using System;
using State;
using State.Game;
using UnityEngine;

namespace Management
{
    /// <summary>
    /// Bootstrap is the first user added object that should be run.
    /// It should be added to a game object in the Bootstrap scene, which should be the first
    /// scene loaded when the game starts.
    ///
    /// Bootstrap initializes the game state machine, and starts it based on
    /// the value of "Start Type" selected in the Inspector.
    /// </summary>
    public class Bootstrap : MonoBehaviour
    {
        // Hold a static reference to this instance so we can enforce singleton
        private static Bootstrap _instance;
        
        // Determines what state the configure state machine will start in
        private enum StartType
        {
            Splash,
            MainMenu,
            StartGame,
            Game
        }

        [SerializeField]  private StartType startType = StartType.Splash;
        [SerializeField] private Machine gameStateMachine;
        
        private void Awake()
        {
            // enforce singleton
            if (_instance != null && _instance != this)
            {
                Destroy(gameObject);
                return;
            }
            
            // if we got this far, this object didn't exist, set the static instance to this and continue normally.
            _instance = this;
            
            // ensure object survives scene loads
            DontDestroyOnLoad(gameObject);
        }

        private void Start()
        {
            // exit game early if we're misconfigured.
            if (gameStateMachine == null)
            {
                Debug.LogError("no state machine for bootstrap");
                #if UNITY_EDITOR
                UnityEditor.EditorApplication.isPlaying = false;
                #else
                Application.Quit();
                #endif
                return;
            }
            
            // determine what state to start machine in.  Useful for quick testing.
            // Should be "Splash" for release.
            switch (startType)
            {
                case StartType.Splash:
                case StartType.StartGame:
                    gameStateMachine.ChangeState(new StartGameState());
                    break;
                case StartType.Game:
                    gameStateMachine.ChangeState(new GameRunningState());
                    break;
                case StartType.MainMenu:
                default:
                    gameStateMachine.ChangeState(new MainMenuState());
                    break;
            }
        }
    }
}