defmodule ShootingEventPhx.Auth do
  @moduledoc false
  alias ShootingEventPhx.Auth.SessionStore

  def admin_user, do: System.get_env("ADMIN_USER", "datwyler")
  def admin_pass, do: System.get_env("ADMIN_PASS", "datwyler")

  def verify_admin(username, password) do
    u = username |> to_string() |> String.trim()
    p = password |> to_string() |> String.trim()

    if u == "" or p == "" do
      false
    else
      secure_compare(u, admin_user()) and secure_compare(p, admin_pass())
    end
  end

  def bearer_token(conn) do
    conn
    |> Plug.Conn.get_req_header("authorization")
    |> List.first()
    |> parse_bearer_token()
  end

  def admin_request?(conn) do
    case bearer_token(conn) do
      nil -> false
      token -> SessionStore.validate_token(token)
    end
  end

  defp parse_bearer_token(nil), do: nil

  defp parse_bearer_token(header) do
    value = String.trim(header || "")

    if String.starts_with?(String.downcase(value), "bearer ") do
      token = value |> String.slice(7..-1//1) |> String.trim()
      if token == "", do: nil, else: token
    else
      nil
    end
  end

  defp secure_compare(left, right) do
    Plug.Crypto.secure_compare(left, right)
  rescue
    _ -> false
  end
end