add Serai JSON-RPC methods (#627)

* add serai rpc methods

* fix machete & dex quote price api

* fix validators api

---------

Co-authored-by: Luke Parker <lukeparker5132@gmail.com>

substrate/client/tests/serai-rpc.rs

@@ -0,0 +1,158 @@
+use std::str::FromStr;
+
+use scale::Decode;
+use zeroize::Zeroizing;
+
+use ciphersuite::{
+  group::{ff::Field, GroupEncoding},
+  Ciphersuite, Ed25519, Secp256k1,
+};
+
+use sp_core::{
+  Pair as PairTrait,
+  sr25519::{Public, Pair},
+};
+
+use serai_abi::{
+  in_instructions::primitives::Shorthand,
+  primitives::{
+    insecure_pair_from_name, ExternalBalance, ExternalCoin, ExternalNetworkId, QuotePriceParams,
+    Amount,
+  },
+  validator_sets::primitives::{ExternalValidatorSet, KeyPair, Session},
+};
+use serai_client::{Serai, SeraiAddress};
+
+use rand_core::{RngCore, OsRng};
+
+mod common;
+use common::{validator_sets::set_keys, in_instructions::mint_coin, dex::add_liquidity};
+
+serai_test!(
+  external_address: (|serai: Serai| async move {
+      test_external_address(serai).await;
+  })
+
+  encoded_shorthand: (|serai: Serai| async move {
+    test_encoded_shorthand(serai).await;
+  })
+
+  dex_quote_price: (|serai: Serai| async move {
+    test_dex_quote_price(serai).await;
+  })
+);
+
+async fn set_network_keys<C: Ciphersuite>(
+  serai: &Serai,
+  set: ExternalValidatorSet,
+  pairs: &[Pair],
+) {
+  // Ristretto key
+  let mut ristretto_key = [0; 32];
+  OsRng.fill_bytes(&mut ristretto_key);
+
+  // network key
+  let network_priv_key = Zeroizing::new(C::F::random(&mut OsRng));
+  let network_key = (C::generator() * *network_priv_key).to_bytes().as_ref().to_vec();
+
+  let key_pair = KeyPair(Public(ristretto_key), network_key.try_into().unwrap());
+  let _ = set_keys(serai, set, key_pair, pairs).await;
+}
+
+async fn test_external_address(serai: Serai) {
+  let pair = insecure_pair_from_name("Alice");
+
+  // set btc keys
+  let network = ExternalNetworkId::Bitcoin;
+  set_network_keys::<Secp256k1>(
+    &serai,
+    ExternalValidatorSet { session: Session(0), network },
+    &[pair.clone()],
+  )
+  .await;
+
+  // get the address from the node
+  let btc_address: String = serai.external_network_address(network).await.unwrap();
+
+  // make sure it is a valid address
+  let _ = bitcoin::Address::from_str(&btc_address)
+    .unwrap()
+    .require_network(bitcoin::Network::Bitcoin)
+    .unwrap();
+
+  // set monero keys
+  let network = ExternalNetworkId::Monero;
+  set_network_keys::<Ed25519>(
+    &serai,
+    ExternalValidatorSet { session: Session(0), network },
+    &[pair],
+  )
+  .await;
+
+  // get the address from the node
+  let xmr_address: String = serai.external_network_address(network).await.unwrap();
+
+  // make sure it is a valid address
+  let _ = monero_wallet::address::MoneroAddress::from_str(
+    monero_wallet::address::Network::Mainnet,
+    &xmr_address,
+  )
+  .unwrap();
+}
+
+async fn test_encoded_shorthand(serai: Serai) {
+  let shorthand = Shorthand::transfer(None, SeraiAddress::new([0u8; 32]));
+  let encoded = serai.encoded_shorthand(shorthand.clone()).await.unwrap();
+
+  assert_eq!(Shorthand::decode::<&[u8]>(&mut encoded.as_slice()).unwrap(), shorthand);
+}
+
+async fn test_dex_quote_price(serai: Serai) {
+  // make a liquid pool to get the quote on
+  let coin1 = ExternalCoin::Bitcoin;
+  let coin2 = ExternalCoin::Monero;
+  let amount1 = Amount(10u64.pow(coin1.decimals()));
+  let amount2 = Amount(10u64.pow(coin2.decimals()));
+  let pair = insecure_pair_from_name("Ferdie");
+
+  // mint sriBTC in the account so that we can add liq.
+  // Ferdie account is already pre-funded with SRI.
+  mint_coin(
+    &serai,
+    ExternalBalance { coin: coin1, amount: amount1 },
+    0,
+    pair.clone().public().into(),
+  )
+  .await;
+
+  // add liquidity
+  let coin_amount = Amount(amount1.0 / 2);
+  let sri_amount = Amount(amount1.0 / 2);
+  let _ = add_liquidity(&serai, coin1, coin_amount, sri_amount, 0, pair.clone()).await;
+
+  // same for xmr
+  mint_coin(
+    &serai,
+    ExternalBalance { coin: coin2, amount: amount2 },
+    0,
+    pair.clone().public().into(),
+  )
+  .await;
+
+  // add liquidity
+  let coin_amount = Amount(amount2.0 / 2);
+  let sri_amount = Amount(amount2.0 / 2);
+  let _ = add_liquidity(&serai, coin2, coin_amount, sri_amount, 1, pair.clone()).await;
+
+  // price for BTC -> SRI -> XMR path
+  let params = QuotePriceParams {
+    coin1: coin1.into(),
+    coin2: coin2.into(),
+    amount: coin_amount.0 / 2,
+    include_fee: true,
+    exact_in: true,
+  };
+
+  let res = serai.quote_price(params).await.unwrap();
+  assert!(res > 0);
+}