feat: implement interactive TUI with scrolling and add OpenSSL dependency support

6 files changed, 177 insertions, 27 deletions

diff --git a/include/ricochet/render/renderer.hh b/include/ricochet/render/renderer.hh
index 8a5c463..f26a788 100644
--- a/include/ricochet/render/renderer.hh
+++ b/include/ricochet/render/renderer.hh
@@ -37,7 +37,7 @@ public:
    * @brief Traverse the DOM tree and output the formatted result to the terminal using ANSI escape codes
    * @param node The root node of the DOM tree
    */
-  void render( const parser::DomNode& node ) const;
+  std::string render( const parser::DomNode& node ) const;
 };
 
 } // namespace ricochet::render
\ No newline at end of file
diff --git a/include/ricochet/tui/terminal.hh b/include/ricochet/tui/terminal.hh
new file mode 100644
index 0000000..5388845
--- /dev/null
+++ b/include/ricochet/tui/terminal.hh
@@ -0,0 +1,45 @@
+/*
+ * Ricochet - A minimalist CLI web browser for fast, distraction-free navigation.
+ * Copyright (C) 2026  Richard Qin
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <termios.h>
+
+namespace ricochet::tui {
+
+class Terminal {
+public:
+    Terminal();
+    ~Terminal();
+
+    Terminal(const Terminal&) = delete;
+    Terminal& operator=(const Terminal&) = delete;
+    Terminal(Terminal&&) = delete;
+    Terminal& operator=(Terminal&&) = delete;
+
+    // Read a single key
+    char read_key() const;
+    
+    // Clear screen and move cursor to top-left
+    void clear_screen() const;
+
+private:
+    struct termios original_termios_{}; // Save terminal original state
+};
+
+} // namespace ricochet::tui
\ No newline at end of file
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 9ddc717..dcc8f49 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -3,8 +3,17 @@ file(GLOB_RECURSE ALL_SOURCES CONFIGURE_DEPENDS "*.cc")
 set(MAIN_SRC "${CMAKE_CURRENT_SOURCE_DIR}/main.cc")
 list(REMOVE_ITEM ALL_SOURCES ${MAIN_SRC})
 
+find_package(OpenSSL REQUIRED)
+message(STATUS "Found OpenSSL Version: ${OPENSSL_VERSION}")
+message(STATUS "OpenSSL Include dir: ${OPENSSL_INCLUDE_DIR}")
+
 add_library(ricochet_core STATIC ${ALL_SOURCES})
 target_include_directories(ricochet_core PUBLIC ${PROJECT_SOURCE_DIR}/include)
+target_link_libraries(ricochet_core 
+    PUBLIC 
+        OpenSSL::SSL 
+        OpenSSL::Crypto
+)
 
 add_executable(ricochet ${MAIN_SRC})
 target_link_libraries(ricochet PRIVATE ricochet_core)
diff --git a/src/core/browser.cc b/src/core/browser.cc
index 31f4df0..0636de6 100644
--- a/src/core/browser.cc
+++ b/src/core/browser.cc
@@ -21,23 +21,11 @@
 #include "ricochet/parser/html_lexer.hh"
 #include "ricochet/parser/tree_builder.hh"
 #include "ricochet/render/renderer.hh"
+#include "ricochet/tui/terminal.hh"
+#include <cstddef>
 #include <iostream>
+#include <sstream>
 
-// namespace {
-// void print_dom_tree( const ricochet::parser::DomNode& node, std::size_t depth = 0 ) // NOLINT(misc-no-recursion)
-// {
-//   const std::string indent( depth * 2, ' ' );
-
-//   if ( node.tag_name.empty() ) {
-//     std::cout << indent << "\"" << node.text_content << "\"\n";
-//   } else {
-//     std::cout << indent << "<" << node.tag_name << ">\n";
-//     for ( const auto& child : node.children ) {
-//       print_dom_tree( child, depth + 1 );
-//     }
-//   }
-// }
-// } // namespace
 namespace ricochet::core {
 
 int Browser::run( std::string_view initial_url )
@@ -63,8 +51,53 @@ int Browser::run( std::string_view initial_url )
   // std::cout << "\033[2J\033[1;1H";
 
   const render::Renderer renderer;
-  renderer.render( dom_root );
+  const std::string rendered_text = renderer.render( dom_root );
 
+  std::vector<std::string> lines;
+  std::stringstream ss(rendered_text);
+  std::string line;
+  while (std::getline(ss, line, '\n')) {
+    lines.push_back(line);
+  }
+
+  // TUI Event Loop
+  const tui::Terminal terminal;
+
+  std::size_t scroll_y = 0;
+  const std::size_t screen_height = 24;
+
+  while (true) {
+    terminal.clear_screen();
+
+    for (std::size_t i = 0; i < screen_height - 1; ++i) {
+      const std::size_t line_idx = scroll_y + i;
+      if (line_idx < lines.size()) {
+        std::cout << lines[line_idx] << "\r\n";
+      } else {
+        std::cout << "~\r\n";
+      }
+    }
+
+    std::cout << "\033[7m" << " URL: " << initial_url 
+                  << " | [j] Down  [k] Up  [q] Quit " << "\033[0m";
+    std::cout.flush();
+
+    const char c = terminal.read_key();
+    if (c == 'q') {
+      break; // Break loop, terminal destructor will restore terminal
+    }
+    if (c == 'j') {
+      if (scroll_y + screen_height - 1 < lines.size()) {
+        scroll_y++; // Scroll down
+      }
+    } else if (c == 'k') {
+      if (scroll_y > 0) {
+        scroll_y--; // Scroll up
+      }
+    }
+  }
+
+  terminal.clear_screen();
   return 0;
 }
 
diff --git a/src/render/renderer.cc b/src/render/renderer.cc
index 81c2be2..0a91d49 100644
--- a/src/render/renderer.cc
+++ b/src/render/renderer.cc
@@ -23,7 +23,7 @@ namespace ricochet::render {
 
 namespace {
 
-void render_node( const parser::DomNode& node ) // NOLINT(misc-no-recursion)
+void render_node( const parser::DomNode& node, std::string& output ) // NOLINT(misc-no-recursion)
 {
   if ( node.tag_name == "head" || node.tag_name == "style" || node.tag_name == "script" || node.tag_name == "meta"
        || node.tag_name == "title" || node.tag_name == "link" ) {
@@ -31,35 +31,36 @@ void render_node( const parser::DomNode& node ) // NOLINT(misc-no-recursion)
   }
 
   if ( node.tag_name.empty() ) {
-    std::cout << node.text_content;
+    output += node.text_content;
     return;
   }
   if ( node.tag_name == "h1" ) {
-    std::cout << "\n\n\033[1;31m";
+    output += "\n\n\033[1;31m";
   } else if ( node.tag_name == "a" ) {
     std::cout << "\033[4;34m";
   } else if ( node.tag_name == "p" || node.tag_name == "div" ) {
-    std::cout << "\n";
+    output += "\n";
   }
 
   for ( const auto& child : node.children ) {
-    render_node( child );
+    render_node( child, output );
   }
   if ( node.tag_name == "h1" || node.tag_name == "a" ) {
-    std::cout << "\033[0m";
+    output += "\033[0m";
   }
 
   if ( node.tag_name == "h1" || node.tag_name == "p" || node.tag_name == "div" ) {
-    std::cout << "\n";
+    output += "\n";
   }
 }
 
 } // namespace
 
-void Renderer::render( const parser::DomNode& node ) const // NOLINT(readability-convert-member-functions-to-static)
+std::string Renderer::render( const parser::DomNode& node ) const // NOLINT(readability-convert-member-functions-to-static)
 {
-  render_node( node );
-  std::cout << "\n";
+  std::string output;
+  render_node( node, output );
+  return output;
 }
 
 } // namespace ricochet::render
\ No newline at end of file
diff --git a/src/tui/terminal.cc b/src/tui/terminal.cc
new file mode 100644
index 0000000..8fdb585
--- /dev/null
+++ b/src/tui/terminal.cc
@@ -0,0 +1,62 @@
+/*
+ * Ricochet - A minimalist CLI web browser for fast, distraction-free navigation.
+ * Copyright (C) 2026  Richard Qin
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "ricochet/tui/terminal.hh"
+#include <cstdlib>
+#include <iostream>
+#include <unistd.h>
+
+namespace ricochet::tui {
+
+Terminal::Terminal() {
+    // get terminal attributes
+    tcgetattr(STDIN_FILENO, &original_termios_);
+    
+    struct termios raw = original_termios_;
+    
+    // close echo, close canonical mode
+    // close terminal signals (ISIG disable Ctrl+C and Ctrl+Z, let the program handle it)
+    raw.c_lflag &= ~(ECHO | ICANON | ISIG);
+    
+    // close software flow control (Ctrl+S, Ctrl+Q)
+    raw.c_iflag &= ~(IXON | ICRNL);
+    
+    // apply new terminal attributes
+    tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw);
+}
+
+Terminal::~Terminal() {
+    // RAII: restore terminal attributes when program exits
+    tcsetattr(STDIN_FILENO, TCSAFLUSH, &original_termios_);
+}
+
+char Terminal::read_key() const { // NOLINT(readability-convert-member-functions-to-static)
+    char c = '\0';
+    // read 1 byte
+    if (read(STDIN_FILENO, &c, 1) == -1) {
+        return '\0';
+    }
+    return c;
+}
+
+void Terminal::clear_screen() const { // NOLINT(readability-convert-member-functions-to-static)
+    // ANSI escape codes: \x1b[2J clear screen, \x1b[H move cursor to (1,1)
+    std::cout << "\x1b[2J\x1b[H";
+}
+
+} // namespace ricochet::tui
\ No newline at end of file