utils/engagement.py

def simulate_retention(words):

    timeline = []
    score = 100

    for i, w in enumerate(words):

        # drop-off logic
        if i > len(words) * 0.7:
            score -= 2

        if w["text"].lower() in ["boring", "slow"]:
            score -= 10

        timeline.append(max(score, 0))

    return timeline