super rough pseudocode, brainstorming how to duplicate some lengthy metadata as few times as possible in a NEAR smart contract

example.rs

struct Token {
    id: u64,
    metadata_id: u64,
}

let metadata_vec = vec![];
let metadata_map = HashMap::new(); // String to metadata_vec index of this String
let creator_id_to_metadata_ids = HashMap<String, Vec<u64>>::new();

fn fetch_token(id: u64) -> Token  {
    Token(id: 1, metadata_id: 1)
}

fn get_token_and_metadata(id: u64) -> (Token, String) {
    let token = fetch_token(id);
    let metadata_string = metadata_vec[token.metadata_id]
    (token, metadata_string)
}

fn find_or_create_metadata(creator_id: String, img_url: String) -> u64 {
    let metdata_string = format!("{}~{}", creator_id, img_url)
    match metadata_map.get(metadata_string) {
        Some(metadata_index) -> metadata_index,
        None -> {
            let array_index = metadata_vec.length;
            metadata_vec.push(metadata_string);
            metadata_map.insert(metadata_string, array_index);
            match creator_id_to_metadata_ids.get(creator_id) {
                Some(array_of_metadata_ids) -> {
                    array_of_metadata_ids.push(array_index);
                },
                None -> {
                    creator_id_to_metadata_ids.insert(creator_id, vec![array_index])
                }
            }
            array_index
        }
    }
}

fn create_token(creator_id: String, img_url: String) -> (Token, String) {
    let metadata_id = find_or_create_metadata(creator_id, img_url);
}

fn get_all_metadata_for_creator(creator_id: String) -> Vec<String> {
    creator_id_to_metadata_ids[creator_id].map(n => {
        metadata_vec[n]
    })
}