using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;

public class ParticleGroupView : MonoBehaviour
{
    [SerializeField] private Text displayName;
    [SerializeField] private List<ParticleSystem> _targets = new();
    [SerializeField] private Dictionary<ParticleSystem, GameObject> _childParticleSaver = new();
    [SerializeField] private int _currentIndex;

    [SerializeField] private Canvas _canvas;
    [SerializeField] private RectTransform _uiParent;

    private void OnValidate()
    {
        if (Application.isEditor)
        {
            _targets = new List<ParticleSystem>();
            _childParticleSaver = new Dictionary<ParticleSystem, GameObject>();

            int count = transform.childCount;

            for (int i = 0; i < count; i++)
            {
                Transform child = transform.GetChild(i);
                ParticleSystem ps = child.GetComponent<ParticleSystem>();

                if (ps != null)
                {
                    _targets.Add(ps);
                }
                else
                {
                    bool loopBreak = false;
                    for (int inner = 0; inner < child.childCount; inner++)
                    {
                        Transform nextChild = child.GetChild(inner);
                        ps = nextChild.GetComponent<ParticleSystem>();

                        if (ps != null)
                        {
                            _targets.Add(ps);
                            _childParticleSaver.Add(ps, child.gameObject);
                            break;
                        }
                        else
                        {
                            for (int tail = 0; tail < nextChild.childCount; tail++)
                            {
                                Transform last = nextChild.GetChild(tail);
                                ps = last.GetComponent<ParticleSystem>();
                                if (ps != null)
                                {
                                    _targets.Add(ps);
                                    _childParticleSaver.Add(ps, child.gameObject);
                                    loopBreak = true;
                                    break;
                                }
                            }

                            if (loopBreak) break;
                        }
                    }
                }
            }
        }

        if (_canvas == null)
        {
            GameObject canvasObject = new GameObject("UI Main Canvas");
            _canvas = canvasObject.AddComponent<Canvas>();
            _canvas.renderMode = RenderMode.ScreenSpaceOverlay;
            canvasObject.AddComponent<CanvasScaler>();
            canvasObject.AddComponent<GraphicRaycaster>();
        }

        if (_uiParent == null)
        {
            GameObject parent = new GameObject("UI Items", typeof(RectTransform));
            parent.transform.SetParent(_canvas.transform);
            _uiParent = parent.transform as RectTransform;
            _uiParent.localScale = Vector3.one;
            _uiParent.anchorMin = Vector3.zero;
            _uiParent.anchorMax = Vector3.one;
            _uiParent.offsetMin = Vector3.zero;
            _uiParent.offsetMax = Vector3.zero;
        }

        if (displayName == null)
        {
            GameObject textViewer = new GameObject("Text Viewer");
            textViewer.transform.SetParent(_uiParent.transform);
            Text text = textViewer.AddComponent<Text>();
            text.rectTransform.anchorMin = new Vector2(0, 1);
            text.rectTransform.anchorMax = new Vector2(1, 1);
            text.rectTransform.pivot = new Vector2(0.5f, 1);
            text.rectTransform.anchoredPosition = new Vector3(0, -50);
            text.fontSize = 55;
            text.alignment = TextAnchor.MiddleCenter;
            displayName = text;
        }

        if (FindObjectOfType<EventSystem>() == null)
        {
            GameObject eventSystem = new GameObject("Event System");
            eventSystem.AddComponent<EventSystem>();
            eventSystem.AddComponent<StandaloneInputModule>();
        }
    }

    private void Start()
    {
        _currentIndex = 0;
        CleanupDestroyedTargets();

        foreach (var particle in _targets)
        {
            if (particle != null)
                particle.gameObject.SetActive(false);
        }

        if (_targets.Count > 0 && _targets[_currentIndex] != null)
        {
            _targets[_currentIndex].gameObject.SetActive(true);
            _targets[_currentIndex].Play(true);
            UpdateDisplayParticleName();
        }
    }

    private void CleanupDestroyedTargets()
    {
        _targets.RemoveAll(p => p == null);
    }

    private void UpdateDisplayParticleName()
    {
        if (displayName != null && _targets.Count > 0 && _targets[_currentIndex] != null)
        {
            displayName.text = _targets[_currentIndex].name;
        }
    }

    private void Update()
    {
        if (_targets == null || _targets.Count == 0) return;

        // 🔹 혹시 Destroy된 ParticleSystem이 리스트에 남아 있다면 제거
        CleanupDestroyedTargets();
        if (_targets.Count == 0) return;

        // ← 방향
        if (Input.GetKeyDown(KeyCode.LeftArrow))
        {
            SwitchParticle(-1);
        }

        // → 방향
        if (Input.GetKeyDown(KeyCode.RightArrow))
        {
            SwitchParticle(1);
        }

        // 스페이스 재생
        if (Input.GetKeyDown(KeyCode.Space))
        {
            var particle = _targets[_currentIndex];
            if (particle != null)
            {
                particle.Simulate(0, true, true);
                particle.Play(true);
            }
        }
    }

    private void SwitchParticle(int direction)
    {
        if (_targets.Count == 0) return;

        var current = _targets[_currentIndex];
        if (current != null)
        {
            if (_childParticleSaver.TryGetValue(current, out var prevParent) && prevParent != null)
                prevParent.SetActive(false);

            current.gameObject.SetActive(false);
        }

        _currentIndex = (_currentIndex + direction + _targets.Count) % _targets.Count;

        var next = _targets[_currentIndex];
        if (next != null)
        {
            if (_childParticleSaver.TryGetValue(next, out var currentParent) && currentParent != null)
                currentParent.SetActive(true);

            next.gameObject.SetActive(true);
            next.Play(true);
            UpdateDisplayParticleName();
        }
    }
}