From 0938752c0051837d5bbf9287395029ca40d180b9 Mon Sep 17 00:00:00 2001
From: Luca Corti <luca@sibill.com>
Date: Tue, 24 Sep 2024 16:58:40 +0200
Subject: [PATCH] WIP

---
 lib/sassone/builder.ex        | 29 +++++++++++++++++++++++------
 lib/sassone/builder/field.ex  | 12 ++++--------
 lib/sassone/xml.ex            |  4 ++++
 test/sassone/builder_test.exs | 20 ++++++++++++++++++++
 test/support/test_schemas.ex  | 14 ++++++++++++++
 5 files changed, 65 insertions(+), 14 deletions(-)
 create mode 100644 test/support/test_schemas.ex

diff --git a/lib/sassone/builder.ex b/lib/sassone/builder.ex
index 3151721..7eed6a7 100644
--- a/lib/sassone/builder.ex
+++ b/lib/sassone/builder.ex
@@ -83,14 +83,14 @@ defimpl Sassone.Builder, for: Any do
         %Field{struct(Field, field_options) | xml_name: xml_name, name: name}
       end)
 
-    {elements, attributes} =
+    {attributes, elements} =
       Enum.split_with(fields, fn %Field{} = field ->
-        field.type == :element
+        field.type == :attribute
       end)
 
     start_document = generate_start_document(module)
     end_document = generate_end_document()
-    start_element = generate_start_element(elements)
+    start_element = generate_start_element(elements, attributes)
     characters = generate_characters(elements)
     end_element = generate_end_element(elements)
 
@@ -163,13 +163,30 @@ defimpl Sassone.Builder, for: Any do
     end
   end
 
-  defp generate_start_element(elements) do
-    Enum.filter(elements, fn %Field{} = field -> field.parse end)
+  defp generate_start_element(elements, attributes) do
+    Enum.filter(elements, fn %Field{} = field -> field.parse and field.type != :content end)
     |> Enum.reduce(
       [
         quote do
           @impl Sassone.Handler
-          def handle_event(:start_element, _data, state), do: {:ok, state}
+          def handle_event(:start_element, {ns, element, attributes}, %Parser{} = parser) do
+            state =
+              unquote(
+                Enum.map(attributes, fn %Field{} = field -> {field.name, field.xml_name} end)
+              )
+              |> Enum.reduce(parser.state, fn {key, xml_name}, state ->
+                value =
+                  Enum.find_value(attributes, fn {_ns, name, value} ->
+                    if name == xml_name, do: value
+                  end)
+
+                unless is_nil(value) do
+                  put_in(state, Enum.reverse([key | parser.keys]), value)
+                end
+              end)
+
+            {:ok, %Parser{parser | state: state}}
+          end
         end
       ],
       fn
diff --git a/lib/sassone/builder/field.ex b/lib/sassone/builder/field.ex
index d22626f..13b4de8 100644
--- a/lib/sassone/builder/field.ex
+++ b/lib/sassone/builder/field.ex
@@ -3,21 +3,17 @@ defmodule Sassone.Builder.Field do
   A struct representing the builder options for a struct field.
   """
 
-  @type type :: :element | :attribute
-
-  @type name :: atom()
-
   @type t :: %__MODULE__{
-          name: name(),
+          name: atom(),
           parse: boolean(),
           many: boolean(),
           struct: module(),
           build: boolean(),
-          type: type(),
+          type: :attribute | :content | :element,
           xml_name: String.t()
         }
 
-  @enforce_keys [:name, :parse, :build, :type, :xml_name]
+  @enforce_keys [:name, :type, :xml_name]
   defstruct build: true,
             name: nil,
             many: false,
@@ -66,7 +62,7 @@ defmodule Sassone.Builder.Field do
             ],
             type: [
               doc: "How the field is represented in XML: `:element`, `:attribute`, `:content`.",
-              type: {:in, [:element, :attribute]},
+              type: {:in, [:attribute, :content, :element]},
               default: :element
             ]
           ]
diff --git a/lib/sassone/xml.ex b/lib/sassone/xml.ex
index 8cbbcd5..64014a0 100644
--- a/lib/sassone/xml.ex
+++ b/lib/sassone/xml.ex
@@ -132,6 +132,10 @@ defmodule Sassone.XML do
     Enum.reduce(values, elements, &build_element(field, &1, &2))
   end
 
+  defp build_element(%Field{type: :content}, value, elements) do
+    [characters(value) | elements]
+  end
+
   defp build_element(%Field{} = field, value, elements) do
     if Builder.impl_for(value) do
       [build(value, field.xml_name) | elements]
diff --git a/test/sassone/builder_test.exs b/test/sassone/builder_test.exs
index 8c7a1a6..e0123bc 100644
--- a/test/sassone/builder_test.exs
+++ b/test/sassone/builder_test.exs
@@ -1,3 +1,23 @@
 defmodule Sassone.BuilderTest do
   use ExUnit.Case, async: true
+
+  alias Sassone.Builder
+  alias Sassone.TestSchemas.Person
+
+  describe "building" do
+    test "encode simple schema" do
+      assert ~s|<person gender="female">Alice</person>| =
+               Builder.build(%Person{gender: "female", name: "Alice"})
+               |> Sassone.encode!()
+    end
+
+    test "decode simple schema" do
+      assert {:ok, {Person, %{gender: "female", name: "Alice"}}} =
+               Sassone.parse_string(
+                 ~s|<person gender="female">Alice</person>|,
+                 Builder.handler(%Person{}),
+                 nil
+               )
+    end
+  end
 end
diff --git a/test/support/test_schemas.ex b/test/support/test_schemas.ex
new file mode 100644
index 0000000..02dc049
--- /dev/null
+++ b/test/support/test_schemas.ex
@@ -0,0 +1,14 @@
+defmodule Sassone.TestSchemas do
+  @moduledoc false
+
+  defmodule Person do
+    @derive {
+      Sassone.Builder,
+      case: :snake,
+      debug: true,
+      root_element: "person",
+      fields: [gender: [type: :attribute], name: [type: :content]]
+    }
+    defstruct [:gender, :name]
+  end
+end