/// <summary>
        /// Update the autocomplete metadata provider when the user connects to a database
        /// </summary>
        /// <param name="info"></param>
        public async Task UpdateLanguageServiceOnConnection(ConnectionInfo info)
        {
            await Task.Run(() =>
            {
                ScriptParseInfo scriptInfo = GetScriptParseInfo(info.OwnerUri, createIfNotExists: true);
                if (Monitor.TryEnter(scriptInfo.BuildingMetadataLock, LanguageService.OnConnectionWaitTimeout))
                {
                    try
                    {
                        scriptInfo.ConnectionKey = this.BindingQueue.AddConnectionContext(info);
                        scriptInfo.IsConnected   = true;
                    }
                    catch (Exception ex)
                    {
                        Logger.Write(LogLevel.Error, "Unknown error in OnConnection " + ex.ToString());
                        scriptInfo.IsConnected = false;
                    }
                    finally
                    {
                        // Set Metadata Build event to Signal state.
                        // (Tell Language Service that I am ready with Metadata Provider Object)
                        Monitor.Exit(scriptInfo.BuildingMetadataLock);
                    }
                }

                AutoCompleteHelper.PrepopulateCommonMetadata(info, scriptInfo, this.BindingQueue);
            });
        }
        /// <summary>
        /// Get quick info hover tooltips for the current position
        /// </summary>
        /// <param name="textDocumentPosition"></param>
        /// <param name="scriptFile"></param>
        internal Hover GetHoverItem(TextDocumentPosition textDocumentPosition, ScriptFile scriptFile)
        {
            int startLine   = textDocumentPosition.Position.Line;
            int startColumn = TextUtilities.PositionOfPrevDelimeter(
                scriptFile.Contents,
                textDocumentPosition.Position.Line,
                textDocumentPosition.Position.Character);
            int endColumn = textDocumentPosition.Position.Character;

            ScriptParseInfo scriptParseInfo = GetScriptParseInfo(textDocumentPosition.TextDocument.Uri);

            if (scriptParseInfo != null && scriptParseInfo.ParseResult != null)
            {
                if (Monitor.TryEnter(scriptParseInfo.BuildingMetadataLock))
                {
                    try
                    {
                        QueueItem queueItem = this.BindingQueue.QueueBindingOperation(
                            key: scriptParseInfo.ConnectionKey,
                            bindingTimeout: LanguageService.HoverTimeout,
                            bindOperation: (bindingContext, cancelToken) =>
                        {
                            // get the current quick info text
                            Babel.CodeObjectQuickInfo quickInfo = Resolver.GetQuickInfo(
                                scriptParseInfo.ParseResult,
                                startLine + 1,
                                endColumn + 1,
                                bindingContext.MetadataDisplayInfoProvider);

                            // convert from the parser format to the VS Code wire format
                            return(AutoCompleteHelper.ConvertQuickInfoToHover(
                                       quickInfo,
                                       startLine,
                                       startColumn,
                                       endColumn));
                        });

                        queueItem.ItemProcessed.WaitOne();
                        return(queueItem.GetResultAsT <Hover>());
                    }
                    finally
                    {
                        Monitor.Exit(scriptParseInfo.BuildingMetadataLock);
                    }
                }
            }

            // return null if there isn't a tooltip for the current location
            return(null);
        }
        /// <summary>
        /// Preinitialize the parser and binder with common metadata.
        /// This should front load the long binding wait to the time the
        /// connection is established.  Once this is completed other binding
        /// requests should be faster.
        /// </summary>
        /// <param name="info"></param>
        /// <param name="scriptInfo"></param>
        internal static void PrepopulateCommonMetadata(
            ConnectionInfo info,
            ScriptParseInfo scriptInfo,
            ConnectedBindingQueue bindingQueue)
        {
            if (scriptInfo.IsConnected)
            {
                var scriptFile = AutoCompleteHelper.WorkspaceServiceInstance.Workspace.GetFile(info.OwnerUri);
                LanguageService.Instance.ParseAndBind(scriptFile, info);

                if (Monitor.TryEnter(scriptInfo.BuildingMetadataLock, LanguageService.OnConnectionWaitTimeout))
                {
                    try
                    {
                        QueueItem queueItem = bindingQueue.QueueBindingOperation(
                            key: scriptInfo.ConnectionKey,
                            bindingTimeout: AutoCompleteHelper.PrepopulateBindTimeout,
                            waitForLockTimeout: AutoCompleteHelper.PrepopulateBindTimeout,
                            bindOperation: (bindingContext, cancelToken) =>
                        {
                            // parse a simple statement that returns common metadata
                            ParseResult parseResult = Parser.Parse(
                                "select ",
                                bindingContext.ParseOptions);

                            List <ParseResult> parseResults = new List <ParseResult>();
                            parseResults.Add(parseResult);
                            bindingContext.Binder.Bind(
                                parseResults,
                                info.ConnectionDetails.DatabaseName,
                                BindMode.Batch);

                            // get the completion list from SQL Parser
                            var suggestions = Resolver.FindCompletions(
                                parseResult, 1, 8,
                                bindingContext.MetadataDisplayInfoProvider);

                            // this forces lazy evaluation of the suggestion metadata
                            AutoCompleteHelper.ConvertDeclarationsToCompletionItems(suggestions, 1, 8, 8);

                            parseResult = Parser.Parse(
                                "exec ",
                                bindingContext.ParseOptions);

                            parseResults = new List <ParseResult>();
                            parseResults.Add(parseResult);
                            bindingContext.Binder.Bind(
                                parseResults,
                                info.ConnectionDetails.DatabaseName,
                                BindMode.Batch);

                            // get the completion list from SQL Parser
                            suggestions = Resolver.FindCompletions(
                                parseResult, 1, 6,
                                bindingContext.MetadataDisplayInfoProvider);

                            // this forces lazy evaluation of the suggestion metadata
                            AutoCompleteHelper.ConvertDeclarationsToCompletionItems(suggestions, 1, 6, 6);
                            return(null);
                        });

                        queueItem.ItemProcessed.WaitOne();
                    }
                    catch
                    {
                    }
                    finally
                    {
                        Monitor.Exit(scriptInfo.BuildingMetadataLock);
                    }
                }
            }
        }
        /// <summary>
        /// Return the completion item list for the current text position.
        /// This method does not await cache builds since it expects to return quickly
        /// </summary>
        /// <param name="textDocumentPosition"></param>
        public CompletionItem[] GetCompletionItems(
            TextDocumentPosition textDocumentPosition,
            ScriptFile scriptFile,
            ConnectionInfo connInfo)
        {
            // initialize some state to parse and bind the current script file
            this.currentCompletionParseInfo = null;
            CompletionItem[] resultCompletionItems = null;
            string           filePath = textDocumentPosition.TextDocument.Uri;
            int startLine             = textDocumentPosition.Position.Line;
            int parserLine            = textDocumentPosition.Position.Line + 1;
            int startColumn           = TextUtilities.PositionOfPrevDelimeter(
                scriptFile.Contents,
                textDocumentPosition.Position.Line,
                textDocumentPosition.Position.Character);
            int endColumn = TextUtilities.PositionOfNextDelimeter(
                scriptFile.Contents,
                textDocumentPosition.Position.Line,
                textDocumentPosition.Position.Character);
            int  parserColumn            = textDocumentPosition.Position.Character + 1;
            bool useLowerCaseSuggestions = this.CurrentSettings.SqlTools.IntelliSense.LowerCaseSuggestions.Value;

            // get the current script parse info object
            ScriptParseInfo scriptParseInfo = GetScriptParseInfo(textDocumentPosition.TextDocument.Uri);

            if (scriptParseInfo == null)
            {
                return(AutoCompleteHelper.GetDefaultCompletionItems(
                           startLine,
                           startColumn,
                           endColumn,
                           useLowerCaseSuggestions));
            }

            // reparse and bind the SQL statement if needed
            if (RequiresReparse(scriptParseInfo, scriptFile))
            {
                ParseAndBind(scriptFile, connInfo);
            }

            // if the parse failed then return the default list
            if (scriptParseInfo.ParseResult == null)
            {
                return(AutoCompleteHelper.GetDefaultCompletionItems(
                           startLine,
                           startColumn,
                           endColumn,
                           useLowerCaseSuggestions));
            }

            // need to adjust line & column for base-1 parser indices
            Token  token     = GetToken(scriptParseInfo, parserLine, parserColumn);
            string tokenText = token != null ? token.Text : null;

            // check if the file is connected and the file lock is available
            if (scriptParseInfo.IsConnected && Monitor.TryEnter(scriptParseInfo.BuildingMetadataLock))
            {
                try
                {
                    // queue the completion task with the binding queue
                    QueueItem queueItem = this.BindingQueue.QueueBindingOperation(
                        key: scriptParseInfo.ConnectionKey,
                        bindingTimeout: LanguageService.BindingTimeout,
                        bindOperation: (bindingContext, cancelToken) =>
                    {
                        // get the completion list from SQL Parser
                        scriptParseInfo.CurrentSuggestions = Resolver.FindCompletions(
                            scriptParseInfo.ParseResult,
                            parserLine,
                            parserColumn,
                            bindingContext.MetadataDisplayInfoProvider);

                        // cache the current script parse info object to resolve completions later
                        this.currentCompletionParseInfo = scriptParseInfo;

                        // convert the suggestion list to the VS Code format
                        return(AutoCompleteHelper.ConvertDeclarationsToCompletionItems(
                                   scriptParseInfo.CurrentSuggestions,
                                   startLine,
                                   startColumn,
                                   endColumn));
                    },
                        timeoutOperation: (bindingContext) =>
                    {
                        // return the default list if the connected bind fails
                        return(AutoCompleteHelper.GetDefaultCompletionItems(
                                   startLine,
                                   startColumn,
                                   endColumn,
                                   useLowerCaseSuggestions,
                                   tokenText));
                    });

                    // wait for the queue item
                    queueItem.ItemProcessed.WaitOne();

                    var completionItems = queueItem.GetResultAsT <CompletionItem[]>();
                    if (completionItems != null && completionItems.Length > 0)
                    {
                        resultCompletionItems = completionItems;
                    }
                    else if (!ShouldShowCompletionList(token))
                    {
                        resultCompletionItems = AutoCompleteHelper.EmptyCompletionList;
                    }
                }
                finally
                {
                    Monitor.Exit(scriptParseInfo.BuildingMetadataLock);
                }
            }

            // if there are no completions then provide the default list
            if (resultCompletionItems == null)
            {
                resultCompletionItems = AutoCompleteHelper.GetDefaultCompletionItems(
                    startLine,
                    startColumn,
                    endColumn,
                    useLowerCaseSuggestions,
                    tokenText);
            }

            return(resultCompletionItems);
        }