From 4a796f55944b560b52d18107e23b175c5171df9f Mon Sep 17 00:00:00 2001
From: salmonik <raisersoft@proton.me>
Date: Sun, 19 Apr 2026 00:47:42 +0200
Subject: error handling in plot.py

Signed-off-by: salmonik <raisersoft@proton.me>
---
 cogs/plot.py | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/cogs/plot.py b/cogs/plot.py
index 4fcde44..ee19de9 100644
--- a/cogs/plot.py
+++ b/cogs/plot.py
@@ -20,10 +20,10 @@ _plot_available = False
 
 def _ensure_plot():
     global _plt_module, _plot_available
-    
+
     if _plt_module is not None:
         return _plot_available
-    
+
     try:
         import matplotlib
         matplotlib.use("Agg")
@@ -61,12 +61,12 @@ class Plot(commands.Cog):
 
     def _generate_plot(self, func_expr: str, output_path: str):
         global _plt_module
-        
+
         if not _ensure_plot():
             raise RuntimeError("matplotlib not available")
 
         plt = _plt_module
-        
+
         if is_implicit(func_expr):
             self._generate_implicit_plot(func_expr, output_path)
             return
@@ -100,6 +100,10 @@ class Plot(commands.Cog):
             except Exception:
                 y.append(float("nan"))
 
+        valid_y = [yi for yi in y if not math.isnan(yi)]
+        if not valid_y:
+            raise ValueError("Brak danych do wykreślenia dla podanej funkcji")
+
         fig, ax = plt.subplots(figsize=(10, 6))
         ax.plot(x, y, linewidth=2, color="#00ff00")
         ax.set_title(f"y = {func_expr}", fontsize=14)
@@ -117,15 +121,15 @@ class Plot(commands.Cog):
     def _generate_implicit_plot(self, func_expr: str, output_path: str):
         global _plt_module
         plt = _plt_module
-        
+
         lhs, rhs = parse_implicit(func_expr)
-        
+
         x_range = 20
         y_range = 20
-        
+
         x_vals = []
         y_vals = []
-        
+
         for xi in range(-x_range * 10, x_range * 10 + 1):
             x = xi / 10.0
             for yi in range(-y_range * 10, y_range * 10 + 1):
@@ -139,7 +143,10 @@ class Plot(commands.Cog):
                         y_vals.append(y)
                 except Exception:
                     pass
-        
+
+        if not x_vals or not y_vals:
+            raise ValueError("Brak danych do wykreślenia dla podanej funkcji")
+
         fig, ax = plt.subplots(figsize=(10, 10))
         ax.scatter(x_vals, y_vals, s=1, color="#00ff00", alpha=0.5)
         ax.set_title(f"{func_expr}", fontsize=14)
@@ -153,7 +160,7 @@ class Plot(commands.Cog):
         ax.set_aspect("equal")
         ax.set_facecolor("#1a1a1a")
         fig.patch.set_facecolor("#1a1a1a")
-        
+
         plt.savefig(output_path, dpi=100, bbox_inches="tight")
         plt.close()
 
@@ -185,4 +192,4 @@ class Plot(commands.Cog):
 
 
 def setup(bot):
-    bot.add_cog(Plot(bot))
\ No newline at end of file
+    bot.add_cog(Plot(bot))
-- 
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