using System.Collections.Generic;
using OTGIntegrated.Items;
using UnityEngine;
using UnityEngine.UI;

namespace OTGIntegrated.Inventory
{
    public sealed class InventoryUI : MonoBehaviour
    {
        public GameObject panelRoot;
        public Transform slotGrid;
        public Text titleText;
        public Text descriptionText;
        public Text hintText;
        public Button closeButton;
        public Font uiFont;

        private Inventory inventory;
        private readonly List<GameObject> spawnedSlots = new List<GameObject>();

        public void Initialize(Inventory inventory)
        {
            this.inventory = inventory;
            if (inventory != null)
            {
                inventory.OnInventoryChanged -= Refresh;
                inventory.OnInventoryChanged += Refresh;
            }

            if (closeButton != null)
            {
                closeButton.onClick.RemoveAllListeners();
                closeButton.onClick.AddListener(() => FindObjectOfType<OTGIntegrated.UI.UIManager>()?.CloseCurrentWindow());
            }

            Refresh();
        }

        private void OnEnable()
        {
            Refresh();
        }

        private void OnDestroy()
        {
            if (inventory != null)
            {
                inventory.OnInventoryChanged -= Refresh;
            }
        }

        public void Refresh()
        {
            if (slotGrid == null)
            {
                return;
            }

            ClearSlots();
            IReadOnlyList<InventorySlot> slots = inventory != null ? inventory.GetAllSlots() : null;
            int maxSlots = inventory != null ? inventory.MaxSlots : 20;

            for (int i = 0; i < maxSlots; i++)
            {
                InventorySlot slot = slots != null && i < slots.Count ? slots[i] : null;
                CreateSlot(i, slot);
            }

            if (titleText != null)
            {
                titleText.text = "Инвентарь";
            }

            if (hintText != null)
            {
                hintText.text = "I — закрыть    F5 — сохранить    F9 — загрузить";
            }

            if (descriptionText != null && string.IsNullOrEmpty(descriptionText.text))
            {
                descriptionText.text = "Выберите предмет.";
            }
        }

        private void CreateSlot(int index, InventorySlot slot)
        {
            GameObject root = new GameObject($"InventorySlot_{index}", typeof(RectTransform), typeof(Image), typeof(Button));
            root.transform.SetParent(slotGrid, false);
            spawnedSlots.Add(root);

            RectTransform rect = root.GetComponent<RectTransform>();
            rect.sizeDelta = new Vector2(90f, 90f);

            Image background = root.GetComponent<Image>();
            background.color = slot != null && !slot.IsEmpty()
                ? Color.Lerp(new Color(0.09f, 0.1f, 0.12f, 0.95f), slot.item.itemColor, 0.35f)
                : new Color(0.07f, 0.08f, 0.1f, 0.82f);

            Text label = CreateText(root.transform, "Label", slot != null && !slot.IsEmpty() ? slot.item.displayName : string.Empty, 14, TextAnchor.MiddleCenter);
            label.rectTransform.anchorMin = new Vector2(0.08f, 0.24f);
            label.rectTransform.anchorMax = new Vector2(0.92f, 0.78f);
            label.rectTransform.offsetMin = Vector2.zero;
            label.rectTransform.offsetMax = Vector2.zero;

            Text count = CreateText(root.transform, "Count", slot != null && !slot.IsEmpty() ? slot.amount.ToString() : string.Empty, 14, TextAnchor.LowerRight);
            count.rectTransform.anchorMin = new Vector2(0.1f, 0.05f);
            count.rectTransform.anchorMax = new Vector2(0.95f, 0.35f);
            count.rectTransform.offsetMin = Vector2.zero;
            count.rectTransform.offsetMax = Vector2.zero;

            Button button = root.GetComponent<Button>();
            button.onClick.AddListener(() => SelectSlot(slot));
        }

        private void SelectSlot(InventorySlot slot)
        {
            if (descriptionText == null)
            {
                return;
            }

            if (slot == null || slot.IsEmpty())
            {
                descriptionText.text = "Пустой слот.";
                return;
            }

            ItemData item = slot.item;
            descriptionText.text = $"{item.displayName}\n\n{item.description}\n\nТип: {item.itemType}\nКоличество: {slot.amount}";
        }

        private Text CreateText(Transform parent, string name, string value, int fontSize, TextAnchor anchor)
        {
            GameObject textObject = new GameObject(name, typeof(RectTransform), typeof(Text));
            textObject.transform.SetParent(parent, false);
            Text text = textObject.GetComponent<Text>();
            text.text = value;
            text.font = uiFont != null ? uiFont : Resources.GetBuiltinResource<Font>("Arial.ttf");
            text.fontSize = fontSize;
            text.alignment = anchor;
            text.color = new Color(0.94f, 0.93f, 0.88f, 1f);
            text.resizeTextForBestFit = true;
            text.resizeTextMinSize = 10;
            text.resizeTextMaxSize = fontSize;
            return text;
        }

        private void ClearSlots()
        {
            for (int i = 0; i < spawnedSlots.Count; i++)
            {
                if (spawnedSlots[i] != null)
                {
                    Destroy(spawnedSlots[i]);
                }
            }

            spawnedSlots.Clear();
        }
    }
}