This repository houses two primary projects:

1. NFTCredit Smart Contract: A unique Ethereum smart contract designed to facilitate the minting of NFTs in exchange for credit card payments.
2. Subgraph: A subgraph project to track and index events emitted by the NFTCredit smart contract, making it easier to query and retrieve data about transactions.

The primary objective of the NFTCredit smart contract is to allow users to acquire NFTs & off-chain game credits by paying with credit card. These NFTs represent a certain "credit" value, which can be used off-chain, for example, in a game or a platform. The smart contract ensures that:

• Users can mint NFTs by paying with credit card.
• The contract owner can mint special NFTs intended for secondary market sales.
• NFT transfers are restricted to prevent users from misleading others about the off-chain credit value associated with the NFT.

• Primary Sales: When a user directly interacts with the smart contract to mint an NFT using its credit card. This is the direct minting process.

• Secondary Sales: These are sales that occur on marketplaces like OpenSea. The contract owner can mint special NFTs and list them on these marketplaces. When another user purchases one of these NFTs, it becomes non-transferable. This mechanism ensures that the NFT's off-chain credit value is honored and prevents misleading secondary sales.

To ensure the integrity of the system:

• Transfers, approvals, and other ERC721 functions are overridden to enforce the rules of primary and secondary sales.
• Only the contract owner can mint NFTs intended for secondary sales.
• Events are emitted to track and verify off-chain credit awards.

The subgraph project is designed to track, index, and make it easy to query the events emitted by the NFTCredit smart contract. This ensures transparency and provides a reliable way to fetch data about the transactions.

To retrieve the latest transactions under the CreditAcquired entities:

{
  creditAcquireds(orderBy: timestamp, orderDirection: desc, first: 10) {
    id
    to
    quantity
    creditAmount
    totalCreditAmount
    minted
    timestamp
  }
}