Add getDocumentState to language server

Author: desplesda

YarnSpinner.LanguageServer/src/Server/Commands/Commands.cs

@@ -73,4 +73,6 @@ public static class Commands
     /// The command to get all projects in the current workspace.
     /// </summary>
     public const string ListProjects = "yarnspinner.listProjects";
+
+    public const string GetDocumentState = "yarnspinner.getDocumentState";
 }

YarnSpinner.LanguageServer/src/Server/Workspace/CompilerOutput.cs

@@ -1,4 +1,6 @@
 using Newtonsoft.Json;
+using Newtonsoft.Json.Converters;
+using OmniSharp.Extensions.LanguageServer.Protocol;
 using System.Collections.Generic;
 
 namespace YarnLanguageServer;
@@ -32,3 +34,37 @@ public record CompilerOutput
     [JsonProperty("errors")]
     public string[]? Errors { get; set; }
 }
+
+
+public record DocumentStateOutput
+{
+    [JsonProperty("uri")]
+    public string? Uri { get; set; }
+    [JsonProperty("nodes")]
+    public List<NodeInfo>? Nodes { get; set; } = new();
+
+    [JsonConverter(typeof(StringEnumConverter))]
+    public enum DocumentState
+    {
+        Unknown,
+        NotFound,
+        InvalidUri,
+        ContainsErrors,
+        Valid,
+    };
+
+    [JsonProperty("state")]
+    public DocumentState State { get; set; } = DocumentState.Unknown;
+
+    private DocumentStateOutput()
+    {
+    }
+
+    public static readonly DocumentStateOutput InvalidUri = new() { State = DocumentState.InvalidUri };
+
+    public DocumentStateOutput(DocumentUri uri)
+    {
+        this.Uri = uri.ToString();
+    }
+
+}

YarnSpinner.LanguageServer/src/Server/YarnLanguageServer.cs

@@ -1,6 +1,7 @@
 using Google.Protobuf;
 using Microsoft.Extensions.DependencyInjection;
 using Newtonsoft.Json.Linq;
+using OmniSharp.Extensions.LanguageServer.Protocol;
 using OmniSharp.Extensions.LanguageServer.Protocol.Models;
 using OmniSharp.Extensions.LanguageServer.Protocol.Server;
 using OmniSharp.Extensions.LanguageServer.Protocol.Window;
@@ -166,6 +167,14 @@ public static LanguageServerOptions ConfigureOptions(LanguageServerOptions optio
                 }
             );
 
+            // Register 'get document state' command
+            options.OnExecuteCommand<DocumentStateOutput>(
+                (commandParams) => GetDocumentStateAsync(workspace, commandParams), (_, _) => new ExecuteCommandRegistrationOptions
+                {
+                    Commands = new[] { Commands.GetDocumentState }
+                }
+            );
+
             return options;
         }
 
@@ -213,6 +222,55 @@ private static Task<Container<ProjectInfo>> ListProjectsAsync(Workspace workspac
             return Task.FromResult(Container.From(info));
         }
 
+        private static Task<DocumentStateOutput> GetDocumentStateAsync(Workspace workspace, ExecuteCommandParams<DocumentStateOutput> commandParams)
+        {
+            if (commandParams.Arguments?.Count < 1)
+            {
+                throw new ArgumentException("Expected at least one argument passed to " + Commands.GetDocumentState);
+            }
+            if (commandParams.Arguments![0].Type != JTokenType.String)
+            {
+                throw new ArgumentException("Expected parameter 0 of " + Commands.GetDocumentState + " to be a string");
+            }
+
+
+            DocumentUri uri;
+            try
+            {
+                uri = DocumentUri.Parse((string)commandParams.Arguments[0], strict: true);
+            }
+            catch
+            {
+                return Task.FromResult(DocumentStateOutput.InvalidUri);
+            }
+
+            var projects = workspace.GetProjectsForUri(uri);
+
+            if (!projects.Any())
+            {
+                return Task.FromResult(new DocumentStateOutput(uri)
+                {
+                    State = DocumentStateOutput.DocumentState.NotFound
+                });
+            }
+
+            var nodes = projects
+                .SelectMany(project => project.Nodes.Where(n => n.File != null && uri == n.File.Uri))
+                .NonNull()
+                .DistinctBy(n => n.UniqueTitle)
+                ;
+
+            // The document contains errors if any of its projects have an error
+            // diagnostic attributable to this file
+            var containsErrors = projects.SelectMany(p => p.Diagnostics.Where(d => d.FileName == uri.ToString())).Any(d => d.Severity == Yarn.Compiler.Diagnostic.DiagnosticSeverity.Error);
+
+            return Task.FromResult(new DocumentStateOutput(uri)
+            {
+                Nodes = nodes.ToList(),
+                State = containsErrors ? DocumentStateOutput.DocumentState.ContainsErrors : DocumentStateOutput.DocumentState.Valid
+            });
+        }
+
         private static Task<TextDocumentEdit> AddNodeToDocumentAsync(Workspace workspace, ExecuteCommandParams<TextDocumentEdit> commandParams)
         {
             if (commandParams.Arguments == null)