add specific network/coin/balance types (#619)

* add specific network/coin/balance types

* misc fixes

* fix clippy

* misc fixes

* fix pr comments

* Make halting for external networks

* fix encode/decode

substrate/validator-sets/primitives/src/lib.rs

@@ -17,7 +17,7 @@ use sp_core::{ConstU32, sr25519::Public, bounded::BoundedVec};
 #[cfg(not(feature = "std"))]
 use sp_std::vec::Vec;
 
-use serai_primitives::NetworkId;
+use serai_primitives::{ExternalNetworkId, NetworkId};
 
 /// The maximum amount of key shares per set.
 pub const MAX_KEY_SHARES_PER_SET: u32 = 150;
@@ -43,6 +43,33 @@ pub struct ValidatorSet {
   pub network: NetworkId,
 }
 
+/// The type used to identify a specific validator set during a specific session.
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, Encode, Decode, TypeInfo, MaxEncodedLen)]
+#[cfg_attr(feature = "std", derive(Zeroize))]
+#[cfg_attr(feature = "borsh", derive(BorshSerialize, BorshDeserialize))]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct ExternalValidatorSet {
+  pub session: Session,
+  pub network: ExternalNetworkId,
+}
+
+impl From<ExternalValidatorSet> for ValidatorSet {
+  fn from(set: ExternalValidatorSet) -> Self {
+    ValidatorSet { session: set.session, network: set.network.into() }
+  }
+}
+
+impl TryFrom<ValidatorSet> for ExternalValidatorSet {
+  type Error = ();
+
+  fn try_from(set: ValidatorSet) -> Result<Self, Self::Error> {
+    match set.network {
+      NetworkId::Serai => Err(())?,
+      NetworkId::External(network) => Ok(ExternalValidatorSet { session: set.session, network }),
+    }
+  }
+}
+
 type MaxKeyLen = ConstU32<MAX_KEY_LEN>;
 /// The type representing a Key from an external network.
 pub type ExternalKey = BoundedVec<u8, MaxKeyLen>;
@@ -100,14 +127,14 @@ pub fn musig_key(set: ValidatorSet, set_keys: &[Public]) -> Public {
 
 /// The message for the set_keys signature.
 pub fn set_keys_message(
-  set: &ValidatorSet,
+  set: &ExternalValidatorSet,
   removed_participants: &[Public],
   key_pair: &KeyPair,
 ) -> Vec<u8> {
   (b"ValidatorSets-set_keys", set, removed_participants, key_pair).encode()
 }
 
-pub fn report_slashes_message(set: &ValidatorSet, slashes: &[(Public, u32)]) -> Vec<u8> {
+pub fn report_slashes_message(set: &ExternalValidatorSet, slashes: &[(Public, u32)]) -> Vec<u8> {
   (b"ValidatorSets-report_slashes", set, slashes).encode()
 }