Generation and recognition of tickets sold online through ecommerce.

I'm developing an e-commerce to sell tickets to a park. The customer can choose different types of tickets (individual or group) and pay by credit card. After the payment has been acknowledged, the system must include in the client's profile the amount of tickets purchased so that the customer can use them to enter the park on the day that he wants. Tickets must be sequentially numbered, regardless of customer, and this number must be shown by barcode or qcode. To enter the park the client must present, digitally or physically (printed), the ticket at the reception. The attendant should scan the ticket and validate it (verify that the code exists and has never been used). This validation should be by reading the code digitally, preferably through a mobile app (mobile phone or tablet for Android and / or iOS). Once validated the ticket should be marked as used and a mail must be sent to the customer.