feat(tui): add document navigation and text selection

1 files changed, 52 insertions, 1 deletions

diff --git a/ricochet/src/tui/layout.hh b/ricochet/src/tui/layout.hh
index 5feb0cd..7e02e76 100644
--- a/ricochet/src/tui/layout.hh
+++ b/ricochet/src/tui/layout.hh
@@ -31,6 +31,8 @@
 
 namespace ricochet::tui::detail {
 
+class DocumentText;
+
 using HitTarget = std::variant<LinkId, ControlId>;
 
 struct LayoutPoint
@@ -46,6 +48,22 @@ struct LayoutHit
   std::optional<HitTarget> target {};
 };
 
+struct ScrollWindow
+{
+  BlockId block {};
+  std::int64_t left { 0 };
+  std::int64_t width { 0 };
+  std::int64_t offset { 0 };
+  std::int64_t maximum { 0 };
+};
+
+enum class WordMotion : std::uint8_t
+{
+  Next,
+  Previous,
+  End
+};
+
 struct LayoutGlyph
 {
   LayoutPoint position {};
@@ -63,6 +81,10 @@ struct LayoutGlyph
   bool decoration { false };
   bool line_break { false };
   bool fill { false };
+  bool word_start { false };
+  bool word_end { false };
+  // Inner-to-outer windows allow a code block inside a table to be revealed.
+  std::vector<ScrollWindow> scrolls {};
 };
 
 struct LayoutData
@@ -88,11 +110,40 @@ public:
   std::size_t rows() const;
   std::optional<LayoutPoint> locate( const DisplayPosition& position ) const;
   std::optional<LayoutHit> hit( LayoutPoint point ) const;
-  void append_frame( Frame& frame, std::size_t first_row, CellPoint origin, ScreenSize viewport ) const;
+  DisplayPosition first() const;
+  DisplayPosition last() const;
+  DisplayPosition adjacent( const DisplayPosition& position, int direction ) const;
+  DisplayPosition word( const DisplayPosition& position, WordMotion motion ) const;
+  DisplayPosition on_row( LayoutPoint point ) const;
+  DisplayPosition line_edge( const DisplayPosition& position, bool end ) const;
+  DocumentRange unit( const DisplayPosition& position ) const;
+  std::optional<HitTarget> target( const DisplayPosition& position ) const;
+  std::optional<LayoutPoint> cursor_cell( const DisplayPosition& position ) const;
+  std::vector<HorizontalScroll> reveal( const DisplayPosition& position ) const;
+  std::vector<HorizontalScroll> pan( const DisplayPosition& position, int direction ) const;
+  void append_frame( Frame& frame,
+                     std::size_t first_row,
+                     CellPoint origin,
+                     ScreenSize viewport,
+                     const DocumentText& content,
+                     std::optional<DocumentRange> selection,
+                     const DisplayPosition& cursor,
+                     std::optional<HitTarget> focus = {} ) const;
 
 private:
+  struct ReadingPosition
+  {
+    std::size_t index { 0 };
+    bool at_start { true };
+  };
+  ReadingPosition reading_position( const DisplayPosition& position ) const;
+  std::size_t nearest_stop( LayoutPoint point ) const;
+  const LayoutGlyph& cursor_glyph( const DisplayPosition& position ) const;
+  DisplayPosition stop( std::size_t index ) const;
+
   int columns_;
   LayoutData data_;
+  std::vector<std::size_t> stops_ {};
 };
 
 } // namespace ricochet::tui::detail