import lustre/effect.{type Effect}

import rcade/inputs/controls.{type Controls, type SystemButtons}
import rcade/inputs/spinner.{type Spinner}
import rcade/player.{type Player, Player1, Player2}

/// Combined input state for a player.
pub type Player1Inputs {
  Player1Inputs(controls: Controls, spinner: Spinner)
}

/// Combined input state for a player.
pub type Player2Inputs {
  Player2Inputs(controls: Controls, spinner: Spinner)
}

/// Poll all input states at a given interval (in milliseconds).
///
/// Returns an effect that builds a msg from the states of both players'
/// controls and spinners, as well as the state of the system buttons.
pub fn poll(
  every interval: Int,
  with to_msg: fn(Player1Inputs, Player2Inputs, SystemButtons) -> msg,
) -> Effect(msg) {
  effect.from(fn(dispatch) {
    let _stop =
      start_polling(interval, fn() {
        let player1 =
          Player1Inputs(
            controls: controls.read_player(Player1),
            spinner: spinner.read(Player1),
          )
        let player2 =
          Player2Inputs(
            controls: controls.read_player(Player2),
            spinner: spinner.read(Player2),
          )
        let system = controls.read_system()

        dispatch(to_msg(player1, player2, system))
      })
    Nil
  })
}

@external(javascript, "./inputs_ffi.mjs", "start_polling")
fn start_polling(interval: Int, callback: fn() -> Nil) -> fn() -> Nil

/// A button press event from the classic controls.
pub type ButtonPress {
  PlayerButton(player: Player, button: String)
  SystemButton(String)
}

/// Subscribe to "classic" control press events.
///
/// Each press dispatches a `ButtonPress` with the provided msg constructor.
pub fn on_press(with to_msg: fn(ButtonPress) -> msg) -> Effect(msg) {
  effect.from(fn(dispatch) {
    let _unsubscribe =
      controls.subscribe(fn(player_int, button, is_system) {
        let event = case is_system {
          False -> {
            let player = case player_int {
              1 -> Player1
              _ -> Player2
            }

            PlayerButton(player:, button:)
          }
          True -> SystemButton(button)
        }

        dispatch(to_msg(event))
      })

    Nil
  })
}