defmodule Aerospike.Command.BatchUdf do
  @moduledoc false

  alias Aerospike.BatchResult
  alias Aerospike.Command.Batch, as: MixedBatch
  alias Aerospike.Command.BatchCommand.Entry
  alias Aerospike.Error
  alias Aerospike.Key
  alias Aerospike.Policy

  @type option :: {:timeout, non_neg_integer()} | {:socket_timeout, non_neg_integer()}
  @type result :: {:ok, [BatchResult.t()]} | {:error, Error.t()} | {:error, :cluster_not_ready}

  @spec execute(GenServer.server(), [Key.t()], String.t(), String.t(), list(), [option()]) ::
          result()
  def execute(tender, keys, package, function, args, opts \\ [])

  def execute(_tender, [], package, function, args, opts)
      when is_binary(package) and is_binary(function) and is_list(args) and is_list(opts) do
    with {:ok, _parent_policy} <- Policy.batch(Policy.batch_parent_opts(opts)),
         {:ok, _write_policy} <- Policy.batch_record_write(Policy.batch_record_opts(opts)) do
      {:ok, []}
    end
  end

  def execute(tender, keys, package, function, args, opts)
      when is_list(keys) and is_binary(package) and is_binary(function) and is_list(args) and
             is_list(opts) do
    with :ok <- validate_keys(keys),
         {:ok, _parent_policy} <- Policy.batch(Policy.batch_parent_opts(opts)),
         {:ok, write_policy} <- Policy.batch_record_write(Policy.batch_record_opts(opts)),
         {:ok, results} <-
           MixedBatch.execute(
             tender,
             entries(keys, package, function, args, write_policy),
             Policy.batch_parent_opts(opts)
           ) do
      {:ok, MixedBatch.to_public_results(results)}
    end
  end

  defp entries(keys, package, function, args, %Policy.BatchWrite{} = policy) do
    keys
    |> Enum.with_index()
    |> Enum.map(fn {key, index} ->
      %Entry{
        index: index,
        key: key,
        kind: :udf,
        dispatch: :write,
        payload: Map.merge(payload(policy), %{package: package, function: function, args: args})
      }
    end)
  end

  defp payload(%Policy.BatchWrite{} = policy) do
    Map.take(policy, [
      :ttl,
      :generation,
      :generation_policy,
      :filter,
      :exists,
      :commit_level,
      :durable_delete,
      :respond_per_op,
      :send_key,
      :read_mode_ap,
      :read_mode_sc,
      :read_touch_ttl_percent
    ])
  end

  defp validate_keys(keys) do
    if Enum.all?(keys, &match?(%Key{}, &1)) do
      :ok
    else
      invalid_argument("Aerospike.batch_udf/6 expects a list of %Aerospike.Key{} values")
    end
  end

  defp invalid_argument(message) do
    {:error, Error.from_result_code(:invalid_argument, message: message)}
  end
end