defmodule PhxAdmin do
  {:ok, _} = Application.ensure_all_started(:postgrex)

  {:ok, pid} =
    Postgrex.start_link(
      hostname: "localhost",
      username: "postgres",
      password: "postgres",
      database: "phx_admin_dev"
    )

  tables_query = """
  select table_name from information_schema.tables
  where table_schema != 'pg_catalog'
    and table_schema != 'information_schema'
    and table_name != 'schema_migrations'
  """

  %{rows: tables} =
    Postgrex.query!(
      pid,
      tables_query,
      []
    )

  relations =
    Enum.map(tables, fn [table_name] ->
      module_name = ("Elixir.Relations." <> Macro.camelize(table_name)) |> String.to_atom()

      columns_query = """
      select column_name, data_type
        from information_schema.columns
      where table_name = $1
      order by ordinal_position
      """

      %{rows: columns} = Postgrex.query!(pid, columns_query, [table_name])

      fields =
        Enum.map(columns, fn
          ["id", "bigint"] ->
            nil

          [column_name, "character varying"] ->
            {column_name, "string"}

          _ ->
            nil
        end)
        |> Enum.filter(& &1)

      module = """
      defmodule module_name do
        use Ecto.Schema
        schema table_name do
          <%= for {column_name, column_type} <- fields do %>
            field :<%= column_name %>, :<%= column_type %>
          <% end %>
        end
      end
      """

      module
      |> EEx.eval_string(fields: fields)
      |> Code.eval_string(module_name: module_name, table_name: table_name)

      module_name
    end)

  @relations relations

  def relations(), do: @relations
end