defmodule Radius.Dict do
  alias Radius.Dict.Parser
  alias Radius.Dict.EntryNotFoundError

  defmacro __using__(_) do
    quote do
      require Radius.Dict
      import Radius.Dict
    end
  end

  extra_dictionaries = Application.compile_env(:elixir_radius, :extra_dictionaries, [])

  {includes, generic_attributes, generic_values} =
    Path.join(["dicts", "dictionary"])
    |> File.read!()
    |> Parser.parse_index()

  filtered_includes =
    if config_includes = Application.compile_env(:elixir_radius, :included_dictionaries) do
      Enum.filter(includes, &(&1 in config_includes))
    else
      includes
    end

  dict_files =
    Enum.map(filtered_includes, fn dict -> Path.join(["dicts", "dictionary.#{dict}"]) end)

  {vendors, attributes, values} =
    Enum.reduce(
      dict_files ++ extra_dictionaries,
      {[], generic_attributes, generic_values},
      fn dict_file, {acc_vendors, acc_attributes, acc_values} ->
        dict =
          dict_file
          |> File.read!()
          |> Parser.parse()

        {acc_attributes, rest} =
          case Map.pop(dict, :attributes) do
            {[], rest} -> {acc_attributes, rest}
            {attributes, rest} -> {attributes ++ acc_attributes, rest}
          end

        {acc_values, rest} =
          case Map.pop(rest, :values) do
            {[], rest} -> {acc_values, rest}
            {values, rest} -> {values ++ acc_values, rest}
          end

        acc_vendors =
          if vendor = Map.get(rest, :vendor) do
            [vendor | acc_vendors]
          else
            acc_vendors
          end

        {acc_vendors, acc_attributes, acc_values}
      end
    )

  for attribute <- attributes do
    attr_fun_name = "attr_#{attribute.name}" |> String.replace("-", "_") |> String.to_atom()

    defmacro unquote(attr_fun_name)(), do: unquote(attribute.id)
    defmacro unquote(attr_fun_name)(val), do: {unquote(attribute.id), val}
    def attribute_by_id(unquote(attribute.id)), do: unquote(Macro.escape(attribute))
    def attribute_by_name(unquote(attribute.name)), do: unquote(Macro.escape(attribute))
  end

  for val <- values do
    val_fun_name = "val_#{val.attr}_#{val.name}" |> String.replace("-", "_") |> String.to_atom()

    defmacro unquote(val_fun_name)(), do: unquote(val.value)
    def value_by_value(unquote(val.attr), unquote(val.value)), do: unquote(Macro.escape(val))
    def value_by_name(unquote(val.attr), unquote(val.name)), do: unquote(Macro.escape(val))
  end

  for vendor <- vendors do
    mod = Module.concat(__MODULE__, :"Vendor#{String.replace(vendor.name, "-", "_")}")
    [tl, ll] = Keyword.get(vendor.opts, :format) || [1, 1]
    vendor_data = %{id: vendor.id, name: vendor.name, format: {tl, ll}, module: mod}
    def vendor_by_id(unquote(vendor.id)), do: unquote(Macro.escape(vendor_data))
    def vendor_by_name(unquote(vendor.name)), do: unquote(Macro.escape(vendor_data))

    attribute_funs =
      for attribute <- vendor.attributes do
        attr_fun_name = "attr_#{attribute.name}" |> String.replace("-", "_") |> String.to_atom()

        quote location: :keep do
          defmacro unquote(attr_fun_name)(), do: unquote(attribute.id)
          defmacro unquote(attr_fun_name)(val), do: {unquote(attribute.id), val}
          def attribute_by_id(unquote(attribute.id)), do: unquote(Macro.escape(attribute))
          def attribute_by_name(unquote(attribute.name)), do: unquote(Macro.escape(attribute))
        end
      end

    elixir_compiler_limit = 1024

    value_funs =
      if Enum.count(vendor.attributes ++ vendor.values) < elixir_compiler_limit do
        for val <- vendor.values do
          val_fun_name =
            "val_#{val.attr}_#{val.name}" |> String.replace("-", "_") |> String.to_atom()

          quote location: :keep do
            defmacro unquote(val_fun_name)(), do: unquote(val.value)

            def value_by_value(unquote(val.attr), unquote(val.value)),
              do: unquote(Macro.escape(val))

            def value_by_name(unquote(val.attr), unquote(val.name)),
              do: unquote(Macro.escape(val))
          end
        end
      else
        for {attr, vals} <- Enum.group_by(vendor.values, & &1.attr) do
          val_fun_name = "val_#{attr}" |> String.replace("-", "_") |> String.to_atom()

          quote location: :keep do
            defmacro unquote(val_fun_name)(val_name),
              do:
                Enum.find_value(
                  unquote(Macro.escape(vals)),
                  &(&1.name == val_name && &1.value)
                )

            def value_by_value(unquote(attr), val_value),
              do:
                Enum.find(
                  unquote(Macro.escape(vals)),
                  &(&1.value == val_value)
                )

            def value_by_name(unquote(attr), val_name),
              do:
                Enum.find(
                  unquote(Macro.escape(vals)),
                  &(&1.name == val_name)
                )
          end
        end
      end

    IO.puts("Compiling #{mod}")
    Module.create(mod, attribute_funs ++ value_funs, Macro.Env.location(__ENV__))
  end

  def attribute_by_id(id), do: raise(EntryNotFoundError, type: :attribute, key: id)
  def attribute_by_name(name), do: raise(EntryNotFoundError, type: :attribute, key: name)
  def value_by_value(attr, _val), do: raise(EntryNotFoundError, type: :value, key: attr)
  def value_by_name(attr, _val_name), do: raise(EntryNotFoundError, type: :value, key: attr)
  def vendor_by_id(id), do: raise(EntryNotFoundError, type: :vendor, key: id)
  def vendor_by_name(name), do: raise(EntryNotFoundError, type: :vendor, key: name)
end