From 30cf227ef52a78a037282e406e85f799def8520c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Magiera?= <magik6k@gmail.com>
Date: Sat, 11 Nov 2023 12:44:36 +0100
Subject: [PATCH] lpwinning: select lowest epoch task id for mining task

---
 provider/lpwinning/winning_task.go | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/provider/lpwinning/winning_task.go b/provider/lpwinning/winning_task.go
index e65823921..06bff5255 100644
--- a/provider/lpwinning/winning_task.go
+++ b/provider/lpwinning/winning_task.go
@@ -398,7 +398,23 @@ func (t *WinPostTask) CanAccept(ids []harmonytask.TaskID, engine *harmonytask.Ta
 		return nil, nil
 	}
 
-	return &ids[0], nil
+	// select lowest epoch
+	var lowestEpoch abi.ChainEpoch
+	var lowestEpochID = ids[0]
+	for _, id := range ids {
+		var epoch uint64
+		err := t.db.QueryRow(context.Background(), `SELECT epoch FROM mining_tasks WHERE task_id = $1`, id).Scan(&epoch)
+		if err != nil {
+			return nil, err
+		}
+
+		if lowestEpoch == 0 || abi.ChainEpoch(epoch) < lowestEpoch {
+			lowestEpoch = abi.ChainEpoch(epoch)
+			lowestEpochID = id
+		}
+	}
+
+	return &lowestEpochID, nil
 }
 
 func (t *WinPostTask) TypeDetails() harmonytask.TaskTypeDetails {