Create rules_engine.py

rules_engine.py

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+# rules_engine.py
+
+def compute_bmi(height_cm, weight_kg):
+    """Compute BMI = weight (kg) / height (m^2)."""
+    if height_cm <= 0:
+        return 0.0
+    h_m = height_cm / 100
+    return round(weight_kg / (h_m * h_m), 2)
+
+
+def evaluate_risks(age, bmi, glucose, sbp, dbp, hr=70, spo2=98):
+    """Simple numeric risk scoring for conditions."""
+    risks = {}
+
+    # Type 2 Diabetes
+    risks["Type 2 Diabetes Risk"] = min(1.0, (glucose - 90) / 100 + bmi / 40)
+
+    # Hypertension
+    risks["Hypertension Risk"] = min(1.0, (sbp - 120) / 60 + (dbp - 80) / 40)
+
+    # Depression / Mood
+    risks["Depression/Mood Concern"] = 0.3 if age > 40 else 0.2
+
+    # Migraine
+    risks["Migraine Risk"] = 0.4 if sbp > 135 else 0.2
+
+    # Sleep Apnea
+    risks["Sleep Apnea Risk"] = 0.5 if bmi > 30 else 0.2
+
+    # Anemia
+    risks["Anemia Risk"] = 0.3 if spo2 < 92 else 0.1
+
+    return risks
+
+
+def rules_risk_assessment(age, sex, sbp, dbp, hr, spo2, glucose, bmi, symptoms):
+    """
+    Return (scores, explanations).
+    scores: dict of condition → 0–1 float
+    explanations: dict of condition → reason string
+    """
+    scores = {}
+    explain = {}
+
+    risks = evaluate_risks(age, bmi, glucose, sbp, dbp, hr, spo2)
+    for cond, val in risks.items():
+        scores[cond] = round(val, 3)
+        if cond == "Type 2 Diabetes Risk":
+            explain[cond] = f"Glucose={glucose}, BMI={bmi}"
+        elif cond == "Hypertension Risk":
+            explain[cond] = f"SBP={sbp}, DBP={dbp}"
+        elif cond == "Depression/Mood Concern":
+            explain[cond] = f"Age={age}, Sex={sex}"
+        elif cond == "Migraine Risk":
+            explain[cond] = "Headache symptom" if "Headache" in symptoms else "Vitals"
+        elif cond == "Sleep Apnea Risk":
+            explain[cond] = "Snoring / daytime sleepiness" if any(s in symptoms for s in ["Loud snoring", "Daytime sleepiness"]) else "BMI factor"
+        elif cond == "Anemia Risk":
+            explain[cond] = f"SpO₂={spo2}"
+        else:
+            explain[cond] = "Rule-based heuristic"
+
+    return scores, explain
+
+
+def explain_rules(explain_dict):
+    """Format explanation dict into readable text."""
+    lines = [f"- **{cond}**: {reason}" for cond, reason in explain_dict.items()]
+    return "\n".join(lines)