fix: handle horizontal vs vertical bar plot orientation in subplot iteration

Co-authored-by: jooyoungseo <[email protected]>

Author: Copilot

maidr/core/plot/barplot.py

@@ -3,7 +3,7 @@
 from matplotlib.axes import Axes
 from matplotlib.container import BarContainer
 
-from maidr.core.enum import PlotType
+from maidr.core.enum import MaidrKey, PlotType
 from maidr.core.plot import MaidrPlot
 from maidr.exception import ExtractionError
 from maidr.util.mixin import (
@@ -18,44 +18,96 @@ def __init__(self, ax: Axes) -> None:
         super().__init__(ax, PlotType.BAR)
 
     def _extract_plot_data(self) -> list:
+        """
+        Extract plot data for bar plots.
+        
+        For vertical bar plots, categories are on X-axis and values on Y-axis.
+        For horizontal bar plots, categories are on Y-axis and values on X-axis.
+        
+        Returns
+        -------
+        list
+            List of dictionaries containing x and y data points.
+        """
         plot = self.extract_container(self.ax, BarContainer, include_all=True)
         data = self._extract_bar_container_data(plot)
-        levels = self.extract_level(self.ax)
+        
+        # Extract appropriate axis labels based on bar orientation
+        if plot and plot[0].orientation == "vertical":
+            # For vertical bars: categories on X-axis, values on Y-axis
+            levels = self.extract_level(self.ax, MaidrKey.X)
+        else:
+            # For horizontal bars: categories on Y-axis, values on X-axis
+            levels = self.extract_level(self.ax, MaidrKey.Y)
+        
+        # Handle the case where levels might be None or empty
+        if levels is None or data is None:
+            if data is None:
+                raise ExtractionError(self.type, plot)
+            # If levels is None but data exists, create default labels
+            levels = [f"Item {i+1}" for i in range(len(data))]
+        
         formatted_data = []
         combined_data = list(
             zip(levels, data)
-            if plot[0].orientation == "vertical"
-            else zip(data, levels)  # type: ignore
+            if plot and plot[0].orientation == "vertical"
+            else zip(data, levels)
         )
-        if combined_data:  # type: ignore
-            for x, y in combined_data:  # type: ignore
+        
+        if combined_data:
+            for x, y in combined_data:
                 formatted_data.append({"x": x, "y": y})
             return formatted_data
+        
+        # If no formatted data could be created, raise an error
         if len(formatted_data) == 0:
             raise ExtractionError(self.type, plot)
-        if data is None:
-            raise ExtractionError(self.type, plot)
 
         return data
 
     def _extract_bar_container_data(
         self, plot: list[BarContainer] | None
     ) -> list | None:
+        """
+        Extract bar container data with proper orientation handling.
+        
+        Parameters
+        ----------
+        plot : list[BarContainer] | None
+            List of bar containers from the plot.
+            
+        Returns
+        -------
+        list | None
+            List of bar heights/widths, or None if extraction fails.
+        """
         if plot is None:
             return None
 
         # Since v0.13, Seaborn has transitioned from using `list[Patch]` to
         # `list[BarContainers] for plotting bar plots.
         # So, extract data correspondingly based on the level.
         # Flatten all the `list[BarContainer]` to `list[Patch]`.
-        plot = [patch for container in plot for patch in container.patches]
-        level = self.extract_level(self.ax)
-        if len(level) == 0:  # type: ignore
-            level = ["" for _ in range(len(plot))]  # type: ignore
+        plot_patches = [patch for container in plot for patch in container.patches]
+        
+        # Extract appropriate axis labels based on bar orientation
+        if plot[0].orientation == "vertical":
+            # For vertical bars: categories on X-axis
+            level = self.extract_level(self.ax, MaidrKey.X)
+        else:
+            # For horizontal bars: categories on Y-axis
+            level = self.extract_level(self.ax, MaidrKey.Y)
+            
+        if level is None or len(level) == 0:
+            level = ["" for _ in range(len(plot_patches))]
 
-        if len(plot) != len(level):
+        if len(plot_patches) != len(level):
             return None
 
-        self._elements.extend(plot)
+        self._elements.extend(plot_patches)
 
-        return [float(patch.get_height()) for patch in plot]
+        # For horizontal bars, use width; for vertical bars, use height
+        if plot[0].orientation == "horizontal":
+            return [float(patch.get_width()) for patch in plot_patches]
+        else:
+            return [float(patch.get_height()) for patch in plot_patches]