[NFTs] Add mint price to the witness object on mint and confirm it

frame/nfts/src/lib.rs

@@ -636,6 +636,8 @@ pub mod pallet {
 		WrongNamespace,
 		/// Can't delete non-empty collections.
 		CollectionNotEmpty,
+		/// The witness data should be provided.
+		WitnessRequired,
 	}
 
 	#[pallet::call]
@@ -771,7 +773,8 @@ pub mod pallet {
 		/// - `item`: An identifier of the new item.
 		/// - `mint_to`: Account into which the item will be minted.
 		/// - `witness_data`: When the mint type is `HolderOf(collection_id)`, then the owned
-		///   item_id from that collection needs to be provided within the witness data object.
+		///   item_id from that collection needs to be provided within the witness data object. If
+		///   the mint price is set, then it should be additionally confirmed in the `witness_data`.
 		///
 		/// Note: the deposit will be taken from the `origin` and not the `owner` of the `item`.
 		///
@@ -785,7 +788,7 @@ pub mod pallet {
 			collection: T::CollectionId,
 			item: T::ItemId,
 			mint_to: AccountIdLookupOf<T>,
-			witness_data: Option<MintWitness<T::ItemId>>,
+			witness_data: Option<MintWitness<T::ItemId, DepositBalanceOf<T, I>>>,
 		) -> DispatchResult {
 			let caller = ensure_signed(origin)?;
 			let mint_to = T::Lookup::lookup(mint_to)?;
@@ -817,8 +820,8 @@ pub mod pallet {
 							);
 						},
 						MintType::HolderOf(collection_id) => {
-							let MintWitness { owned_item } =
-								witness_data.ok_or(Error::<T, I>::BadWitness)?;
+							let MintWitness { owned_item, .. } =
+								witness_data.clone().ok_or(Error::<T, I>::WitnessRequired)?;
 
 							let owns_item = Account::<T, I>::contains_key((
 								&caller,
@@ -858,6 +861,10 @@ pub mod pallet {
 					}
 
 					if let Some(price) = mint_settings.price {
+						let MintWitness { mint_price, .. } =
+							witness_data.clone().ok_or(Error::<T, I>::WitnessRequired)?;
+						let mint_price = mint_price.ok_or(Error::<T, I>::BadWitness)?;
+						ensure!(mint_price >= price, Error::<T, I>::BadWitness);
 						T::Currency::transfer(
 							&caller,
 							&collection_details.owner,

frame/nfts/src/tests.rs

@@ -369,7 +369,37 @@ fn mint_should_work() {
 			MintSettings { mint_type: MintType::Public, price: Some(1), ..Default::default() }
 		));
 		Balances::make_free_balance_be(&account(2), 100);
-		assert_ok!(Nfts::mint(RuntimeOrigin::signed(account(2)), 0, 43, account(2), None));
+		assert_noop!(
+			Nfts::mint(RuntimeOrigin::signed(account(2)), 0, 43, account(2), None,),
+			Error::<Test>::WitnessRequired
+		);
+		assert_noop!(
+			Nfts::mint(
+				RuntimeOrigin::signed(account(2)),
+				0,
+				43,
+				account(2),
+				Some(MintWitness { ..Default::default() })
+			),
+			Error::<Test>::BadWitness
+		);
+		assert_noop!(
+			Nfts::mint(
+				RuntimeOrigin::signed(account(2)),
+				0,
+				43,
+				account(2),
+				Some(MintWitness { mint_price: Some(0), ..Default::default() })
+			),
+			Error::<Test>::BadWitness
+		);
+		assert_ok!(Nfts::mint(
+			RuntimeOrigin::signed(account(2)),
+			0,
+			43,
+			account(2),
+			Some(MintWitness { mint_price: Some(1), ..Default::default() })
+		));
 		assert_eq!(Balances::total_balance(&account(2)), 99);
 
 		// validate types
@@ -385,19 +415,19 @@ fn mint_should_work() {
 		));
 		assert_noop!(
 			Nfts::mint(RuntimeOrigin::signed(account(3)), 1, 42, account(3), None),
-			Error::<Test>::BadWitness
+			Error::<Test>::WitnessRequired
 		);
 		assert_noop!(
 			Nfts::mint(RuntimeOrigin::signed(account(2)), 1, 42, account(2), None),
-			Error::<Test>::BadWitness
+			Error::<Test>::WitnessRequired
 		);
 		assert_noop!(
 			Nfts::mint(
 				RuntimeOrigin::signed(account(2)),
 				1,
 				42,
 				account(2),
-				Some(MintWitness { owned_item: 42 })
+				Some(MintWitness { owned_item: 42, ..Default::default() })
 			),
 			Error::<Test>::BadWitness
 		);
@@ -406,7 +436,7 @@ fn mint_should_work() {
 			1,
 			42,
 			account(2),
-			Some(MintWitness { owned_item: 43 })
+			Some(MintWitness { owned_item: 43, ..Default::default() })
 		));
 
 		// can't mint twice
@@ -416,7 +446,7 @@ fn mint_should_work() {
 				1,
 				46,
 				account(2),
-				Some(MintWitness { owned_item: 43 })
+				Some(MintWitness { owned_item: 43, ..Default::default() })
 			),
 			Error::<Test>::AlreadyClaimed
 		);

frame/nfts/src/types.rs

@@ -124,10 +124,12 @@ impl<AccountId, DepositBalance> CollectionDetails<AccountId, DepositBalance> {
 }
 
 /// Witness data for items mint transactions.
-#[derive(Clone, Encode, Decode, Eq, PartialEq, RuntimeDebug, TypeInfo)]
-pub struct MintWitness<ItemId> {
+#[derive(Clone, Encode, Decode, Default, Eq, PartialEq, RuntimeDebug, TypeInfo)]
+pub struct MintWitness<ItemId, Balance> {
 	/// Provide the id of the item in a required collection.
 	pub owned_item: ItemId,
+	/// The price specified in mint settings.
+	pub mint_price: Option<Balance>,
 }
 
 /// Information concerning the ownership of a single unique item.