Method setCursorRuneOffset

internal/tui/prompt.go:418–444

setCursorRuneOffset moves the cursor to an absolute rune position. textarea has no (row, col) setter, so we step CursorUp/Down to the target row then SetCursor the column. The step cap bounds the walk so a buggy textarea can't wedge the loop.

(offset int)

// SetCursor the column. The step cap bounds the walk so a buggy textarea can't
// wedge the loop.
func (p *promptInput) setCursorRuneOffset(offset int) {
	value := p.ta.Value()
	targetRow, targetCol := runeOffsetToRowCol(value, offset)

	for range 2048 {
		curRow := p.ta.Line()
		if curRow == targetRow {
			break
		}
		info := p.ta.LineInfo()
		if curRow < targetRow {
			p.ta.CursorDown()
		} else {
			p.ta.CursorUp()
		}
		// Inside a soft-wrapped logical line a cursor step moves only the
		// visual position (LineInfo), not Line(); that's progress toward the
		// target row, not a wedged textarea. Bail only when nothing moved, or
		// the walk stops one visual row short and SetCursor lands on the
		// wrong logical row.
		if next := p.ta.LineInfo(); p.ta.Line() == curRow &&
			next.RowOffset == info.RowOffset && next.ColumnOffset == info.ColumnOffset {
			break
		}
	}
	p.ta.SetCursor(targetCol)
}

// runeOffsetToRowCol converts an absolute rune offset into (row, col).
func runeOffsetToRowCol(value string, offset int) (int, int) {