From af001ce1bc5c0080ea9c22a011a1496e8e24888b Mon Sep 17 00:00:00 2001
From: Ayman Bagabas <ayman.bagabas@gmail.com>
Date: Thu, 6 Feb 2025 15:55:15 -0500
Subject: [PATCH] feat(cellbuf): append runes to cell without changing width
 and accept escape sequences

---
 cellbuf/cell.go   | 13 +++++++++++++
 cellbuf/screen.go | 39 +++++++++++++++++++--------------------
 2 files changed, 32 insertions(+), 20 deletions(-)

diff --git a/cellbuf/cell.go b/cellbuf/cell.go
index 368f63db..a8a57654 100644
--- a/cellbuf/cell.go
+++ b/cellbuf/cell.go
@@ -34,6 +34,19 @@ type Cell struct {
 	Rune rune
 }
 
+// Append appends runes to the cell without changing the width. This is useful
+// when we want to use the cell to store escape sequences or other runes that
+// don't affect the width of the cell.
+func (c *Cell) Append(r ...rune) {
+	for i, r := range r {
+		if i == 0 && c.Rune == 0 {
+			c.Rune = r
+			continue
+		}
+		c.Comb = append(c.Comb, r)
+	}
+}
+
 // String returns the string content of the cell excluding any styles, links,
 // and escape sequences.
 func (c Cell) String() string {
diff --git a/cellbuf/screen.go b/cellbuf/screen.go
index 19eb3c10..647ea943 100644
--- a/cellbuf/screen.go
+++ b/cellbuf/screen.go
@@ -1520,21 +1520,15 @@ func (s *Screen) printString(x, y int, bounds Rectangle, str string, truncate bo
 		}
 	}
 
+	var cell Cell
 	var state byte
 	for len(str) > 0 {
 		seq, width, n, newState := s.method.DecodeSequenceInString(str, state, p)
 
-		var cell *Cell
 		switch width {
 		case 1, 2, 3, 4: // wide cells can go up to 4 cells wide
-			cell = &Cell{Width: width}
-			for i, r := range seq {
-				if i == 0 {
-					cell.Rune = r
-				} else {
-					cell.Comb = append(cell.Comb, r)
-				}
-			}
+			cell.Width += width
+			cell.Append([]rune(seq)...)
 
 			if !truncate && x+cell.Width > bounds.Max.X {
 				// Wrap the string to the width of the window
@@ -1553,7 +1547,8 @@ func (s *Screen) printString(x, y int, bounds Rectangle, str string, truncate bo
 					// Print the cell to the screen
 					cell.Style = s.cur.Style
 					cell.Link = s.cur.Link
-					s.SetCell(x, y, cell) //nolint:errcheck
+					s.SetCell(x, y, &cell) //nolint:errcheck
+					cell.Reset()
 					x += width
 				}
 			} // String is too long for the line, truncate it.
@@ -1561,20 +1556,18 @@ func (s *Screen) printString(x, y int, bounds Rectangle, str string, truncate bo
 			// Valid sequences always have a non-zero Cmd.
 			// TODO: Handle cursor movement and other sequences
 			switch {
-			case ansi.HasCsiPrefix(seq) && p.Command() != 0:
-				switch p.Command() {
-				case 'm': // SGR - Select Graphic Rendition
-					ReadStyle(p.Params(), &s.cur.Style)
-				}
-			case ansi.HasOscPrefix(seq) && p.Command() != 0:
-				switch p.Command() {
-				case 8: // Hyperlinks
-					ReadLink(p.Data(), &s.cur.Link)
-				}
+			case ansi.HasCsiPrefix(seq) && p.Command() == 'm':
+				// SGR - Select Graphic Rendition
+				ReadStyle(p.Params(), &s.cur.Style)
+			case ansi.HasOscPrefix(seq) && p.Command() == 8:
+				// Hyperlinks
+				ReadLink(p.Data(), &s.cur.Link)
 			case ansi.Equal(seq, "\n"):
 				y++
 			case ansi.Equal(seq, "\r"):
 				x = bounds.Min.X
+			default:
+				cell.Append([]rune(seq)...)
 			}
 		}
 
@@ -1582,4 +1575,10 @@ func (s *Screen) printString(x, y int, bounds Rectangle, str string, truncate bo
 		state = newState
 		str = str[n:]
 	}
+
+	// Make sure to set the last cell if it's not empty.
+	if !cell.Empty() {
+		s.SetCell(x, y, &cell) //nolint:errcheck
+		cell.Reset()
+	}
 }