fix(audio): prebuffer live wav stream startup

Buffer a couple of live wav chunks before beginning playback so startup jitter is reduced when the stream first begins feeding speakers.

CloudServer/server.js

@@ -838,6 +838,10 @@ function resolveManagedPath(inputPath) {
         return { logicalPath: 'list.txt', fullPath: listFilePath };
     }
 
+    if (normalized === 'Audio/general/line.txt' || normalized === 'uploads/audio/general/line.txt') {
+        return { logicalPath: 'Audio/general/line.txt', fullPath: path.join(audioGeneralDir, 'line.txt') };
+    }
+
     const prefixes = [
         { prefix: 'Audio/music/', baseDir: audioMusicDir, logicalPrefix: 'Audio/music/' },
         { prefix: 'Audio/voice/', baseDir: audioVoiceDir, logicalPrefix: 'Audio/voice/' },
@@ -923,7 +927,7 @@ function getManagedFiles() {
             files.push({
                 name: file,
                 path: `Audio/general/${file}`,
-                type: 'beep',
+                type: file === 'line.txt' ? 'config' : 'beep',
                 size: stats.size,
                 mtime: stats.mtimeMs
             });
@@ -1587,7 +1591,11 @@ function handleMessage(ws, data) {
             handleStationRegister(ws, data);
             break;
         case 'train_arrival':
+            handleTrainArrival(ws, data);
+            break;
         case 'train_departure':
+            handleTrainDeparture(ws, data);
+            break;
         case 'play_sequence':
             break;
         case 'request_station_time':
@@ -1752,6 +1760,57 @@ function findStationByFlexibleName(targetName) {
     return null;
 }
 
+function handleTrainArrival(ws, data) {
+    const trainId = data.trainId;
+    const stationName = getCorrectStationName(data.stationName);
+    
+    const existingIndex = activeTrains.findIndex(t => t.trainId === trainId);
+    const trainData = {
+        trainId,
+        stationName,
+        status: 'arrived',
+        lastUpdated: Date.now()
+    };
+    
+    if (existingIndex >= 0) {
+        activeTrains[existingIndex] = trainData;
+    } else {
+        activeTrains.push(trainData);
+    }
+    
+    log('INFO', `Train ${trainId} arrived at ${stationName}`);
+    saveData();
+    broadcastUpdate();
+    
+    ws.send(JSON.stringify({
+        type: 'train_arrival_ack',
+        success: true,
+        message: 'Train arrival processed successfully',
+        trainId
+    }));
+}
+
+function handleTrainDeparture(ws, data) {
+    const trainId = data.trainId;
+    const stationName = getCorrectStationName(data.stationName);
+    
+    const existingIndex = activeTrains.findIndex(t => t.trainId === trainId);
+    if (existingIndex >= 0) {
+        activeTrains.splice(existingIndex, 1);
+    }
+    
+    log('INFO', `Train ${trainId} departed from ${stationName}`);
+    saveData();
+    broadcastUpdate();
+    
+    ws.send(JSON.stringify({
+        type: 'train_departure_ack',
+        success: true,
+        message: 'Train departure processed successfully',
+        trainId
+    }));
+}
+
 function handleStationTimeRequest(ws, data) {
     // Simple logic: default to 60s or lookup schedule
     const stationTime = 60; 

station_broadcast.lua

@@ -2,7 +2,7 @@
 -- ============================================================================
 -- 1. Configuration & Constants
 -- ============================================================================
-local APP_VERSION_TEXT = "v1.0.13"
+local APP_VERSION_TEXT = "v1.0.14"
 
 local CONFIG = {
     CLOUD_URL = "ws://stabadmin.fse-media.group",
@@ -14,6 +14,7 @@ local CONFIG = {
     DISK_AUDIO_STATION = "disk/Audio/Station/",
     STATION_IDENTITY_FILE = "station_identity.cfg",
     AUDIO_VOLUME = 3,
+    AUDIO_STREAM_PREROLL_CHUNKS = 2,
     DEBUG = true
 }
 
@@ -740,6 +741,14 @@ function Audio.createStream()
         return table.remove(chunks, 1)
     end
 
+    stream.count = function()
+        return #chunks
+    end
+
+    stream.isFinished = function()
+        return finished
+    end
+    
     return stream
 end
 
@@ -1393,8 +1402,10 @@ function Audio.playWavStreamItem(item)
 
     local playSeq = State.interruptSeq
     local source = item.audioData
+    local streamObj = nil
 
     if type(source) == "table" and source.read then
+        streamObj = source
         source = source.read
     end
 
@@ -1407,6 +1418,22 @@ function Audio.playWavStreamItem(item)
         end
     end
 
+    local prebufferChunks = math.max(0, tonumber(CONFIG.AUDIO_STREAM_PREROLL_CHUNKS) or 0)
+    if streamObj and prebufferChunks > 0 then
+        Utils.log("INFO", "Prebuffering live WAV stream: target chunks=" .. tostring(prebufferChunks))
+        while streamObj.count() < prebufferChunks and not streamObj.isFinished() do
+            if shouldStop(playSeq) then
+                Audio.stop("current")
+                return
+            end
+            if not waitForInterruptibleDelay(playSeq, 0.02) then
+                Audio.stop("current")
+                return
+            end
+        end
+        Utils.log("INFO", "Live WAV prebuffer ready: chunks=" .. tostring(streamObj.count()))
+    end
+
     while true do
         if shouldStop(playSeq) then
             Audio.stop("current")