# Pleroma: A lightweight social networking server
# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only

defmodule Pleroma.HTTP do
  @moduledoc """
    Wrapper for `Tesla.request/2`.
  """

  alias Pleroma.HTTP.Connection
  alias Pleroma.HTTP.Request
  alias Pleroma.HTTP.RequestBuilder, as: Builder
  alias Tesla.Client
  alias Tesla.Env

  require Logger

  @type t :: __MODULE__

  @doc """
  Performs GET request.

  See `Pleroma.HTTP.request/5`
  """
  @spec get(Request.url() | nil, Request.headers(), keyword()) ::
          nil | {:ok, Env.t()} | {:error, any()}
  def get(url, headers \\ [], options \\ [])
  def get(nil, _, _), do: nil
  def get(url, headers, options), do: request(:get, url, "", headers, options)

  @doc """
  Performs POST request.

  See `Pleroma.HTTP.request/5`
  """
  @spec post(Request.url(), String.t(), Request.headers(), keyword()) ::
          {:ok, Env.t()} | {:error, any()}
  def post(url, body, headers \\ [], options \\ []),
    do: request(:post, url, body, headers, options)

  @doc """
  Builds and performs http request.

  # Arguments:
  `method` - :get, :post, :put, :delete
  `url` - full url
  `body` - request body
  `headers` - a keyworld list of headers, e.g. `[{"content-type", "text/plain"}]`
  `options` - custom, per-request middleware or adapter options

  # Returns:
  `{:ok, %Tesla.Env{}}` or `{:error, error}`

  """
  @spec request(atom(), Request.url(), String.t(), Request.headers(), keyword()) ::
          {:ok, Env.t()} | {:error, any()}
  def request(method, url, body, headers, options) when is_binary(url) do
    with uri <- URI.parse(url),
         received_adapter_opts <- Keyword.get(options, :adapter, []),
         adapter_opts <- Connection.options(uri, received_adapter_opts),
         options <- put_in(options[:adapter], adapter_opts),
         params <- Keyword.get(options, :params, []),
         request <- build_request(method, headers, options, url, body, params),
         client <- Tesla.client([Tesla.Middleware.FollowRedirects], tesla_adapter()),
         pid <- Process.whereis(adapter_opts[:pool]) do
      pool_alive? =
        if tesla_adapter() == Tesla.Adapter.Gun && pid do
          Process.alive?(pid)
        else
          false
        end

      request_opts =
        adapter_opts
        |> Enum.into(%{})
        |> Map.put(:env, Pleroma.Config.get([:env]))
        |> Map.put(:pool_alive?, pool_alive?)

      response = request(client, request, request_opts)

      Connection.after_request(adapter_opts)

      response
    end
  end

  @spec request(Client.t(), keyword(), map()) :: {:ok, Env.t()} | {:error, any()}
  def request(%Client{} = client, request, %{env: :test}), do: request_try(client, request)

  def request(%Client{} = client, request, %{body_as: :chunks}) do
    request_try(client, request)
  end

  def request(%Client{} = client, request, %{pool_alive?: false}) do
    request_try(client, request)
  end

  def request(%Client{} = client, request, %{pool: pool, timeout: timeout}) do
    try do
      :poolboy.transaction(
        pool,
        &Pleroma.Pool.Request.execute(&1, client, request, timeout + 500),
        timeout + 1_000
      )
    rescue
      e ->
        {:error, e}
    catch
      :exit, {:timeout, _} ->
        Logger.warn("Receive response from pool failed #{request[:url]}")
        {:error, :recv_pool_timeout}

      :exit, e ->
        {:error, e}
    end
  end

  @spec request_try(Client.t(), keyword()) :: {:ok, Env.t()} | {:error, any()}
  def request_try(client, request) do
    try do
      Tesla.request(client, request)
    rescue
      e ->
        {:error, e}
    catch
      :exit, e ->
        {:error, e}
    end
  end

  defp build_request(method, headers, options, url, body, params) do
    Builder.new()
    |> Builder.method(method)
    |> Builder.headers(headers)
    |> Builder.opts(options)
    |> Builder.url(url)
    |> Builder.add_param(:body, :body, body)
    |> Builder.add_param(:query, :query, params)
    |> Builder.convert_to_keyword()
  end

  defp tesla_adapter, do: Application.get_env(:tesla, :adapter)
end