From 3cf3563b77d70ae5ac14763330fe98b71397f557 Mon Sep 17 00:00:00 2001
From: Ayman Bagabas <ayman.bagabas@gmail.com>
Date: Fri, 28 Jul 2023 12:17:22 -0400
Subject: [PATCH] fix!: output race condition

BREAKING!

`ColorProfile` reads the terminal environment every time the function is
called. This is inefficient. We only need to read the `$TERM`
environment variable once when we initialize the output. So we cache
the value we read.

Rename `ColorProfile` to `termColorProfile` and rely on
`EnvColorProfile` to detect the profile. Ideally, we rely on the
terminal Terminfo to detect the profile and fallback to the environment.

Make output profile accessible through `ColorProfile`.
Use `SetColorProfile` to change the output color profile.
Use a mutex to guard output writes.
Use pointer receiver since we have a lock in the struct

Fixes: https://github.com/charmbracelet/lipgloss/pull/210
Fixes: https://github.com/muesli/termenv/issues/145
---
 copy.go            |  4 +--
 output.go          | 37 ++++++++++++++-----
 output_test.go     | 22 ++++++++++++
 screen.go          | 88 +++++++++++++++++++++++-----------------------
 templatehelper.go  |  4 +--
 termenv.go         | 11 ++++--
 termenv_other.go   |  8 ++---
 termenv_test.go    | 14 ++++----
 termenv_unix.go    | 10 +++---
 termenv_windows.go |  6 ++--
 10 files changed, 127 insertions(+), 77 deletions(-)
 create mode 100644 output_test.go

diff --git a/copy.go b/copy.go
index 4bf5c9f..e2ac2bf 100644
--- a/copy.go
+++ b/copy.go
@@ -7,7 +7,7 @@ import (
 )
 
 // Copy copies text to clipboard using OSC 52 escape sequence.
-func (o Output) Copy(str string) {
+func (o *Output) Copy(str string) {
 	s := osc52.New(str)
 	if strings.HasPrefix(o.environ.Getenv("TERM"), "screen") {
 		s = s.Screen()
@@ -17,7 +17,7 @@ func (o Output) Copy(str string) {
 
 // CopyPrimary copies text to primary clipboard (X11) using OSC 52 escape
 // sequence.
-func (o Output) CopyPrimary(str string) {
+func (o *Output) CopyPrimary(str string) {
 	s := osc52.New(str).Primary()
 	if strings.HasPrefix(o.environ.Getenv("TERM"), "screen") {
 		s = s.Screen()
diff --git a/output.go b/output.go
index e22d369..d7245b6 100644
--- a/output.go
+++ b/output.go
@@ -22,7 +22,7 @@ type OutputOption = func(*Output)
 
 // Output is a terminal output.
 type Output struct {
-	Profile
+	profile Profile
 	tty     io.Writer
 	environ Environ
 
@@ -33,6 +33,8 @@ type Output struct {
 	fgColor   Color
 	bgSync    *sync.Once
 	bgColor   Color
+
+	mtx sync.RWMutex
 }
 
 // Environ is an interface for getting environment variables.
@@ -66,7 +68,7 @@ func NewOutput(tty io.Writer, opts ...OutputOption) *Output {
 	o := &Output{
 		tty:     tty,
 		environ: &osEnviron{},
-		Profile: -1,
+		profile: -1,
 		fgSync:  &sync.Once{},
 		fgColor: NoColor{},
 		bgSync:  &sync.Once{},
@@ -79,8 +81,8 @@ func NewOutput(tty io.Writer, opts ...OutputOption) *Output {
 	for _, opt := range opts {
 		opt(o)
 	}
-	if o.Profile < 0 {
-		o.Profile = o.EnvColorProfile()
+	if o.profile < 0 {
+		o.profile = o.EnvColorProfile()
 	}
 
 	return o
@@ -96,7 +98,7 @@ func WithEnvironment(environ Environ) OutputOption {
 // WithProfile returns a new OutputOption for the given profile.
 func WithProfile(profile Profile) OutputOption {
 	return func(o *Output) {
-		o.Profile = profile
+		o.profile = profile
 	}
 }
 
@@ -133,6 +135,21 @@ func WithUnsafe() OutputOption {
 	}
 }
 
+// ColorProfile returns the color profile.
+// Ascii, ANSI, ANSI256, or TrueColor.
+func (o *Output) ColorProfile() Profile {
+	o.mtx.RLock()
+	defer o.mtx.RUnlock()
+	return o.profile
+}
+
+// SetColorProfile sets the color profile.
+func (o *Output) SetColorProfile(profile Profile) {
+	o.mtx.Lock()
+	defer o.mtx.Unlock()
+	o.profile = profile
+}
+
 // ForegroundColor returns the terminal's default foreground color.
 func (o *Output) ForegroundColor() Color {
 	f := func() {
@@ -140,7 +157,9 @@ func (o *Output) ForegroundColor() Color {
 			return
 		}
 
+		o.mtx.Lock()
 		o.fgColor = o.foregroundColor()
+		o.mtx.Unlock()
 	}
 
 	if o.cache {
@@ -159,7 +178,9 @@ func (o *Output) BackgroundColor() Color {
 			return
 		}
 
+		o.mtx.Lock()
 		o.bgColor = o.backgroundColor()
+		o.mtx.Unlock()
 	}
 
 	if o.cache {
@@ -180,18 +201,18 @@ func (o *Output) HasDarkBackground() bool {
 
 // TTY returns the terminal's file descriptor. This may be nil if the output is
 // not a terminal.
-func (o Output) TTY() File {
+func (o *Output) TTY() File {
 	if f, ok := o.tty.(File); ok {
 		return f
 	}
 	return nil
 }
 
-func (o Output) Write(p []byte) (int, error) {
+func (o *Output) Write(p []byte) (int, error) {
 	return o.tty.Write(p)
 }
 
 // WriteString writes the given string to the output.
-func (o Output) WriteString(s string) (int, error) {
+func (o *Output) WriteString(s string) (int, error) {
 	return o.Write([]byte(s))
 }
diff --git a/output_test.go b/output_test.go
new file mode 100644
index 0000000..f300530
--- /dev/null
+++ b/output_test.go
@@ -0,0 +1,22 @@
+package termenv
+
+import (
+	"io"
+	"testing"
+)
+
+func TestOutputRace(t *testing.T) {
+	o := NewOutput(io.Discard)
+	for i := 0; i < 100; i++ {
+		t.Run("Test race", func(t *testing.T) {
+			t.Parallel()
+			o.Write([]byte("test"))
+			o.SetColorProfile(ANSI)
+			o.ColorProfile()
+			o.HasDarkBackground()
+			o.TTY()
+			o.ForegroundColor()
+			o.BackgroundColor()
+		})
+	}
+}
diff --git a/screen.go b/screen.go
index a71181b..ee80824 100644
--- a/screen.go
+++ b/screen.go
@@ -70,234 +70,234 @@ const (
 )
 
 // Reset the terminal to its default style, removing any active styles.
-func (o Output) Reset() {
+func (o *Output) Reset() {
 	fmt.Fprint(o.tty, CSI+ResetSeq+"m")
 }
 
 // SetForegroundColor sets the default foreground color.
-func (o Output) SetForegroundColor(color Color) {
+func (o *Output) SetForegroundColor(color Color) {
 	fmt.Fprintf(o.tty, OSC+SetForegroundColorSeq, color)
 }
 
 // SetBackgroundColor sets the default background color.
-func (o Output) SetBackgroundColor(color Color) {
+func (o *Output) SetBackgroundColor(color Color) {
 	fmt.Fprintf(o.tty, OSC+SetBackgroundColorSeq, color)
 }
 
 // SetCursorColor sets the cursor color.
-func (o Output) SetCursorColor(color Color) {
+func (o *Output) SetCursorColor(color Color) {
 	fmt.Fprintf(o.tty, OSC+SetCursorColorSeq, color)
 }
 
 // RestoreScreen restores a previously saved screen state.
-func (o Output) RestoreScreen() {
+func (o *Output) RestoreScreen() {
 	fmt.Fprint(o.tty, CSI+RestoreScreenSeq)
 }
 
 // SaveScreen saves the screen state.
-func (o Output) SaveScreen() {
+func (o *Output) SaveScreen() {
 	fmt.Fprint(o.tty, CSI+SaveScreenSeq)
 }
 
 // AltScreen switches to the alternate screen buffer. The former view can be
 // restored with ExitAltScreen().
-func (o Output) AltScreen() {
+func (o *Output) AltScreen() {
 	fmt.Fprint(o.tty, CSI+AltScreenSeq)
 }
 
 // ExitAltScreen exits the alternate screen buffer and returns to the former
 // terminal view.
-func (o Output) ExitAltScreen() {
+func (o *Output) ExitAltScreen() {
 	fmt.Fprint(o.tty, CSI+ExitAltScreenSeq)
 }
 
 // ClearScreen clears the visible portion of the terminal.
-func (o Output) ClearScreen() {
+func (o *Output) ClearScreen() {
 	fmt.Fprintf(o.tty, CSI+EraseDisplaySeq, 2)
 	o.MoveCursor(1, 1)
 }
 
 // MoveCursor moves the cursor to a given position.
-func (o Output) MoveCursor(row int, column int) {
+func (o *Output) MoveCursor(row int, column int) {
 	fmt.Fprintf(o.tty, CSI+CursorPositionSeq, row, column)
 }
 
 // HideCursor hides the cursor.
-func (o Output) HideCursor() {
+func (o *Output) HideCursor() {
 	fmt.Fprint(o.tty, CSI+HideCursorSeq)
 }
 
 // ShowCursor shows the cursor.
-func (o Output) ShowCursor() {
+func (o *Output) ShowCursor() {
 	fmt.Fprint(o.tty, CSI+ShowCursorSeq)
 }
 
 // SaveCursorPosition saves the cursor position.
-func (o Output) SaveCursorPosition() {
+func (o *Output) SaveCursorPosition() {
 	fmt.Fprint(o.tty, CSI+SaveCursorPositionSeq)
 }
 
 // RestoreCursorPosition restores a saved cursor position.
-func (o Output) RestoreCursorPosition() {
+func (o *Output) RestoreCursorPosition() {
 	fmt.Fprint(o.tty, CSI+RestoreCursorPositionSeq)
 }
 
 // CursorUp moves the cursor up a given number of lines.
-func (o Output) CursorUp(n int) {
+func (o *Output) CursorUp(n int) {
 	fmt.Fprintf(o.tty, CSI+CursorUpSeq, n)
 }
 
 // CursorDown moves the cursor down a given number of lines.
-func (o Output) CursorDown(n int) {
+func (o *Output) CursorDown(n int) {
 	fmt.Fprintf(o.tty, CSI+CursorDownSeq, n)
 }
 
 // CursorForward moves the cursor up a given number of lines.
-func (o Output) CursorForward(n int) {
+func (o *Output) CursorForward(n int) {
 	fmt.Fprintf(o.tty, CSI+CursorForwardSeq, n)
 }
 
 // CursorBack moves the cursor backwards a given number of cells.
-func (o Output) CursorBack(n int) {
+func (o *Output) CursorBack(n int) {
 	fmt.Fprintf(o.tty, CSI+CursorBackSeq, n)
 }
 
 // CursorNextLine moves the cursor down a given number of lines and places it at
 // the beginning of the line.
-func (o Output) CursorNextLine(n int) {
+func (o *Output) CursorNextLine(n int) {
 	fmt.Fprintf(o.tty, CSI+CursorNextLineSeq, n)
 }
 
 // CursorPrevLine moves the cursor up a given number of lines and places it at
 // the beginning of the line.
-func (o Output) CursorPrevLine(n int) {
+func (o *Output) CursorPrevLine(n int) {
 	fmt.Fprintf(o.tty, CSI+CursorPreviousLineSeq, n)
 }
 
 // ClearLine clears the current line.
-func (o Output) ClearLine() {
+func (o *Output) ClearLine() {
 	fmt.Fprint(o.tty, CSI+EraseEntireLineSeq)
 }
 
 // ClearLineLeft clears the line to the left of the cursor.
-func (o Output) ClearLineLeft() {
+func (o *Output) ClearLineLeft() {
 	fmt.Fprint(o.tty, CSI+EraseLineLeftSeq)
 }
 
 // ClearLineRight clears the line to the right of the cursor.
-func (o Output) ClearLineRight() {
+func (o *Output) ClearLineRight() {
 	fmt.Fprint(o.tty, CSI+EraseLineRightSeq)
 }
 
 // ClearLines clears a given number of lines.
-func (o Output) ClearLines(n int) {
+func (o *Output) ClearLines(n int) {
 	clearLine := fmt.Sprintf(CSI+EraseLineSeq, 2)
 	cursorUp := fmt.Sprintf(CSI+CursorUpSeq, 1)
 	fmt.Fprint(o.tty, clearLine+strings.Repeat(cursorUp+clearLine, n))
 }
 
 // ChangeScrollingRegion sets the scrolling region of the terminal.
-func (o Output) ChangeScrollingRegion(top, bottom int) {
+func (o *Output) ChangeScrollingRegion(top, bottom int) {
 	fmt.Fprintf(o.tty, CSI+ChangeScrollingRegionSeq, top, bottom)
 }
 
 // InsertLines inserts the given number of lines at the top of the scrollable
 // region, pushing lines below down.
-func (o Output) InsertLines(n int) {
+func (o *Output) InsertLines(n int) {
 	fmt.Fprintf(o.tty, CSI+InsertLineSeq, n)
 }
 
 // DeleteLines deletes the given number of lines, pulling any lines in
 // the scrollable region below up.
-func (o Output) DeleteLines(n int) {
+func (o *Output) DeleteLines(n int) {
 	fmt.Fprintf(o.tty, CSI+DeleteLineSeq, n)
 }
 
 // EnableMousePress enables X10 mouse mode. Button press events are sent only.
-func (o Output) EnableMousePress() {
+func (o *Output) EnableMousePress() {
 	fmt.Fprint(o.tty, CSI+EnableMousePressSeq)
 }
 
 // DisableMousePress disables X10 mouse mode.
-func (o Output) DisableMousePress() {
+func (o *Output) DisableMousePress() {
 	fmt.Fprint(o.tty, CSI+DisableMousePressSeq)
 }
 
 // EnableMouse enables Mouse Tracking mode.
-func (o Output) EnableMouse() {
+func (o *Output) EnableMouse() {
 	fmt.Fprint(o.tty, CSI+EnableMouseSeq)
 }
 
 // DisableMouse disables Mouse Tracking mode.
-func (o Output) DisableMouse() {
+func (o *Output) DisableMouse() {
 	fmt.Fprint(o.tty, CSI+DisableMouseSeq)
 }
 
 // EnableMouseHilite enables Hilite Mouse Tracking mode.
-func (o Output) EnableMouseHilite() {
+func (o *Output) EnableMouseHilite() {
 	fmt.Fprint(o.tty, CSI+EnableMouseHiliteSeq)
 }
 
 // DisableMouseHilite disables Hilite Mouse Tracking mode.
-func (o Output) DisableMouseHilite() {
+func (o *Output) DisableMouseHilite() {
 	fmt.Fprint(o.tty, CSI+DisableMouseHiliteSeq)
 }
 
 // EnableMouseCellMotion enables Cell Motion Mouse Tracking mode.
-func (o Output) EnableMouseCellMotion() {
+func (o *Output) EnableMouseCellMotion() {
 	fmt.Fprint(o.tty, CSI+EnableMouseCellMotionSeq)
 }
 
 // DisableMouseCellMotion disables Cell Motion Mouse Tracking mode.
-func (o Output) DisableMouseCellMotion() {
+func (o *Output) DisableMouseCellMotion() {
 	fmt.Fprint(o.tty, CSI+DisableMouseCellMotionSeq)
 }
 
 // EnableMouseAllMotion enables All Motion Mouse mode.
-func (o Output) EnableMouseAllMotion() {
+func (o *Output) EnableMouseAllMotion() {
 	fmt.Fprint(o.tty, CSI+EnableMouseAllMotionSeq)
 }
 
 // DisableMouseAllMotion disables All Motion Mouse mode.
-func (o Output) DisableMouseAllMotion() {
+func (o *Output) DisableMouseAllMotion() {
 	fmt.Fprint(o.tty, CSI+DisableMouseAllMotionSeq)
 }
 
 // EnableMouseExtendedMotion enables Extended Mouse mode (SGR). This should be
 // enabled in conjunction with EnableMouseCellMotion, and EnableMouseAllMotion.
-func (o Output) EnableMouseExtendedMode() {
+func (o *Output) EnableMouseExtendedMode() {
 	fmt.Fprint(o.tty, CSI+EnableMouseExtendedModeSeq)
 }
 
 // DisableMouseExtendedMotion disables Extended Mouse mode (SGR).
-func (o Output) DisableMouseExtendedMode() {
+func (o *Output) DisableMouseExtendedMode() {
 	fmt.Fprint(o.tty, CSI+DisableMouseExtendedModeSeq)
 }
 
 // EnableMousePixelsMotion enables Pixel Motion Mouse mode (SGR-Pixels). This
 // should be enabled in conjunction with EnableMouseCellMotion, and
 // EnableMouseAllMotion.
-func (o Output) EnableMousePixelsMode() {
+func (o *Output) EnableMousePixelsMode() {
 	fmt.Fprint(o.tty, CSI+EnableMousePixelsModeSeq)
 }
 
 // DisableMousePixelsMotion disables Pixel Motion Mouse mode (SGR-Pixels).
-func (o Output) DisableMousePixelsMode() {
+func (o *Output) DisableMousePixelsMode() {
 	fmt.Fprint(o.tty, CSI+DisableMousePixelsModeSeq)
 }
 
 // SetWindowTitle sets the terminal window title.
-func (o Output) SetWindowTitle(title string) {
+func (o *Output) SetWindowTitle(title string) {
 	fmt.Fprintf(o.tty, OSC+SetWindowTitleSeq, title)
 }
 
 // EnableBracketedPaste enables bracketed paste.
-func (o Output) EnableBracketedPaste() {
+func (o *Output) EnableBracketedPaste() {
 	fmt.Fprintf(o.tty, CSI+EnableBracketedPasteSeq)
 }
 
 // DisableBracketedPaste disables bracketed paste.
-func (o Output) DisableBracketedPaste() {
+func (o *Output) DisableBracketedPaste() {
 	fmt.Fprintf(o.tty, CSI+DisableBracketedPasteSeq)
 }
 
diff --git a/templatehelper.go b/templatehelper.go
index d75b079..57a33b2 100644
--- a/templatehelper.go
+++ b/templatehelper.go
@@ -5,8 +5,8 @@ import (
 )
 
 // TemplateFuncs returns template helpers for the given output.
-func (o Output) TemplateFuncs() template.FuncMap {
-	return TemplateFuncs(o.Profile)
+func (o *Output) TemplateFuncs() template.FuncMap {
+	return TemplateFuncs(o.ColorProfile())
 }
 
 // TemplateFuncs contains a few useful template helpers.
diff --git a/termenv.go b/termenv.go
index 4ceb271..f29f4b8 100644
--- a/termenv.go
+++ b/termenv.go
@@ -44,6 +44,11 @@ func ColorProfile() Profile {
 	return output.ColorProfile()
 }
 
+// SetColorProfile sets the color profile.
+func SetColorProfile(profile Profile) {
+	output.SetColorProfile(profile)
+}
+
 // ForegroundColor returns the terminal's default foreground color.
 func ForegroundColor() Color {
 	return output.ForegroundColor()
@@ -80,7 +85,7 @@ func EnvNoColor() bool {
 // EnvColorProfile returns the color profile based on environment variables set
 // Supports NO_COLOR (https://no-color.org/)
 // and CLICOLOR/CLICOLOR_FORCE (https://bixense.com/clicolors/)
-// If none of these environment variables are set, this behaves the same as ColorProfile()
+// If none of these environment variables are set, it tries to detect the color profile from TERM.
 // It will return the Ascii color profile if EnvNoColor() returns true
 // If the terminal does not support any colors, but CLICOLOR_FORCE is set and not "0"
 // then the ANSI color profile will be returned.
@@ -91,7 +96,7 @@ func EnvColorProfile() Profile {
 // EnvColorProfile returns the color profile based on environment variables set
 // Supports NO_COLOR (https://no-color.org/)
 // and CLICOLOR/CLICOLOR_FORCE (https://bixense.com/clicolors/)
-// If none of these environment variables are set, this behaves the same as ColorProfile()
+// If none of these environment variables are set, it tries to detect the color profile from TERM.
 // It will return the Ascii color profile if EnvNoColor() returns true
 // If the terminal does not support any colors, but CLICOLOR_FORCE is set and not "0"
 // then the ANSI color profile will be returned.
@@ -99,7 +104,7 @@ func (o *Output) EnvColorProfile() Profile {
 	if o.EnvNoColor() {
 		return Ascii
 	}
-	p := o.ColorProfile()
+	p := o.termColorProfile()
 	if o.cliColorForced() && p == Ascii {
 		return ANSI
 	}
diff --git a/termenv_other.go b/termenv_other.go
index 93a43b6..2200a45 100644
--- a/termenv_other.go
+++ b/termenv_other.go
@@ -5,18 +5,18 @@ package termenv
 
 import "io"
 
-// ColorProfile returns the supported color profile:
+// colorProfile returns the supported color profile:
 // ANSI256
-func (o Output) ColorProfile() Profile {
+func (o *Output) termColorProfile() Profile {
 	return ANSI256
 }
 
-func (o Output) foregroundColor() Color {
+func (o *Output) foregroundColor() Color {
 	// default gray
 	return ANSIColor(7)
 }
 
-func (o Output) backgroundColor() Color {
+func (o *Output) backgroundColor() Color {
 	// default black
 	return ANSIColor(0)
 }
diff --git a/termenv_test.go b/termenv_test.go
index 3f750d6..8e8030d 100644
--- a/termenv_test.go
+++ b/termenv_test.go
@@ -36,8 +36,9 @@ func TestLegacyTermEnv(t *testing.T) {
 
 func TestTermEnv(t *testing.T) {
 	o := NewOutput(os.Stdout)
-	if o.Profile != TrueColor && o.Profile != Ascii {
-		t.Errorf("Expected %d, got %d", TrueColor, o.Profile)
+	p := o.ColorProfile()
+	if p != TrueColor && p != Ascii {
+		t.Errorf("Expected %d, got %d", TrueColor, p)
 	}
 
 	fg := o.ForegroundColor()
@@ -360,8 +361,9 @@ func TestEnvNoColor(t *testing.T) {
 func TestPseudoTerm(t *testing.T) {
 	buf := &bytes.Buffer{}
 	o := NewOutput(buf)
-	if o.Profile != Ascii {
-		t.Errorf("Expected %d, got %d", Ascii, o.Profile)
+	p := o.ColorProfile()
+	if p != Ascii {
+		t.Errorf("Expected %d, got %d", Ascii, p)
 	}
 
 	fg := o.ForegroundColor()
@@ -377,8 +379,8 @@ func TestPseudoTerm(t *testing.T) {
 	}
 
 	exp := "foobar"
-	out := o.String(exp)
-	out = out.Foreground(o.Color("#abcdef"))
+	out := p.String(exp)
+	out = out.Foreground(p.Color("#abcdef"))
 	o.Write([]byte(out.String()))
 
 	if buf.String() != exp {
diff --git a/termenv_unix.go b/termenv_unix.go
index 24d519a..f32b33d 100644
--- a/termenv_unix.go
+++ b/termenv_unix.go
@@ -18,9 +18,9 @@ const (
 	OSCTimeout = 5 * time.Second
 )
 
-// ColorProfile returns the supported color profile:
+// termColorProfile returns the supported color profile:
 // Ascii, ANSI, ANSI256, or TrueColor.
-func (o *Output) ColorProfile() Profile {
+func (o *Output) termColorProfile() Profile {
 	if !o.isTTY() {
 		return Ascii
 	}
@@ -69,7 +69,7 @@ func (o *Output) ColorProfile() Profile {
 	return Ascii
 }
 
-func (o Output) foregroundColor() Color {
+func (o *Output) foregroundColor() Color {
 	s, err := o.termStatusReport(10)
 	if err == nil {
 		c, err := xTermColor(s)
@@ -91,7 +91,7 @@ func (o Output) foregroundColor() Color {
 	return ANSIColor(7)
 }
 
-func (o Output) backgroundColor() Color {
+func (o *Output) backgroundColor() Color {
 	s, err := o.termStatusReport(11)
 	if err == nil {
 		c, err := xTermColor(s)
@@ -223,7 +223,7 @@ func (o *Output) readNextResponse() (response string, isOSC bool, err error) {
 	return "", false, ErrStatusReport
 }
 
-func (o Output) termStatusReport(sequence int) (string, error) {
+func (o *Output) termStatusReport(sequence int) (string, error) {
 	// screen/tmux can't support OSC, because they can be connected to multiple
 	// terminals concurrently.
 	term := o.environ.Getenv("TERM")
diff --git a/termenv_windows.go b/termenv_windows.go
index 1d9c618..a1b933c 100644
--- a/termenv_windows.go
+++ b/termenv_windows.go
@@ -10,7 +10,7 @@ import (
 	"golang.org/x/sys/windows"
 )
 
-func (o *Output) ColorProfile() Profile {
+func (o *Output) termColorProfile() Profile {
 	if !o.isTTY() {
 		return Ascii
 	}
@@ -43,12 +43,12 @@ func (o *Output) ColorProfile() Profile {
 	return TrueColor
 }
 
-func (o Output) foregroundColor() Color {
+func (o *Output) foregroundColor() Color {
 	// default gray
 	return ANSIColor(7)
 }
 
-func (o Output) backgroundColor() Color {
+func (o *Output) backgroundColor() Color {
 	// default black
 	return ANSIColor(0)
 }