fix(fx): realtime VST ngắt quãng khi mở MASTERING PANEL + PWR master không ảnh hưởng âm; pacing WS input/output, gate fxRt theo masterConnected, worklet cap 32

app/api/v1/plugins.py

@@ -1,7 +1,7 @@
-import os, sys, uuid, json, tempfile, subprocess, time as _time, threading
+import os, sys, uuid, json, tempfile, subprocess, time as _time, threading, asyncio
 import numpy as np
 import soundfile as sf
-from fastapi import APIRouter, HTTPException, Depends, UploadFile, File, BackgroundTasks, Header, Query
+from fastapi import APIRouter, HTTPException, Depends, UploadFile, File, BackgroundTasks, Header, Query, WebSocket, WebSocketDisconnect
 from fastapi.responses import FileResponse
 from pydantic import BaseModel
 from typing import Optional, Any
@@ -12,6 +12,8 @@ from app.core.soundfont_inspector import SoundFontInspector
 from app.core.soundfont_converter import SoundFontConverter
 from app.core.soundfont_scanner import SoundFontAutoScanner
 from app.api.v1.auth import get_current_user, enforce_password_changed
+from app.core import fx_realtime
+from app.core.auth import decode_token
 
 router = APIRouter()
 
@@ -1179,7 +1181,12 @@ async def fx_render(req: FxRenderRequest, current_user: dict = Depends(get_curre
         if not fid:
             raise HTTPException(status_code=400,
                                 detail="Cần input_file_id hoặc input_path")
-        src = os.path.join(settings.PROCESSED_DIR, os.path.basename(fid))
+        # File từ client upload (audio/upload → UPLOADS_DIR) hoặc đã xử lý
+        # (PROCESSED_DIR) — resolve cả hai như audio.download.
+        fid = os.path.basename(fid)
+        src = os.path.join(settings.PROCESSED_DIR, fid)
+        if not os.path.isfile(src):
+            src = os.path.join(settings.UPLOADS_DIR, fid)
     if not os.path.isfile(src):
         raise HTTPException(status_code=404,
                             detail=f"File đầu vào không tồn tại: {src}")
@@ -1222,6 +1229,108 @@ def _render_fx_locked(input_path: str, fx_chain: list, sample_rate: int, out_pat
                     sample_rate=sample_rate, out_path=out_path)
 
 
+class FxRealtimeStartRequest(BaseModel):
+    """Start một session FX realtime (master chain qua fx_vst_bridge
+    --realtime-fx + SHM ring). Trả session_id để client mở WebSocket
+    /ws/fx-realtime/{session_id} đẩy/kéo block audio."""
+    fx_chain: list = []
+    sample_rate: int = 44100
+
+class FxRealtimeStopRequest(BaseModel):
+    session_id: str = ""
+
+@router.post("/fx-realtime/start")
+async def fx_realtime_start(req: FxRealtimeStartRequest,
+                            current_user: dict = Depends(get_current_user)):
+    """Start bridge realtime FX loop + SHM. Client mở WS /ws/fx-realtime/{id}
+    (token qua query param 'token' hoặc Authorization Bearer) rồi gửi block
+    stereo float32 interleaved (block_size*2 float = 2048B), nhận block đã xử lý."""
+    enforce_password_changed(current_user)
+    try:
+        sess = fx_realtime.start_session(req.fx_chain, req.sample_rate)
+    except HTTPException:
+        raise
+    except Exception as e:
+        raise HTTPException(status_code=500,
+                            detail=f"Không khởi động FX realtime: {e}")
+    return {
+        "success": True,
+        "session_id": sess.name,
+        "ws_url": f"/api/v1/plugins/ws/fx-realtime/{sess.name}",
+        "block_size": sess.block_size,
+        "sample_rate": sess.sample_rate,
+    }
+
+@router.post("/fx-realtime/stop")
+async def fx_realtime_stop(req: FxRealtimeStopRequest,
+                           current_user: dict = Depends(get_current_user)):
+    """Dừng session realtime (running=0 → bridge thoát, SHM unlink)."""
+    enforce_password_changed(current_user)
+    ok = fx_realtime.stop_session(req.session_id or "")
+    return {"success": True, "stopped": ok}
+
+@router.websocket("/ws/fx-realtime/{session_id}")
+async def ws_fx_realtime(websocket: WebSocket, session_id: str):
+    """Vòng lặp FX realtime: receive block input → SHM → bridge → SHM → send
+    block output. Binary frames: 2048B stereo float32 interleaved (256*2)."""
+    # Auth: token qua query param (JS WebSocket không set header dễ) hoặc
+    # Authorization Bearer. Desktop app có thể chưa login → token rỗng được
+    # phép (endpoint /start vẫn yêu cầu auth).
+    token = websocket.query_params.get("token", "") or ""
+    if not token:
+        auth = websocket.headers.get("authorization", "")
+        if auth.lower().startswith("bearer "):
+            token = auth.split(" ", 1)[1].strip()
+    if token:
+        try:
+            payload = decode_token(token)
+        except Exception:
+            payload = None
+        if not payload:
+            await websocket.close(code=4401)
+            return
+    sess = fx_realtime.get_session(session_id)
+    if not sess:
+        await websocket.close(code=4404)
+        return
+    await websocket.accept()
+    # Output pump riêng: bridge sản xuất block KHÔNG đồng bộ với input client —
+    # nếu chỉ drain trong vòng receive_bytes, output thừa kẹt lại trong SHM ring
+    # (client ngừng gửi → server block ở receive → âm tắc).
+    async def _pump_output():
+        # Pace mỗi block theo tốc độ âm thật (256/sr ~ 5.8ms): bridge sản xuất
+        # output theo burst khi nhận input dồn; bắn toàn bộ cùng lúc → worklet
+        # overflow drop block cũ nhất → âm ngắt quãng.
+        block_sec = (sess.block_size or 256) / max(int(sess.sample_rate or 44100), 1)
+        try:
+            while True:
+                blks = sess.read_output()
+                if not blks:
+                    await asyncio.sleep(0.002)
+                    continue
+                for blk in blks:
+                    await websocket.send_bytes(blk)
+                    await asyncio.sleep(block_sec)
+        except Exception:
+            pass
+    pump_task = asyncio.create_task(_pump_output())
+    try:
+        while True:
+            data = await websocket.receive_bytes()
+            if not sess.alive():
+                break
+            sess.write_input(data)
+    except WebSocketDisconnect:
+        pass
+    except Exception:
+        pass
+    finally:
+        try:
+            pump_task.cancel()
+        except Exception:
+            pass
+        fx_realtime.stop_session(session_id)
+
 class SoundfontRenderRequest(BaseModel):
     """Render MIDI notes → WAV bằng soundfont THẬT qua native FluidSynth
     (pyfluidsynth) — luồng âm instrument cho môi trường STANDALONE (xử lí