From 52c2cbd630ba2a22bdec9f52e93e761d9dce3997 Mon Sep 17 00:00:00 2001
From: Michael Vines <mvines@gmail.com>
Date: Fri, 11 Dec 2020 10:47:32 -0800
Subject: [PATCH] stake-account command no longer errors when time goes
 backwards over an epoch

---
 cli-output/src/cli_output.rs |  9 ++++++---
 cli/src/stake.rs             | 28 ++++++++++++++++++----------
 2 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/cli-output/src/cli_output.rs b/cli-output/src/cli_output.rs
index 444449137..69c8f98e3 100644
--- a/cli-output/src/cli_output.rs
+++ b/cli-output/src/cli_output.rs
@@ -592,7 +592,7 @@ pub struct CliEpochReward {
     pub amount: u64,       // lamports
     pub post_balance: u64, // lamports
     pub percent_change: f64,
-    pub apr: f64,
+    pub apr: Option<f64>,
 }
 
 fn show_votes_and_credits(
@@ -652,13 +652,16 @@ fn show_epoch_rewards(
         for reward in epoch_rewards {
             writeln!(
                 f,
-                "  {:<8}  {:<11}  ◎{:<14.9}  ◎{:<14.9}  {:>13.9}%  {:>13.9}%",
+                "  {:<8}  {:<11}  ◎{:<14.9}  ◎{:<14.9}  {:>13.9}%  {}",
                 reward.epoch,
                 reward.effective_slot,
                 lamports_to_sol(reward.amount),
                 lamports_to_sol(reward.post_balance),
                 reward.percent_change,
-                reward.apr,
+                reward
+                    .apr
+                    .map(|apr| format!("{:>13.9}%", apr))
+                    .unwrap_or_default(),
             )?;
         }
     }
diff --git a/cli/src/stake.rs b/cli/src/stake.rs
index 68eb7fb59..2ddfdf457 100644
--- a/cli/src/stake.rs
+++ b/cli/src/stake.rs
@@ -1647,29 +1647,37 @@ pub(crate) fn fetch_epoch_rewards(
         let previous_epoch_rewards = first_confirmed_block.rewards;
 
         if let Some((effective_slot, epoch_end_time, epoch_rewards)) = epoch_info {
-            let wallclock_epoch_duration =
-                { Local.timestamp(epoch_end_time, 0) - Local.timestamp(epoch_start_time, 0) }
-                    .to_std()?
-                    .as_secs_f64();
-
-            let wallclock_epochs_per_year =
-                (SECONDS_PER_DAY * 356) as f64 / wallclock_epoch_duration;
+            let wallclock_epoch_duration = if epoch_end_time > epoch_start_time {
+                Some(
+                    { Local.timestamp(epoch_end_time, 0) - Local.timestamp(epoch_start_time, 0) }
+                        .to_std()?
+                        .as_secs_f64(),
+                )
+            } else {
+                None
+            };
 
             if let Some(reward) = epoch_rewards
                 .into_iter()
                 .find(|reward| reward.pubkey == address.to_string())
             {
                 if reward.post_balance > reward.lamports.try_into().unwrap_or(0) {
-                    let balance_increase_percent = reward.lamports.abs() as f64
+                    let percent_change = reward.lamports.abs() as f64
                         / (reward.post_balance as f64 - reward.lamports as f64);
 
+                    let apr = wallclock_epoch_duration.map(|wallclock_epoch_duration| {
+                        let wallclock_epochs_per_year =
+                            (SECONDS_PER_DAY * 356) as f64 / wallclock_epoch_duration;
+                        percent_change * wallclock_epochs_per_year
+                    });
+
                     all_epoch_rewards.push(CliEpochReward {
                         epoch,
                         effective_slot,
                         amount: reward.lamports.abs() as u64,
                         post_balance: reward.post_balance,
-                        percent_change: balance_increase_percent,
-                        apr: balance_increase_percent * wallclock_epochs_per_year,
+                        percent_change,
+                        apr,
                     });
                 }
             }