cross-contract.rs

use near_sdk::serde::{Deserialize, Serialize};
use near_sdk::borsh::{self, BorshDeserialize, BorshSerialize};
use near_sdk::json_types::{U128};
use near_sdk::{env, log, PromiseResult, near_bindgen, ext_contract, Gas, PanicOnDefault, Promise};
near_sdk::setup_alloc!();

const POOL: &str = "test-account-1632065640639-6140484";
const TGAS: Gas = 1_000_000_000_000;
const NO_DEPOSIT: u128 = 0;

#[derive(BorshDeserialize, BorshSerialize, Deserialize, Serialize)]
#[serde(crate = "near_sdk::serde")]
pub struct PoolInfo {
  pub staked_balance: U128,
  pub unstaked_balance: U128,
  pub available: bool
}

// Our contracts interface
#[ext_contract(this_contract)]
trait Callbacks {
  fn get_pool_information_callback(&mut self);  
}

// Pool interface
#[ext_contract(pool_contract)]
trait Pool {
    fn get_account(&self, account_id: AccountId) -> PoolInfo;
}

#[near_bindgen]
#[derive(BorshDeserialize, BorshSerialize, PanicOnDefault)]
pub struct Contract {}


#[near_bindgen]
impl Contract {

    #[init]
    pub fn new( ) -> Self {
        assert!(!env::state_exists(), "Already initialized");
        Self {}
    }

    pub fn get_pool_information(&mut self) -> Promise {
        pool_contract::get_account(
            env::current_account_id(),
            &POOL,
            NO_DEPOSIT,
            5*TGAS
        ).then(this_contract::get_pool_information_callback(
            &env::predecessor_account_id(),
            NO_DEPOSIT,
            5*TGAS,
        ))
    }

    #[private]
    pub fn get_pool_information_callback(&mut self) -> bool {
      if env::promise_results_count() != 1 {
        log!("Expected a result on the callback");
        return false;
      }

      // Get response, return false if failed
      let pool_info: PoolInfo = match env::promise_result(0) {
          PromiseResult::Successful(value) => near_sdk::serde_json::from_slice::<PoolInfo>(&value).unwrap(),
          _ => { log!("Getting info from Pool Party failed"); return false; },
      };

      log!("{}", pool_info.available);
      return true
    }
}