Better line wrapping

document.go

@@ -337,6 +337,16 @@ func (d *Document) CursorPositionRow() (row istrings.RuneNumber) {
 	return
 }
 
+// TextEndPositionRow returns the row of the end of the current text. (0-based.)
+func (d *Document) TextEndPositionRow() (row istrings.RuneNumber) {
+	textLength := istrings.RuneCount(d.Text)
+	if textLength == 0 {
+		return 0
+	}
+	row, _ = d.findLineStartIndex(textLength - 1)
+	return
+}
+
 // CursorPositionCol returns the current column. (0-based.)
 func (d *Document) CursorPositionCol() (col istrings.RuneNumber) {
 	_, index := d.findLineStartIndex(d.cursorPosition)

position_test.go

@@ -32,6 +32,14 @@ func TestPositionAtEndOfString(t *testing.T) {
 				Y: 0,
 			},
 		},
+		"one word": {
+			input:   "foo",
+			columns: 20,
+			want: Position{
+				X: 3,
+				Y: 0,
+			},
+		},
 		"one-line fits in columns": {
 			input:   "foo bar",
 			columns: 20,
@@ -48,6 +56,14 @@ func TestPositionAtEndOfString(t *testing.T) {
 				Y: 2,
 			},
 		},
+		"one-line wrapping": {
+			input:   "foobar",
+			columns: 3,
+			want: Position{
+				X: 0,
+				Y: 2,
+			},
+		},
 	}
 
 	for name, tc := range tests {

prompt.go

@@ -208,8 +208,8 @@ keySwitch:
 		p.buf = NewBuffer()
 		p.history.Clear()
 	case Up, ControlP:
-		cursor := p.buf.Document().GetCursorPosition(p.renderer.col)
-		if cursor.Y != 0 {
+		line := p.buf.Document().CursorPositionRow()
+		if line > 0 {
 			p.buf.CursorUp(1)
 			break
 		}
@@ -222,9 +222,9 @@ keySwitch:
 		}
 
 	case Down, ControlN:
-		endOfTextCursor := p.buf.Document().GetEndOfTextPosition(p.renderer.col)
-		cursor := p.buf.Document().GetCursorPosition(p.renderer.col)
-		if endOfTextCursor.Y > cursor.Y {
+		endOfTextRow := p.buf.Document().TextEndPositionRow()
+		row := p.buf.Document().CursorPositionRow()
+		if endOfTextRow > row {
 			p.buf.CursorDown(1)
 			break
 		}

renderer.go

@@ -1,7 +1,6 @@
 package prompt
 
 import (
-	"runtime"
 	"strings"
 	"unicode/utf8"
 
@@ -126,6 +125,7 @@ func (r *Renderer) renderCompletion(buf *Buffer, completions *CompletionManager)
 		return
 	}
 	prefix := r.prefixCallback()
+	prefixWidth := istrings.GetWidth(prefix)
 	formatted, width := formatSuggestions(
 		suggestions,
 		r.col-istrings.GetWidth(prefix)-1, // -1 means a width of scrollbar
@@ -140,7 +140,7 @@ func (r *Renderer) renderCompletion(buf *Buffer, completions *CompletionManager)
 	formatted = formatted[completions.verticalScroll : completions.verticalScroll+windowHeight]
 	r.prepareArea(windowHeight)
 
-	cursor := positionAtEndOfString(prefix+buf.Document().TextBeforeCursor(), r.col)
+	cursor := positionAtEndOfString(prefix+buf.Document().TextBeforeCursor(), r.col-prefixWidth)
 	x := cursor.X
 	if x+width >= r.col {
 		cursor = r.backward(cursor, x+width-r.col)
@@ -194,7 +194,6 @@ func (r *Renderer) renderCompletion(buf *Buffer, completions *CompletionManager)
 		r.out.SetColor(DefaultColor, DefaultColor, false)
 
 		c := cursor.Add(Position{X: width})
-		r.lineWrap(&c)
 		r.backward(c, width)
 	}
 
@@ -219,7 +218,7 @@ func (r *Renderer) Render(buffer *Buffer, completion *CompletionManager, lexer L
 	text := buffer.Text()
 	prefix := r.prefixCallback()
 	prefixWidth := istrings.GetWidth(prefix)
-	cursor := positionAtEndOfString(text, r.col)
+	cursor := positionAtEndOfString(text, r.col-prefixWidth)
 	cursor.X += prefixWidth
 
 	// prepare area
@@ -239,10 +238,9 @@ func (r *Renderer) Render(buffer *Buffer, completion *CompletionManager, lexer L
 
 	r.out.SetColor(DefaultColor, DefaultColor, false)
 
-	r.lineWrap(&cursor)
-
-	targetCursor := buffer.DisplayCursorPosition(r.col)
+	targetCursor := buffer.DisplayCursorPosition(r.col - prefixWidth)
 	targetCursor.X += prefixWidth
+	// Log("col: %#v, targetCursor: %#v, cursor: %#v\n", r.col-prefixWidth, targetCursor, cursor)
 	cursor = r.move(cursor, targetCursor)
 
 	r.renderCompletion(buffer, completion)
@@ -263,9 +261,7 @@ func (r *Renderer) Render(buffer *Buffer, completion *CompletionManager, lexer L
 
 		r.out.SetColor(DefaultColor, DefaultColor, false)
 
-		cursor = cursor.Join(positionAtEndOfString(rest, r.col))
-
-		r.lineWrap(&cursor)
+		cursor = cursor.Join(positionAtEndOfString(rest, r.col-prefixWidth))
 
 		cursor = r.move(cursor, endOfSuggestionPos)
 	}
@@ -279,21 +275,32 @@ func (r *Renderer) renderText(lexer Lexer, text string) {
 	}
 
 	prefix := r.prefixCallback()
+	prefixWidth := istrings.GetWidth(prefix)
+	col := r.col - prefixWidth
 	multilinePrefix := r.getMultilinePrefix(prefix)
 	firstIteration := true
 	var lineBuffer strings.Builder
+	var lineCharIndex istrings.Width
+
 	for _, char := range text {
-		lineBuffer.WriteRune(char)
-		if char != '\n' {
+		if lineCharIndex >= col || char == '\n' {
+			lineBuffer.WriteRune('\n')
+			r.renderLine(prefix, lineBuffer.String(), r.inputTextColor)
+			lineCharIndex = 0
+			lineBuffer.Reset()
+			if char != '\n' {
+				lineBuffer.WriteRune(char)
+				lineCharIndex += istrings.GetRuneWidth(char)
+			}
+			if firstIteration {
+				prefix = multilinePrefix
+				firstIteration = false
+			}
 			continue
 		}
 
-		r.renderLine(prefix, lineBuffer.String(), r.inputTextColor)
-		lineBuffer.Reset()
-		if firstIteration {
-			prefix = multilinePrefix
-			firstIteration = false
-		}
+		lineBuffer.WriteRune(char)
+		lineCharIndex += istrings.GetRuneWidth(char)
 	}
 
 	r.renderLine(prefix, lineBuffer.String(), r.inputTextColor)
@@ -353,8 +360,11 @@ func (r *Renderer) lex(lexer Lexer, input string) {
 	s := input
 
 	prefix := r.prefixCallback()
-	r.renderPrefix(prefix)
+	prefixWidth := istrings.GetWidth(prefix)
+	col := r.col - prefixWidth
 	multilinePrefix := r.getMultilinePrefix(prefix)
+	r.renderPrefix(prefix)
+	var lineCharIndex istrings.Width
 	for {
 		token, ok := lexer.Next()
 		if !ok {
@@ -365,15 +375,25 @@ func (r *Renderer) lex(lexer Lexer, input string) {
 		s = strings.TrimPrefix(s, text)
 
 		var lineBuffer strings.Builder
+
 		for _, char := range text {
-			lineBuffer.WriteRune(char)
-			if char != '\n' {
+			if lineCharIndex >= col || char == '\n' {
+				if char != '\n' {
+					lineBuffer.WriteByte('\n')
+				}
+				r.writeString(lineBuffer.String(), token.Color())
+				r.renderPrefix(multilinePrefix)
+				lineCharIndex = 0
+				lineBuffer.Reset()
+				if char != '\n' {
+					lineBuffer.WriteRune(char)
+					lineCharIndex += istrings.GetRuneWidth(char)
+				}
 				continue
 			}
 
-			r.writeString(lineBuffer.String(), token.Color())
-			r.renderPrefix(multilinePrefix)
-			lineBuffer.Reset()
+			lineBuffer.WriteRune(char)
+			lineCharIndex += istrings.GetRuneWidth(char)
 		}
 		r.writeString(lineBuffer.String(), token.Color())
 	}
@@ -382,11 +402,17 @@ func (r *Renderer) lex(lexer Lexer, input string) {
 // BreakLine to break line.
 func (r *Renderer) BreakLine(buffer *Buffer, lexer Lexer) {
 	// Erasing and Renderer
-	cursor := positionAtEndOfString(buffer.Document().TextBeforeCursor()+r.prefixCallback(), r.col)
+	prefix := r.prefixCallback()
+	prefixWidth := istrings.GetWidth(prefix)
+	cursor := positionAtEndOfString(buffer.Document().TextBeforeCursor(), r.col-prefixWidth)
+	cursor.X += prefixWidth
 	r.clear(cursor)
 
-	text := buffer.Document().Text + "\n"
+	text := buffer.Document().Text
 	r.renderText(lexer, text)
+	if _, err := r.out.WriteString("\n"); err != nil {
+		panic(err)
+	}
 
 	r.out.SetColor(DefaultColor, DefaultColor, false)
 
@@ -420,14 +446,6 @@ func (r *Renderer) move(from, to Position) Position {
 	return to
 }
 
-func (r *Renderer) lineWrap(cursor *Position) {
-	if runtime.GOOS != "windows" && cursor.X > 0 && cursor.X%r.col == 0 {
-		cursor.X = 0
-		cursor.Y += 1
-		r.out.WriteRaw([]byte{'\n'})
-	}
-}
-
 func clamp(high, low, x float64) float64 {
 	switch {
 	case high < x: