feat: detect Apex logs in .log/.txt files with content-based analysis

lana/package.json

@@ -50,7 +50,8 @@
     "Other"
   ],
   "activationEvents": [
-    "onLanguage:apexlog"
+    "onLanguage:apexlog",
+    "onStartupFinished"
   ],
   "contributes": {
     "commands": [
@@ -77,44 +78,41 @@
           "ApexLog",
           "DebugLog"
         ],
-        "extensions": [
-          ".log",
-          ".txt"
-        ],
+        "extensions": [],
         "firstLine": "^\\d\\d.\\d.+?APEX_CODE,\\w.+$"
       }
     ],
     "menus": {
       "commandPalette": [
         {
           "command": "lana.showLogAnalysis",
-          "when": "resourceLangId == apexlog"
+          "when": "resourceLangId == apexlog || lana.isApexLog"
         }
       ],
       "editor/context": [
         {
           "command": "lana.showLogAnalysis",
-          "when": "resourceLangId == apexlog"
+          "when": "resourceLangId == apexlog || lana.isApexLog"
         }
       ],
       "editor/title/context": [
         {
           "command": "lana.showLogAnalysis",
-          "when": "resourceLangId == apexlog",
+          "when": "resourceLangId == apexlog || lana.isApexLog",
           "group": "lana"
         }
       ],
       "editor/title/run": [
         {
           "command": "lana.showLogAnalysis",
-          "when": "resourceLangId == apexlog",
+          "when": "resourceLangId == apexlog || lana.isApexLog",
           "group": "lana"
         }
       ],
       "explorer/context": [
         {
           "command": "lana.showLogAnalysis",
-          "when": "resourceLangId == apexlog"
+          "when": "resourceLangId == apexlog || lana.isApexLog"
         }
       ]
     },

lana/src/Context.ts

@@ -14,6 +14,7 @@ import { RawLogLineDecoration } from './decorations/RawLogLineDecoration.js';
 import { Display } from './display/Display.js';
 import { WhatsNewNotification } from './display/WhatsNewNotification.js';
 import { RawLogFoldingProvider } from './folding/RawLogFoldingProvider.js';
+import { ApexLogLanguageDetector } from './language/ApexLogLanguageDetector.js';
 import { SymbolFinder } from './salesforce/codesymbol/SymbolFinder.js';
 import { VSWorkspace } from './workspace/VSWorkspace.js';
 
@@ -33,6 +34,7 @@ export class Context {
       });
     }
 
+    ApexLogLanguageDetector.apply(this);
     LogEventCache.apply(this);
     RetrieveLogFile.apply(this);
     ShowLogAnalysis.apply(this);

lana/src/codelenses/ShowAnalysisCodeLens.ts

@@ -2,18 +2,22 @@ import { CodeLens, Range, languages, type CodeLensProvider, type TextDocument }
 
 import { Context } from '../Context.js';
 import { ShowLogAnalysis } from '../commands/ShowLogAnalysis.js';
+import { isApexLogContent } from '../language/ApexLogLanguageDetector.js';
 
 class ShowAnalysisCodeLens implements CodeLensProvider {
   context: Context;
+
   constructor(context: Context) {
     this.context = context;
   }
-  // Each provider requires a provideCodeLenses function which will give the various documents the code lenses
-  async provideCodeLenses(_document: TextDocument): Promise<CodeLens[]> {
-    // Define where the CodeLens will exist
+
+  async provideCodeLenses(document: TextDocument): Promise<CodeLens[]> {
+    if (!isApexLogContent(document)) {
+      return [];
+    }
+
     const topOfDocument = new Range(0, 0, 0, 0);
 
-    // Define what command we want to trigger when activating the CodeLens
     const command = ShowLogAnalysis.getCommand(this.context);
     const codeLens = new CodeLens(topOfDocument, {
       command: command.fullName,
@@ -24,17 +28,17 @@ class ShowAnalysisCodeLens implements CodeLensProvider {
   }
 
   static apply(context: Context): void {
-    // Get a document selector for the CodeLens provider
-    // This one is any file that has the language of apexlog
-    const docSelector = [{ scheme: 'file', language: 'apexlog' }];
+    const docSelector = [
+      { scheme: 'file', language: 'apexlog' },
+      { scheme: 'file', pattern: '**/*.log' },
+      { scheme: 'file', pattern: '**/*.txt' },
+    ];
 
-    // Register our CodeLens provider
     const codeLensProviderDisposable = languages.registerCodeLensProvider(
       docSelector,
       new ShowAnalysisCodeLens(context),
     );
 
-    // Push the command and CodeLens provider to the context so it can be disposed of later
     context.context.subscriptions.push(codeLensProviderDisposable);
   }
 }

lana/src/decorations/LogTimingDecoration.ts

@@ -11,6 +11,7 @@ import {
 } from 'vscode';
 
 import { Context } from '../Context.js';
+import { isApexLogContent } from '../language/ApexLogLanguageDetector.js';
 import { formatDuration, TIMESTAMP_REGEX } from '../log-utils.js';
 
 // Pattern to find EXECUTION_STARTED line
@@ -84,8 +85,7 @@ export class LogTimingDecoration {
   private updateDecorations(editor: TextEditor): void {
     const document = editor.document;
 
-    // Only process apexlog files
-    if (document.languageId !== 'apexlog') {
+    if (!isApexLogContent(document)) {
       editor.setDecorations(decorationType, []);
       return;
     }

lana/src/decorations/RawLogLineDecoration.ts

@@ -15,6 +15,7 @@ import type { LogEvent } from 'apex-log-parser';
 
 import { Context } from '../Context.js';
 import { LogEventCache } from '../cache/LogEventCache.js';
+import { isApexLogContent } from '../language/ApexLogLanguageDetector.js';
 import { buildMetricParts, formatDuration, TIMESTAMP_REGEX } from '../log-utils.js';
 
 // Decoration type for ghost text on cursor line - no isWholeLine so hover only triggers at end
@@ -72,7 +73,7 @@ export class RawLogLineDecoration {
   private async updateDecoration(editor: TextEditor): Promise<void> {
     const document = editor.document;
 
-    if (document.languageId !== 'apexlog') {
+    if (!isApexLogContent(document)) {
       this.clearDecorations(editor);
       return;
     }

lana/src/language/ApexLogLanguageDetector.ts

@@ -0,0 +1,142 @@
+/*
+ * Copyright (c) 2026 Certinia Inc. All rights reserved.
+ */
+import { closeSync, openSync, readSync } from 'node:fs';
+import { extname } from 'node:path';
+
+import {
+  TabInputText,
+  commands,
+  languages,
+  window,
+  workspace,
+  type TextDocument,
+  type Uri,
+} from 'vscode';
+
+import { Context } from '../Context.js';
+
+const APEXLOG_HEADER = /^\d\d\.\d.+?APEX_CODE,\w.+$/;
+const DETECT_EXTENSIONS = new Set(['.log', '.txt']);
+const MAX_LINES_TO_CHECK = 100;
+
+export function isApexLogContent(doc: TextDocument): boolean {
+  if (doc.lineCount === 0) {
+    return false;
+  }
+
+  const linesToCheck = Math.min(MAX_LINES_TO_CHECK, doc.lineCount);
+  for (let i = 0; i < linesToCheck; i++) {
+    if (APEXLOG_HEADER.test(doc.lineAt(i).text)) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+function isApexLogFile(fsPath: string): boolean {
+  let fd: number;
+  try {
+    fd = openSync(fsPath, 'r');
+  } catch {
+    return false;
+  }
+
+  try {
+    const buf = Buffer.alloc(4096);
+    const bytesRead = readSync(fd, buf, 0, 4096, 0);
+    const text = buf.toString('utf8', 0, bytesRead);
+    const lines = text.split('\n');
+
+    const linesToCheck = Math.min(MAX_LINES_TO_CHECK, lines.length);
+    for (let i = 0; i < linesToCheck; i++) {
+      if (APEXLOG_HEADER.test(lines[i] ?? '')) {
+        return true;
+      }
+    }
+    return false;
+  } finally {
+    closeSync(fd);
+  }
+}
+
+function hasDetectExtension(uri: Uri): boolean {
+  return DETECT_EXTENSIONS.has(extname(uri.fsPath).toLowerCase());
+}
+
+function getActiveTabUri(): Uri | undefined {
+  const activeTab = window.tabGroups.activeTabGroup.activeTab;
+  if (activeTab?.input instanceof TabInputText) {
+    return activeTab.input.uri;
+  }
+  return undefined;
+}
+
+function updateContextKey(): void {
+  const editor = window.activeTextEditor;
+  if (editor && editor.document.uri.scheme === 'file') {
+    const doc = editor.document;
+    if (hasDetectExtension(doc.uri)) {
+      const detected = isApexLogContent(doc);
+      commands.executeCommand('setContext', 'lana.isApexLog', detected);
+      return;
+    }
+    commands.executeCommand('setContext', 'lana.isApexLog', false);
+    return;
+  }
+
+  // Fallback to tab API for large files where activeTextEditor is undefined
+  const tabUri = getActiveTabUri();
+  if (tabUri && tabUri.scheme === 'file' && hasDetectExtension(tabUri)) {
+    const detected = isApexLogFile(tabUri.fsPath);
+    commands.executeCommand('setContext', 'lana.isApexLog', detected);
+    return;
+  }
+
+  commands.executeCommand('setContext', 'lana.isApexLog', false);
+}
+
+export class ApexLogLanguageDetector {
+  static apply(context: Context): void {
+    for (const doc of workspace.textDocuments) {
+      detectAndSetLanguage(doc);
+    }
+
+    context.context.subscriptions.push(
+      workspace.onDidOpenTextDocument((doc) => {
+        detectAndSetLanguage(doc);
+      }),
+    );
+
+    // Update context key when the active editor or tab changes
+    context.context.subscriptions.push(
+      window.onDidChangeActiveTextEditor(() => {
+        updateContextKey();
+      }),
+    );
+
+    context.context.subscriptions.push(
+      window.tabGroups.onDidChangeTabs(() => {
+        updateContextKey();
+      }),
+    );
+
+    // Set initial context
+    updateContextKey();
+  }
+}
+
+function detectAndSetLanguage(doc: TextDocument): void {
+  if (doc.languageId === 'apexlog' || doc.uri.scheme !== 'file') {
+    return;
+  }
+
+  if (!hasDetectExtension(doc.uri)) {
+    return;
+  }
+
+  if (isApexLogContent(doc)) {
+    languages.setTextDocumentLanguage(doc, 'apexlog');
+  }
+}