Fix minor bugs and add language detection.

include/internal/buffer/decl.h

@@ -33,7 +33,7 @@ struct Buffer {
   virtual bool waste() = 0;
   virtual uint64_t lines() = 0;
   virtual uint64_t bytes() = 0;
-  virtual void set_filename(std::filesystem::path path) = 0;
+  virtual void set_filename(BEd &ctx, std::filesystem::path path) = 0;
   virtual std::filesystem::path filename() = 0;
   virtual void saved_hook() = 0;
   virtual void load(BEd &ctx, vase::Shard *text) = 0;

include/internal/buffer/types/clip.h

@@ -14,7 +14,7 @@ struct ClipBuffer : Buffer {
   uint64_t lines() override;
   uint64_t bytes() override;
   void load(BEd &ctx, vase::Shard *text) override;
-  void set_filename(std::filesystem::path path) override;
+  void set_filename(BEd &ctx, std::filesystem::path path) override;
   std::filesystem::path filename() override;
   vase::Shard *copy(uint64_t start_line, uint64_t end_line) override;
   void substitute(

include/internal/buffer/types/generic.h

@@ -34,7 +34,7 @@ struct GenericBuffer : ShardBuffer {
   void saved_hook() override;
   bool waste() override;
   void load(BEd &ctx, vase::Shard *text) override;
-  void set_filename(std::filesystem::path path) override;
+  void set_filename(BEd &ctx, std::filesystem::path path) override;
   std::filesystem::path filename() override;
   void substitute(
     BEd &ctx, uint64_t start_line, uint64_t end_line,

include/internal/buffer/types/readonly.h

@@ -19,7 +19,7 @@ struct ReadonlyBuffer : ShardBuffer {
   void load(BEd &, vase::Shard *) override {
     throw ed_error("This buffer is read-only.");
   }
-  void set_filename(std::filesystem::path) override {}
+  void set_filename(BEd &, std::filesystem::path) override {}
   std::filesystem::path filename() override {
     return {};
   }

include/internal/vase/shard.h

@@ -6,6 +6,9 @@
 #include "storage/storage.h"
 
 namespace bed::internal::vase {
+// TODO: rewrite with invariant, text ends with a newline, as right now both 1 real and empty line and no text mean teh same thing,
+//       which causes a ton of issues.
+
 struct Shard {
   enum struct Kind : uint8_t {
     Branch,