gram: source

> ./lib/source.ex

# A generic module able to read change-logged sources;
# can be rendered as machine-compilable code,
# essay pages, or in numerous unique schemas.

defmodule Source do
  @doc "
  Read module configs.
  "
  def call(param), do: (
    case Application.fetch_env(:source, param) do
      {:ok, response} -> response
      :error -> nil
    end)

  @doc "
  [migration] Needs to move to `Source.Changes`.
  "
  def changes(base) do
    log = Git.new(base.locus) |> Git.log([
      "--format=format:%h (%ai) %aN: %s",
    ]) |> elem(1) |> String.trim |> String.split("\n")

    # parse!
    log |> Enum.map(fn ln ->
      [hash, "("<>day, clock, zone, _composer | message ] = ln |> String.split(" ")
      zone = zone |> String.replace(~r/\)$/, "")
      # composer = composer |> String.replace(~r/:$/, "")
      message = message |> Enum.join(" ")

      ## Oh no! Parens inside a changelog mess up labels.
      # [message, labels] = if (message |> String.ends_with?(")")) do
      #   [ message | [labels] ] = message |> String.split("(")
      #   [message, labels |> String.trim_trailing(")") |> String.split(",") |> Enum.map(&String.trim/1) ]
      #   else [message, labels] end
      labels = []

      [ hash, day, clock, zone, labels, message ]
    end)
  end

  @doc "
  [migration] Needs to move to `Source.Changes`.
  "
  def changes_by_day(base) do
    changes(base)
    |> Enum.group_by(fn [_, day | _] -> day end)
    |> Enum.sort(:desc)
  end
end