Implement WIT document formatter with comprehensive tests

Co-authored-by: GordonSmith <966863+GordonSmith@users.noreply.github.com>

Author: Copilot

package.json

@@ -181,6 +181,11 @@
                 "command": "wit-idl.extractCoreWasm",
                 "title": "Extract Core Wasm",
                 "category": "WIT"
+            },
+            {
+                "command": "wit-idl.formatDocument",
+                "title": "Format Document",
+                "category": "WIT"
             }
         ],
         "submenus": [
@@ -196,6 +201,11 @@
                     "when": "resourceExtname == .wit",
                     "group": "navigation"
                 },
+                {
+                    "command": "wit-idl.formatDocument",
+                    "when": "resourceExtname == .wit",
+                    "group": "1_modification@10"
+                },
                 {
                     "submenu": "wit-idl.generateBindings.submenu",
                     "when": "resourceExtname == .wit || witIdl.isWasmComponent",
@@ -289,6 +299,10 @@
                 {
                     "command": "wit-idl.extractCoreWasm",
                     "when": "witIdl.isWasmComponent"
+                },
+                {
+                    "command": "wit-idl.formatDocument",
+                    "when": "editorLangId == wit"
                 }
             ]
         },
@@ -301,6 +315,11 @@
             {
                 "command": "wit-idl.syntaxCheckWorkspace",
                 "key": "shift+f7"
+            },
+            {
+                "command": "wit-idl.formatDocument",
+                "key": "shift+alt+f",
+                "when": "editorTextFocus && editorLangId == wit"
             }
         ],
         "customEditors": [

src/extension.ts

@@ -2,6 +2,7 @@ import * as vscode from "vscode";
 import * as path from "node:path";
 import * as fs from "node:fs";
 import { WitSyntaxValidator } from "./validator.js";
+import { WitFormatter } from "./formatter.js";
 import { isWasmComponentFile } from "./wasmDetection.js";
 import {
     getWitBindgenVersionFromWasm,
@@ -319,6 +320,34 @@ export function activate(context: vscode.ExtensionContext) {
         }
     });
 
+    // Register WIT formatter
+    const witFormatter = new WitFormatter();
+    const formattingProvider = vscode.languages.registerDocumentFormattingEditProvider("wit", witFormatter);
+
+    // Register format document command
+    const formatDocumentCommand = vscode.commands.registerCommand("wit-idl.formatDocument", async () => {
+        const activeEditor = vscode.window.activeTextEditor;
+
+        if (!activeEditor) {
+            vscode.window.showWarningMessage("No active editor found");
+            return;
+        }
+
+        if (activeEditor.document.languageId !== "wit") {
+            vscode.window.showWarningMessage("Active file is not a WIT file");
+            return;
+        }
+
+        try {
+            await vscode.commands.executeCommand("editor.action.formatDocument");
+        } catch (error) {
+            console.error("Failed to format document:", error);
+            vscode.window.showErrorMessage(
+                `Failed to format document: ${error instanceof Error ? error.message : String(error)}`
+            );
+        }
+    });
+
     // Implement extractWit command
     const extractWitCommand = vscode.commands.registerCommand("wit-idl.extractWit", async (resource?: vscode.Uri) => {
         try {
@@ -725,9 +754,11 @@ export function activate(context: vscode.ExtensionContext) {
         providerDisposable,
         witExtractProvider,
         provider,
+        formattingProvider,
         syntaxCheckCommand,
         syntaxCheckWorkspaceCommand,
         showVersionCommand,
+        formatDocumentCommand,
         extractWitCommand,
         extractCoreWasmCommand,
         generateRustBindingsCommand,