Rough idea

gistfile1.txt

#[repr(C)]
#[derive(BorshSerialize, BorshDeserialize, PartialEq, Debug, Clone)]
pub enum CollectionStatus {
    Unverified,
    Verified,
    CollectionMasterEdition,
}

#[repr(C)]
#[derive(BorshSerialize, BorshDeserialize, PartialEq, Debug, Clone)]
pub enum UseType {
    Burn,
    Multiple,
    Single,
}

#[repr(C)]
#[derive(BorshSerialize, BorshDeserialize, PartialEq, Debug, Clone)]
pub enum TokenType {
    NonFungible,
    SemiFungible,
    Fungible,
    Edition,
}

#[repr(C)]
#[derive(BorshSerialize, BorshDeserialize, PartialEq, Debug, Clone)]
pub struct Uses {
    pub use_type: UseType,
    pub uses: u64,
    pub available_uses: u64,
}

#[repr(C)]
#[derive(BorshSerialize, BorshDeserialize, PartialEq, Debug, Clone)]
pub struct Collection {
    pub status: CollectionStatus,
    pub collection_key: Pubkey,
}

#[repr(C)]
#[derive(BorshSerialize, BorshDeserialize, PartialEq, Debug, Clone)]
pub struct DataV2 {
    /// The name of the asset
    pub name: String,
    /// The symbol for the asset
    pub symbol: String,
    /// URI pointing to JSON representing the asset
    pub uri: String,
    /// Royalty basis points that goes to creators in secondary sales (0-10000)
    pub seller_fee_basis_points: u16,
    /// Array of creators, optional
    pub creators: Option<Vec<Creator>>,
    /// Collection
    pub collection: Option<Collection>,
    /// Uses
    pub uses: Option<Uses>,
}

#[repr(C)]
#[derive(Clone, BorshSerialize, BorshDeserialize, Debug)]
pub struct Metadata {
    pub key: Key,
    pub update_authority: Pubkey,
    pub mint: Pubkey,
    pub data: Data,
    // Immutable, once flipped, all sales of this metadata are considered secondary.
    pub primary_sale_happened: bool,
    // Whether or not the data struct is mutable, default is not
    pub is_mutable: bool,
    /// nonce for easy calculation of editions, if present
    pub edition_nonce: Option<u8>,
    /// Since we cannot easily change Metadata, we add the new DataV2 fields here at the end.
    /// Collection
    pub collection: Option<Collection>,
    /// Uses
    pub uses: Option<Uses>,
    /// Token type is deterministic and will change from SemiFungible to NonFungible if
    /// you call the create master edition call and it succeeds.
    pub token_type: Option<TokenType>,
}