From f47fda7c8061303c0762c6b11b5f916993ead7ca Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@gmail.com>
Date: Wed, 17 Jun 2026 10:09:34 +0200
Subject: lib: add basic tc attibute RAII type

---
 CMakeLists.txt               |   8 +++
 ttwhy/lib.cppm               |  10 +---
 ttwhy/main.cpp               |   9 ++--
 ttwhy/scoped_attributes.cppm | 124 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 138 insertions(+), 13 deletions(-)
 create mode 100644 ttwhy/scoped_attributes.cppm

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4eb75c1..3091b9e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -41,6 +41,7 @@ target_sources("ttwhy-core" PUBLIC
   FILES
 
   "ttwhy/lib.cppm"
+  "ttwhy/scoped_attributes.cppm"
 )
 
 target_include_directories("ttwhy-core" PUBLIC
@@ -55,6 +56,13 @@ target_link_libraries("ttwhy-core" PUBLIC
   "ext::asio"
 )
 
+target_compile_options("ttwhy-core" PUBLIC
+  "$<$<CXX_COMPILER_ID:Clang,GNU>:-Wall>"
+  "$<$<CXX_COMPILER_ID:Clang,GNU>:-Wextra>"
+  "$<$<CXX_COMPILER_ID:Clang,GNU>:-Werror>"
+  "$<$<CXX_COMPILER_ID:Clang,GNU>:-pedantic-errors>"
+)
+
 ### Main Executable
 
 add_executable("ttwhy")
diff --git a/ttwhy/lib.cppm b/ttwhy/lib.cppm
index c7527ee..fe7486f 100644
--- a/ttwhy/lib.cppm
+++ b/ttwhy/lib.cppm
@@ -1,11 +1,3 @@
 export module ttwhy;
 
-namespace ttwhy
-{
-
-  export auto multiply(int lhs, int rhs) -> int
-  {
-    return lhs * rhs;
-  }
-
-}  // namespace ttwhy
+export import :scoped_attributes;
diff --git a/ttwhy/main.cpp b/ttwhy/main.cpp
index fdaba88..32324c0 100644
--- a/ttwhy/main.cpp
+++ b/ttwhy/main.cpp
@@ -1,14 +1,15 @@
 #include <asio/io_context.hpp>
 
-#include <print>
+#include <stdio.h>
 
 import ttwhy;
 
 auto main() -> int
 {
-  auto context = asio::io_context{};
-
-  std::println("The answer is {}", ttwhy::multiply(6, 7));
+  auto terminal_attributes = ttwhy::scoped_attributes{fileno(stdin)}  //
+                                 .canonical_mode(false)
+                                 .echo(false);
 
+  auto context = asio::io_context{};
   context.run();
 }
diff --git a/ttwhy/scoped_attributes.cppm b/ttwhy/scoped_attributes.cppm
new file mode 100644
index 0000000..dd66b54
--- /dev/null
+++ b/ttwhy/scoped_attributes.cppm
@@ -0,0 +1,124 @@
+module;
+
+#include <cerrno>
+#include <system_error>
+#include <termios.h>
+#include <unistd.h>
+#include <utility>
+
+export module ttwhy:scoped_attributes;
+
+namespace ttwhy
+{
+
+  auto static read_attributes(int file_descriptor) -> termios
+  {
+    auto active_attributes = termios{};
+    if (tcgetattr(file_descriptor, &active_attributes))
+    {
+      throw std::system_error(errno, std::system_category(), "failed to read termios attributes");
+    }
+    return active_attributes;
+  }
+
+  auto static get_line_discipline_flag(int file_descriptor, int flag) -> bool
+  {
+    auto active_attributes = read_attributes(file_descriptor);
+    return active_attributes.c_lflag & flag;
+  }
+
+  auto static set_line_discipline_flag(int file_descriptor, int flag, bool enabled) -> void
+  {
+    auto active_attributes = read_attributes(file_descriptor);
+
+    if ((active_attributes.c_lflag & flag) == enabled)
+    {
+      return;
+    }
+
+    if (enabled)
+    {
+      active_attributes.c_lflag = active_attributes.c_lflag | flag;
+    }
+    else
+    {
+      active_attributes.c_lflag = active_attributes.c_lflag & ~flag;
+    }
+
+    tcsetattr(file_descriptor, TCSANOW, &active_attributes);
+  }
+
+  //! Store the current TC attributes and restore them on destruction.
+  export struct scoped_attributes
+  {
+    explicit scoped_attributes(int file_descriptor)
+        : m_file_descriptor{dup(file_descriptor)}
+        , m_attributes{read_attributes(file_descriptor)}
+    {}
+
+    scoped_attributes(scoped_attributes const &) = delete;
+
+    scoped_attributes(scoped_attributes && other)
+        : m_file_descriptor{std::exchange(other.m_file_descriptor, -1)}
+        , m_attributes{std::move(other.m_attributes)}
+    {}
+
+    ~scoped_attributes()
+    {
+      if (m_file_descriptor > 0)
+      {
+        tcsetattr(m_file_descriptor, TCSANOW, &m_attributes);
+      }
+    }
+
+    auto operator=(scoped_attributes const &) -> scoped_attributes & = delete;
+
+    auto operator=(scoped_attributes && other) -> scoped_attributes &
+    {
+      std::ranges::swap(m_file_descriptor, other.m_file_descriptor);
+      std::ranges::swap(m_attributes, other.m_attributes);
+      return *this;
+    }
+
+    //! Check if canonical mode is currently active
+    [[nodiscard]] auto canonical_mode() const noexcept -> bool
+    {
+      return get_line_discipline_flag(m_file_descriptor, ICANON);
+    }
+
+    //! Set whether canonical mode is active or not.
+    auto canonical_mode(bool enabled) & -> scoped_attributes &
+    {
+      set_line_discipline_flag(m_file_descriptor, ICANON, enabled);
+      return *this;
+    }
+
+    auto canonical_mode(bool enabled) && -> scoped_attributes
+    {
+      set_line_discipline_flag(m_file_descriptor, ICANON, enabled);
+      return std::move(*this);
+    }
+
+    [[nodiscard]] auto echo() const noexcept -> bool
+    {
+      return get_line_discipline_flag(m_file_descriptor, ECHO);
+    }
+
+    auto echo(bool enabled) & -> scoped_attributes &
+    {
+      set_line_discipline_flag(m_file_descriptor, ECHO, enabled);
+      return *this;
+    }
+
+    auto echo(bool enabled) && -> scoped_attributes
+    {
+      set_line_discipline_flag(m_file_descriptor, ECHO, enabled);
+      return std::move(*this);
+    }
+
+  private:
+    int m_file_descriptor;
+    termios m_attributes;
+  };
+
+}  // namespace ttwhy
-- 
cgit v1.2.3