BLOODJOE/Assets/Scripts/Managers/PlayerJoiner.cs

using System.Collections.Generic;
using State;
using State.GameStateMachine;
using State.PlayerStateMachine;
using UnityEngine;
using UnityEngine.InputSystem;
using UnityEngine.InputSystem.UI;

namespace Managers
{
    public class PlayerJoiner : MonoBehaviour
    {
        [SerializeField] private GameStateMachine stateMachine;
        [SerializeField] private PlayerInputManager playerInputManager;
        [SerializeField] private InputSystemUIInputModule uiModule;
        [SerializeField] private GameObject[] characterPrefabs = new GameObject[2];


        private readonly List<PlayerInput> _players = new();
        private PlayerInput _currentUIOwner;

        private void OnEnable()
        {
            playerInputManager.onPlayerJoined += HandlePlayerJoined;
            playerInputManager.onPlayerLeft += HandlePlayerLeft;
            stateMachine.OnStateChange += HandleStateChanged;
        }

        private void OnDisable()
        {
            playerInputManager.onPlayerJoined -= HandlePlayerJoined;
            playerInputManager.onPlayerLeft -= HandlePlayerLeft;
            stateMachine.OnStateChange -= HandleStateChanged;
        }

        private void HandleStateChanged(GameState newState)
        {
            switch (newState)
            {
                case MainMenu:
                    EnableUIFor(null);
                    break;
                case PlayLevel:
                    EnableActionMaps(true);
                    break;
                case Paused:
                    break;
                default:
                    break;
            }
        }

        private void HandlePlayerJoined(PlayerInput playerInput)
        {
            Debug.Log("Player joined!");
            _players.Add(playerInput);
            
            // TODO:  Move all of this to a player spawner
            var character = Instantiate(characterPrefabs[_players.Count - 1]);
            var playerStateMachine = playerInput.gameObject.GetComponent<PlayerStateMachine>();
            playerStateMachine.controlledPawn = character.GetComponent<Pawn>();
            playerInput.actions.Enable();
        }
        
        private void HandlePlayerLeft(PlayerInput playerInput)
        {
            _players.Remove(playerInput);
            if(_currentUIOwner == playerInput) _currentUIOwner = null;
        }
        
        private void EnableUIFor(PlayerInput owner)
        {
            _currentUIOwner = owner;
            var asset = uiModule.actionsAsset;
            if (owner == null)
            {
                asset.devices = null;                // any device can drive UI (boot)
                asset.bindingMask = null;
            }
            else
            {
                asset.devices = owner.devices;       // owner's paired devices only
                asset.bindingMask = InputBinding.MaskByGroup(owner.currentControlScheme);
            }

            // Ensure UI actions are enabled
            asset.FindActionMap("UI", true).Enable();
        }
        
        private void EnableActionMaps(bool gameplayEnabled)
        {
            foreach (var p in _players)
            {
                if (gameplayEnabled)
                {
                    p.ActivateInput();
                    if (p.currentActionMap?.name != "Player")
                        p.SwitchCurrentActionMap("Player");
                }
                else
                {
                    p.DeactivateInput(); // disables player actions, keeps device pairing
                }
            }
        }
        
        private void ReleaseUIFocus()
        {
            var asset = uiModule.actionsAsset;
            asset.devices = null;
            asset.bindingMask = null;
            _currentUIOwner = null;
        }

        // Called by UI Button (Resume) or router "Back" when paused.
        public void ResumeFromPause()
        {
            stateMachine.ChangeState(new PlayLevel());
        }
    }
}