# scoring.py
BAND_CRITERIA = {
    'vocab': {
        9: {"threshold": 0.9, "description": "Sophisticated lexical items"},
        8: {"threshold": 0.8, "description": "Wide resource, occasional errors"},
        7: {"threshold": 0.7, "description": "Adequate range"},
        6: {"threshold": 0.6, "description": "Limited range"}
    },
    'grammar': {
        9: {"errors": 0, "description": "Virtually error-free"},
        8: {"errors": 2, "description": "Rare minor errors"},
        7: {"errors": 4, "description": "Some errors"},
        6: {"errors": 6, "description": "Frequent errors"}
    }
}

def convert_to_band(raw_score, category):
    """Convert raw model output to IELTS band"""
    bands = sorted(BAND_CRITERIA[category].items(), reverse=True)
    for band, criteria in bands:
        if category == 'vocab' and raw_score >= criteria['threshold']:
            return band
        elif category == 'grammar' and raw_score <= criteria['errors']:
            return band
    return 4  # Minimum band