defmodule Toolshed.HTTP do
  @moduledoc """
  Helpers that make HTTP requests
  """

  @doc """
  Display the local weather

  See http://wttr.in/:help for more information.
  """
  @spec weather() :: :"do not show this result in output"
  def weather() do
    check_inets()

    {:ok, {_status, _headers, body}} = :httpc.request('http://v2.wttr.in/?An0')

    body |> :binary.list_to_bin() |> IO.puts()
    IEx.dont_display_result()
  end

  @doc """
  Generate an ASCII art QR code

  See https://github.com/chubin/qrenco.de for more information.
  """
  @spec qr_encode(String.t()) :: :"do not show this result in output"
  def qr_encode(message) do
    check_inets()

    encoded = message |> URI.encode() |> to_charlist()
    form_data = [?x, ?= | encoded]

    {:ok, {_status, _headers, body}} =
      :httpc.request(
        :post,
        {'http://qrenco.de/', [{'User-Agent', 'curl'}], 'application/x-www-form-urlencoded',
         form_data},
        [],
        []
      )

    body |> :binary.list_to_bin() |> IO.puts()
    IEx.dont_display_result()
  end

  @doc """
  Post text to a paste service

  This is a convenient way of sharing text data with others. It currently
  posts to "exbin.call-cc.be". Keep in mind that the text is posted in the
  clear and the server may retain it indefinitely.

  On success, this function returns a URL to the posted text.
  """
  @spec pastebin(String.t()) :: String.t() | {:error, term()}
  def pastebin(contents) do
    {:ok, socket} = :gen_tcp.connect('exbin.call-cc.be', 9999, [])
    :ok = :gen_tcp.send(socket, contents)
    :ok = :gen_tcp.shutdown(socket, :write)

    case read_until_closed(socket) do
      {:ok, result} ->
        IO.iodata_to_binary(result) |> String.trim()

      {:error, _message} = error ->
        error
    end
  end

  defp read_until_closed(socket, result \\ []) do
    receive do
      {:tcp, ^socket, bytes} ->
        read_until_closed(socket, [result, bytes])

      {:tcp_closed, ^socket} ->
        {:ok, result}
    after
      1000 ->
        {:error, :timeout}
    end
  end

  defp check_inets() do
    case Application.ensure_all_started(:inets) do
      {:ok, _} ->
        :ok

      {:error, _} ->
        raise RuntimeError, """
        :inets can't be started.
        This probably means that it isn't in the OTP release.
        To fix, edit your mix.exs and add :inets to the :extra_applications list.
        """
    end
  end
end