refactor: extract emotional analysis out of stat_gen

server/analysis/emotional.py

@@ -0,0 +1,41 @@
+import pandas as pd
+
+class EmotionalAnalysis:
+    def __init__(self, df: pd.DataFrame):
+        self.df = df
+
+    def avg_emotion_by_topic(self) -> dict:
+        emotion_exclusions = [
+            "emotion_neutral",
+            "emotion_surprise"
+        ]
+
+        emotion_cols = [
+            col for col in self.df.columns
+            if col.startswith("emotion_") and col not in emotion_exclusions
+        ]
+
+        counts = (
+            self.df[
+                (self.df["topic"] != "Misc")
+            ]
+            .groupby("topic")
+            .size()
+            .rename("n")
+        )
+
+        avg_emotion_by_topic = (
+            self.df[
+                (self.df["topic"] != "Misc")
+            ]
+            .groupby("topic")[emotion_cols]
+            .mean()
+            .reset_index()
+        )
+
+        avg_emotion_by_topic = avg_emotion_by_topic.merge(
+            counts,
+            on="topic"
+        )
+
+        return avg_emotion_by_topic.to_dict(orient='records')