live_guard

defprotocol LiveGuard.Allowed do
  @moduledoc """
  By this protocol you can implement `allowed?/4` functions.
  """

  @fallback_to_any true

  @doc """
  By this function you can protect the LiveView lifecycle stages.

  You can pattern match by the **user**, **LiveView module**, **LiveView lifecycle stage** and **LiveView lifecycle stage inputs**.
  You can put this file anywhere but `/lib/my_app_web/live/abilities.ex` is recommended.

  **It must return boolean.**

  ## Example

  ```elixir
  # /lib/my_app_web/live/abilities.ex

  defimpl LiveGuard.Allowed, for: User do
    @before_compile {LiveGuard, :before_compile_allowed}

    def allowed?(
          %User{role: role},
          MyModuleLive,
          :handle_event,
          {"delete_item", _params, _socket}
        )
        when role in [:viewer, :customer],
        do: false

    # other `allowed?/4` functions...
  end
  ```
  > Note: As you can see, you don't have to define catch-all `allowed?/4` function because we used `@before_compile {LiveGuard, :before_compile_allowed}` hook. It returns `true`.

  If the user is not authenticated you can add the following implementation as below:
  ```elixir
  defimpl LiveGuard.Allowed, for: Atom do
    @before_compile {LiveGuard, :before_compile_allowed}

    def allowed?(nil, MyModuleLive, :handle_event, {"delete_item", _params, _socket}),
      do: false

    # other `allowed?/4` functions...
  end
  ```
  """

  @typedoc "A user struct or nil when the user is not authenticated."
  @type t() :: struct() | nil
  @spec allowed?(
          struct() | nil,
          module(),
          :mount | :handle_params | :handle_event | :handle_info | :after_render,
          tuple()
        ) :: boolean()
  def allowed?(user, live_view_module, stage, stage_inputs)
end

defprotocol LiveGuard.GuardedStages do
  @moduledoc """
  #### _Optional_

  By this protocol you can implement `guarded_stages/1` functions.
  """

  @doc """
  #### _Optional_

  This function is for optimization.

  By default if you use the `on_mount/4` callback of LiveGuard, it will attach hooks to all attachable LiveView lifecycle stages (`:handle_params`, `:handle_event`, `:handle_info` and `:after_render`).

  If you need to protect for example only the `:handle_event` LiveView lifecycle stage for an individual LiveView module you can use this function.
  You can put this file anywhere but `/lib/my_app_web/live/guarded_stages.ex` is recommended.

  **It must return a list of [valid attachable LiveView lifecycle stages](https://hexdocs.pm/phoenix_live_view/Phoenix.LiveView.html#attach_hook/4).**

  ## Example

  ```elixir
  # /lib/my_app_web/live/guarded_stages.ex

  defimpl LiveGuard.GuardedStages, for: Atom do
    @before_compile {LiveGuard, :before_compile_guarded_stages}

    def guarded_stages(MyModuleLive), do: [:handle_event]

    # other `guarded_stages?/1` functions...
  end
  ```
  In this case it will only attach hook to `:handle_event` LiveView lifecycle stage.
  > Note: As you can see, you don't have to define catch-all `guarded_stages/1` function because we used `@before_compile {LiveGuard, :before_compile_guarded_stages}` hook. It returns all the attachable LiveView lifecycle stages.
  """

  @typedoc "A LiveView module."
  @type t() :: module()
  @spec guarded_stages(module()) :: [
          :handle_params | :handle_event | :handle_info | :after_render
        ]
  def guarded_stages(live_view_module)
end