defmodule Kvasir.Dev.Downloader do
  require Logger

  def clear(component) do
    File.rm_rf!(dir(component))
  end

  def commit(component) do
    case File.read(Path.join(dir(component), ".commit")) do
      {:ok, v} -> v
      _ -> nil
    end
  end

  def component(component, commit \\ nil) do
    path = dir(component)
    c = commit(component)

    pull = if(String.trim(commit || "") != "", do: commit, else: "release/v1.0")

    cond do
      c == pull ->
        :noop

      pull == "release/v1" and c != nil ->
        :noop

      :download ->
        Logger.info("Downloading: #{component}")
        name = if(component == "core", do: "kvasir", else: "kvasir_#{component}")
        url = "https://github.com/IanLuites/#{name}/tarball/#{pull}"
        IO.puts(url)

        with :ok <- File.mkdir_p(path),
             {:ok, %{body: data}} <-
               HTTPX.get(url, settings: [follow_redirect: true]),
             {:ok, files} <- :erl_tar.extract({:binary, data}, [:memory, :compressed]) do
          Logger.info("Extracting: #{component}")

          Enum.each(files, fn {file, content} ->
            case Path.split(to_string(file)) do
              [_, "lib" | f] ->
                ff = Path.join([path | f])
                File.mkdir_p!(Path.dirname(ff))
                File.write!(ff, content)

              _ ->
                :ok
            end
          end)

          c =
            if String.length(pull) == 40 do
              commit
            else
              HTTPX.get!("https://api.github.com/repos/IanLuites/#{name}/git/ref/heads/#{pull}",
                format: :json
              ).body["object"]["sha"]
            end

          File.write!(Path.join(path, ".commit"), c)

          :ok
        else
          {:error, err} -> Logger.error("Failed: #{component} => #{inspect(err)}")
        end
    end
  end

  defp dir(component), do: Path.join([__DIR__, "components", component])
end