Cancel superseded Enigma2 startup and select programs throughout playback

server/services/mpegTsProgram.js

@@ -0,0 +1,19 @@
+/** Optional MPEG-TS service/program identifier; reject structured or malformed input. */
+function parseProgram(value) {
+    if (value === undefined || value === null) return null;
+    if (!['string', 'number'].includes(typeof value) || !/^\d{1,5}$/.test(String(value))) {
+        throw new Error('Program must be an integer from 1 to 65535');
+    }
+    const program = Number(value);
+    if (program < 1 || program > 65535) throw new Error('Program must be an integer from 1 to 65535');
+    return String(program);
+}
+
+function selectProgramStreams(result, program) {
+    if (program === null) return result.streams || [];
+    const selected = result.programs?.find(item => String(item.program_id ?? item.program_num) === program);
+    if (!selected) throw new Error('Requested program was not found in the stream');
+    return selected.streams || [];
+}
+
+module.exports = { parseProgram, selectProgramStreams };