using System.Collections;
using System.Collections.Generic;
using AibisDream.Framework;
using UnityEngine;
using UnityEngine.UI;

namespace AibisDream
{
    public class CursorManager : MonoBehaviour
    {
        private const float DelayTime = 0.2f;

        [Header("指针图片")] public Sprite defaultCursor;
        public Sprite nextTalk, talking, option, interactive, holding, disable, eye;

        private Image _cursor;
        private RectTransform _cursorCanvas;

        #region 状态相关

        private Coroutine _switchCoroutine;
        private CursorState _curState = CursorState.Default;

        #endregion

        // 卸载时注销事件
        private List<IUnRegister> _unRegisters = new();

        public void Awake()
        {
            InitRefs();
            InitCursor();
        }

        private void InitCursor()
        {
            Cursor.visible = false;
            SwitchCursor(defaultCursor);
        }

        private void OnEnable()
        {
            RegisterEvent();
        }

        private void OnDisable()
        {
            // 注销所有事件
            foreach (var eventUnRegister in _unRegisters)
            {
                eventUnRegister.UnRegister();
            }

            _unRegisters.Clear();
        }

        private void InitRefs()
        {
            _cursor = transform.Find("Cursor").GetComponent<Image>();
            _cursorCanvas = GetComponent<RectTransform>();
        }

        private void RegisterEvent()
        {
            // 此处监听所有可能对鼠标状态产生影响的事件
            // 对话相关
            _unRegisters.Add(EnumEventSystem.Global.Register<DialogEventEnum, DialogLine>(DialogEventEnum.LineStart,
                _ => SwitchCursor(talking)));
            _unRegisters.Add(EnumEventSystem.Global.Register(DialogEventEnum.LineShowed, () => SwitchCursor(nextTalk)));
            _unRegisters.Add(EnumEventSystem.Global.Register(DialogEventEnum.LineEnd,
                () => SwitchCursorDelay(defaultCursor)));
            _unRegisters.Add(EnumEventSystem.Global.Register(DialogEventEnum.OptionShow, () => SwitchCursor(option)));
            _unRegisters.Add(
                EnumEventSystem.Global.Register<DialogEventEnum, DialogLine>(DialogEventEnum.OptionSelected,
                    _ => SwitchCursorDelay(defaultCursor)));

            // 交互相关
            _unRegisters.Add(EnumEventSystem.Global.Register(InteractionEventEnum.Start, OnInteractiveStart));
            _unRegisters.Add(EnumEventSystem.Global.Register(InteractionEventEnum.End, OnInteractiveEnd));
        }

        private void LateUpdate()
        {
            // 将虚拟指针与鼠标位置同步
            RectTransformUtility.ScreenPointToLocalPointInRectangle(_cursorCanvas, Input.mousePosition,
                CameraKit.Instance.uiCamera, out var worldPos);

            _cursor.rectTransform.localPosition = worldPos;

            // 在输入状态，要单独处理
        }

        #region 交互状态相关

        private void OnInteractiveStart()
        {
            _curState = CursorState.Interactive;
        }

        private void OnInteractiveEnd()
        {
            _curState = CursorState.Interactive;
        }

        #endregion

        #region 指针切换

        /// <summary>
        /// 直接切指针
        /// </summary>
        /// <param name="sprite">指针图片</param>
        private void SwitchCursor(Sprite sprite)
        {
            StopDelayCursor();
            _cursor.sprite = sprite;
        }

        /// <summary>
        /// 延迟切换指针。如果后面有其他切换状态，就直接打断
        /// </summary>
        /// <param name="sprite">指针图片</param>
        private void SwitchCursorDelay(Sprite sprite)
        {
            StopDelayCursor();
            _switchCoroutine = StartCoroutine(SwitchCursorAsync(sprite));
        }

        private IEnumerator SwitchCursorAsync(Sprite sprite)
        {
            yield return new WaitForSeconds(DelayTime);
            _cursor.sprite = sprite;
        }

        private void StopDelayCursor()
        {
            if (_switchCoroutine != null)
            {
                StopCoroutine(_switchCoroutine);
                _switchCoroutine = null;
            }
        }

        #endregion
    }

    public enum CursorState
    {
        Default,
        Interactive,
        Eye
    }
}