"""Original offline examples, not recorded AI responses. Python 3; no network."""
import json

def pairs(values):
    result = {}
    for key, value in values:
        if key in result:
            raise ValueError('duplicate key')
        result[key] = value
    return result

def constant(value):
    raise ValueError('non-standard JSON constant')

def validate(text):
    try:
        data = json.loads(text, object_pairs_hook=pairs, parse_constant=constant)
    except (json.JSONDecodeError, ValueError):
        return 'NG (json)'
    if type(data) is not dict or set(data) != {'name', 'quantity'}:
        return 'NG (keys)'
    if type(data['name']) is not str or not data['name'].strip():
        return 'NG (name)'
    if type(data['quantity']) is not int or not 1 <= data['quantity'] <= 99:
        return 'NG (quantity)'
    return 'OK'

if __name__ == '__main__':
    samples = {
        'valid': '{"name":"notebook","quantity":2}',
        'syntax': '{"name":"notebook","quantity":2,}',
        'wrong-type': '{"name":"notebook","quantity":"2"}',
        'extra-field': '{"name":"notebook","quantity":2,"price":300}',
    }
    for label, text in samples.items():
        print(label + ': ' + validate(text))