From d46324fe783b67fb18cb68c0fcea0d586ad1c43a Mon Sep 17 00:00:00 2001
From: Arpad Ryszka <arpad.ryszka@gmail.com>
Date: Tue, 10 Nov 2020 01:33:46 +0100
Subject: [PATCH] handle multiple non-wrapped long nodes following each other

---
 fprint.go      | 25 ++++++++++++++++++++-----
 sprint_test.go | 11 ++++++++---
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/fprint.go b/fprint.go
index d06d78d..f1f37da 100644
--- a/fprint.go
+++ b/fprint.go
@@ -115,23 +115,38 @@ func wrapNode(t, c0, c1 int, n node) node {
 
 	n.wrap = true
 	cc0, cc1 := c0, c1
-	for i, p := range n.parts {
+	lastWrapperIndex := -1
+	var trackBack bool
+	for i := 0; i < len(n.parts); i++ {
+		p := n.parts[i]
 		switch part := p.(type) {
 		case node:
 			part = wrapNode(t, cc0, cc1, part)
 			n.parts[i] = part
 			if part.wrap {
-				cc0 -= part.wrapLen.last
-				cc1 -= part.wrapLen.last
+				// This is an approximation: sometimes part.fullWrap.first is applied here,
+				// but usually those are the same.
+				cc0 -= part.wrapLen.first
+				cc1 -= part.wrapLen.first
 			} else {
 				cc0 -= part.len
 				cc1 -= part.len
 			}
+
+			if !trackBack && cc1 < 0 {
+				cc0 = 0
+				cc1 = 0
+				i = lastWrapperIndex
+				trackBack = true
+			}
 		case wrapper:
-			if len(part.items) > 0 {
-				cc0, cc1 = c0, c1
+			if len(part.items) == 0 {
+				continue
 			}
 
+			cc0, cc1 = c0, c1
+			trackBack = false
+			lastWrapperIndex = i
 			switch part.mode {
 			case line:
 				c0, c1 = c0-t, c1-t
diff --git a/sprint_test.go b/sprint_test.go
index b1ae138..dbb2a22 100644
--- a/sprint_test.go
+++ b/sprint_test.go
@@ -910,11 +910,13 @@ func TestSortedMap(t *testing.T) {
 }
 
 func TestBytes(t *testing.T) {
-	const expectNotWrapped = `[]{00 01 02 03 04 05 06 07 08 09 0a 0b}`
-	const expectWrapped = `[]{
+	const (
+		expectNotWrapped = `[]{00 01 02 03 04 05 06 07 08 09 0a 0b}`
+		expectWrapped    = `[]{
 	00 01 02 03 04 05
 	06 07 08 09 0a 0b
 }`
+	)
 
 	b := []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}
 	t.Run("not wrapped", func(t *testing.T) {
@@ -940,7 +942,10 @@ func TestBytes(t *testing.T) {
 }
 
 func TestNonWrapperNodes(t *testing.T) {
-	const expect = `map[struct{foo int; bar int}]struct{
+	const expect = `map[struct{
+	foo int
+	bar int
+}]struct{
 	foo int
 	bar int
 }{}`