add encoders for blob, bool and box

lib/ssb_bfe/encoder.ex

@@ -1,5 +1,22 @@
+# might be good to use a multiclause function for the `encode` function
+# - use the `where` conditional guard with e.g. `is_number` 
+
 defmodule SsbBfe.Encoder do
-  def encode_bool(blob_id) do
-    # Enum.sum(list) / Kernel.length(list)
+  def encode_blob(blob_id) do
+    blob_tf_tag = SsbBfe.Types.get_blob_type(blob_id)
+    base64_data = String.slice(blob_id, 1, 44)
+    {:ok, decoded_base64_data} = Base.decode64(base64_data)
+    blob_tf_tag <> decoded_base64_data
+  end
+
+  def encode_bool(true), do: <<6, 1, 1>>
+
+  def encode_bool(false), do: <<6, 1, 0>>
+
+  def encode_box(box_str) do
+    box_tf_tag = SsbBfe.Types.get_box_type(box_str)
+    [base64_data, _] = String.split(box_str, ".")
+    {:ok, decoded_base64_data} = Base.decode64(base64_data)
+    box_tf_tag <> decoded_base64_data
   end
 end