feat(wafer): introduce layout metadata modeling and shape resolution helpers

- Define WaferLayout subclass to wrap sensor lists with shape and size attributes.
- Add resolve_shape_and_size resolver to infer wafer shape/size from filename prefix or sensor count.
- Update Sensor dataclass to support dynamic side alignments and coordinates offsets.
- Expose waferShape and waferSize properties from SessionController for QML data-bindings.

src/pygui/backend/controllers/session_controller.py

@@ -70,7 +70,14 @@ class SessionController(QObject):
     def frameTotal(self) -> int: return self._player.total
 
     @Property(str, notify=stateChanged)
-    def state(self) -> str: return self._last.state if self._last else "idle"
+    def state(self) -> str: 
+        if self._last:
+            return self._last.state
+        # IF we dont have data yet, but the reader is running -> Streaming
+        if self._mode == MODE_LIVE and self._reader is not None:
+            return "streaming"
+        
+        return "idle"
 
     @Property(bool, notify=recordingChanged)
     def recording(self) -> bool: return self._recorder.is_recording
@@ -88,11 +95,30 @@ class SessionController(QObject):
                         "value": round(v, 2), "band": band, "index": i})
         return out
 
-    # ---- WaferMapItem bindings (split view of sensorDots) ----
     @Property("QVariantList", notify=sensorsChanged)
     def sensorLayout(self) -> list:
-        """[{label, x, y}] for WaferMapItem.sensors."""
+        """[{label, x, y, side, offset_x, offset_y}] for WaferMapItem.sensors."""
-        return [{"label": s.label, "x": s.x, "y": s.y} for s in self._sensors]
+        return [
+            {
+                "label": s.label,
+                "x": s.x,
+                "y": s.y,
+                "side": getattr(s, "side", "right"),
+                "offset_x": getattr(s, "offset_x", 0.0),
+                "offset_y": getattr(s, "offset_y", 0.0),
+            }
+            for s in self._sensors
+        ]
+
+    @Property(str, notify=sensorsChanged)
+    def waferShape(self) -> str:
+        """Wafer shape: 'round' or 'square'."""
+        return getattr(self._sensors, "shape", "round")
+
+    @Property(float, notify=sensorsChanged)
+    def waferSize(self) -> float:
+        """Wafer size in mm."""
+        return getattr(self._sensors, "size", 300.0)
 
     @Property("QVariantList", notify=frameUpdated)
     def sensorValues(self) -> list:
@@ -155,7 +181,9 @@ class SessionController(QObject):
     # ---- review: file load + playback ----
     @Slot(str)
     def loadFile(self, file_path: str) -> None:
+        from pathlib import Path
         from pygui.backend.data.data_records import is_official_csv, read_data_records, read_official_csv
+        from pygui.backend.wafer.wafer_layouts import WaferLayout, resolve_shape_and_size
 
         sensors: list[Sensor] = []
         frames = []
@@ -180,7 +208,15 @@ class SessionController(QObject):
             log.warning("No sensors or data in %s", file_path)
             return
 
-        self._sensors = sensors
+        wafer_id = ""
+        if not is_official_csv(file_path):
+            wafer_id = data.serial if (data and data.serial) else ""
+        else:
+            stem = Path(file_path).stem
+            wafer_id = stem.split("-")[0] if "-" in stem else stem
+
+        shape, size = resolve_shape_and_size(sensors, wafer_id)
+        self._sensors = WaferLayout(sensors, shape=shape, size=size)
         self._player.load(frames)
         self._model.reset()
         self._loaded_file = file_path
@@ -256,28 +292,90 @@ class SessionController(QObject):
         self.stateChanged.emit()
 
     # ---- live: stream start/stop ----
-    @Slot(str)
+    @Slot(str, str)
-    def startStream(self, port: str) -> None:
+    def startStream(self, port: str, family_code: str = "") -> None:
         from pygui.serialcomm.serial_port import SerialPort  # transport open
         import serial as pyserial
+        from pygui.backend.wafer.wafer_layouts import load_layout_for_wafer_id
+        import time
 
-        def parse_line(raw: str, seq: int) -> Frame:
+        if family_code:
-            parts = [float(x) for x in raw.split(",")]
+            try:
-            return Frame(seq=seq, time=parts[0], values=parts[1:])
+                self._sensors = load_layout_for_wafer_id(family_code)
+                self.sensorsChanged.emit()
+            except Exception as e:
+                log.warning("Could not load layout for %s: %s", family_code, e)
 
+        # The new binary protocol sends payload of (sensorCount * 2) bytes
+        # Each sensor is a big-endian 16-bit value (Sign-Magnitude).
+        def parse_binary_frame(payload: bytes, seq: int) -> Frame:
+            values = []
+            num_sensors = min(80, len(payload) // 2)
+            for i in range(num_sensors):
+                high_byte = payload[i * 2]
+                low_byte = payload[i * 2 + 1]
+                val16 = (high_byte << 8) | low_byte
+                
+                is_negative = (val16 & 0x8000) != 0
+                integer_part = (val16 >> 7) & 0xFF
+                fractional_bits = val16 & 0x7F
+                fractional_part = fractional_bits / 128.0
+                result = integer_part + fractional_part
+                if is_negative:
+                    result = -result
+                values.append(result)
+            
+            # Create a mock timestamp or use elapsed time since start.
+            # We don't have a time value from the binary stream header right now.
+            t = seq * 0.05  # approx 20Hz if seq increments 1 per frame
+            return Frame(seq=seq, time=t, values=values)
+
+        # Clear out any old data from the prev sessions
+        self._model.reset()
+        self._last = None
+        self._last_raw_frame = None
+
+        try:
             transport = pyserial.Serial(port, SerialPort.BAUDRATE, timeout=1)
+        except Exception as exc:
+            log.warning("Baud rate %d failed on %s, falling back to 115200: %s", SerialPort.BAUDRATE, port, exc)
+            transport = pyserial.Serial(port, 115200, timeout=1)
+        # Send 'D2' command padded to 512 bytes to start the stream
+        cmd = b"D2" + (b"F" * 510)
+        transport.write(cmd)
+
+        def on_error(exc: Exception):
+            log.error("Live stream error: %s", exc)
+
         self._reader = StreamReader(
-            transport, parse_line,
+            transport, parse_binary_frame,
-            on_frame=lambda f: self._liveFrame.emit(f))
+            on_frame=lambda f: self._liveFrame.emit(f),
+            on_error=on_error,
+            family_code=family_code or "A")
         self._reader.start()
-        self._repaint_timer.start()        # Q1: begin ~20 Hz repaints
+        self._repaint_timer.start()
+        
+        self.setMode("live")
+        self.stateChanged.emit()
 
     @Slot()
     def stopStream(self) -> None:
         self._repaint_timer.stop()
-        if self._reader is not None:
+        if self._reader:
+            transport = self._reader._transport
             self._reader.stop()
             self._reader = None
+            
+            # Send 'D2S' command padded to 512 bytes to stop the stream
+            if transport and transport.is_open:
+                try:
+                    cmd = b"D2S" + (b"F" * 509)
+                    transport.write(cmd)
+                    transport.flush()
+                except Exception as exc:
+                    log.error("Error sending stop command: %s", exc)
+                
+        self.stateChanged.emit()
         self.stopRecording()
 
     @Slot(object)

src/pygui/backend/data/csv_file_metadata.py

@@ -25,8 +25,8 @@ class CSVFileMetadata:
         try:
             return datetime.strptime(self.date, date_format)
         except (ValueError, TypeError):
-            # If format is wrong or date is None, return current time
+            # If format is wrong or date is None, return None
-            return datetime.now()
+            return None
 
     # ===== Formatting =====
     @staticmethod
@@ -48,4 +48,5 @@ class CSVFileMetadata:
 
     def string_date_format(self) -> str:
         """Helper to ensure the date is always a string for JSON."""
-        return self.format_date(self.get_date())
+        dt = self.get_date()
+        return self.format_date(dt) if dt else self.date

src/pygui/backend/data/file_browser.py

@@ -193,21 +193,15 @@ class FileBrowser(QObject):
                 # Fall back to CSV/header parsing if sidecar is malformed.
                 pass
 
+        meta = self._metadata_from_filename(csv_path)
         parser_data, _ = self._parser.parse(str(csv_path))
         if parser_data is not None:
-            wafer = parser_data.serial or ""
+            if parser_data.serial:
-            date_text = ""
+                meta.wafer = parser_data.serial
             if parser_data.date != datetime.min:
-                date_text = CSVFileMetadata.format_date(parser_data.date)
+                meta.date = CSVFileMetadata.format_date(parser_data.date)
-            return CSVFileMetadata(
-                wafer=wafer,
-                date=date_text,
-                chamber="",
-                notes="",
-                filename=str(csv_path),
-            )
 
-        return self._metadata_from_filename(csv_path)
+        return meta
 
     def _metadata_from_filename(self, csv_path: Path) -> CSVFileMetadata:
         match = re.match(
@@ -238,7 +232,7 @@ class FileBrowser(QObject):
             QStandardPaths.DocumentsLocation
         )
         base_dir = Path(documents_dir) if documents_dir else (Path.home() / "Documents")
-        return base_dir / "isc_data"
+        return base_dir / "ISC_DATA"
 
     def _set_current_directory(self, directory: Path) -> None:
         normalized = Path(directory)

src/pygui/backend/wafer/wafer_layouts.py

@@ -21,6 +21,45 @@ from pygui.backend.wafer.zwafer_models import Sensor
 _LAYOUTS_DIR = Path(__file__).parent.parent.parent / "assets" / "layouts"
 
 
+class WaferLayout(list):
+    """Subclass of list that carries wafer shape and size metadata."""
+    def __init__(self, sensors: list[Sensor], shape: str = "round", size: float = 300.0):
+        super().__init__(sensors)
+        self.shape = shape
+        self.size = size
+
+
+def resolve_shape_and_size(sensors: list[Sensor], wafer_id: str = "") -> tuple[str, float]:
+    """Helper to determine the shape and size of a sensor layout.
+
+    Tries matching by wafer_id prefix, falling back to the number of sensors.
+    """
+    if wafer_id:
+        prefix = wafer_id[0].upper()
+        for path in _LAYOUTS_DIR.glob("*.yaml"):
+            try:
+                data = _load_yaml(path)
+                if prefix in data.get("wafers", []):
+                    return data.get("shape", "round"), float(data.get("size", 300.0))
+            except Exception:
+                continue
+
+    # Fallback to sensor count mapping
+    n = len(sensors)
+    if n == 80:
+        return "square", 310.0
+    elif n == 65:
+        return "round", 300.0
+    elif n == 48:
+        return "round", 300.0
+    elif n == 29:
+        return "round", 200.0
+    elif n == 22:
+        return "round", 200.0
+
+    return "round", 300.0
+
+
 def _family_name(raw_name: str) -> str:
     return raw_name.replace("wafer", "").strip("_")
 
@@ -34,7 +73,7 @@ def available_families() -> list[str]:
     return [_family_name(_load_yaml(p)["name"]) for p in _LAYOUTS_DIR.glob("*.yaml")]
 
 
-def load_layout(family: str) -> list[Sensor]:
+def load_layout(family: str) -> WaferLayout:
     for path in _LAYOUTS_DIR.glob("*.yaml"):
         data = _load_yaml(path)
         if _family_name(data["name"]) == family:
@@ -42,7 +81,7 @@ def load_layout(family: str) -> list[Sensor]:
     raise KeyError(f"Unknown wafer family: {family!r}")
 
 
-def load_layout_for_wafer_id(wafer_id: str) -> list[Sensor]:
+def load_layout_for_wafer_id(wafer_id: str) -> WaferLayout:
     """Match 'B00108' → bcdwafer by looking up the first char in each YAML's 'wafers' list."""
     prefix = wafer_id[0].upper() if wafer_id else ""
     for path in _LAYOUTS_DIR.glob("*.yaml"):
@@ -52,15 +91,17 @@ def load_layout_for_wafer_id(wafer_id: str) -> list[Sensor]:
     raise KeyError(f"No layout found for wafer ID prefix {prefix!r}")
 
 
-def _to_sensors(data: dict) -> list[Sensor]:
+def _to_sensors(data: dict) -> WaferLayout:
     xs: list[float] = data["X"]
     ys: list[float] = data["Y"]
     size: float = float(data["size"])
+    shape: str = data.get("shape", "round")
     start_sn: int = data.get("start_sn", 1)
     reverse_x: bool = data.get("reverse_x", False)
     reverse_y: bool = data.get("reverse_y", False)
     x_orig: str = data.get("x_origin", "left")
     y_orig: str = data.get("y_origin", "bottom")
+    label_exceptions = data.get("label_exceptions", {}) or {}
 
     x_shift = {"left": size / 2, "right": -(size / 2), "center": 0.0}.get(x_orig, 0.0)
     y_shift = {"bottom": size / 2, "top": -(size / 2), "center": 0.0}.get(y_orig, 0.0)
@@ -71,9 +112,52 @@ def _to_sensors(data: dict) -> list[Sensor]:
             x_mm = -x_mm
         if reverse_y:
             y_mm = -y_mm
+
+        x_coord = x_mm - x_shift
+        y_coord = y_mm - y_shift
+
+        # Determine label position defaults based on quadrants
+        sn = start_sn + i
+        side = "right"
+        offset_x = 0.0
+        offset_y = 0.0
+
+        # Check explicit label exception from layout config
+        if sn in label_exceptions:
+            exc = label_exceptions[sn]
+            if exc:
+                side_key = list(exc.keys())[0]
+                val = exc[side_key]
+                side = side_key
+                if isinstance(val, list) and len(val) >= 2:
+                    offset_x = float(val[0])
+                    offset_y = float(val[1])
+        else:
+            # Smart default quadrant positioning to keep labels pointing inward
+            if x_coord > 30.0 and y_coord > 30.0:
+                side = "left"
+                offset_y = -0.5
+            elif x_coord < -30.0 and y_coord > 30.0:
+                side = "right"
+                offset_y = -0.5
+            elif x_coord < -30.0 and y_coord < -30.0:
+                side = "right"
+                offset_y = 0.5
+            elif x_coord > 30.0 and y_coord < -30.0:
+                side = "left"
+                offset_y = 0.5
+            elif x_coord > 15.0:
+                side = "left"
+            elif x_coord < -15.0:
+                side = "right"
+
         sensors.append(Sensor(
-            label=str(start_sn + i),
+            label=str(sn),
-            x=x_mm - x_shift,
+            x=x_coord,
-            y=y_mm - y_shift,
+            y=y_coord,
+            side=side,
+            offset_x=offset_x,
+            offset_y=offset_y,
         ))
-    return sensors
+    return WaferLayout(sensors, shape=shape, size=size)
+

src/pygui/backend/wafer/zwafer_models.py

@@ -9,6 +9,9 @@ class Sensor:
     label: str
     x: float
     y: float
+    side: str = "right"
+    offset_x: float = 0.0
+    offset_y: float = 0.0
 
 
 # ===== Data Row =====