get_links.ex

defmodule GetLinks do
  @moduledoc false

  # TODO: Get this to be able to take an argument
  def is_current_month?(file) do
    {{file_year, file_month, _day}, _time} =
      file
      |> File.stat!(time: :local)
      |> Map.get(:mtime)

    {{system_year, system_month, _day}, _time} =
      :calendar.local_time()

    {file_year, file_month} == {system_year, system_month}
  end

  def print_reference(file) do
    file
    |> File.read!
    |> extract_title
    |> extract_content
    |> extract_link
    |> build_markdown
  end

  def extract_title(string) do
    title =
      string
      |> String.split("\n")
      |> hd

    %{title: title, source: string}
  end

  def extract_content(obj = %{source: string}) do
    content =
      string
      |> String.split("\n", trim: true)
      |> Enum.slice(1..-2)
      |> Enum.join("\n\n")

    Map.put(obj, :content, content)
  end

  def extract_link(obj) do
    link =
      ~r/((([A-Za-z]{3,9}:(?:\/\/)?)(?:[-;:&=\+\$,\w]+@)?[A-Za-z0-9.-]+|(?:www.|[-;:&=\+\$,\w]+@)[A-Za-z0-9.-]+)((?:\/[\+~%\/.\w-_]*)?\??(?:[-\+=&;%@.\w_]*)#?(?:[\w]*))?)/
        |> Regex.run(obj.source)
        |> hd

    obj
    |> Map.put(:link, link)
  end

  def build_markdown(obj) do
    """
    ## [#{obj.title}](#{obj.link})

    #{obj.content}

    [Read more...](#{obj.link})

    """
  end

  def run do
    with :ok <- File.cd(Path.expand("~/dropbox/wiki/links")) do
      File.ls!()
      |> Enum.filter(& &1 =~ ~r/.txt/)
      |> Enum.filter(&is_current_month?/1)
    end
    |> Enum.sort_by(&File.stat!(&1, time: :local))
    |> Enum.map(&print_reference/1)
    |> Enum.join
    |> IO.puts
  end
end

GetLinks.run()