from typing import Optional

from generator.services.exercise_selector import extract_movement_families


def focus_key_for_exercise(exercise) -> Optional[str]:
    """Classify exercise into a coarse focus key used for variety checks."""
    if exercise is None:
        return None
    families = sorted(extract_movement_families(getattr(exercise, 'name', '') or ''))
    if families:
        return families[0]
    patterns = (getattr(exercise, 'movement_patterns', '') or '').lower()
    for token in ('upper pull', 'upper push', 'hip hinge', 'squat', 'lunge', 'core', 'carry'):
        if token in patterns:
            return token
    return None


def has_duplicate_focus(exercises: list) -> bool:
    """True when two exercises in one superset map to the same focus key."""
    seen = set()
    for ex in exercises or []:
        key = focus_key_for_exercise(ex)
        if not key:
            continue
        if key in seen:
            return True
        seen.add(key)
    return False


def focus_keys_for_exercises(exercises: list) -> set:
    """Return non-empty focus keys for a list of exercises."""
    keys = set()
    for ex in exercises or []:
        key = focus_key_for_exercise(ex)
        if key:
            keys.add(key)
    return keys