From 36cdf6d4bf5ae36a6b5cf5041f572de4609a3cd2 Mon Sep 17 00:00:00 2001
From: Luke Parker <lukeparker5132@gmail.com>
Date: Sun, 16 Apr 2023 02:57:19 -0400
Subject: [PATCH] Have InInstructions track the latest block for a network in
 storage

---
 substrate/client/src/serai/in_instructions.rs | 15 ++++++++++++++-
 substrate/client/tests/batch.rs               |  1 +
 substrate/in-instructions/pallet/src/lib.rs   | 11 +++++++++--
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/substrate/client/src/serai/in_instructions.rs b/substrate/client/src/serai/in_instructions.rs
index aa0cfd78..fadd3fe0 100644
--- a/substrate/client/src/serai/in_instructions.rs
+++ b/substrate/client/src/serai/in_instructions.rs
@@ -4,11 +4,24 @@ use primitives::SignedBatch;
 
 use subxt::utils::Encoded;
 
-use crate::{Serai, SeraiError};
+use crate::{
+  primitives::{BlockHash, NetworkId},
+  SeraiError, Serai, scale_value,
+};
 
 pub type InInstructionsEvent = in_instructions::Event<Runtime>;
 
+const PALLET: &str = "InInstructions";
+
 impl Serai {
+  pub async fn get_latest_block_for_network(
+    &self,
+    hash: [u8; 32],
+    network: NetworkId,
+  ) -> Result<Option<BlockHash>, SeraiError> {
+    self.storage(PALLET, "LatestBlock", Some(vec![scale_value(network)]), hash).await
+  }
+
   pub async fn get_batch_events(
     &self,
     block: [u8; 32],
diff --git a/substrate/client/tests/batch.rs b/substrate/client/tests/batch.rs
index 66bd4688..31f669dc 100644
--- a/substrate/client/tests/batch.rs
+++ b/substrate/client/tests/batch.rs
@@ -41,6 +41,7 @@ serai_test!(
     let block = provide_batch(batch).await;
 
     let serai = serai().await;
+    assert_eq!(serai.get_latest_block_for_network(block, network).await.unwrap(), Some(block_hash));
     let batches = serai.get_batch_events(block).await.unwrap();
     assert_eq!(batches, vec![InInstructionsEvent::Batch { network, id, block: block_hash }]);
 
diff --git a/substrate/in-instructions/pallet/src/lib.rs b/substrate/in-instructions/pallet/src/lib.rs
index 17ea1abe..31038901 100644
--- a/substrate/in-instructions/pallet/src/lib.rs
+++ b/substrate/in-instructions/pallet/src/lib.rs
@@ -52,11 +52,17 @@ pub mod pallet {
   #[pallet::pallet]
   pub struct Pallet<T>(PhantomData<T>);
 
-  // Latest block number agreed upon for a coin
+  // The amount of batches a network has issued, which is also the ID to use for the next batch
   #[pallet::storage]
-  #[pallet::getter(fn batch)]
+  #[pallet::getter(fn batches)]
   pub(crate) type Batches<T: Config> = StorageMap<_, Blake2_256, NetworkId, u32, OptionQuery>;
 
+  // The latest block a network has acknowledged as finalized
+  #[pallet::storage]
+  #[pallet::getter(fn last_block)]
+  pub(crate) type LatestBlock<T: Config> =
+    StorageMap<_, Blake2_256, NetworkId, BlockHash, OptionQuery>;
+
   impl<T: Config> Pallet<T> {
     fn execute(instruction: InInstructionWithBalance) -> Result<(), ()> {
       match instruction.instruction {
@@ -77,6 +83,7 @@ pub mod pallet {
       let mut batch = batch.batch;
 
       Batches::<T>::insert(batch.network, batch.id);
+      LatestBlock::<T>::insert(batch.network, batch.block);
       Self::deposit_event(Event::Batch {
         network: batch.network,
         id: batch.id,