From 2827e8fa038ad228d3b3c9195cfe51747152cf90 Mon Sep 17 00:00:00 2001
From: "Eric S. Raymond" <esr@thyrsus.com>
Date: Thu, 26 May 2022 16:38:23 -0400
Subject: [PATCH] Create SetDebug method. Non-stub only on a terminfo screen.

---
 console_win.go |  6 +++++
 screen.go      |  5 ++++
 simulation.go  |  4 ++++
 tscreen.go     | 62 +++++++++++++++++++++++++++++++++++++++++++++-----
 4 files changed, 71 insertions(+), 6 deletions(-)

diff --git a/console_win.go b/console_win.go
index 5f0063e..b32e0e2 100644
--- a/console_win.go
+++ b/console_win.go
@@ -1327,3 +1327,9 @@ func (s *cScreen) Suspend() error {
 func (s *cScreen) Resume() error {
 	return s.engage()
 }
+
+// Set Debug disables tty mode munging and makes
+// control sequences visible. The ma
+func (t *tScreen) SetDebug(mode bool) {
+	return errors.New("SetDebug is not supported on the Windows console")
+}
diff --git a/screen.go b/screen.go
index 43c3a54..b972df7 100644
--- a/screen.go
+++ b/screen.go
@@ -248,6 +248,11 @@ type Screen interface {
 	// does not support application-initiated resizing, whereas the legacy terminal does.
 	// Also, some emulators can support this but may have it disabled by default.
 	SetSize(int, int)
+
+	// Set debug mode.  Must be called before Init(). Inhibits switching to alternate
+	// buffer, disables tty mode-switching. Control sequences are shipped in a ASCII-ized
+	// form.  Note, this entry point is experimental and subect to change.
+	SetDebug(bool) error
 }
 
 // NewScreen returns a default Screen suitable for the user's terminal
diff --git a/simulation.go b/simulation.go
index 9ad6131..5f1abef 100644
--- a/simulation.go
+++ b/simulation.go
@@ -547,3 +547,7 @@ func (s *simscreen) Suspend() error {
 func (s *simscreen) Resume() error {
 	return nil
 }
+
+func (s *simscreen) SetDebug(bool) error {
+	return nil
+}
diff --git a/tscreen.go b/tscreen.go
index 59afd2c..56fc8b9 100644
--- a/tscreen.go
+++ b/tscreen.go
@@ -17,6 +17,7 @@ package tcell
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"io"
 	"os"
 	"strconv"
@@ -159,6 +160,7 @@ type tScreen struct {
 	wg           sync.WaitGroup
 	mouseFlags   MouseFlags
 	pasteEnabled bool
+	debug        bool
 
 	sync.Mutex
 }
@@ -876,6 +878,39 @@ func (t *tScreen) writeString(s string) {
 }
 
 func (t *tScreen) TPuts(s string) {
+	if t.debug {
+		v := ""
+		for i := range s {
+			// First, deal with printables
+			if s[i] >= 33 && s[i] <= 126 {
+				v += string(s[i])
+				continue
+			}
+			switch s[i] {
+			case 7: // BEL
+				v += `\a`
+			case 8: // BS
+				v += `\b`
+			case 9: // TAB
+				v += `\t`
+			case 10: // LF
+				v += `\n`
+			case 11: // VT
+				v += `\v`
+			case 12: // FF
+				v += `\f`
+			case 13: // CR
+				v += `\r`
+			case 27: // ESC		// ESC is why we have custom code here
+				v += `\e`
+			case 32: // SPC
+				v += `\s`
+			default:
+				v += fmt.Sprintf(`\%02x`, s[i])
+			}
+		}
+		s = v
+	}
 	if t.buffering {
 		t.ti.TPuts(&t.buf, s)
 	} else {
@@ -1777,7 +1812,7 @@ func (t *tScreen) Resume() error {
 func (t *tScreen) engage() error {
 	t.Lock()
 	defer t.Unlock()
-	if t.tty == nil {
+	if !t.debug && t.tty == nil {
 		return ErrNoScreen
 	}
 	t.tty.NotifyResize(func() {
@@ -1789,8 +1824,10 @@ func (t *tScreen) engage() error {
 	if t.running {
 		return errors.New("already engaged")
 	}
-	if err := t.tty.Start(); err != nil {
-		return err
+	if !t.debug {
+		if err := t.tty.Start(); err != nil {
+			return err
+		}
 	}
 	t.running = true
 	if w, h, err := t.tty.WindowSize(); err == nil && w != 0 && h != 0 {
@@ -1828,7 +1865,9 @@ func (t *tScreen) disengage() {
 	t.running = false
 	stopQ := t.stopQ
 	close(stopQ)
-	_ = t.tty.Drain()
+	if !t.debug {
+		_ = t.tty.Drain()
+	}
 	t.Unlock()
 
 	t.tty.NotifyResize(nil)
@@ -1850,7 +1889,9 @@ func (t *tScreen) disengage() {
 	t.enableMouse(0)
 	t.enablePasting(false)
 
-	_ = t.tty.Stop()
+	if !t.debug {
+		_ = t.tty.Stop()
+	}
 }
 
 // Beep emits a beep to the terminal.
@@ -1863,5 +1904,14 @@ func (t *tScreen) Beep() error {
 // to it's initial state.  It should not be called more than once.
 func (t *tScreen) finalize() {
 	t.disengage()
-	_ = t.tty.Close()
+	if !t.debug {
+		_ = t.tty.Close()
+	}
+}
+
+// Set Debug disables tty mode munging and makes
+// control sequences visible.
+func (t *tScreen) SetDebug(mode bool) error {
+	t.debug = mode
+	return nil
 }
-- 
2.30.2