From 9a35baf55277dd1c149c0f5e4f76a1a51588b767 Mon Sep 17 00:00:00 2001
From: dtfiedler <dylan@ar.io>
Date: Tue, 9 Jan 2024 18:51:23 -0700
Subject: [PATCH] fix(epoch): fix function for calculating epochs

---
 src/actions/write/evolveState.ts | 10 ++++------
 src/actions/write/tick.test.ts   |  2 +-
 src/observers.test.ts            |  6 +++---
 src/observers.ts                 |  3 ++-
 4 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/src/actions/write/evolveState.ts b/src/actions/write/evolveState.ts
index b50a65ba..9e401680 100644
--- a/src/actions/write/evolveState.ts
+++ b/src/actions/write/evolveState.ts
@@ -15,13 +15,11 @@ export const evolveState = async (
     throw new ContractError(NON_CONTRACT_OWNER_MESSAGE);
   }
 
-  const epochEndHeight =
-    +SmartWeave.block.height + DEFAULT_EPOCH_BLOCK_LENGTH - 1;
-
+  const epochStartHeight = +SmartWeave.block.height;
   state.distributions = {
-    epochZeroStartHeight: +SmartWeave.block.height,
-    epochStartHeight: +SmartWeave.block.height,
-    epochEndHeight,
+    epochZeroStartHeight: epochStartHeight,
+    epochStartHeight: epochStartHeight,
+    epochEndHeight: epochStartHeight + DEFAULT_EPOCH_BLOCK_LENGTH - 1,
     gateways: {},
     observers: {},
   };
diff --git a/src/actions/write/tick.test.ts b/src/actions/write/tick.test.ts
index a9967cb0..7eeb5b59 100644
--- a/src/actions/write/tick.test.ts
+++ b/src/actions/write/tick.test.ts
@@ -861,7 +861,7 @@ describe('tickRewardDistribution', () => {
     TALLY_PERIOD_BLOCKS + 1,
     Number.MAX_SAFE_INTEGER,
   ])(
-    'should not distribute rewards if the current block height is equal to the last epoch end height + the required tallying period',
+    'should not distribute rewards if the current block height is equal to the last epoch end height + %s blocks',
     async (blockHeight) => {
       const initialState: IOState = {
         ...getBaselineState(),
diff --git a/src/observers.test.ts b/src/observers.test.ts
index 27294f51..93df298b 100644
--- a/src/observers.test.ts
+++ b/src/observers.test.ts
@@ -281,12 +281,12 @@ describe('isGatewayEligibleForDistribution', () => {
 
 describe('getEpochBoundariesForHeight', () => {
   it.each([
-    [1, 1, 1, 2, 2], // --> this is a weird case
+    [1, 1, 1, 1, 1],
     [19, 2, 100, 2, 101],
     [34, 0, Number.MAX_SAFE_INTEGER, 0, Number.MAX_SAFE_INTEGER - 1],
-    // [5, 0, undefined, 0, DEFAULT_EPOCH_BLOCK_LENGTH],
+    [1340134, 1339961, 50, 1340111, 1340160],
   ])(
-    'should, given current height of %d, zero block height of %d and epoch length of %d return the epoch start of %d and epoch end %d for block height %d',
+    'should for current height of %d, zero block height of %d and epoch length of %d return the epoch start of %d and epoch end %d',
     (
       currentHeight,
       zeroHeight,
diff --git a/src/observers.ts b/src/observers.ts
index 5d8fc34f..c21bfae4 100644
--- a/src/observers.ts
+++ b/src/observers.ts
@@ -28,7 +28,8 @@ export function getEpochBoundariesForHeight({
   epochEndHeight: BlockHeight;
 } {
   const epochIndexForCurrentBlockHeight = Math.floor(
-    currentBlockHeight.valueOf() / epochBlockLength.valueOf(),
+    (currentBlockHeight.valueOf() - epochZeroStartHeight.valueOf()) /
+      epochBlockLength.valueOf(),
   );
   const epochStartHeight =
     epochZeroStartHeight.valueOf() +