Referral

[roaminro]

referral code generation:
a referral code is an object that is encoded in base64-url (for easy sharing), it has the following fields:

• the chain id (to prevent replay attack)
• the referral contract id (to prevent replay attack)
• an issuer address
• an issuance date
• an expiration date (a timestamp in milliseconds, 0 means no expiration)
• an optional field to only allow a contract to redeem the referral code
• an optional field to only allow an account to redeem the referral code
• an optional arbitrary data field
• a signature generated by the issuer address

Referral codes are generated off-chain (since issuance date is part of the signed payload, generating a code every 1 ms would generate a unique referral code everytime)

Referral contract (this contract can be leveraged by other smart contracts too):
implement redeem function:

• check expiration date
• check allowed contract/account
• calculate hash of the referral code object
• signature is verified against calculated hash and issuer address provided
• return true/false depending on the result of the verification
• valid codes hashes are stored so that they cannot be reused

Name-service contract:

• Updated authorizeMint, authorizeBurn and authorizeRenewal to allow for passing arbitrary bytes to the underlying domain contract
• Updated ABI accordingly

Koin domain contract:

• call referral contract to validate referral code
• verify referral code issuer is a premium account
• verify premium account can still issue referral codes (number of referrals and refresh period can be set via contract metadata)
• if buying a premium account with referral code, apply discount (percentage to apply can be set via contract metadata)
• if buying a free account with referral code, allow minting