pyGUI/backend/graph_view.py

"""pyqtgraph PlotWidget wrapper for embedding in QML.

Exposes a QWidget with a pyqtgraph PlotWidget that can be displayed
via QML's `import QtWidgets` or `QtWidgets.QWidget` integration.
"""

from __future__ import annotations

import logging
from typing import Any, Optional

from PySide6.QtCore import QObject, Property, Signal, Slot
from PySide6.QtWidgets import QWidget

log = logging.getLogger(__name__)

# Import pyqtgraph after Qt is initialized
import pyqtgraph as pg
from pyqtgraph import PlotWidget


class GraphView(QObject):
    """QML-exposed controller for a pyqtgraph line chart.

    Accepts sensor temperature data (list of lists) and renders
    each sensor as a separate line series.
    """

    # ---- signals ----
    dataReady = Signal(object)  # {"success": bool, "sensory_names": list, "series": list}

    def __init__(self, parent: Optional[QObject] = None) -> None:
        super().__init__(parent)
        self._plot_widget: Optional[PlotWidget] = None
        self._plot_window: Optional[QWidget] = None
        self._series: list[Any] = []
        self._sensor_names: list[str] = []

    @Property(object, notify=dataReady)
    def plotWidget(self) -> Any:
        """Return the QWidget hosting the pyqtgraph PlotWidget for QML embedding."""
        return self._plot_window

    @Slot()
    def createPlotWidget(self, parent_widget: Optional[QWidget] = None) -> None:
        """Create and return a QWidget containing a pyqtgraph PlotWidget.

        Args:
            parent_widget: Optional parent widget.
        """
        pg.setConfigOption("background", "default")
        pg.setConfigOption("foreground", "default")

        self._plot_window = QWidget(parent=parent_widget)
        self._plot_widget = PlotWidget()
        self._plot_widget.setBackground("default")

        from PySide6.QtWidgets import QVBoxLayout
        layout = QVBoxLayout(self._plot_window)
        layout.setContentsMargins(0, 0, 0, 0)
        layout.setSpacing(0)
        layout.addWidget(self._plot_widget)

        # Set axis labels
        self._plot_widget.setLabel("left", "Temperature", units="°C")
        self._plot_widget.setLabel("bottom", "Measurement Interval")
        self._plot_widget.setTitle("Sensor Temperature Over Time")

    @Slot(str, str)
    def updateChart(self, sensor_names_str: str, series_data_str: str) -> None:
        """Update the chart with sensor data.

        Args:
            sensor_names_str: Comma-separated sensor names (e.g. "Sensor1,Sensor2").
            series_data_str: JSON-like string of nested lists for each sensor's values.
        """
        import json

        if not self._plot_widget:
            log.warning("PlotWidget not created yet")
            return

        try:
            sensor_names = [s.strip() for s in sensor_names_str.split(",") if s.strip()]
            series_data = json.loads(series_data_str)
        except (json.JSONDecodeError, AttributeError) as exc:
            log.error("Failed to parse chart data: %s", exc)
            return

        # Clear existing series
        self._plot_widget.clear()
        self._series = []

        if not series_data:
            return

        # Determine Y-axis range from all data
        all_values = []
        for sensor_values in series_data:
            for v in sensor_values:
                try:
                    all_values.append(float(v))
                except (ValueError, TypeError):
                    pass

        if all_values:
            y_min = min(all_values)
            y_max = max(all_values)
            y_range = y_max - y_min
            buffer = max(y_range * 0.1, 1.0)  # At least 1 degree buffer
            self._plot_widget.setYRange(y_min - buffer, y_max + buffer)
        else:
            self._plot_widget.setYRange(-50, 150)

        # X-axis: measurement intervals (0-based index)
        num_points = len(series_data[0]) if series_data else 0
        x_axis = list(range(num_points))

        # Define a set of distinct colors for series
        colors = [
            (255, 87, 87),    # Red
            (66, 165, 245),   # Blue
            (102, 187, 106),  # Green
            (255, 167, 38),   # Orange
            (171, 71, 188),   # Purple
            (0, 188, 212),    # Cyan
            (255, 112, 67),   # Deep Orange
            (121, 85, 72),    # Brown
            (92, 107, 192),   # Indigo
            (48, 125, 117),   # Teal
        ]

        # Add each sensor as a line series
        for i, sensor_name in enumerate(sensor_names):
            if i >= len(series_data):
                break

            sensor_values = series_data[i]
            y_values = []
            for v in sensor_values:
                try:
                    y_values.append(float(v))
                except (ValueError, TypeError):
                    y_values.append(0.0)

            color = colors[i % len(colors)]
            pen = pg.mkPen(color=color, width=1)

            curve = self._plot_widget.plot(x_axis, y_values, name=sensor_name, pen=pen)
            self._series.append(curve)

        self._sensor_names = sensor_names

    @Slot()
    def resetChart(self) -> None:
        """Clear the chart."""
        if self._plot_widget:
            self._plot_widget.clear()
            self._series = []
            self._sensor_names = []

    @Slot()
    def destroyPlotWidget(self) -> None:
        """Destroy the plot widget."""
        if self._plot_window:
            self._plot_window.deleteLater()
            self._plot_window = None
            self._plot_widget = None
            self._series = []