From a6016e31fdd142d4d2b3b612d7fd305e2c7e6308 Mon Sep 17 00:00:00 2001
From: Robert Prehn <3952444+prehnRA@users.noreply.github.com>
Date: Fri, 23 Feb 2024 12:19:58 -0600
Subject: [PATCH] feat: Recursively generate resource code

---
 lib/kindling/schema.ex                     | 14 ++++++++
 lib/kindling/schema/resource.ex            | 42 +++++++++++++++++++---
 lib/kindling/template.eex                  | 20 +++++++++++
 lib/kindling/templates.ex                  | 19 +++++++---
 lib/kindling/templates/functions.ex        |  3 ++
 lib/mix/tasks/kindling/generate_schemas.ex | 25 +++++++++++++
 6 files changed, 115 insertions(+), 8 deletions(-)
 create mode 100644 lib/mix/tasks/kindling/generate_schemas.ex

diff --git a/lib/kindling/schema.ex b/lib/kindling/schema.ex
index 7e20ffa..f786e0b 100644
--- a/lib/kindling/schema.ex
+++ b/lib/kindling/schema.ex
@@ -1,5 +1,6 @@
 defmodule Kindling.Schema do
   alias Kindling.Version
+  alias Kindling.Schema.Resource
 
   def schema_object(version) do
     filename = Path.join(Version.version_dir(version), "fhir.schema.json")
@@ -8,4 +9,17 @@ defmodule Kindling.Schema do
     |> File.read!()
     |> Jason.decode!()
   end
+
+  def refs_recursive(schema, root_name) do
+    do_recurse(schema, MapSet.new([root_name]), [root_name])
+  end
+
+  defp do_recurse(_schema, visited, []), do: visited
+
+  defp do_recurse(schema, visited, [hd | tail]) do
+    refs = Resource.refs(schema["definitions"][hd])
+    new_refs = MapSet.difference(refs, visited)
+    new_visited = MapSet.union(visited, refs)
+    do_recurse(schema, new_visited, MapSet.to_list(new_refs) ++ tail)
+  end
 end
diff --git a/lib/kindling/schema/resource.ex b/lib/kindling/schema/resource.ex
index 156f8b8..623a696 100644
--- a/lib/kindling/schema/resource.ex
+++ b/lib/kindling/schema/resource.ex
@@ -1,5 +1,5 @@
 defmodule Kindling.Schema.Resource do
-  @empty_properties %{const: [], has_one: [], has_many: [], enum: [], value: []}
+  @empty_properties %{array: [], const: [], has_one: [], has_many: [], enum: [], value: []}
 
   def properties(df) do
     df["properties"]
@@ -7,7 +7,7 @@ defmodule Kindling.Schema.Resource do
 
   def grouped_properties(df) do
     properties =
-      (df["properties"] || [])
+      (df["properties"] || %{})
       |> Enum.map(fn {key, value} -> {key, value, property_type(value)} end)
       |> Enum.group_by(fn {_key, _value, type} ->
         type
@@ -16,8 +16,25 @@ defmodule Kindling.Schema.Resource do
     Map.merge(@empty_properties, properties)
   end
 
+  def all_fields(df) do
+    (df["properties"] || %{})
+    |> Enum.filter(fn {_name, definition} ->
+      property_type(definition) in [:array, :enum, :value]
+    end)
+    |> Enum.map(fn {name, _} -> name end)
+  end
+
+  def required_fields(df) do
+    df
+    |> required()
+    |> Enum.filter(fn {_name, definition} ->
+      property_type(definition) in [:array, :enum, :value]
+    end)
+    |> Enum.map(fn {name, _} -> name end)
+  end
+
   def required(df) do
-    Map.take(df["properties"], df["required"])
+    Map.take(df["properties"] || %{}, df["required"] || [])
   end
 
   def required?(df, key) do
@@ -26,7 +43,24 @@ defmodule Kindling.Schema.Resource do
 
   def property_type(%{"const" => _}), do: :const
   def property_type(%{"$ref" => _}), do: :has_one
-  def property_type(%{"items" => _}), do: :has_many
+  def property_type(%{"items" => %{"$ref" => _}}), do: :has_many
+  def property_type(%{"items" => %{"enum" => _}}), do: :array
   def property_type(%{"enum" => _}), do: :enum
   def property_type(_), do: :value
+
+  def refs(df) do
+    (df["properties"] || %{})
+    |> Enum.map(fn
+      {_, %{"$ref" => "#/definitions/" <> name}} ->
+        name
+
+      {_, %{"items" => %{"$ref" => "#/definitions/" <> name}}} ->
+        name
+
+      _other ->
+        nil
+    end)
+    |> Enum.reject(&is_nil/1)
+    |> MapSet.new()
+  end
 end
diff --git a/lib/kindling/template.eex b/lib/kindling/template.eex
index 84efc8f..8544436 100644
--- a/lib/kindling/template.eex
+++ b/lib/kindling/template.eex
@@ -1,5 +1,13 @@
 defmodule <%= @namespace %>.<%= @version %>.<%= @resource_name %> do
   use Ecto.Schema
+  import Ecto.Changeset
+
+  @fields [
+    <%= @all_fields |> Enum.map(fn name -> ~s("#{Recase.to_snake(name)}") end) |> Enum.join(",\n") %>
+  ]
+  @required_fields [
+    <%= @required_fields |> Enum.map(fn name -> ~s("#{Recase.to_snake(name)}") end) |> Enum.join(",\n") %>
+  ]
 
   schema "<%= Recase.to_snake(@resource_name) %>" do
     <%= if @properties.const != [] do %># Constants<% end %>
@@ -8,6 +16,8 @@ defmodule <%= @namespace %>.<%= @version %>.<%= @resource_name %> do
     <%= if @properties.value != [] do %># Fields<% end %>
     <%= for {name, df, _} <- @properties.value do %>field :<%= Recase.to_snake(name) %>, :<%= fhir_type_to_ecto(df) %>
     <% end %>
+    <%= for {name, df, _} <- @properties.array do %>field :<%= Recase.to_snake(name) %>, <%= inspect(fhir_type_to_ecto(df)) %>
+    <% end %>
     <%= if @properties.enum != [] do %># Enum<% end %>
     <%= for {name, df, _} <- @properties.enum do %>field :<%= Recase.to_snake(name) %>, Ecto.Enum, values: <%= inspect(df["enum"] |> Enum.map(&Recase.to_snake(&1)) |> Enum.map(&String.to_atom/1)) %>
     <% end %>
@@ -18,4 +28,14 @@ defmodule <%= @namespace %>.<%= @version %>.<%= @resource_name %> do
     <%= for {name, df, _} <- @properties.has_many do %>has_many :<%= Recase.to_snake(name) %>, <%= @namespace %>.<%= @version %>.<%= ref_to_class_name(df["items"]["$ref"]) %>
     <% end %>
   end
+
+  def base_changeset(data \\ %__MODULE__{}, attrs) do
+    data
+    |> cast(attrs, @fields)
+    <%= for {name, df, _} <- @properties.has_one do %>|> cast_assoc(:<%= Recase.to_snake(name) %>, with: &<%= @namespace %>.<%= @version %>.<%= ref_to_class_name(df["$ref"]) %>.base_changeset/1)
+    <% end %>
+    <%= for {name, df, _} <- @properties.has_many do %>|> cast_assoc(:<%= Recase.to_snake(name) %>, with: &<%= @namespace %>.<%= @version %>.<%= ref_to_class_name(df["items"]["$ref"]) %>.base_changeset/1)
+    <% end %>
+    |> validate_required(@required_fields)
+  end
 end
diff --git a/lib/kindling/templates.ex b/lib/kindling/templates.ex
index 4e1752e..314253d 100644
--- a/lib/kindling/templates.ex
+++ b/lib/kindling/templates.ex
@@ -12,17 +12,28 @@ defmodule Kindling.Templates do
       namespace: namespace,
       version: version,
       resource_name: resource_name,
-      properties: Resource.grouped_properties(resource)
+      properties: Resource.grouped_properties(resource),
+      all_fields: Resource.all_fields(resource),
+      required_fields: Resource.required_fields(resource)
     }
 
     assigns |> render() |> Code.format_string!(file: "#{resource_name}.ex")
   end
 
   def write_code(namespace, version, resource_name, resource) do
-    dir = Path.join(String.downcase(namespace), String.downcase(version))
-    file = Path.join(dir, "#{Recase.to_snake(resource_name)}.ex")
+    dir = Path.join(["lib", String.downcase(namespace), String.downcase(version)])
+    file = Path.join([dir | to_source_file_name(resource_name)])
 
-    File.mkdir_p!(dir)
+    File.mkdir_p!(Path.dirname(file))
     File.write!(file, resource_code(namespace, version, resource_name, resource))
   end
+
+  def to_source_file_name(resource_name) do
+    resource_name
+    |> String.split("_")
+    |> Enum.reverse()
+    |> Enum.map(&Recase.to_snake/1)
+    |> then(fn [hd | tail] -> ["#{hd}.ex" | tail] end)
+    |> Enum.reverse()
+  end
 end
diff --git a/lib/kindling/templates/functions.ex b/lib/kindling/templates/functions.ex
index e8559a3..e286365 100644
--- a/lib/kindling/templates/functions.ex
+++ b/lib/kindling/templates/functions.ex
@@ -8,6 +8,7 @@ defmodule Kindling.Templates.Functions do
   @decimal_patterns ["^-?(0|[1-9][0-9]*)(\\.[0-9]+)?([eE][+-]?[0-9]+)?$"]
 
   def fhir_type_to_ecto(%{"type" => "string"}), do: :string
+  def fhir_type_to_ecto(%{"type" => "boolean"}), do: :boolean
 
   def fhir_type_to_ecto(%{"type" => "number", "pattern" => pattern})
       when pattern in @int_patterns,
@@ -17,6 +18,8 @@ defmodule Kindling.Templates.Functions do
       when pattern in @decimal_patterns,
       do: :decimal
 
+  def fhir_type_to_ecto(%{"type" => "array", "items" => %{"enum" => _}}), do: {:array, :string}
+
   def ref_to_class_name("#/definitions/" <> name),
     do: name |> String.replace("_", ".") |> Recase.to_pascal()
 end
diff --git a/lib/mix/tasks/kindling/generate_schemas.ex b/lib/mix/tasks/kindling/generate_schemas.ex
new file mode 100644
index 0000000..ada570b
--- /dev/null
+++ b/lib/mix/tasks/kindling/generate_schemas.ex
@@ -0,0 +1,25 @@
+defmodule Mix.Tasks.Kindling.GenerateSchemas do
+  @moduledoc "Generates FHIR schemas"
+  @shortdoc "Generates FHIR schemas"
+
+  use Mix.Task
+
+  @impl Mix.Task
+  def run(args) do
+    if Enum.count(args) != 3 do
+      Mix.shell().error(
+        "usage: mix mix kindling.generate_schemas <namespace> <R5|R4|R3> <root resource name>"
+      )
+    end
+
+    [namespace, version, root] = args
+
+    schema = Kindling.Schema.schema_object(version)
+    to_generate = Kindling.Schema.refs_recursive(schema, root)
+
+    Enum.each(
+      to_generate,
+      &Kindling.Templates.write_code(namespace, version, &1, schema["definitions"][&1])
+    )
+  end
+end