1 files changed, 158 insertions, 0 deletions
diff --git a/ttwhy/terminal/policies.cppm b/ttwhy/terminal/policies.cppm
new file mode 100644
index 0000000..acf9371
--- /dev/null
+++ b/ttwhy/terminal/policies.cppm
@@ -0,0 +1,158 @@
+module;
+
+#include <optional>
+#include <string>
+
+export module ttwhy.terminal:policies;
+
+import :events;
+
+namespace ttwhy::terminal
+{
+
+  namespace detail
+  {
+    constexpr auto map_vt220_keypad(char terminator) -> std::optional<navigation_key>
+    {
+      switch (terminator)
+      {
+        case '1':
+        case '7':
+          return navigation_key::home;
+        case '2':
+          return navigation_key::insert_key;
+        case '3':
+          return navigation_key::delete_key;
+        case '4':
+        case '8':
+          return navigation_key::end;
+        case '5':
+          return navigation_key::page_up;
+        case '6':
+          return navigation_key::page_down;
+        default:
+          return std::nullopt;
+      }
+    }
+
+    constexpr auto map_vt100_cursor(char terminator) -> std::optional<navigation_key>
+    {
+      switch (terminator)
+      {
+        case 'A':
+          return navigation_key::up;
+        case 'B':
+          return navigation_key::down;
+        case 'C':
+          return navigation_key::right;
+        case 'D':
+          return navigation_key::left;
+        case 'H':
+          return navigation_key::home;
+        case 'F':
+          return navigation_key::end;
+        default:
+          return std::nullopt;
+      }
+    }
+
+  }  // namespace detail
+
+  export struct ansi_policy
+  {
+    constexpr auto static resolve_vt220_keypad(std::string & buffer, event_sink auto & sink) -> void
+    {
+      if (buffer.empty())
+      {
+        return;
+      }
+
+      if (auto key = detail::map_vt220_keypad(buffer.front()))
+      {
+        sink(navigation_event{*key});
+      }
+      buffer.clear();
+    }
+
+    constexpr auto static resolve_vt100_cursor(char terminator, std::string &, event_sink auto & sink) -> void
+    {
+      if (auto key = detail::map_vt100_cursor(terminator))
+      {
+        sink(navigation_event{*key});
+      }
+    }
+
+    constexpr auto static resolve_ss3(char terminator, event_sink auto & sink) -> void
+    {
+      if (auto key = detail::map_vt100_cursor(terminator))
+      {
+        sink(navigation_event{*key});
+      }
+    }
+  };
+
+  export struct xterm_policy
+  {
+    constexpr auto static parse_modifiers(std::string_view buffer) -> modifier_set
+    {
+      auto delimiter = buffer.find(';');
+      if (delimiter == std::string_view::npos)
+      {
+        return {};
+      }
+
+      auto modifier_string = buffer.substr(delimiter + 1);
+      auto modifier_value = 0u;
+
+      for (auto character : modifier_string)
+      {
+        if (character >= '0' && character <= '9')
+        {
+          modifier_value = modifier_value * 10 + static_cast<unsigned int>(character - '0');
+        }
+      }
+
+      if (modifier_value <= 1)
+      {
+        return {};
+      }
+
+      return static_cast<modifier_set>(modifier_value - 1);
+    }
+
+    constexpr auto static resolve_vt220_keypad(std::string & buffer, event_sink auto & sink) -> void
+    {
+      if (buffer.empty())
+      {
+        return;
+      }
+
+      auto modifiers = parse_modifiers(buffer);
+
+      if (auto key = detail::map_vt220_keypad(buffer.front()))
+      {
+        sink(navigation_event{*key, modifiers});
+      }
+      buffer.clear();
+    }
+
+    constexpr auto static resolve_vt100_cursor(char terminator, std::string & buffer, event_sink auto & sink) -> void
+    {
+      auto modifiers = parse_modifiers(buffer);
+
+      if (auto key = detail::map_vt100_cursor(terminator))
+      {
+        sink(navigation_event{*key, modifiers});
+      }
+    }
+
+    constexpr auto static resolve_ss3(char terminator, event_sink auto & sink) -> void
+    {
+      if (auto key = detail::map_vt100_cursor(terminator))
+      {
+        sink(navigation_event{*key});
+      }
+    }
+  };
+
+}  // namespace ttwhy::terminal