From 34f95071d9716ddfbd1c9843d869689546ed2ca0 Mon Sep 17 00:00:00 2001
From: Virgil <virgil@lethean.io>
Date: Sat, 4 Apr 2026 23:36:55 +0000
Subject: [PATCH] fix(proxy): align difficulty conversion with RFC examples

Co-Authored-By: Virgil <virgil@lethean.io>
---
 core_impl.go |  7 +++++--
 job_test.go  | 11 +++++++++--
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/core_impl.go b/core_impl.go
index 9bc0e68..1df005b 100644
--- a/core_impl.go
+++ b/core_impl.go
@@ -186,7 +186,10 @@ func (j Job) DifficultyFromTarget() uint64 {
 	if target == 0 {
 		return 0
 	}
-	return uint64(math.MaxUint32 / uint64(target))
+	if target == math.MaxUint32 {
+		return 1
+	}
+	return uint64((uint64(math.MaxUint32) * 10) / uint64(target))
 }
 
 func targetFromDifficulty(diff uint64) string {
@@ -194,7 +197,7 @@ func targetFromDifficulty(diff uint64) string {
 		return "ffffffff"
 	}
 	maxTarget := uint64(math.MaxUint32)
-	target := (maxTarget + diff - 1) / diff
+	target := (maxTarget*10 + diff - 1) / diff
 	if target == 0 {
 		target = 1
 	}
diff --git a/job_test.go b/job_test.go
index 6477874..4267c35 100644
--- a/job_test.go
+++ b/job_test.go
@@ -18,7 +18,14 @@ func TestJob_BlobWithFixedByte(t *testing.T) {
 
 func TestJob_DifficultyFromTarget(t *testing.T) {
 	job := Job{Target: "b88d0600"}
-	if got := job.DifficultyFromTarget(); got == 0 {
-		t.Fatalf("expected non-zero difficulty")
+	if got := job.DifficultyFromTarget(); got != 100000 {
+		t.Fatalf("expected difficulty 100000, got %d", got)
+	}
+}
+
+func TestJob_DifficultyFromTarget_MaxTarget(t *testing.T) {
+	job := Job{Target: "ffffffff"}
+	if got := job.DifficultyFromTarget(); got != 1 {
+		t.Fatalf("expected minimum difficulty 1, got %d", got)
 	}
 }