Application Main Manager

AppManager.cs

using System.Collections;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using UnityEngine;
using UnityEngine.Events;
using UnityEngine.SceneManagement;

namespace BrkLib.Scripts.Core {
    [SuppressMessage("ReSharper", "UseNullPropagation")]
    public class AppManager : SingletonMonoBehaviour<AppManager> {
        [SerializeField]
        private float _defaultTimeScale = 1f;

        [Range(0, 10)]
        [SerializeField]
        private float _timeScale = 1f;

        [SerializeField]
        private string _defaultScenePath;

        private List<IOnAppLaunch> _onAppLaunchLst = new List<IOnAppLaunch>();
        private List<IOnAppQuit> _onAppQuitLst = new List<IOnAppQuit>();
        private List<IOnAppPaused> _onAppPauseLst = new List<IOnAppPaused>();

        private void Start() {
            // Load the default scene
            StartCoroutine(ExecuteLauncherCallback());
        }

        protected virtual IEnumerator ExecuteLauncherCallback() {
            yield return new WaitForEndOfFrame();
            foreach (var launcher in _onAppLaunchLst) {
                if (launcher != null) {
                    launcher.OnAppLaunch();
                }
            }
        }

        private void Update() {
            if (!Mathf.Approximately(Time.timeScale, _timeScale)) {
                Time.timeScale = _timeScale;
            }
        }

        private void OnApplicationQuit() {
            foreach (var quit in _onAppQuitLst) {
                if (quit != null) {
                    quit.OnAppQuit();
                }
            }

            // Clean up quit list
            _onAppQuitLst = _onAppQuitLst.Where(x => x != null).ToList();
        }

        private void OnApplicationPause(bool pauseStatus) {
            foreach (var callback in _onAppPauseLst) {
                if (callback != null) {
                    callback.OnAppPaused(pauseStatus);
                }
            }

            // Clean up the null object
            _onAppLaunchLst = _onAppLaunchLst.Where(x => x != null).ToList();
        }

        #region Application public process
        /// <summary>
        /// Setting App time scale
        /// </summary>
        /// <param name="timeScale">Time scale value</param>
        public void SetUpAppTimeScale(float timeScale) {
            _timeScale = timeScale;
        }

        /// <summary>
        /// Reset app timescale
        /// </summary>
        public void ResetTimeScale() {
            Time.timeScale = _defaultTimeScale;
        }

        /// <summary>
        /// Add callback which will called when application finished load first frame
        /// </summary>
        public void AddOnAppLaunch(IOnAppLaunch onAppLaunch) {
            _onAppLaunchLst.Add(onAppLaunch);
        }

        /// <summary>
        /// Add callback which will called when application paused or resumed
        /// </summary>
        public void AddOnAppPaused(IOnAppPaused onAppPaused) {
            _onAppPauseLst.Add(onAppPaused);
        }

        /// <summary>
        /// Add callback which will called when application quited
        /// </summary>
        public void AddOnAppQuit(IOnAppQuit onAppQuit) {
            _onAppQuitLst.Add(onAppQuit);
        }
        #endregion
    }

    /// <summary>
    /// Interface that will be call when application launched.
    /// THIS INTERFACE SHOULD BE USE WITH THE SINGLETON OBJECT ONLY. THIS INTERFACE WILL BE CALL ONLY ONE TIME SINCE APP START
    /// (Best fit for the init process of singleton object)
    /// <seealso cref="AppManager.AddOnAppLaunch"/>
    /// </summary>
    public interface IOnAppLaunch {
        void OnAppLaunch();
    }

    /// <summary>
    /// Interface that will be call when application paused or resumed.
    /// <seealso cref="AppManager.AddOnAppPaused"/>
    /// </summary>
    public interface IOnAppPaused {
        void OnAppPaused(bool isPaused);
    }

    /// <summary>
    /// Interface that will be call before application completely quit. 
    /// <seealso cref="AppManager.AddOnAppQuit"/>
    /// </summary>
    public interface IOnAppQuit {
        void OnAppQuit();
    }
}