# Copyright 2024-2025 tiksan
# 
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# 
# http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

defmodule Tornex.Query do
  @moduledoc """
  The query struct containing API request data.

  The `Tornex.Query` struct is utilized by `Tornex.API.torn_get/1` and `Tornex.Scheduler.Bucket.enqueue/1` to make API calls. The struct stores the required information to perform the API call.
  """

  defstruct [
    :resource,
    :resource_id,
    :key,
    :selections,
    :from,
    :to,
    :timestamp,
    :limit,
    :sort,
    :params,

    # Values required for the scheduler
    :key_owner,
    :nice,
    :origin
  ]

  @type t :: %__MODULE__{
          resource: String.t(),
          resource_id: integer() | String.t(),
          key: String.t(),
          selections: [String.t()] | nil,
          from: integer() | nil,
          to: integer() | nil,
          timestamp: integer() | nil,
          limit: integer() | nil,
          sort: :asc | :desc | nil,
          params: Keyword | nil,

          # Values required for the scheduler
          key_owner: integer(),
          nice: integer(),
          origin: GenServer.from() | nil
        }

  @doc """
  Determines the priority of a `Tornex.Query` by the `nice` value as a priority "bucket" atom.

  The nice value of a query is based on the Linux niceness value between -20 and 19. A niceness of -20 is the highest priority request and 19 is the lowest priority. For more information on the scheduling of requests against `Tornex.Query`, see `Tornex.Scheduler.Bucket`.

  There are three priority buckets:
  - generic requests (nice > 0) => Requests that are intended to be made with as much latency as needed
  - high priority requests (-10 < nice <= 0) => Requests where latency matters
  - user requests (nice <= -10) => Requests that should be performed immediately, typically initiated by a user action
  """
  @spec query_priority(Tornex.Query.t()) :: :user_request | :high_priority | :generic_request
  def query_priority(%Tornex.Query{} = query) do
    cond do
      query.nice <= -10 -> :user_request
      query.nice <= 0 -> :high_priority
      true -> :generic_request
    end
  end
end