using UnityEngine;
using UnityEngine.UI;
using TMPro;

/// <summary>
/// Создаёт UI инвентаря программно с использованием TextMeshPro
/// </summary>
public class InventoryUIBuilder : MonoBehaviour
{
    [Header("Settings")]
    public int hotbarSlots = 9;
    public int inventoryRows = 4;
    public int inventoryCols = 9;

    [Header("Visual Settings")]
    public float slotSize = 50f;
    public float slotSpacing = 4f;
    public float inventoryPadding = 10f;
    public float hotbarPadding = 10f;

    [Header("Colors")]
    [SerializeField] private Color inventoryPanelColor = new Color(0.15f, 0.15f, 0.15f, 0.95f);
    [SerializeField] private Color hotbarPanelColor = new Color(0.1f, 0.1f, 0.1f, 0.9f);
    [SerializeField] private Color slotEmptyColor = new Color(0.25f, 0.25f, 0.25f, 0.8f);
    [SerializeField] private Color slotFilledColor = new Color(0.35f, 0.35f, 0.35f, 0.95f);

    [Header("Container References")]
    public RectTransform inventoryPanelRect;
    public RectTransform hotbarPanelRect;
    public Canvas inventoryCanvas;

    void Start()
    {
        // Проверяем, не запущен ли уже BuildInventoryUI
        if (InventoryManager.Instance != null &&
            InventoryManager.Instance.slots != null &&
            InventoryManager.Instance.slots.Length > 0)
        {
            Debug.Log("[InventoryUIBuilder] UI already built, skipping");
            return;
        }

        BuildInventoryUI();
    }

    public void BuildInventoryUI()
    {
        // Создаём или получаем Canvas
        var canvas = GetComponent<Canvas>();
        if (canvas == null)
        {
            canvas = gameObject.AddComponent<Canvas>();
            canvas.renderMode = RenderMode.ScreenSpaceOverlay;
            canvas.sortingOrder = 100;
            gameObject.AddComponent<GraphicRaycaster>();
        }
        inventoryCanvas = canvas;

        // Настраиваем EventSystem если нет
        if (FindObjectOfType<TMPro.TMP_InputField>() != null || FindObjectsOfType<TMPro.TextMeshProUGUI>().Length > 0)
        {
            // EventSystem уже есть
        }

        // Создаём панель инвентаря
        GameObject inventoryPanel = CreatePanel("InventoryPanel", transform, inventoryPanelColor);
        inventoryPanelRect = inventoryPanel.GetComponent<RectTransform>();

        float inventoryWidth = inventoryCols * (slotSize + slotSpacing) + inventoryPadding * 2;
        float inventoryHeight = inventoryRows * (slotSize + slotSpacing) + inventoryPadding * 2 + 40; // +40 для заголовка

        inventoryPanelRect.anchorMin = new Vector2(0.5f, 0.5f);
        inventoryPanelRect.anchorMax = new Vector2(0.5f, 0.5f);
        inventoryPanelRect.pivot = new Vector2(0.5f, 0.5f);
        inventoryPanelRect.anchoredPosition = Vector2.zero;
        inventoryPanelRect.sizeDelta = new Vector2(inventoryWidth, inventoryHeight);

        // Заголовок
        CreateTitle(inventoryPanel.transform, "Инвентарь", new Vector2(0, inventoryHeight / 2 - 20));

        // Сетка инвентаря (4x9 = 36 слотов)
        float gridHeight = inventoryRows * (slotSize + slotSpacing);
        var inventoryGrid = CreateGrid(
            inventoryPanel.transform,
            "InventoryGrid",
            inventoryCols,
            inventoryRows,
            slotSize,
            slotSpacing,
            new Vector2(inventoryPadding, inventoryPadding + 30)
        );
        InventoryManager.Instance.slots = CreateSlots(inventoryGrid, "InventorySlot_", 0, inventoryCols * inventoryRows);

        // Создаём хотбар
        GameObject hotbarPanel = CreatePanel("HotbarPanel", transform, hotbarPanelColor);
        hotbarPanelRect = hotbarPanel.GetComponent<RectTransform>();

        float hotbarWidth = hotbarSlots * (slotSize + slotSpacing) + hotbarPadding * 2;

        hotbarPanelRect.anchorMin = new Vector2(0.5f, 0f);
        hotbarPanelRect.anchorMax = new Vector2(0.5f, 0f);
        hotbarPanelRect.pivot = new Vector2(0.5f, 0f);
        hotbarPanelRect.anchoredPosition = new Vector2(0, 15);
        hotbarPanelRect.sizeDelta = new Vector2(hotbarWidth, slotSize + hotbarPadding * 2);

        var hotbarGrid = CreateGrid(
            hotbarPanel.transform,
            "HotbarGrid",
            hotbarSlots,
            1,
            slotSize,
            slotSpacing,
            new Vector2(hotbarPadding, hotbarPadding)
        );
        InventoryManager.Instance.hotbarSlots = CreateSlots(hotbarGrid, "HotbarSlot_", 0, hotbarSlots);

        // Настраиваем InventoryManager
        InventoryManager.Instance.inventoryPanel = inventoryPanel;
        InventoryManager.Instance.inventoryCanvas = inventoryCanvas;

        Debug.Log($"[InventoryUIBuilder] Created {inventoryCols * inventoryRows} inventory slots + {hotbarSlots} hotbar slots");
    }

    GameObject CreatePanel(string name, Transform parent, Color color)
    {
        GameObject panel = new GameObject(name);
        panel.transform.SetParent(parent, false);

        var rect = panel.AddComponent<RectTransform>();
        panel.AddComponent<Image>().color = color;

        return panel;
    }

    void CreateTitle(Transform parent, string text, Vector2 position)
    {
        GameObject titleObj = new GameObject("Title");
        titleObj.transform.SetParent(parent, false);

        var rect = titleObj.AddComponent<RectTransform>();
        rect.anchorMin = new Vector2(0, 1);
        rect.anchorMax = new Vector2(1, 1);
        rect.pivot = new Vector2(0.5f, 1);
        rect.anchoredPosition = position;
        rect.sizeDelta = new Vector2(-20, 30);

        var tmp = titleObj.AddComponent<TextMeshProUGUI>();
        tmp.text = text;
        tmp.fontSize = 18;
        tmp.alignment = TextAlignmentOptions.Center;
        tmp.color = Color.white;
    }

    Transform CreateGrid(Transform parent, string name, int cols, int rows, float cellSize, float spacing, Vector2 offset)
    {
        GameObject gridObj = new GameObject(name);
        gridObj.transform.SetParent(parent, false);

        var rect = gridObj.AddComponent<RectTransform>();
        rect.anchorMin = Vector2.zero;
        rect.anchorMax = Vector2.one;
        rect.offsetMin = offset;
        rect.offsetMax = -offset;

        var grid = gridObj.AddComponent<GridLayoutGroup>();
        grid.cellSize = new Vector2(cellSize, cellSize);
        grid.spacing = new Vector2(spacing, spacing);
        grid.startCorner = GridLayoutGroup.Corner.UpperLeft;
        grid.startAxis = GridLayoutGroup.Axis.Horizontal;
        grid.constraint = GridLayoutGroup.Constraint.FixedColumnCount;
        grid.constraintCount = cols;
        grid.padding = new RectOffset(0, 0, 0, 0);

        return gridObj.transform;
    }

    Slot[] CreateSlots(Transform parent, string prefix, int startIndex, int count)
    {
        var slots = new Slot[count];

        for (int i = 0; i < count; i++)
        {
            GameObject slotObj = new GameObject(prefix + (startIndex + i));
            slotObj.transform.SetParent(parent, false);

            var rect = slotObj.AddComponent<RectTransform>();
            rect.sizeDelta = new Vector2(slotSize, slotSize);

            // Background
            var bg = slotObj.AddComponent<Image>();
            bg.color = slotEmptyColor;

            // Slot компонент
            var slot = slotObj.AddComponent<Slot>();
            slot.slotIndex = startIndex + i;

            // Icon
            GameObject iconObj = new GameObject("Icon");
            iconObj.transform.SetParent(slotObj.transform, false);
            var iconRect = iconObj.AddComponent<RectTransform>();
            iconRect.anchorMin = Vector2.zero;
            iconRect.anchorMax = Vector2.one;
            iconRect.offsetMin = new Vector2(4, 4);
            iconRect.offsetMax = new Vector2(-4, -4);
            slot.iconImage = iconObj.AddComponent<Image>();
            slot.iconImage.preserveAspect = true;
            slot.iconImage.enabled = false;

            // Amount panel
            GameObject amountObj = new GameObject("AmountPanel");
            amountObj.transform.SetParent(slotObj.transform, false);
            var amountRect = amountObj.AddComponent<RectTransform>();
            amountRect.anchorMin = Vector2.one;
            amountRect.anchorMax = Vector2.one;
            amountRect.pivot = new Vector2(1, 0);
            amountRect.anchoredPosition = new Vector2(-2, 2);
            amountRect.sizeDelta = new Vector2(22, 22);
            slot.amountPanel = amountObj;

            var amountBg = amountObj.AddComponent<Image>();
            amountBg.color = new Color(0, 0, 0, 0.7f);

            GameObject amountTextObj = new GameObject("Text");
            amountTextObj.transform.SetParent(amountObj.transform, false);
            var amountTextRect = amountTextObj.AddComponent<RectTransform>();
            amountTextRect.anchorMin = Vector2.zero;
            amountTextRect.anchorMax = Vector2.one;
            slot.amountText = amountTextObj.AddComponent<TextMeshProUGUI>();
            slot.amountText.fontSize = 14;
            slot.amountText.alignment = TextAlignmentOptions.Right;
            slot.amountText.color = Color.white;
            slot.amountText.fontStyle = FontStyles.Bold;

            // Применяем настройки через сеттер
            slot.amountPanel.SetActive(false);
            slot.slotBackground = bg;

            // Drag & Drop
            var dragDrop = slotObj.AddComponent<InventoryDragDrop>();
            dragDrop.slot = slot;
            dragDrop.slotIndex = slot.slotIndex;

            // Подписка на события слота
            slot.OnSlotClicked += OnSlotClicked;

            slots[i] = slot;
        }

        return slots;
    }

    private int _selectedSlot = -1;

    private void OnSlotClicked(Slot slot)
    {
        // Снимаем выделение с предыдущего
        if (_selectedSlot >= 0 && _selectedSlot < InventoryManager.Instance.slots.Length)
        {
            InventoryManager.Instance.slots[_selectedSlot].SetSelected(false);
        }

        // Выделяем новый
        slot.SetSelected(true);
        _selectedSlot = slot.slotIndex;

        Debug.Log($"[UI] Selected slot: {_selectedSlot} - {slot.GetItem()?.itemName ?? "Empty"}");
    }

    /// <summary>
    /// Пересоздать UI (например, при изменении настроек)
    /// </summary>
    public void Rebuild()
    {
        // Удаляем старые панели
        if (inventoryPanelRect != null)
            Destroy(inventoryPanelRect.gameObject);
        if (hotbarPanelRect != null)
            Destroy(hotbarPanelRect.gameObject);

        BuildInventoryUI();
    }

    /// <summary>
    /// Показать/скрыть инвентарь
    /// </summary>
    public void ToggleInventory(bool show)
    {
        if (inventoryPanelRect != null)
            inventoryPanelRect.gameObject.SetActive(show);
    }
}