fix: windows: enable mouse mode on demand

This fixes an issue where mouse mode is always enabled on Windows. With
this patch, we enable mouse events only it is requested.

Needs: charmbracelet/x#386
Related: #1313

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/charmbracelet/x/ansi v0.8.0
 	github.com/charmbracelet/x/cellbuf v0.0.12-0.20250212155406-f75055277088
 	github.com/charmbracelet/x/exp/golden v0.0.0-20241212170349-ad4b7ae0f25f
-	github.com/charmbracelet/x/input v0.3.3
+	github.com/charmbracelet/x/input v0.3.4-0.20250224172324-3bbc6f7ae9d3
 	github.com/charmbracelet/x/term v0.2.1
 	github.com/muesli/cancelreader v0.2.2
 	golang.org/x/sync v0.11.0

go.sum

@@ -10,6 +10,8 @@ github.com/charmbracelet/x/exp/golden v0.0.0-20241212170349-ad4b7ae0f25f h1:UytX
 github.com/charmbracelet/x/exp/golden v0.0.0-20241212170349-ad4b7ae0f25f/go.mod h1:wDlXFlCrmJ8J+swcL/MnGUuYnqgQdW9rhSD61oNMb6U=
 github.com/charmbracelet/x/input v0.3.3 h1:JfLopDmw7pFy6Sezr42RkRfy1UPTh3xDR4sM3PXrrGw=
 github.com/charmbracelet/x/input v0.3.3/go.mod h1:JI8RcvdZWQIhn09VzeK3hdp4lTz7+yhiEdpEQtZN+2c=
+github.com/charmbracelet/x/input v0.3.4-0.20250224172324-3bbc6f7ae9d3 h1:ZLj8cla3PwZR8RIcnjxepmUwXiN3l+TNxFX19UxmE/4=
+github.com/charmbracelet/x/input v0.3.4-0.20250224172324-3bbc6f7ae9d3/go.mod h1:JI8RcvdZWQIhn09VzeK3hdp4lTz7+yhiEdpEQtZN+2c=
 github.com/charmbracelet/x/term v0.2.1 h1:AQeHeLZ1OqSXhrAWpYUtZyX1T3zVxfpZuEQMIQaGIAQ=
 github.com/charmbracelet/x/term v0.2.1/go.mod h1:oQ4enTYFV7QN4m0i9mzHrViD7TQKvNEEkHUMCmsxdUg=
 github.com/charmbracelet/x/windows v0.2.0 h1:ilXA1GJjTNkgOm94CLPeSz7rar54jtFatdmoiONPuEw=

tea.go

@@ -240,6 +240,7 @@ type Program struct {
 	inputReader           *input.Reader
 	traceInput            bool // true if input should be traced
 	readLoopDone          chan struct{}
+	mouseMode             bool // indicates whether we should enable mouse on Windows
 
 	// modes keeps track of terminal modes that have been enabled or disabled.
 	modes         ansi.Modes
@@ -550,6 +551,20 @@ func (p *Program) eventLoop(model Model, cmds chan Cmd) (Model, error) {
 					// and get a response in the eventLoop.
 					p.execute(ansi.SetGraphemeClusteringMode + ansi.RequestGraphemeClusteringMode)
 				default:
+					if runtime.GOOS == "windows" {
+						if msg.Mode == ansi.ButtonEventMouseMode || msg.Mode == ansi.AnyEventMouseMode {
+							// XXX: This is used to enable mouse mode on Windows. We need
+							// to reinitialize the cancel reader to get the mouse events to
+							// work.
+							if !p.mouseMode {
+								p.mouseMode = true
+								p.initInputReader(true) //nolint:errcheck
+							}
+
+							// We don't need to send reset mouse mode sequence on Windows.
+							break
+						}
+					}
 					p.execute(ansi.SetMode(msg.Mode))
 				}
 
@@ -567,6 +582,20 @@ func (p *Program) eventLoop(model Model, cmds chan Cmd) (Model, error) {
 				case ansi.TextCursorEnableMode:
 					p.renderer.hideCursor()
 				default:
+					if runtime.GOOS == "windows" {
+						if msg.Mode == ansi.ButtonEventMouseMode || msg.Mode == ansi.AnyEventMouseMode {
+							// XXX: On Windows, mouse mode is enabled on the input reader
+							// level. We need to instruct the input reader to stop reading
+							// mouse events.
+							if p.mouseMode {
+								p.mouseMode = false
+								p.initInputReader(true) //nolint:errcheck
+							}
+
+							// We don't need to send reset mouse mode sequence on Windows.
+							break
+						}
+					}
 					p.execute(ansi.ResetMode(msg.Mode))
 				}
 
@@ -896,7 +925,7 @@ func (p *Program) Run() (Model, error) {
 	// Init the input reader and initial model.
 	model := p.initialModel
 	if p.input != nil {
-		if err := p.initInputReader(); err != nil {
+		if err := p.initInputReader(false); err != nil {
 			return model, err
 		}
 	}
@@ -934,6 +963,10 @@ func (p *Program) Run() (Model, error) {
 		p.modes.Set(ansi.AnyEventMouseMode, ansi.SgrExtMouseMode)
 	}
 
+	// XXX: Should we enable mouse mode on Windows?
+	// This needs to happen before initializing the cancel and input reader.
+	p.mouseMode = p.startupOptions&withMouseCellMotion != 0 || p.startupOptions&withMouseAllMotion != 0
+
 	if p.startupOptions&withReportFocus != 0 {
 		p.execute(ansi.SetFocusEventMode)
 		p.modes.Set(ansi.FocusEventMode)
@@ -1112,7 +1145,7 @@ func (p *Program) RestoreTerminal() error {
 	if err := p.initTerminal(); err != nil {
 		return err
 	}
-	if err := p.initInputReader(); err != nil {
+	if err := p.initInputReader(false); err != nil {
 		return err
 	}
 	if p.modes.IsReset(ansi.AltScreenSaveCursorMode) {

tty.go

@@ -100,15 +100,24 @@ func (p *Program) restoreInput() error {
 }
 
 // initInputReader (re)commences reading inputs.
-func (p *Program) initInputReader() error {
+func (p *Program) initInputReader(cancel bool) error {
+	if cancel && p.inputReader != nil {
+		p.inputReader.Cancel()
+		p.waitForReadLoop()
+	}
+
 	term := p.getenv("TERM")
 
 	// Initialize the input reader.
 	// This need to be done after the terminal has been initialized and set to
 	// raw mode.
 	// On Windows, this will change the console mode to enable mouse and window
 	// events.
-	var flags int // TODO: make configurable through environment variables?
+	var flags int
+	if p.mouseMode {
+		flags |= input.FlagMouseMode
+	}
+
 	drv, err := input.NewReader(p.input, term, flags)
 	if err != nil {
 		return err