In this lesson, we are going to see how we can update an existing review.

Here is the changes we have made to lib.rs in this video:

pub fn update_review(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    _title: String,
    rating: u8,
    description: String,
) -> ProgramResult {
    msg!("Updating  review...");

    let account_info_iter = &mut accounts.iter();

    let initializer = next_account_info(account_info_iter)?;
    let pda_account = next_account_info(account_info_iter)?;

    if pda_account.owner != program_id {
        return Err(ProgramError::IllegalOwner);
    }

    if !initializer.is_signer {
        msg!("Missing required signature");
        return Err(ProgramError::MissingRequiredSignature);
    }

    msg!("unpacking state account");
    let mut account_data =
        try_from_slice_unchecked::<AccountState>(&pda_account.data.borrow()).unwrap();
    msg!("review title: {}", account_data.title);

    let (pda, _bump_seed) = Pubkey::find_program_address(
        &[
            initializer.key.as_ref(),
            account_data.title.as_bytes().as_ref(),
        ],
        program_id,
    );
    if pda != *pda_account.key {
        msg!("Invalid seeds for PDA");
        return Err(ReviewError::InvalidPDA.into());
    }

    msg!("checking if  account is initialized");
    if !account_data.is_initialized() {
        msg!("Account is not initialized");
        return Err(ReviewError::UninitializedAccount.into());
    }

    if rating > 10 || rating < 1 {
        return Err(ReviewError::InvalidRating.into());
    }

    msg!("Review before update:");
    msg!("Title: {}", account_data.title);
    msg!("Rating: {}", account_data.rating);
    msg!("Description: {}", account_data.description);

    account_data.rating = rating;
    account_data.description = description;

    msg!("Review after update:");
    msg!("Title: {}", account_data.title);
    msg!("Rating: {}", account_data.rating);
    msg!("Description: {}", account_data.description);

    msg!("serializing account");
    account_data.serialize(&mut &mut pda_account.data.borrow_mut()[..])?;
    msg!("state account serialized");

    Ok(())
}