defmodule PrettyLoggex.Formatters.KvFormatter do
  import PrettyLoggex.Formatters.Helper

  def format(level, message, timestamp, metadata) do
    [timestamp: format_timestamp(timestamp), level: level]
    |> Keyword.merge(metadata)
    |> Keyword.merge(message: message)
    |> Enum.map(&to_kv/1)
    |> Enum.join(" ")
    |> String.to_charlist()
    |> List.insert_at(-1, "\n")
    |> List.insert_at(0, "\n")
    |> List.to_string()
  rescue
    error ->
      """
      Log couldn't be formatted. Reason: #{inspect(error)}
      Details:
        level: #{inspect(level)}
        message: #{inspect(message)}
        timestamp: #{inspect(timestamp)}
        metadata: #{inspect(metadata)}
      """
  end

  defp to_kv({key, value})
       when is_atom(value) or
              is_list(value) or
              is_integer(value) or
              is_float(value),
       do: "#{key}=#{value}"

  defp to_kv({key, value}), do: "#{key}=#{inspect(value)}"
end