defmodule Raxol.Core.Events.Subscription do
  @moduledoc """
  Provides helpers for managing event subscriptions.

  This module makes it easy to:
  * Subscribe to specific event types
  * Filter events based on criteria
  * Handle event cleanup
  * Manage multiple subscriptions
  """

  alias Raxol.Core.Events.EventManager, as: Manager

  @type subscription_ref :: reference()
  @type subscription_opts :: keyword()

  @doc """
  Subscribes to keyboard events with optional key filters.

  ## Options
  * `:keys` - List of specific keys to match
  * `:exclude_keys` - List of keys to ignore

  ## Example
      subscribe_keyboard(keys: [:enter, :esc])
      subscribe_keyboard(exclude_keys: [:tab])
  """
  def subscribe_keyboard(opts \\ []) do
    keys = Keyword.get(opts, :keys)
    _exclude_keys = Keyword.get(opts, :exclude_keys, [])

    filter_opts = build_key_filter(keys)
    Manager.subscribe([:key], filter_opts)
  end

  @spec build_key_filter(any()) :: any()
  defp build_key_filter(nil), do: []
  @spec build_key_filter(any()) :: any()
  defp build_key_filter(keys), do: [key: keys]

  @doc """
  Subscribes to mouse events with optional button and position filters.

  ## Options
  * `:buttons` - List of mouse buttons to match
  * `:drag_only` - Only match drag events
  * `:click_only` - Only match click events
  * `:area` - Tuple of {x, y, width, height} to match position

  ## Example
      subscribe_mouse(buttons: [:left, :right])
      subscribe_mouse(area: {0, 0, 10, 10})
  """
  def subscribe_mouse(opts \\ []) do
    buttons = Keyword.get(opts, :buttons)
    drag_only = Keyword.get(opts, :drag_only, false)
    click_only = Keyword.get(opts, :click_only, false)
    area = Keyword.get(opts, :area)

    filter_opts =
      []
      |> add_filter(:mouse_button, buttons)
      |> add_filter(:drag, if(drag_only, do: true))
      |> add_filter(:click, if(click_only, do: true))
      |> add_filter(:area, area)

    Manager.subscribe([:mouse], filter_opts)
  end

  @doc """
  Subscribes to window events with optional action filters.

  ## Options
  * `:actions` - List of window actions to match (:resize, :focus, :blur)

  ## Example
      subscribe_window(actions: [:resize])
  """
  def subscribe_window(opts \\ []) do
    actions = Keyword.get(opts, :actions)
    filter_opts = build_window_filter(actions)
    Manager.subscribe([:window], filter_opts)
  end

  @spec build_window_filter(any()) :: any()
  defp build_window_filter(nil), do: []
  @spec build_window_filter(any()) :: any()
  defp build_window_filter(actions), do: [window_action: actions]

  @doc """
  Subscribes to timer events with optional data matching.

  ## Options
  * `:match` - Pattern to match against timer data

  ## Example
      subscribe_timer(match: :tick)
  """
  def subscribe_timer(opts \\ []) do
    match = Keyword.get(opts, :match)
    filter_opts = build_match_filter(match)
    Manager.subscribe([:timer], filter_opts)
  end

  @spec build_match_filter(any()) :: any()
  defp build_match_filter(nil), do: []
  @spec build_match_filter(any()) :: any()
  defp build_match_filter(match), do: [data: match]

  @doc """
  Subscribes to custom events with data matching.

  ## Options
  * `:match` - Pattern to match against custom event data

  ## Example
      subscribe_custom(match: {:user_action, _})
  """
  def subscribe_custom(opts \\ []) do
    match = Keyword.get(opts, :match)
    filter_opts = build_match_filter(match)
    Manager.subscribe([:custom], filter_opts)
  end

  @doc """
  Unsubscribes from events using the subscription reference.
  """
  def unsubscribe(ref) when is_reference(ref) do
    Manager.unsubscribe(ref)
  end

  @doc """
  Unsubscribes from multiple subscriptions.
  """
  def unsubscribe_all(refs) when is_list(refs) do
    Enum.each(refs, &unsubscribe/1)
  end

  @doc """
  Subscribes to a list of event types.

  ## Parameters

  - `event_types` - A list of event type atoms (e.g., `[:key, :mouse, :window]`).
                     Can also include tuples like `{:key, opts}` or `{:mouse, opts}`
                     to pass specific options to the individual subscription functions.

  ## Returns

  - `{:ok, list(subscription_ref())}` on success, containing a list of references for each subscription.
  - `{:error, reason}` if any subscription fails. Successfully created subscriptions before the failure will be automatically unsubscribed.
  """
  def events(event_types) when is_list(event_types) do
    do_subscribe_events(event_types, [])
  end

  # Helper function to recursively subscribe and handle cleanup on error
  @spec do_subscribe_events(any(), reference()) :: any()
  defp do_subscribe_events([], successful_refs) do
    {:ok, Enum.reverse(successful_refs)}
  end

  @spec do_subscribe_events(any(), reference()) :: any()
  defp do_subscribe_events([event_spec | rest], successful_refs) do
    case subscribe_single_event(event_spec) do
      {:ok, ref} ->
        do_subscribe_events(rest, [ref | successful_refs])

      {:error, _reason} = error ->
        # Unsubscribe already successful subscriptions
        unsubscribe_all(successful_refs)
        error
    end
  end

  # Helper to call the correct specific subscribe function
  @spec subscribe_single_event(any()) :: any()
  defp subscribe_single_event(:key), do: subscribe_keyboard()
  @spec subscribe_single_event(any()) :: any()
  defp subscribe_single_event({:key, opts}), do: subscribe_keyboard(opts)
  @spec subscribe_single_event(any()) :: any()
  defp subscribe_single_event(:mouse), do: subscribe_mouse()
  @spec subscribe_single_event(any()) :: any()
  defp subscribe_single_event({:mouse, opts}), do: subscribe_mouse(opts)
  @spec subscribe_single_event(any()) :: any()
  defp subscribe_single_event(:window), do: subscribe_window()
  @spec subscribe_single_event(any()) :: any()
  defp subscribe_single_event({:window, opts}), do: subscribe_window(opts)
  @spec subscribe_single_event(any()) :: any()
  defp subscribe_single_event(:timer), do: subscribe_timer()
  @spec subscribe_single_event(any()) :: any()
  defp subscribe_single_event({:timer, opts}), do: subscribe_timer(opts)
  @spec subscribe_single_event(any()) :: any()
  defp subscribe_single_event(:custom), do: subscribe_custom()
  @spec subscribe_single_event(any()) :: any()
  defp subscribe_single_event({:custom, opts}), do: subscribe_custom(opts)
  @spec subscribe_single_event(any()) :: any()
  defp subscribe_single_event(other), do: {:error, {:invalid_event_type, other}}

  # Private Helpers

  @spec add_filter(keyword(), any(), any()) :: any()
  defp add_filter(opts, _key, nil), do: opts

  @spec add_filter(keyword(), any(), any()) :: any()
  defp add_filter(opts, key, value) do
    Keyword.put(opts, key, value)
  end
end