private static String renderParameter(
     ValueParameterDescriptor descriptor, boolean named, BindingContext bindingContext) {
   StringBuilder builder = new StringBuilder();
   if (named) builder.append("[");
   if (descriptor.getVarargElementType() != null) {
     builder.append("vararg ");
   }
   builder
       .append(descriptor.getName())
       .append(": ")
       .append(DescriptorRenderer.TEXT.renderType(getActualParameterType(descriptor)));
   if (descriptor.hasDefaultValue()) {
     PsiElement element = BindingContextUtils.descriptorToDeclaration(bindingContext, descriptor);
     String defaultExpression = "?";
     if (element instanceof JetParameter) {
       JetParameter parameter = (JetParameter) element;
       JetExpression defaultValue = parameter.getDefaultValue();
       if (defaultValue != null) {
         if (defaultValue instanceof JetConstantExpression) {
           JetConstantExpression constantExpression = (JetConstantExpression) defaultValue;
           defaultExpression = constantExpression.getText();
           if (defaultExpression.length() > 10) {
             if (defaultExpression.startsWith("\"")) defaultExpression = "\"...\"";
             else if (defaultExpression.startsWith("\'")) defaultExpression = "\'...\'";
             else defaultExpression = defaultExpression.substring(0, 7) + "...";
           }
         }
       }
     }
     builder.append(" = ").append(defaultExpression);
   }
   if (named) builder.append("]");
   return builder.toString();
 }
 private static String renderParameter(ValueParameterDescriptor parameter, boolean named) {
   StringBuilder builder = new StringBuilder();
   if (named) builder.append("[");
   if (parameter.getVarargElementType() != null) {
     builder.append("vararg ");
   }
   builder
       .append(parameter.getName())
       .append(": ")
       .append(
           DescriptorRenderer.SHORT_NAMES_IN_TYPES.renderType(getActualParameterType(parameter)));
   if (DescriptorUtilPackage.hasDefaultValue(parameter)) {
     PsiElement parameterDeclaration = DescriptorToSourceUtils.descriptorToDeclaration(parameter);
     builder.append(" = ").append(getDefaultExpressionString(parameterDeclaration));
   }
   if (named) builder.append("]");
   return builder.toString();
 }
  @Override
  public void updateUI(
      Pair<? extends FunctionDescriptor, ResolutionFacade> itemToShow,
      @NotNull ParameterInfoUIContext context) {
    // todo: when we will have ability to pass Array as vararg, implement such feature here too?
    if (context == null
        || context.getParameterOwner() == null
        || !context.getParameterOwner().isValid()) {
      context.setUIComponentEnabled(false);
      return;
    }

    PsiElement parameterOwner = context.getParameterOwner();
    if (!(parameterOwner instanceof JetValueArgumentList)) {
      context.setUIComponentEnabled(false);
      return;
    }

    JetValueArgumentList argumentList = (JetValueArgumentList) parameterOwner;

    FunctionDescriptor functionDescriptor = itemToShow.first;
    ResolutionFacade resolutionFacade = itemToShow.second;

    List<ValueParameterDescriptor> valueParameters = functionDescriptor.getValueParameters();
    List<JetValueArgument> valueArguments = argumentList.getArguments();

    int currentParameterIndex = context.getCurrentParameterIndex();
    int boldStartOffset = -1;
    int boldEndOffset = -1;
    boolean isGrey = false;
    boolean isDeprecated = KotlinBuiltIns.isDeprecated(functionDescriptor);

    boolean[] usedIndexes = new boolean[valueParameters.size()];
    Arrays.fill(usedIndexes, false);

    boolean namedMode = false;

    if (!isIndexValid(valueParameters, currentParameterIndex)) {
      isGrey = true;
    }

    StringBuilder builder = new StringBuilder();

    PsiElement owner = context.getParameterOwner();
    BindingContext bindingContext =
        resolutionFacade.analyze((JetElement) owner, BodyResolveMode.FULL);

    for (int i = 0; i < valueParameters.size(); ++i) {
      if (i != 0) {
        builder.append(", ");
      }

      boolean highlightParameter =
          i == currentParameterIndex
              || (!namedMode
                  && i < currentParameterIndex
                  && Iterables.getLast(valueParameters).getVarargElementType() != null);

      if (highlightParameter) {
        boldStartOffset = builder.length();
      }

      if (!namedMode) {
        if (valueArguments.size() > i) {
          JetValueArgument argument = valueArguments.get(i);
          if (argument.isNamed()) {
            namedMode = true;
          } else {
            ValueParameterDescriptor param = valueParameters.get(i);
            builder.append(renderParameter(param, false));
            if (i <= currentParameterIndex
                && !isArgumentTypeValid(bindingContext, argument, param)) {
              isGrey = true;
            }
            usedIndexes[i] = true;
          }
        } else {
          ValueParameterDescriptor param = valueParameters.get(i);
          builder.append(renderParameter(param, false));
        }
      }

      if (namedMode) {
        boolean takeAnyArgument = true;
        if (valueArguments.size() > i) {
          JetValueArgument argument = valueArguments.get(i);
          if (argument.isNamed()) {
            for (int j = 0; j < valueParameters.size(); ++j) {
              JetSimpleNameExpression referenceExpression =
                  argument.getArgumentName().getReferenceExpression();
              ValueParameterDescriptor param = valueParameters.get(j);
              if (referenceExpression != null
                  && !usedIndexes[j]
                  && param.getName().equals(referenceExpression.getReferencedNameAsName())) {
                takeAnyArgument = false;
                usedIndexes[j] = true;
                builder.append(renderParameter(param, true));
                if (i < currentParameterIndex
                    && !isArgumentTypeValid(bindingContext, argument, param)) {
                  isGrey = true;
                }
                break;
              }
            }
          }
        }

        if (takeAnyArgument) {
          if (i < currentParameterIndex) {
            isGrey = true;
          }

          for (int j = 0; j < valueParameters.size(); ++j) {
            ValueParameterDescriptor param = valueParameters.get(j);
            if (!usedIndexes[j]) {
              usedIndexes[j] = true;
              builder.append(renderParameter(param, true));
              break;
            }
          }
        }
      }

      if (highlightParameter) {
        boldEndOffset = builder.length();
      }
    }

    if (valueParameters.size() == 0) {
      builder.append(CodeInsightBundle.message("parameter.info.no.parameters"));
    }

    assert !builder.toString().isEmpty()
        : "A message about 'no parameters' or some parameters should be present: "
            + functionDescriptor;

    Color color =
        isResolvedToDescriptor(argumentList, functionDescriptor, bindingContext)
            ? GREEN_BACKGROUND
            : context.getDefaultParameterColor();
    context.setupUIComponentPresentation(
        builder.toString(), boldStartOffset, boldEndOffset, isGrey, isDeprecated, false, color);
  }
  @Override
  public void updateUI(Object descriptor, ParameterInfoUIContext context) {
    // todo: when we will have ability to pass Array as vararg, implement such feature here too?
    if (context == null
        || context.getParameterOwner() == null
        || !context.getParameterOwner().isValid()) {
      return;
    }
    PsiElement parameterOwner = context.getParameterOwner();
    if (parameterOwner instanceof JetValueArgumentList) {
      JetValueArgumentList argumentList = (JetValueArgumentList) parameterOwner;
      if (descriptor instanceof FunctionDescriptor) {
        JetFile file = (JetFile) argumentList.getContainingFile();
        BindingContext bindingContext = AnalyzeSingleFileUtil.getContextForSingleFile(file);
        FunctionDescriptor functionDescriptor = (FunctionDescriptor) descriptor;
        StringBuilder builder = new StringBuilder();
        List<ValueParameterDescriptor> valueParameters = functionDescriptor.getValueParameters();
        List<JetValueArgument> valueArguments = argumentList.getArguments();
        int currentParameterIndex = context.getCurrentParameterIndex();
        int boldStartOffset = -1;
        int boldEndOffset = -1;
        boolean isGrey = false;
        boolean isDeprecated = false; // todo: add deprecation check
        Color color = context.getDefaultParameterColor();
        PsiElement parent = argumentList.getParent();
        if (parent instanceof JetCallElement) {
          JetCallElement callExpression = (JetCallElement) parent;
          JetExpression calleeExpression = callExpression.getCalleeExpression();
          JetSimpleNameExpression refExpression = null;
          if (calleeExpression instanceof JetSimpleNameExpression) {
            refExpression = (JetSimpleNameExpression) calleeExpression;
          } else if (calleeExpression instanceof JetConstructorCalleeExpression) {
            JetConstructorCalleeExpression constructorCalleeExpression =
                (JetConstructorCalleeExpression) calleeExpression;
            if (constructorCalleeExpression.getConstructorReferenceExpression()
                instanceof JetSimpleNameExpression) {
              refExpression =
                  (JetSimpleNameExpression)
                      constructorCalleeExpression.getConstructorReferenceExpression();
            }
          }
          if (refExpression != null) {
            DeclarationDescriptor declarationDescriptor =
                bindingContext.get(BindingContext.REFERENCE_TARGET, refExpression);
            if (declarationDescriptor != null) {
              if (declarationDescriptor == functionDescriptor) {
                color = GREEN_BACKGROUND;
              }
            }
          }
        }

        boolean[] usedIndexes = new boolean[valueParameters.size()];
        boolean namedMode = false;
        Arrays.fill(usedIndexes, false);
        if ((currentParameterIndex >= valueParameters.size()
                && (valueParameters.size() > 0 || currentParameterIndex > 0))
            && (valueParameters.size() == 0
                || valueParameters.get(valueParameters.size() - 1).getVarargElementType()
                    == null)) {
          isGrey = true;
        }
        if (valueParameters.size() == 0)
          builder.append(CodeInsightBundle.message("parameter.info.no.parameters"));
        for (int i = 0; i < valueParameters.size(); ++i) {
          if (i != 0) builder.append(", ");
          boolean highlightParameter =
              i == currentParameterIndex
                  || (!namedMode
                      && i < currentParameterIndex
                      && valueParameters.get(valueParameters.size() - 1).getVarargElementType()
                          != null);
          if (highlightParameter) boldStartOffset = builder.length();
          if (!namedMode) {
            if (valueArguments.size() > i) {
              JetValueArgument argument = valueArguments.get(i);
              if (argument.isNamed()) {
                namedMode = true;
              } else {
                ValueParameterDescriptor param = valueParameters.get(i);
                builder.append(renderParameter(param, false, bindingContext));
                if (i < currentParameterIndex) {
                  if (argument.getArgumentExpression() != null) {
                    // check type
                    JetType paramType = getActualParameterType(param);
                    JetType exprType =
                        bindingContext.get(
                            BindingContext.EXPRESSION_TYPE, argument.getArgumentExpression());
                    if (exprType != null
                        && !JetTypeChecker.INSTANCE.isSubtypeOf(exprType, paramType)) isGrey = true;
                  } else isGrey = true;
                }
                usedIndexes[i] = true;
              }
            } else {
              ValueParameterDescriptor param = valueParameters.get(i);
              builder.append(renderParameter(param, false, bindingContext));
            }
          }
          if (namedMode) {
            boolean takeAnyArgument = true;
            if (valueArguments.size() > i) {
              JetValueArgument argument = valueArguments.get(i);
              if (argument.isNamed()) {
                for (int j = 0; j < valueParameters.size(); ++j) {
                  JetSimpleNameExpression referenceExpression =
                      argument.getArgumentName().getReferenceExpression();
                  ValueParameterDescriptor param = valueParameters.get(j);
                  if (referenceExpression != null
                      && !usedIndexes[j]
                      && param.getName().equals(referenceExpression.getReferencedNameAsName())) {
                    takeAnyArgument = false;
                    usedIndexes[j] = true;
                    builder.append(renderParameter(param, true, bindingContext));
                    if (i < currentParameterIndex) {
                      if (argument.getArgumentExpression() != null) {
                        // check type
                        JetType paramType = getActualParameterType(param);
                        JetType exprType =
                            bindingContext.get(
                                BindingContext.EXPRESSION_TYPE, argument.getArgumentExpression());
                        if (exprType != null
                            && !JetTypeChecker.INSTANCE.isSubtypeOf(exprType, paramType))
                          isGrey = true;
                      } else isGrey = true;
                    }
                    break;
                  }
                }
              }
            }

            if (takeAnyArgument) {
              if (i < currentParameterIndex) isGrey = true;

              for (int j = 0; j < valueParameters.size(); ++j) {
                ValueParameterDescriptor param = valueParameters.get(j);
                if (!usedIndexes[j]) {
                  usedIndexes[j] = true;
                  builder.append(renderParameter(param, true, bindingContext));
                  break;
                }
              }
            }
          }
          if (highlightParameter) boldEndOffset = builder.length();
        }
        if (builder.toString().isEmpty()) context.setUIComponentEnabled(false);
        else
          context.setupUIComponentPresentation(
              builder.toString(),
              boldStartOffset,
              boldEndOffset,
              isGrey,
              isDeprecated,
              false,
              color);
      } else context.setUIComponentEnabled(false);
    }
  }