From 0bd0153204815119c632a134c7d33696785374fe Mon Sep 17 00:00:00 2001
From: Robert Prehn <3952444+prehnRA@users.noreply.github.com>
Date: Sat, 24 Feb 2024 10:42:27 -0600
Subject: [PATCH] feat: Implement embedded schemas

---
 .gitignore                                 |  2 +
 lib/kindling/config.ex                     | 19 ++++++++
 lib/kindling/embed_template.eex            | 50 ++++++++++++++++++++++
 lib/kindling/schema.ex                     | 28 ++++++++++++
 lib/kindling/schema/resource.ex            | 40 ++++++++++++++++-
 lib/kindling/template.eex                  | 12 +++++-
 lib/kindling/templates.ex                  | 15 ++++++-
 lib/kindling/templates/functions.ex        | 26 ++++++++++-
 lib/mix/tasks/kindling/generate_schemas.ex |  4 +-
 mix.exs                                    |  1 +
 mix.lock                                   |  2 +
 11 files changed, 192 insertions(+), 7 deletions(-)
 create mode 100644 lib/kindling/config.ex
 create mode 100644 lib/kindling/embed_template.eex

diff --git a/.gitignore b/.gitignore
index 3b2bbf4..4276f2c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -24,3 +24,5 @@ kindling-*.tar
 
 # Temporary files, for example, from tests.
 /tmp/
+
+/lib/fhir/
diff --git a/lib/kindling/config.ex b/lib/kindling/config.ex
new file mode 100644
index 0000000..53cbe1e
--- /dev/null
+++ b/lib/kindling/config.ex
@@ -0,0 +1,19 @@
+defmodule Kindling.Config do
+  @default_embedded_resources [
+    "Coding",
+    "Duration",
+    "Extension",
+    "Identifier",
+    "Meta",
+    "Element",
+    "CodeableConcept",
+    "Narrative",
+    "Period",
+    "Reference",
+    "ResourceList"
+  ]
+
+  def embedded_resources() do
+    Application.get_env(:kindling, :embedded_resources, @default_embedded_resources)
+  end
+end
diff --git a/lib/kindling/embed_template.eex b/lib/kindling/embed_template.eex
new file mode 100644
index 0000000..f4f5e09
--- /dev/null
+++ b/lib/kindling/embed_template.eex
@@ -0,0 +1,50 @@
+defmodule <%= @namespace %>.<%= @version %>.<%= class_name(@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") %>
+  ]
+
+  embedded_schema do
+    <%= if @properties.const != [] do %># Constants<% end %>
+    <%= for {name, df, _} <- @properties.const do %>field :<%= Recase.to_snake(name) %>, :string, virtual: true, default: "<%= df["const"] %>"
+    <% end %>
+    <%= 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 %>
+    <%= if @properties.embed_one != [] do %># Embed One<% end %>
+    <%= for {name, df, _} <- @properties.embed_one do %>embed_one :<%= Recase.to_snake(name) %>, <%= @namespace %>.<%= @version %>.<%= ref_to_class_name(df["$ref"]) %>
+    <% end %>
+    <%= if @properties.embed_many != [] do %># Embed Many<% end %>
+    <%= for {name, df, _} <- @properties.embed_many do %>embed_many :<%= Recase.to_snake(name) %>, <%= @namespace %>.<%= @version %>.<%= ref_to_class_name(df["$ref"]) %>
+    <% end %>
+    <%= if @properties.has_one != [] do %># Has One<% end %>
+    <%= for {name, df, _} <- @properties.has_one do %>has_one :<%= Recase.to_snake(name) %>, <%= @namespace %>.<%= @version %>.<%= ref_to_class_name(df["$ref"]) %>
+    <% end %>
+    <%= if @properties.has_many != [] do %># Has Many<% end %>
+    <%= for {name, df, _} <- @properties.has_many do %>has_many :<%= Recase.to_snake(name) %>, <%= @namespace %>.<%= @version %>.<%= ref_to_class_name(df["items"]["$ref"]) %>
+    <% end %>
+    <%= if @backlinks != [] do %># belongs_to<% end %>
+    <%= for name <- @backlinks do %>belongs_to :<%= Recase.to_snake(name) %>, <%= @namespace %>.<%= @version %>.<%= class_name(name) %>
+    <% 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/schema.ex b/lib/kindling/schema.ex
index f786e0b..05f0a64 100644
--- a/lib/kindling/schema.ex
+++ b/lib/kindling/schema.ex
@@ -1,4 +1,5 @@
 defmodule Kindling.Schema do
+  alias Kindling.Config
   alias Kindling.Version
   alias Kindling.Schema.Resource
 
@@ -8,6 +9,33 @@ defmodule Kindling.Schema do
     filename
     |> File.read!()
     |> Jason.decode!()
+    |> build_backlinks()
+  end
+
+  def build_backlinks(schema) do
+    new_defs =
+      schema["definitions"]
+      |> Enum.map(fn {name, def} -> {name, Map.put(def, "__backlinks", [])} end)
+      |> Map.new()
+
+    schema =
+      Map.put(schema, "definitions", new_defs)
+
+    defs =
+      schema["definitions"]
+      |> Map.drop(Config.embedded_resources())
+      |> Enum.reduce(schema["definitions"], fn {name, df}, definitions ->
+        refs = Resource.refs(df)
+
+        Enum.reduce(refs, definitions, fn ref, definitions ->
+          prior_backlinks = definitions[ref]["__backlinks"]
+          new_backlinks = [name | prior_backlinks]
+          new_def = Map.put(Map.get(definitions, ref), "__backlinks", new_backlinks)
+          Map.put(definitions, ref, new_def)
+        end)
+      end)
+
+    Map.put(schema, "definitions", defs)
   end
 
   def refs_recursive(schema, root_name) do
diff --git a/lib/kindling/schema/resource.ex b/lib/kindling/schema/resource.ex
index 623a696..e592663 100644
--- a/lib/kindling/schema/resource.ex
+++ b/lib/kindling/schema/resource.ex
@@ -1,4 +1,6 @@
 defmodule Kindling.Schema.Resource do
+  alias Kindling.Config
+
   @empty_properties %{array: [], const: [], has_one: [], has_many: [], enum: [], value: []}
 
   def properties(df) do
@@ -8,6 +10,8 @@ defmodule Kindling.Schema.Resource do
   def grouped_properties(df) do
     properties =
       (df["properties"] || %{})
+      |> Map.delete("id")
+      |> Enum.reject(&is_element/1)
       |> Enum.map(fn {key, value} -> {key, value, property_type(value)} end)
       |> Enum.group_by(fn {_key, _value, type} ->
         type
@@ -42,8 +46,31 @@ defmodule Kindling.Schema.Resource do
   end
 
   def property_type(%{"const" => _}), do: :const
-  def property_type(%{"$ref" => _}), do: :has_one
-  def property_type(%{"items" => %{"$ref" => _}}), do: :has_many
+
+  def property_type(%{"$ref" => "#/definitions/" <> name}) do
+    if is_class_name(name) do
+      :has_one
+    else
+      :value
+    end
+  end
+
+  for embed <- Config.embedded_resources() do
+    def property_type(%{"$ref" => "#/definitions/" <> unquote(embed)}), do: :embed_one
+
+    def property_type(%{"items" => %{"$ref" => "#/definitions/" <> unquote(embed)}}) do
+      :embed_many
+    end
+  end
+
+  def property_type(%{"items" => %{"$ref" => "#/definitions/" <> name}}) do
+    if is_class_name(name) do
+      :has_many
+    else
+      :array
+    end
+  end
+
   def property_type(%{"items" => %{"enum" => _}}), do: :array
   def property_type(%{"enum" => _}), do: :enum
   def property_type(_), do: :value
@@ -61,6 +88,15 @@ defmodule Kindling.Schema.Resource do
         nil
     end)
     |> Enum.reject(&is_nil/1)
+    |> Enum.filter(&is_class_name/1)
     |> MapSet.new()
   end
+
+  def is_class_name(name) do
+    !(name in Config.embedded_resources()) && Regex.match?(~r/^[A-Z]/, name)
+  end
+
+  def is_element({_name, %{"$ref" => "#/definitions/Element"}}), do: true
+  def is_element({name, %{"items" => items}}), do: is_element({name, items})
+  def is_element(_), do: false
 end
diff --git a/lib/kindling/template.eex b/lib/kindling/template.eex
index 8544436..061e3fc 100644
--- a/lib/kindling/template.eex
+++ b/lib/kindling/template.eex
@@ -1,4 +1,4 @@
-defmodule <%= @namespace %>.<%= @version %>.<%= @resource_name %> do
+defmodule <%= @namespace %>.<%= @version %>.<%= class_name(@resource_name) %> do
   use Ecto.Schema
   import Ecto.Changeset
 
@@ -9,6 +9,7 @@ defmodule <%= @namespace %>.<%= @version %>.<%= @resource_name %> do
     <%= @required_fields |> Enum.map(fn name -> ~s("#{Recase.to_snake(name)}") end) |> Enum.join(",\n") %>
   ]
 
+  @primary_key {:id, :binary_id, autogenerate: true}
   schema "<%= Recase.to_snake(@resource_name) %>" do
     <%= if @properties.const != [] do %># Constants<% end %>
     <%= for {name, df, _} <- @properties.const do %>field :<%= Recase.to_snake(name) %>, :string, virtual: true, default: "<%= df["const"] %>"
@@ -21,12 +22,21 @@ defmodule <%= @namespace %>.<%= @version %>.<%= @resource_name %> do
     <%= 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 %>
+    <%= if @properties.embed_one != [] do %># Embed One<% end %>
+    <%= for {name, df, _} <- @properties.embed_one do %>embed_one :<%= Recase.to_snake(name) %>, <%= @namespace %>.<%= @version %>.<%= ref_to_class_name(df["$ref"]) %>
+    <% end %>
+    <%= if @properties.embed_many != [] do %># Embed Many<% end %>
+    <%= for {name, df, _} <- @properties.embed_many do %>embed_many :<%= Recase.to_snake(name) %>, <%= @namespace %>.<%= @version %>.<%= ref_to_class_name(df["$ref"]) %>
+    <% end %>
     <%= if @properties.has_one != [] do %># Has One<% end %>
     <%= for {name, df, _} <- @properties.has_one do %>has_one :<%= Recase.to_snake(name) %>, <%= @namespace %>.<%= @version %>.<%= ref_to_class_name(df["$ref"]) %>
     <% end %>
     <%= if @properties.has_many != [] do %># Has Many<% end %>
     <%= for {name, df, _} <- @properties.has_many do %>has_many :<%= Recase.to_snake(name) %>, <%= @namespace %>.<%= @version %>.<%= ref_to_class_name(df["items"]["$ref"]) %>
     <% end %>
+    <%= if @backlinks != [] do %># belongs_to<% end %>
+    <%= for name <- @backlinks do %>belongs_to :<%= Recase.to_snake(name) %>, <%= @namespace %>.<%= @version %>.<%= class_name(name) %>
+    <% end %>
   end
 
   def base_changeset(data \\ %__MODULE__{}, attrs) do
diff --git a/lib/kindling/templates.ex b/lib/kindling/templates.ex
index 314253d..856ff4c 100644
--- a/lib/kindling/templates.ex
+++ b/lib/kindling/templates.ex
@@ -3,9 +3,11 @@ defmodule Kindling.Templates do
 
   import Kindling.Templates.Functions
 
+  alias Kindling.Config
   alias Kindling.Schema.Resource
 
   EEx.function_from_file(:def, :render, "lib/kindling/template.eex", [:assigns])
+  EEx.function_from_file(:def, :render_embedded, "lib/kindling/embed_template.eex", [:assigns])
 
   def resource_code(namespace, version, resource_name, resource) do
     assigns = %{
@@ -14,10 +16,19 @@ defmodule Kindling.Templates do
       resource_name: resource_name,
       properties: Resource.grouped_properties(resource),
       all_fields: Resource.all_fields(resource),
-      required_fields: Resource.required_fields(resource)
+      required_fields: Resource.required_fields(resource),
+      backlinks: resource["__backlinks"]
     }
 
-    assigns |> render() |> Code.format_string!(file: "#{resource_name}.ex")
+    if resource_name in Config.embedded_resources() do
+      assigns
+      |> render_embedded()
+      |> Code.format_string!(file: "#{resource_name}.ex")
+    else
+      assigns
+      |> render()
+      |> Code.format_string!(file: "#{resource_name}.ex")
+    end
   end
 
   def write_code(namespace, version, resource_name, resource) do
diff --git a/lib/kindling/templates/functions.ex b/lib/kindling/templates/functions.ex
index e286365..27b2928 100644
--- a/lib/kindling/templates/functions.ex
+++ b/lib/kindling/templates/functions.ex
@@ -18,8 +18,32 @@ defmodule Kindling.Templates.Functions do
       when pattern in @decimal_patterns,
       do: :decimal
 
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/boolean"}), do: :boolean
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/string"}), do: :string
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/integer"}), do: :integer
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/positiveInt"}), do: :integer
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/unsignedInt"}), do: :integer
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/decimal"}), do: :decimal
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/code"}), do: :string
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/uri"}), do: :string
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/url"}), do: :string
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/xhtml"}), do: :string
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/markdown"}), do: :string
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/base64Binary"}), do: :string
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/dateTime"}), do: :utc_datetime_usec
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/instant"}), do: :utc_datetime_usec
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/time"}), do: :time_usec
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/canonical"}), do: :string
+  def fhir_type_to_ecto(%{"$ref" => "#/definitions/id"}), do: :binary_id
+
   def fhir_type_to_ecto(%{"type" => "array", "items" => %{"enum" => _}}), do: {:array, :string}
 
+  def fhir_type_to_ecto(%{"type" => "array", "items" => items}),
+    do: {:array, fhir_type_to_ecto(items)}
+
   def ref_to_class_name("#/definitions/" <> name),
-    do: name |> String.replace("_", ".") |> Recase.to_pascal()
+    do: class_name(name)
+
+  def class_name(name),
+    do: name |> String.split("_") |> Enum.map(&Recase.to_pascal/1) |> Enum.join(".")
 end
diff --git a/lib/mix/tasks/kindling/generate_schemas.ex b/lib/mix/tasks/kindling/generate_schemas.ex
index ada570b..b22c7e7 100644
--- a/lib/mix/tasks/kindling/generate_schemas.ex
+++ b/lib/mix/tasks/kindling/generate_schemas.ex
@@ -15,7 +15,9 @@ defmodule Mix.Tasks.Kindling.GenerateSchemas do
     [namespace, version, root] = args
 
     schema = Kindling.Schema.schema_object(version)
-    to_generate = Kindling.Schema.refs_recursive(schema, root)
+
+    to_generate =
+      Kindling.Schema.refs_recursive(schema, root)
 
     Enum.each(
       to_generate,
diff --git a/mix.exs b/mix.exs
index 771b5d5..e2c1452 100644
--- a/mix.exs
+++ b/mix.exs
@@ -21,6 +21,7 @@ defmodule Kindling.MixProject do
   # Run "mix help deps" to learn about dependencies.
   defp deps do
     [
+      {:ecto, "~> 3.11", only: [:dev, :test]},
       {:jason, "~> 1.4"},
       {:recase, "~> 0.7.0"},
       {:req, "~> 0.4.11"}
diff --git a/mix.lock b/mix.lock
index d772a51..ac91e31 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,5 +1,7 @@
 %{
   "castore": {:hex, :castore, "1.0.5", "9eeebb394cc9a0f3ae56b813459f990abb0a3dedee1be6b27fdb50301930502f", [:mix], [], "hexpm", "8d7c597c3e4a64c395980882d4bca3cebb8d74197c590dc272cfd3b6a6310578"},
+  "decimal": {:hex, :decimal, "2.1.1", "5611dca5d4b2c3dd497dec8f68751f1f1a54755e8ed2a966c2633cf885973ad6", [:mix], [], "hexpm", "53cfe5f497ed0e7771ae1a475575603d77425099ba5faef9394932b35020ffcc"},
+  "ecto": {:hex, :ecto, "3.11.1", "4b4972b717e7ca83d30121b12998f5fcdc62ba0ed4f20fd390f16f3270d85c3e", [:mix], [{:decimal, "~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "ebd3d3772cd0dfcd8d772659e41ed527c28b2a8bde4b00fe03e0463da0f1983b"},
   "finch": {:hex, :finch, "0.18.0", "944ac7d34d0bd2ac8998f79f7a811b21d87d911e77a786bc5810adb75632ada4", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.3", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 0.2.6 or ~> 1.0", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "69f5045b042e531e53edc2574f15e25e735b522c37e2ddb766e15b979e03aa65"},
   "hpax": {:hex, :hpax, "0.1.2", "09a75600d9d8bbd064cdd741f21fc06fc1f4cf3d0fcc335e5aa19be1a7235c84", [:mix], [], "hexpm", "2c87843d5a23f5f16748ebe77969880e29809580efdaccd615cd3bed628a8c13"},
   "jason": {:hex, :jason, "1.4.1", "af1504e35f629ddcdd6addb3513c3853991f694921b1b9368b0bd32beb9f1b63", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "fbb01ecdfd565b56261302f7e1fcc27c4fb8f32d56eab74db621fc154604a7a1"},