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5. Homework "Tamagotchi NFT"

In this assignment, you'll enhance your Tamagotchi smart contract by incorporating the ability to change ownership and granting approval to other accounts for ownership changes.

Smart contract​

0️⃣ Don't forget to sync your fork with the template repository upstream. Then copy all changes from 02-tamagotchi-interaction folder that you made in the previous lesson to the 03-tamagotchi-nft folder and push them to the master branch. Create a new branch for your current homework. All new changes should be made in the 03-tamagotchi-nft folder.

1️⃣ Let's expand the Tamagotchi state by adding the approved_account field to its structure:

03-tamagotchi-nft/io/src/lib.rs
#[derive(Default, Encode, Decode, TypeInfo)]
pub struct Tamagotchi {
    // ... (copy fields from the previous lesson)
    pub approved_account: Option<ActorId>,
}

2️⃣ Add new actions to the TmgAction enum:

  • Transfer(new_owner) - the action changes the field owner to the indicated account;
  • Approve(account) - use this function to fill the field approved_account for the indicated account;
  • RevokeApproval - the function will remove the current approved_account.
03-tamagotchi-nft/io/src/lib.rs
#[derive(Encode, Decode, TypeInfo)]
pub enum TmgAction {
    // ... (copy variants from the previous lesson)
    Transfer(ActorId),
    Approve(ActorId),
    RevokeApproval,
}

3️⃣ Add new events to the TmgEvent enum:

03-tamagotchi-nft/io/src/lib.rs
#[derive(Encode, Decode, TypeInfo)]
pub enum TmgEvent {
    // ... (copy variants from the previous lesson)
    Transferred(ActorId),
    Approved(ActorId),
    ApprovalRevoked,
}

4️⃣ Implement new actions in the handle function.

  • Transfer(new_owner) - the function changes the field owner to the indicated account. The function should be available only to the current owner of the Tamagotchi or to the approved account. The function should emit the Transferred event.
  • Approve(account) - the function fills the field approved_account for the indicated account. The function should be available only to the current owner of the Tamagotchi. The function should emit the Approved event.
  • RevokeApproval - the function removes the current approved_account. The function should be available only to the current owner of the Tamagotchi. The function should emit the ApprovalRevoked event.

5️⃣ Cover the new actions with tests.

Frontend​

Upload your contract to the blockchain and run the frontend application. Choose Lesson 3.

Also, you can use the frontend deployed in your GitHub Pages.

Please attach a link to the pull request (PR) in your repo with your Tamagotchi contract. Also, please paste your Tamagotchi program address, as shown in the example below: