beyond/Assets/Scripts/UI/Menu/MainMenu.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using PixelCrushers;
using TMPro;
using UnityEngine;
using UnityEngine.SceneManagement;
using UnityEngine.UI;

namespace Beyond
{
    public class MainMenu : MonoBehaviour
    {
        private enum State
        { MAIN_MENU, NEW_GAME, LOAD_GAME, LOADING_SCENE, DIFFICULTY };

        private State m_state = State.MAIN_MENU;
        public GameObject m_mainButtons;
        public GameObject m_newGamePage;
        public GameObject m_slotSelector;
        public GameObject m_loadingScreen;
        public GameObject m_loadGameButton;
        public GameObject m_continueGameButton;
        public GameObject m_difficultyPage;

        public Animator m_doorAnimator;
        public Animator m_cameraAnimator;

        public Button[] m_difficultyButtons;

        public float m_cameraDoorTime = 3f;

        // Start is called before the first frame update
        private void Start()
        {
            SetState(State.MAIN_MENU);
            GameStateManager.Instance.SetDifficulty((GameStateManager.Difficulty)SaveUtility.Instance.GetCurrentDifficulty());
        }

        public void OnNewGameButton()
        {
            SetState(State.NEW_GAME);
        }

        public void OnLoadGameButton()
        {
            SetState(State.LOAD_GAME);
        }

        private void SetState(State state)
        {
            switch (state)
            {
                case State.MAIN_MENU:
                    OnMainMenu();
                    break;

                case State.NEW_GAME:
                    OnNewGame();
                    break;

                case State.LOAD_GAME:
                    OnLoadGame();
                    break;

                case State.LOADING_SCENE:
                    m_mainButtons.SetActive(false);
                    m_newGamePage.SetActive(false);
                    m_loadingScreen.SetActive(true);
                    break;

                case State.DIFFICULTY:
                    OnDifficulty(SaveUtility.Instance.GetCurrentDifficulty());
                    m_difficultyPage.SetActive(true);
                    m_mainButtons.SetActive(false);
                    break;
            }
        }

        private IEnumerator LoadSceneCooroutine(int sceneNum)
        {
            // The Application loads the Scene in the background as the current Scene runs.
            // This is particularly good for creating loading screens.
            // You could also load the Scene by using sceneBuildIndex. In this case Scene2 has
            // a sceneBuildIndex of 1 as shown in Build Settings.
            //yield return new WaitForSeconds(1f);
            AsyncOperation asyncLoad = SceneManager.LoadSceneAsync(sceneNum);
            asyncLoad.allowSceneActivation = false;
            // Wait until the asynchronous scene fully loads
            while (!asyncLoad.isDone)
            {
                //m_bar.transform.localScale = new Vector3(asyncLoad.progress, 0.9f, 1);
                if (asyncLoad.progress >= 0.9f)
                {
                    //m_bar.transform.localScale = new Vector3(0.9f, 0.9f, 1);
                    asyncLoad.allowSceneActivation = true;
                }
                yield return null;
            }
            //m_bar.transform.localScale = new Vector3(1.0f, 0.9f, 1);
            yield return null;
        }

        private void OnMainMenu()
        {
            m_mainButtons.SetActive(true);
            m_newGamePage.SetActive(false);
            m_loadingScreen.SetActive(false);
            m_difficultyPage.SetActive(false);
            bool hasSaves = false;
            for (int i = 0; i < m_slotSelector.transform.childCount; i++)
            {
                if (SaveSystem.HasSavedGameInSlot(i))
                {
                    hasSaves = true;
                    break;
                }
            }
            m_loadGameButton.SetActive(hasSaves);
            m_continueGameButton.SetActive(hasSaves && SaveUtility.Instance.GetCurrentSlot() >= 0);
        }

        private void NewGameInSlot(int slot)
        {
            SaveUtility.Instance.SetCurrentSlot(slot);
            GameStateManager.Instance.SetDifficulty((GameStateManager.Difficulty)SaveUtility.Instance.GetCurrentDifficulty());
            //SceneManager.LoadScene(1);
            ProxySceneLoader.LoadScene($"index:{1}");
        }

        private void OnNewGameSlotSelected(int num)
        {
            Debug.Log("OnNewGameSlot "+num);
            if (SaveSystem.HasSavedGameInSlot(num))
            {
                ModalPopup.Instance.Show(yes =>
                {
                    if (yes)
                    {
                        SaveSystem.DeleteSavedGameInSlot(num);
                        //NewGameInSlot(num);
                        StartCoroutine(StartScene(NewGameInSlot, num));
                    }
                });
            }
            else
            {
                //NewGameInSlot(num);
                StartCoroutine(StartScene(NewGameInSlot, num));
            }
        }

        private delegate void startSceneCallback(int num);

        private IEnumerator StartScene(startSceneCallback callback, int num)
        {
            if (m_cameraAnimator != null)
            {
                m_cameraAnimator.SetTrigger("Door");
            }

            yield return new WaitForSeconds(m_cameraDoorTime);
            callback(num);
            yield return null;
        }

        private void OnLoadGameSlotSelected(int num)
        {
            Debug.Log("OnLoadGameSlot " + num);
            if (SaveSystem.HasSavedGameInSlot(num))
            {
                SaveUtility.Instance.SetCurrentSlot(num);
                //SaveSystem.LoadFromSlot(num);
                StartCoroutine(StartScene(SaveSystem.LoadFromSlot, num));
            }
            else
            {
                //NewGameInSlot(num);
            }
        }

        private void OnDifficulty(int difficulty)
        {
            for (int i = 0; i < (int)GameStateManager.Difficulty.COUNT; i++)
            {
                var txt = m_difficultyButtons[i].GetComponentInChildren<TextMeshProUGUI>();
                txt.color = i == difficulty ? Color.white : Color.gray;
                /*
                var colors = m_difficultyButtons[i].colors;
                colors.normalColor = i == difficulty ? Color.white : Color.gray;
                m_difficultyButtons[i].colors = colors;
                */
            }
        }

        public void OnDifficultySelected(int difficulty)
        {
            OnMainMenu();
            OnDifficulty(difficulty);
            SaveUtility.Instance.SetCurrentDifficulty(difficulty);
            GameStateManager.Instance.SetDifficulty((GameStateManager.Difficulty)difficulty);
        }

        public void OnDifficulty()
        {
            SetState(State.DIFFICULTY);
        }

        public void OnContinue()
        {
            int id = SaveUtility.Instance.GetCurrentSlot();
            if (id < 0)
            {
                Debug.LogError("SaveGame error: slot id < 0");
                return;
            }
            //SaveSystem.LoadFromSlot(id);
            if (m_doorAnimator)
            {
                m_doorAnimator.Play("Open");
            }
            StartCoroutine(StartScene(SaveSystem.LoadFromSlot, id));
        }

        public void OnPlayTrailer()
        {
            VideoCutsceneController.Instance.PlayVideo();
        }

        public void OnBackButton()
        {
            if (m_doorAnimator)
            {
                m_doorAnimator.Play("Close");
            }
            SetState(State.MAIN_MENU);
        }

        private void OnNewGame()
        {
            if (m_doorAnimator)
            {
                m_doorAnimator.Play("Open");
            }

            m_mainButtons.SetActive(false);
            m_newGamePage.SetActive(true);
            for (int i = 0; i < m_slotSelector.transform.childCount; i++)
            {
                var slot = m_slotSelector.transform.GetChild(i).gameObject;
                //Destroy(m_slotSelector.transform.GetChild(i).gameObject);
                var slotTxt = slot.GetComponentInChildren<TextMeshProUGUI>();
                var slotButton = slot.GetComponentInChildren<Button>();
                if (SaveSystem.HasSavedGameInSlot(i))
                {
                    string s = SaveUtility.Instance.GetSlotDesc(i);
                    if (String.IsNullOrEmpty(s))
                        s = "Unknown";
                    slotTxt.text = s;
                }
                int id = i;
                slotButton.onClick.AddListener(() =>
                {
                    OnNewGameSlotSelected(id);
                });
            }
        }

        private void OnLoadGame()
        {
            if (m_doorAnimator)
            {
                m_doorAnimator.Play("Open");
            }
            m_mainButtons.SetActive(false);
            m_newGamePage.SetActive(true);
            for (int i = 0; i < m_slotSelector.transform.childCount; i++)
            {
                var slot = m_slotSelector.transform.GetChild(i).gameObject;
                //Destroy(m_slotSelector.transform.GetChild(i).gameObject);
                var slotTxt = slot.GetComponentInChildren<TextMeshProUGUI>();
                var slotButton = slot.GetComponentInChildren<Button>();
                if (SaveSystem.HasSavedGameInSlot(i))
                {
                    string s = SaveUtility.Instance.GetSlotDesc(i);
                    if (String.IsNullOrEmpty(s))
                        s = "Unknown";
                    slotTxt.text = s;
                    slotButton.interactable = true;
                }
                else
                {
                    slotButton.interactable = false;
                }
                int id = i;
                slotButton.onClick.AddListener(() =>
                {
                    OnLoadGameSlotSelected(id);
                });
            }
        }

        // Update is called once per frame
        private void Update()
        {
        }
    }
}