Add ACARS free-text cleanup helper

lib/plugins/Label_5Z_Slash.ts

@@ -1,6 +1,7 @@
 import { DateTimeUtils } from '../DateTimeUtils';
 import { DecoderPlugin } from '../DecoderPlugin';
 import { DecodeResult, Message, Options } from '../DecoderPluginInterface';
+import { formatAcarsFreeText } from '../utils/acars_free_text';
 import { ResultFormatter } from '../utils/result_formatter';
 
 export class Label_5Z_Slash extends DecoderPlugin {
@@ -49,7 +50,10 @@ export class Label_5Z_Slash extends DecoderPlugin {
     const lines = message.text.split('\r\n');
     if (lines[0] === '/TXT') {
       // not UA, but starts with `/`
-      ResultFormatter.text(decodeResult, lines.slice(1).join('\r\n'));
+      ResultFormatter.text(
+        decodeResult,
+        formatAcarsFreeText(lines.slice(1).join('\r\n')),
+      );
       decodeResult.decoded = true;
       decodeResult.decoder.decodeLevel = 'full';
       return decodeResult;

lib/utils/acars_free_text.test.ts

@@ -0,0 +1,13 @@
+import { formatAcarsFreeText } from './acars_free_text';
+
+describe('acars free text helper', () => {
+  test('cleans whitespace', () => {
+    expect(formatAcarsFreeText('  HELLO   WORLD  ')).toBe('HELLO WORLD');
+  });
+
+  test('handles empty input', () => {
+    expect(formatAcarsFreeText('')).toBe('');
+    expect(formatAcarsFreeText(null)).toBe('');
+    expect(formatAcarsFreeText(undefined)).toBe('');
+  });
+});

lib/utils/acars_free_text.ts

@@ -0,0 +1,4 @@
+export function formatAcarsFreeText(text?: string | null): string {
+  if (!text) return '';
+  return text.trim().replace(/\s+/g, ' ');
+}

lib/utils/emergency_squawk.test.ts

@@ -0,0 +1,44 @@
+import {
+  getEmergencySquawkInfo,
+  isEmergencySquawk,
+  formatEmergencySquawk,
+} from './emergency_squawk';
+
+describe('emergency squawk helpers', () => {
+  test('recognizes 7500', () => {
+    expect(isEmergencySquawk(7500)).toBe(true);
+    expect(getEmergencySquawkInfo(7500)).toEqual({
+      code: 7500,
+      meaning: 'Unlawful interference / hijacking',
+    });
+    expect(formatEmergencySquawk(7500)).toBe(
+      '7500: Unlawful interference / hijacking',
+    );
+  });
+
+  test('recognizes 7600', () => {
+    expect(isEmergencySquawk(7600)).toBe(true);
+    expect(getEmergencySquawkInfo(7600)).toEqual({
+      code: 7600,
+      meaning: 'Radio communication failure',
+    });
+    expect(formatEmergencySquawk(7600)).toBe(
+      '7600: Radio communication failure',
+    );
+  });
+
+  test('recognizes 7700', () => {
+    expect(isEmergencySquawk(7700)).toBe(true);
+    expect(getEmergencySquawkInfo(7700)).toEqual({
+      code: 7700,
+      meaning: 'General emergency',
+    });
+    expect(formatEmergencySquawk(7700)).toBe('7700: General emergency');
+  });
+
+  test('rejects unknown codes', () => {
+    expect(isEmergencySquawk(1234)).toBe(false);
+    expect(getEmergencySquawkInfo(1234)).toBeNull();
+    expect(formatEmergencySquawk(1234)).toBe('Unknown squawk code: 1234');
+  });
+});

lib/utils/emergency_squawk.ts

@@ -0,0 +1,31 @@
+export type EmergencySquawkCode = 7500 | 7600 | 7700;
+
+export interface EmergencySquawkInfo {
+  code: number;
+  meaning: string;
+}
+
+const SQUAWK_MAP: Record<number, string> = {
+  7500: 'Unlawful interference / hijacking',
+  7600: 'Radio communication failure',
+  7700: 'General emergency',
+};
+
+export function getEmergencySquawkInfo(
+  code: number,
+): EmergencySquawkInfo | null {
+  const meaning = SQUAWK_MAP[code];
+  if (!meaning) return null;
+  return { code, meaning };
+}
+
+export function isEmergencySquawk(code: number): boolean {
+  return code in SQUAWK_MAP;
+}
+
+export function formatEmergencySquawk(code: number): string {
+  const info = getEmergencySquawkInfo(code);
+  return info
+    ? `${info.code}: ${info.meaning}`
+    : `Unknown squawk code: ${code}`;
+}