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

public class ImageSlider : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{
    public List<RectTransform> images; // 所有图片的 RectTransform
    GraphicRaycaster raycaster;

    public int currentIndex = 0;       // 当前居中图片索引

    float largeSpacing = 1000f;       // 图片之间的水平间距
    float smallSpacing = 800f;        // 图片之间的水平间距
    float sideScale = 1.0f;     // 侧边图片的缩放比例
    float sideRotation = 60f;   // 侧边图片的倾斜角度

    private Vector2 dragStartPos;
    private bool isDragging = false;

    private Dictionary<RectTransform, Sprite> originalSprites = new Dictionary<RectTransform, Sprite>();

    void Start()
    {
        raycaster = GetComponentInParent<Canvas>().GetComponent<GraphicRaycaster>();
        foreach (var img in images)
        {
            var imageComp = img.GetComponent<Image>();
            if (imageComp != null)
            {
                originalSprites[img] = imageComp.sprite; // 缓存原始图像
            }
        }
        UpdateLayout(true);

    }

    public void OnBeginDrag(PointerEventData eventData)
    {
        // Debug.Log("开始拖动");
        dragStartPos = eventData.position;
        isDragging = true;
    }

    public void OnEndDrag(PointerEventData eventData)
    {
        // Debug.Log("结束拖动");
        isDragging = false;
        float dragDelta = eventData.position.x - dragStartPos.x;

        if (Mathf.Abs(dragDelta) > 100f) // 你可以根据需要调整阈值
        {
            if (dragDelta > 0)
                SlideLeft();
            else
                SlideRight();
        }
    }


    public void SlideLeft()
    {
        currentIndex = (currentIndex - 1 + images.Count) % images.Count; // 循环索引
        UpdateLayout();
    }

    public void SlideRight()
    {
        currentIndex = (currentIndex + 1) % images.Count; // 循环索引
        UpdateLayout();
    }

    // 用于处理循环偏移
    int GetWrappedOffset(int index, int center, int count)
    {
        int offset = index - center;
        if (offset > count / 2)
            offset -= count;
        else if (offset < -count / 2)
            offset += count;
        return offset;
    }

    void ReplaceCenterImage(RectTransform img)
    {
        Image imageComp = img.GetComponent<Image>();
        if (imageComp == null) return;

        string name = img.name;

        // 加载新的图像（可以放在 Resources 文件夹中）
        Sprite newSprite = Resources.Load<Sprite>("CenterImages/" + name);
        if (newSprite != null)
        {
            imageComp.sprite = newSprite;
        }
        else
        {
            Debug.LogWarning("找不到对应的中心图像: " + name);
        }
    }

    void RestoreOriginalImage(RectTransform img)
    {
        Image imageComp = img.GetComponent<Image>();
        if (imageComp == null) return;

        if (originalSprites.ContainsKey(img))
        {
            imageComp.sprite = originalSprites[img];
        }
    }

    void UpdateLayout(bool instant = false)
    {
        for (int i = 0; i < images.Count; i++)
        {
            var img = images[i];

            // int offset = i - currentIndex;
            int offset = GetWrappedOffset(i, currentIndex, images.Count);
            if (Mathf.Abs(offset) > 2)
            {
                img.gameObject.SetActive(false);
                continue;
            }
            else
            {
                img.gameObject.SetActive(true);
            }

            // 判断是否是中心图
            if (offset == 0)
            {
                ReplaceCenterImage(img);
            }
            else
            {
                RestoreOriginalImage(img);
            }

            float spacing = (Mathf.Abs(offset) == 1) ? largeSpacing : smallSpacing;
            float posX = offset * spacing;
            float posZ = Mathf.Abs(offset) * 500f;
            Vector3 targetPos = new Vector3(posX, 0, posZ);

            float alpha = 1.0f;


            // Vector3 targetPos = new Vector3(offset * spacing, 0, 0);
            // Vector3 targetPos = new Vector3(offset * spacing, 0, Mathf.Abs(offset) * 200f); // 加入Z轴位移

            Vector3 targetScale = new Vector3(1f, 1f, 1f) * sideScale;
            Vector3 targetRotation = Vector3.zero;

            if (offset < 0)
            {
                // targetScale = Vector3.one * sideScale;
                targetRotation = new Vector3(0, -sideRotation, 0);
            }
            else if (offset > 0)
            {
                // targetScale = Vector3.one * sideScale;
                targetRotation = new Vector3(0, sideRotation, 0);
            }

            if (Mathf.Abs(offset) > 1)
            {
                img.GetComponent<Image>().DOFade(alpha, 0.5f);
            }

            if (instant)
            {
                img.anchoredPosition3D = targetPos;
                img.localScale = targetScale;
                img.localRotation = Quaternion.Euler(targetRotation);
                img.GetComponent<Image>().color = new Color(1, 1, 1, alpha);
            }
            else
            {
                img.DOAnchorPos3D(targetPos, 0.5f).SetEase(Ease.OutExpo);
                img.DOScale(targetScale, 0.8f).SetEase(Ease.OutExpo);
                img.DOLocalRotate(targetRotation, 0.5f).SetEase(Ease.OutExpo);

            }

            // img.SetSiblingIndex(images.Count - Mathf.Abs(offset)); 
            // 让中间图最高层，左右两边根据距离决定层级
            int sortingOrder = 100 - Mathf.Abs(offset) * 10;
            img.SetSiblingIndex(sortingOrder);

            List<(RectTransform img, int offsetx)> sorted = new();

            for (int j = 0; j < images.Count; j++)
            {
                int offsetx = GetWrappedOffset(j, currentIndex, images.Count);
                sorted.Add((images[j], offsetx));
            }

            // 按 offset 的绝对值升序排序，中心的图在最上
            sorted.Sort((a, b) => Mathf.Abs(b.offsetx).CompareTo(Mathf.Abs(a.offsetx)));

            for (int k = 0; k < sorted.Count; k++)
            {
                sorted[k].img.SetSiblingIndex(k);
            }
        }
    }

    public void OnDrag(PointerEventData eventData)
    {

    }

    void Update()
    {
        if (Input.GetMouseButtonDown(0))
        {
            dragStartPos = Input.mousePosition;
            isDragging = false;
        }

        if (Input.GetMouseButtonUp(0))
        {
            float dragDistance = (Input.mousePosition - (Vector3)dragStartPos).magnitude;

            if (dragDistance > 50f)
            {
                isDragging = true; // 视为拖动
            }
            else
            {
                isDragging = false; // 视为点击
            }

            if (!isDragging)
            {
                // 执行点击检测（只允许点击中心图）
                DetectClick();
            }
        }
    }

    void DetectClick()
    {
        PointerEventData pointerData = new PointerEventData(EventSystem.current);
        pointerData.position = Input.mousePosition;

        List<RaycastResult> results = new List<RaycastResult>();
        raycaster.Raycast(pointerData, results);

        if (results.Count > 0)
        {
            GameObject clicked = results[0].gameObject;
            Debug.Log("🖱️ 点击了: " + clicked.name);

            // 判断是否是当前居中的图像
            if (clicked == images[currentIndex].gameObject)
            {

                // 判断是否是指定区域
                string name = clicked.name;
                if (name == "杭州市淳安县" ||
                    name == "湖州市安吉县" ||
                    name == "湖州市长兴县" ||
                    name == "金华浦江县金狮湖" ||
                    name == "金华浦江县三江口湿地" ||
                    name == "金华义乌市水系统" ||
                    name == "宁波市三江口" ||
                    name == "宁波象山县" ||
                    name == "宁波月湖整治" ||
                    name == "绍兴诸暨市浦阳江" ||
                    name == "温州市龙湾区")
                {
                    // InPanel inpanel = UIManager.Instance.ShowPanel<InPanel>();
                    // inpanel.setImage(clicked.name);
                    // UIManager.Instance.HidePanel<MainPanel>();
                }
            }
            else
            {
                Debug.Log("点击了非中心图，不响应点击");
            }
        }
    }
}