lez-programs/programs/token/src/mint.rs

use lez_authority::AuthoritySlot;
use nssa_core::{
    account::{Account, AccountWithMetadata, Data},
    program::{AccountPostState, Claim, ProgramId},
};
use token_core::{TokenDefinition, TokenHolding};

pub fn mint(
    definition_account: AccountWithMetadata,
    authority_account: AccountWithMetadata,
    user_holding_account: AccountWithMetadata,
    amount_to_mint: u128,
    token_program_id: ProgramId,
) -> Vec<AccountPostState> {
    assert_eq!(
        definition_account.account.program_owner, token_program_id,
        "Token definition must be owned by token program"
    );

    let mut definition = TokenDefinition::try_from(&definition_account.account.data)
        .expect("Token Definition account must be valid");

    // LP-0013 / RFP-001: gate minting through lez-authority. The authority_account
    // is the signer and must match the stored mint authority.
    if let TokenDefinition::Fungible { mint_authority, .. } = &definition {
        assert!(
            authority_account.is_authorized,
            "Mint authority must sign the transaction"
        );
        let signer: [u8; 32] = authority_account
            .account_id
            .as_ref()
            .try_into()
            .expect("AccountId is always 32 bytes");
        let slot = AuthoritySlot(*mint_authority);
        slot.check(signer).expect("Mint authority check failed");
    }

    let mut holding = if user_holding_account.account == Account::default() {
        TokenHolding::zeroized_from_definition(definition_account.account_id, &definition)
    } else {
        TokenHolding::try_from(&user_holding_account.account.data)
            .expect("Token Holding account must be valid")
    };

    assert_eq!(
        definition_account.account_id,
        holding.definition_id(),
        "Mismatch Token Definition and Token Holding"
    );

    match (&mut definition, &mut holding) {
        (
            TokenDefinition::Fungible {
                name: _,
                metadata_id: _,
                total_supply,
                mint_authority: _,
            },
            TokenHolding::Fungible {
                definition_id: _,
                balance,
            },
        ) => {
            *balance = balance
                .checked_add(amount_to_mint)
                .expect("Balance overflow on minting");

            *total_supply = total_supply
                .checked_add(amount_to_mint)
                .expect("Total supply overflow");
        }
        (
            TokenDefinition::NonFungible { .. },
            TokenHolding::NftMaster { .. } | TokenHolding::NftPrintedCopy { .. },
        ) => {
            panic!("Cannot mint additional supply for Non-Fungible Tokens");
        }
        _ => panic!("Mismatched Token Definition and Token Holding types"),
    }

    let mut definition_post = definition_account.account;
    definition_post.data = Data::from(&definition);

    let mut holding_post = user_holding_account.account;
    holding_post.data = Data::from(&holding);

    vec![
        AccountPostState::new(definition_post),
        AccountPostState::new(authority_account.account),
        AccountPostState::new_claimed_if_default(holding_post, Claim::Authorized),
    ]
}