
public static boolean shouldBeLiteral(XExpression actual, Object expected) {
	if (actual instanceof XNumberLiteral) {
		return shouldBe((XNumberLiteral) actual, expected);
	}
	if (actual instanceof XBooleanLiteral) {
		return shouldBe((XBooleanLiteral) actual, expected);
	}
	if (actual instanceof XStringLiteral) {
		return shouldBe((XStringLiteral) actual, expected);
	}
	if (actual instanceof XTypeLiteral) {
		return shouldBe((XTypeLiteral) actual, expected);
	}
	if (actual instanceof XNullLiteral) {
		return Objects.equals("null", expected); //$NON-NLS-1$
	}
	if (actual instanceof XCollectionLiteral) {
		return shouldBe((XCollectionLiteral) actual, expected);
	}
	if (actual instanceof XBinaryOperation) {
		final XBinaryOperation op = (XBinaryOperation) actual;
		if ("operator_mappedTo".equals(op.getFeature().getSimpleName())) { //$NON-NLS-1$
			final Object key;
			final Object value;
			if (expected instanceof Pair<?, ?>) {
				key = ((Pair<?, ?>) expected).getKey();
				value = ((Pair<?, ?>) expected).getValue();
			} else if (expected instanceof Entry<?, ?>) {
				key = ((Entry<?, ?>) expected).getKey();
				value = ((Entry<?, ?>) expected).getValue();
			} else {
				return false;
			}
			return shouldBeLiteral(op.getLeftOperand(), key)
					&& shouldBeLiteral(op.getRightOperand(), value);
		}
	}
	return false;
}
 

private static boolean isLiteral(XExpression expr) {
	return expr instanceof XBooleanLiteral || expr instanceof XStringLiteral
			|| expr instanceof XNumberLiteral || expr instanceof XCollectionLiteral
			|| expr instanceof XSetLiteral || expr instanceof XNullLiteral || expr instanceof XTypeLiteral;
}