def score_clip(words):
    """
    Returns virality score (0–100)
    based on speech + structure signals
    """

    if not words:
        return 0

    text = " ".join([w["text"] for w in words]).lower()

    score = 0

    # -----------------------------
    # HOOK SIGNAL (first words)
    # -----------------------------
    hook_words = ["you", "imagine", "stop", "listen", "this", "never", "why"]

    if any(h in text[:50] for h in hook_words):
        score += 25

    # -----------------------------
    # EMOTION SIGNAL
    # -----------------------------
    exclamations = sum(1 for w in words if "!" in w["text"])
    score += min(exclamations * 5, 20)

    # -----------------------------
    # LENGTH OPTIMIZATION
    # -----------------------------
    duration = words[-1]["end"] - words[0]["start"]

    if 6 <= duration <= 25:
        score += 25
    elif duration < 6:
        score -= 10
    else:
        score -= 5

    # -----------------------------
    # WORD DENSITY
    # -----------------------------
    score += min(len(words) / 2, 20)

    # Clamp
    return max(0, min(100, score))