/*
* author: mark joshwel
* date: 29/5/2024
* description: game manager singleton for single source of truth state management
*/
using UnityEngine;
///
/// singleton class for managing the game state as a single source of truth
///
public class GameManager : MonoBehaviour
{
///
/// enum for available menus in the game, for use with ShowMenu()
///
public enum DisplayState
{
Game,
ScreenMainMenu,
ScreenOptionsMenu,
ScreenCreditsMenu,
ScreenPauseMenu,
ScreenCaughtPause,
ScreenEscapedMenu,
UnassociatedState
}
///
/// singleton pattern: define instance field for accessing the singleton elsewhere
///
public static GameManager Instance;
///
/// the current state of the game
///
private DisplayState _state = DisplayState.UnassociatedState;
///
/// property to check if the game is paused based on the current DisplayState
///
// TODO: remove this if not needed
public bool Paused => _state != DisplayState.Game;
///
/// function to set don't destroy on load and check for multiple instances
///
private void Awake()
{
// check if instance hasn't been set yet
if (Instance == null)
{
// set this instance as the singleton instance
Instance = this;
// don't destroy this instance on scene load
DontDestroyOnLoad(gameObject);
Debug.Log("GameManager: Awake as singleton instance");
}
// check if instance is already set and it's not this instance
else if (Instance != null && Instance != this)
{
Debug.Log("GameManager: Awake as non-singleton instance, destroying self");
// destroy the new instance if it's not the singleton instance
Destroy(gameObject);
}
}
///
/// called when game starts, sets state to main menu
///
private void Start()
{
SetDisplayState(DisplayState.ScreenMainMenu);
}
///
/// helper function to hide any menu that is currently showing
///
private void HideMenuHelper()
{
// get all child menus in the "Menus" parent object
foreach (var menu in GameObject.FindGameObjectsWithTag("Menus"))
foreach (Transform menuChild in menu.transform)
{
// disable the menu
Debug.Log($"GameManager: HideMenuHelper - hiding menu '{menuChild}'");
menuChild.gameObject.SetActive(false);
}
}
///
/// helper function for SetDisplayState() to pause the game,
/// called before the incoming game state is set
///
/// the to-be-set state of the game
private void PauseGameHelper(DisplayState incomingState)
{
// if we're transitioning from a state of gameplay to a state of non-gameplay,
// then we should pause the game
if (_state == DisplayState.Game && incomingState != DisplayState.Game)
{
Debug.Log("GameManager: PauseGameHelper - actually pausing game");
Time.timeScale = 0f;
Cursor.lockState = CursorLockMode.None;
Cursor.visible = true;
}
// if the current and incoming states are the same, then we shouldn't do anything,
// so we return early
if (_state == incomingState)
{
Debug.Log("GameManager: PauseGameHelper - states are the same, returning early");
return;
}
// hide any menu that is currently showing
HideMenuHelper();
// get all child menus in the "Menus" parent object
foreach (var menuParent in GameObject.FindGameObjectsWithTag("Menus"))
foreach (Transform menu in menuParent.transform)
{
// show the menu based on the incoming state
// get the associated state of the menu
var associatedState = menu.gameObject.GetComponent().associatedState;
Debug.Log(
$"GameManager: PauseGameHelper - found menu '{menu}' "
+ $"with associated state {associatedState} "
+ $"against incoming state {incomingState}");
// guard clause if the menu isn't what we're looking for
if (associatedState != incomingState)
continue;
// if the associated state is the same as the incoming state, then show the menu
Debug.Log($"GameManager: PauseGameHelper - showing menu for {incomingState}");
menu.gameObject.SetActive(true);
}
}
///
/// helper function for SetDisplayState() to resume the game,
/// called before the incoming game state is set
///
/// the to-be-set state of the game
private void ResumeGameHelper(DisplayState incomingState)
{
// if we're NOT transitioning from a state of non-gameplay to a state of gameplay,
// (which means currently we are in a state of gameplay),
// then we shouldn't do anything, because the game is already running,
// so we return early
if (_state == DisplayState.Game || incomingState != DisplayState.Game)
{
Debug.Log(
"GameManager: ResumeGameHelper - returning prematurely as" +
$" _state={_state} and incomingState={incomingState}");
return;
}
// else, we should resume the game
Time.timeScale = 1f;
Cursor.lockState = CursorLockMode.Locked;
Cursor.visible = false;
// hide any menu that is currently showing
HideMenuHelper();
}
///
/// function to show a menu based on the enum passed,
/// and any other necessary actions
///
/// the game menu to show
public void SetDisplayState(DisplayState displayState)
{
// check if the game is paused or not
if (displayState == DisplayState.Game)
{
Debug.Log($"GameManager: SetDisplayState({displayState}) - resuming game");
ResumeGameHelper(displayState);
}
else
{
Debug.Log($"GameManager: SetDisplayState({displayState}) - pausing game");
PauseGameHelper(displayState);
}
// set the state of the game to the incoming state
_state = displayState;
// post-state change actions case switch
switch (displayState)
{
// if we're transitioning to the game state,
// change camera to the player camera
case DisplayState.Game:
// TODO: change camera to player camera
return;
// if we're transitioning to the main menu state,
// change camera to the main menu camera
case DisplayState.ScreenMainMenu:
// TODO: change camera to main menu camera
return;
}
}
///
/// wrapper function to quit the game
/// in case of any cleanup needed
///
public void Quit()
{
// quit the application
Application.Quit();
}
///
/// resets game state and starts a new game, will call SetDisplayState()
///
public void NewGame()
{
// set to game state
SetDisplayState(DisplayState.Game);
// TODO
}
}