neiam /gitgud

defmodule GitGudWeb.HookController do
  @moduledoc """
  Receives post-receive payloads from the on-disk git hook.

  See `priv/scripts/gitgud-hook`. The request body is the raw stdin of
  the hook (`<old> <new> <ref>\\n…`). The repo is identified via the
  `x-repo-path: <absolute path>` header.

  Loopback-only — bind to 127.0.0.1 in production.
  """

  use GitGudWeb, :controller

  import Ecto.Query, warn: false

  alias GitGud.Repo
  alias GitGud.Repositories.HookReceiver
  alias GitGud.Repositories.Repository

  def post_receive(conn, _params) do
    case Plug.Conn.get_req_header(conn, "x-repo-path") do
      [path | _] ->
        {:ok, body, conn} = Plug.Conn.read_body(conn, length: 1_000_000)

        case find_repo(path) do
          %Repository{id: rid} ->
            _ = HookReceiver.receive(rid, body, pusher_id(conn))
            send_resp(conn, 200, "ok\n")

          _ ->
            send_resp(conn, 404, "unknown repo\n")
        end

      _ ->
        send_resp(conn, 400, "missing x-repo-path\n")
    end
  end

  defp find_repo(path) do
    Repo.one(from r in Repository, where: r.disk_path == ^path)
  end

  # The transport (SSH channel / smart-HTTP CGI) sets GITGUD_PUSHER_ID
  # in the git hook environment; `gitgud-hook` forwards it as a header.
  # Absent / non-numeric → nil (unattributed push).
  defp pusher_id(conn) do
    with [val | _] <- Plug.Conn.get_req_header(conn, "x-pusher-id"),
         {id, ""} <- Integer.parse(val) do
      id
    else
      _ -> nil
    end
  end
end