Merge pull request #54 from dwyl/query-all

Query all

lib/alog/connection.ex

@@ -27,7 +27,63 @@ defmodule Alog.Connection do
   defdelegate to_constraints(error_struct), to: EAPC
 
   @impl true
-  defdelegate all(query), to: EAPC
+  def all(query) do
+    iodata_query =  EAPC.all(query)
+
+    query = iodata_query
+    |> IO.iodata_to_binary()
+    |> alogify_all_query()
+
+    query
+  end
+
+  defp alogify_all_query(query) do
+    query_data = get_query_data(query)
+    # if all query is called during migration, some column used in the
+    # alogify version might not be yet defined.
+    # Return the "normal" query
+    if (query_data["table_name"] == "\"schema_migrations\"") do
+      query
+    else
+      subquery = IO.iodata_to_binary(
+                  [ "SELECT DISTINCT ON (#{query_data["table_as"]}.\"entry_id\" ) ",
+                    query_data["subquery_fields"],
+                    get_deleted_field(query_data),
+                    " FROM ",
+                    query_data["table_name"], " AS ", query_data["table_as"],
+                    query_data["rest_query"],
+                    " ORDER BY #{query_data["table_as"]}.\"entry_id\", #{query_data["table_as"]}.\"inserted_at\" DESC"
+                ]
+              )
+
+      IO.iodata_to_binary(
+        ["SELECT ", query_data["field_names"], " FROM (", subquery, ") AS alogsubquery WHERE (NOT alogsubquery.\"deleted\")"]
+      )
+    end
+  end
+
+  defp get_query_data(query) do
+    data = Regex.named_captures(~r/(\bSELECT\b)\s(?<fields>.*)\sFROM\s(?<table_name>.*)\sas\s(?<table_as>.*)(?<rest_query>.*)/i, query)
+    data = Map.put(data, "field_names", Regex.replace(~r/#{data["table_as"]}/, data["fields"], "alogsubquery"))
+
+    subquery_fields = data["fields"]
+      |> String.split(",")
+      |> Enum.map(fn f ->
+        field_name = Regex.replace(~r/#{data["table_as"]}./, f, "")
+        f <> " AS #{field_name}"
+      end)
+      |> Enum.join(", ")
+
+    Map.put(data, "subquery_fields", subquery_fields)
+  end
+
+  defp get_deleted_field(query_data) do
+    if String.contains?(query_data["subquery_fields"], "#{query_data["table_as"]}.\"deleted\"") do
+      ""
+    else
+      ", #{query_data["table_as"]}.\"deleted\" AS \"deleted\""
+    end
+  end
 
   @impl true
   defdelegate update_all(query, prefix \\ nil), to: EAPC

test/all_test.exs

@@ -1,31 +1,14 @@
 defmodule AlogTest.AllTest do
   use Alog.TestApp.DataCase
 
-  # alias Alog.TestApp.{User, Helpers}
-  #
-  # describe "all/0:" do
-  #   test "succeeds" do
-  #     {:ok, _} = %User{} |> User.changeset(Helpers.user_1_params()) |> User.insert()
-  #     {:ok, _} = %User{} |> User.changeset(Helpers.user_2_params()) |> User.insert()
-  #
-  #     assert length(User.all()) == 2
-  #   end
-  #
-  #   test "does not include old items" do
-  #     {:ok, user} = %User{} |> User.changeset(Helpers.user_1_params()) |> User.insert()
-  #     {:ok, _} = %User{} |> User.changeset(Helpers.user_2_params()) |> User.insert()
-  #     {:ok, _} = user |> User.changeset(%{postcode: "W2 3EC"}) |> User.update()
-  #
-  #     assert length(User.all()) == 2
-  #   end
-  #
-  #   test "all return inserted_at original value" do
-  #     {:ok, user} = %User{} |> User.changeset(Helpers.user_3_params()) |> User.insert()
-  #     {:ok, user_updated} = user |> User.changeset(%{postcode: "W2 3EC"}) |> User.update()
-  #
-  #     [user_all] = User.all()
-  #     assert user_all.inserted_at == user.inserted_at
-  #     assert user_all.postcode == user_updated.postcode
-  #   end
-  # end
+  alias Alog.TestApp.{Comment}
+
+  describe "all/0:" do
+    test "succeeds" do
+      {:ok, _comment} = %Comment{comment: "Hello Rob"}  |> Repo.insert()
+      {:ok, _} = %Comment{comment: "Hello Dan"} |> Repo.insert()
+
+      assert length(Repo.all(Comment)) == 2
+    end
+  end
 end