engine/drift.py

def apply_stimuli(persona, event):
    drift = persona.get("segment_drift", {}).get("triggers", {})
    state = persona.get("dynamic_state", {})
    inertia = state.get("inertia", 0.5)

    for key, raw_impact in drift.items():
        if key == event["event"]:
            try:
                impact = float(raw_impact)
            except ValueError:
                continue  # skip if impact isn't numeric

            for trait, value in state.items():
                if isinstance(value, (int, float)) and trait != "inertia":
                    updated = round(value + impact * (1 - inertia), 3)
                    state[trait] = max(0.0, min(1.0, updated))  # clamp between 0–1

    state["last_updated"] = event.get("date", "unknown")
    return persona