fix: editor whitespaces

text_editor.go

@@ -761,7 +761,7 @@ func normalizeLineEndings(value string) string {
 
 type editorVisualLine struct {
 	text                     string
-	start, end               int
+	start, displayStart, end int
 	logicalStart, logicalEnd int
 }
 
@@ -826,9 +826,11 @@ func moveEditorCursorLine(value string, cursor, delta, wrapWidth int, normal boo
 	if targetIndex == index {
 		return cursor
 	}
-	column := lipgloss.Width(string(runes[lines[index].start:clamp(cursor, lines[index].start, lines[index].end)]))
+	current := lines[index]
+	columnStart := min(current.end, max(current.start, current.displayStart))
+	column := lipgloss.Width(string(runes[columnStart:clamp(cursor, columnStart, current.end)]))
 	target := lines[targetIndex]
-	position, usedWidth := target.start, 0
+	position, usedWidth := max(target.start, target.displayStart), 0
 	for position < target.end {
 		runeWidth := lipgloss.Width(string(runes[position]))
 		if usedWidth+runeWidth > column {
@@ -887,23 +889,39 @@ func editorCursorVisualPosition(editor textEditor, width int) (int, int) {
 	visual := editorVisualLines(editor.Text, width)
 	index := editorVisualLineIndex(visual, cursor)
 	line := visual[index]
-	column := lipgloss.Width(string(runes[line.start:clamp(cursor, line.start, line.end)]))
+	columnStart := min(line.end, max(line.start, line.displayStart))
+	column := lipgloss.Width(string(runes[columnStart:clamp(cursor, columnStart, line.end)]))
 	return index, column
 }
 
 func wrapEditorLogicalLine(runes []rune, start, end, width int) []editorVisualLine {
 	if start == end {
 		return []editorVisualLine{{
-			start: start, end: end, logicalStart: start, logicalEnd: end,
+			start: start, displayStart: start, end: end,
+			logicalStart: start, logicalEnd: end,
 		}}
 	}
 	var lines []editorVisualLine
 	for offset := start; offset < end; {
-		next := offset
+		displayStart := offset
+		if offset > start {
+			for displayStart < end && unicode.IsSpace(runes[displayStart]) {
+				displayStart++
+			}
+		}
+		if displayStart == end {
+			lines = append(lines, editorVisualLine{
+				start: offset, displayStart: displayStart, end: end,
+				logicalStart: start, logicalEnd: end,
+			})
+			break
+		}
+
+		next := displayStart
 		lineWidth := 0
 		for next < end {
 			runeWidth := lipgloss.Width(string(runes[next]))
-			if next > offset && lineWidth+runeWidth > width {
+			if next > displayStart && lineWidth+runeWidth > width {
 				break
 			}
 			lineWidth += runeWidth
@@ -912,14 +930,32 @@ func wrapEditorLogicalLine(runes []rune, start, end, width int) []editorVisualLi
 				break
 			}
 		}
-		if next == offset {
+		if next == displayStart {
 			next++
 		}
+		lineEnd := next
+		if next < end {
+			breakAt := -1
+			haveWord := false
+			for index := displayStart; index < next; index++ {
+				if unicode.IsSpace(runes[index]) {
+					if haveWord {
+						breakAt = index
+					}
+				} else {
+					haveWord = true
+				}
+			}
+			if breakAt > displayStart {
+				lineEnd = breakAt
+			}
+		}
 		lines = append(lines, editorVisualLine{
-			text: string(runes[offset:next]), start: offset, end: next,
+			text:  string(runes[displayStart:lineEnd]),
+			start: offset, displayStart: displayStart, end: lineEnd,
 			logicalStart: start, logicalEnd: end,
 		})
-		offset = next
+		offset = lineEnd
 	}
 	return lines
 }
@@ -941,12 +977,16 @@ func renderEditorVisualLine(
 		underlineEnd   = "\x1b[24m"
 	)
 	runes := []rune(line.text)
+	displayCursor := cursor
+	if displayCursor < line.displayStart {
+		displayCursor = line.displayStart
+	}
 	var rendered strings.Builder
 	selected := false
 	protectedColor := ""
 	markdownStyle := editorMarkdownPlain
 	for offset, value := range runes {
-		position := line.start + offset
+		position := line.displayStart + offset
 		nextProtectedColor := ""
 		if position < protectedPrefix {
 			nextProtectedColor = editorMarkdownTheme.Dim
@@ -991,7 +1031,7 @@ func renderEditorVisualLine(
 			}
 			selected = nowSelected
 		}
-		if showCursor && position == cursor {
+		if showCursor && position == displayCursor {
 			switch mode {
 			case textEditorInsert:
 				if hardwareCursor {

text_editor_test.go

@@ -308,6 +308,65 @@ func TestEditorKeepsWrappedRowsAndContextRailsVisible(t *testing.T) {
 	}
 }
 
+func TestEditorWordWrapHidesSoftWrapSpacesWithoutChangingText(t *testing.T) {
+	const value = "abcdefghij hello"
+	visual := editorVisualLines(value, 10)
+	if len(visual) != 2 || visual[0].text != "abcdefghij" || visual[1].text != "hello" {
+		t.Fatalf("word-wrapped lines = %#v", visual)
+	}
+	if visual[1].start != 10 || visual[1].displayStart != 11 {
+		t.Fatalf("wrapped separator offsets = %#v", visual[1])
+	}
+
+	editor := newTextEditor(value, true)
+	editor.Cursor = len([]rune(value))
+	rendered := renderTextEditor(editor, 10, false)
+	if got := ansi.Strip(rendered[1].text); got != "hello" {
+		t.Fatalf("wrapped row begins with separator space: %q", got)
+	}
+	if editor.Text != value {
+		t.Fatalf("word wrapping changed stored text: %q", editor.Text)
+	}
+
+	visual = editorVisualLines("hello world", 10)
+	if len(visual) != 2 || visual[0].text != "hello" || visual[1].text != "world" {
+		t.Fatalf("overflowing word was split instead of moved: %#v", visual)
+	}
+}
+
+func TestEditorBoundarySpaceCreatesEmptyVisualRow(t *testing.T) {
+	const value = "abcdefghij "
+	visual := editorVisualLines(value, 10)
+	if len(visual) != 2 || visual[0].text != "abcdefghij" || visual[1].text != "" {
+		t.Fatalf("boundary-space lines = %#v", visual)
+	}
+	if visual[1].start != 10 || visual[1].displayStart != 11 || visual[1].end != 11 {
+		t.Fatalf("boundary-space offsets = %#v", visual[1])
+	}
+	editor := newTextEditor(value, true)
+	editor.Cursor = len([]rune(value))
+	if line, column := editorCursorVisualPosition(editor, 10); line != 1 || column != 0 {
+		t.Fatalf("boundary-space cursor = row %d column %d, want row 1 column 0", line, column)
+	}
+}
+
+func TestEditorWordWrapHardWrapsWordsWiderThanViewport(t *testing.T) {
+	const value = "hi abcdefghijklmnopqrstuv"
+	visual := editorVisualLines(value, 10)
+	want := []string{"hi", "abcdefghij", "klmnopqrst", "uv"}
+	if len(visual) != len(want) {
+		t.Fatalf("long-word rows = %#v, want %q", visual, want)
+	}
+	for index, line := range visual {
+		if line.text != want[index] {
+			t.Fatalf("long-word row %d = %q, want %q", index, line.text, want[index])
+		}
+		if ansi.StringWidth(line.text) > 10 {
+			t.Fatalf("long-word row %d exceeds viewport: %q", index, line.text)
+		}
+	}
+}
+
 func TestVimEditorTreatsSoftWrapsAsVisualLinesWithoutChangingText(t *testing.T) {
 	const value = "abcdefghijklmnopqrstuv"
 	editor := newTextEditor(value, true)

version.go

@@ -1,3 +1,3 @@
 package main
 
-const dipleVersion = "0.3.3"
+const dipleVersion = "0.3.4"