using UnityEngine;

namespace BulletHellTemplate
{
    /// <summary>
    /// Handles saving and loading inventory-related data locally (such as item upgrade levels),
    /// and optionally syncing specific items to the backend.
    /// </summary>
    public class InventorySave : MonoBehaviour
    {
        public static InventorySave Singleton;

        private void Awake()
        {
            if (Singleton == null)
            {
                Singleton = this;
            }
            else
            {
                Destroy(gameObject);
            }
        }

        /// <summary>
        /// Saves the upgrade level of a purchased item locally and then updates only
        /// that specific item in the backend (if initialized). Does not re-save the entire list.
        /// </summary>
        /// <param name="uniqueItemGuid">Unique GUID identifying the purchased item.</param>
        /// <param name="level">The new upgrade level.</param>
        public static async void SetItemUpgradeLevelSingle(string uniqueItemGuid, int level)
        {
            // 1) Save locally using PlayerSave
            PlayerSave.SetItemUpgradeLevel(uniqueItemGuid, level);

            // 2) Update the item in MonetizationManager
            var purchasedItems = MonetizationManager.Singleton.GetPurchasedInventoryItems();
            var foundItem = purchasedItems.Find(i => i.uniqueItemGuid == uniqueItemGuid);
            if (foundItem != null)
            {
                foundItem.itemLevel = level;

                // 3) Save ONLY this item in Firestore, if the backend is initialized
                if (BackendManager.Singleton.CheckInitialized())
                {
                    await BackendManager.Singleton.SavePurchasedInventoryItemAsync(foundItem);
                }
            }
            else
            {
                Debug.LogWarning($"SetItemUpgradeLevelSingle: No purchased item found with GUID {uniqueItemGuid}");
            }
        }

        /// <summary>
        /// (Original) Saves the upgrade level of a purchased item locally,
        /// then re-saves the entire purchased list to the backend (and also this item individually).
        /// </summary>
        /// <param name="uniqueItemGuid">Unique GUID of the item.</param>
        /// <param name="level">The new level.</param>
        public static async void SetItemUpgradeLevel(string uniqueItemGuid, int level)
        {
            // 1) Save locally
            PlayerSave.SetItemUpgradeLevel(uniqueItemGuid, level);

            // 2) Update the item in MonetizationManager
            var purchasedItems = MonetizationManager.Singleton.GetPurchasedInventoryItems();
            var foundItem = purchasedItems.Find(i => i.uniqueItemGuid == uniqueItemGuid);
            if (foundItem != null)
            {
                foundItem.itemLevel = level;

                // Re-saves all items
                MonetizationManager.Singleton.UpdatePurchasedItems(
                    MonetizationManager.Singleton.GetPurchasedCharacters(),
                    MonetizationManager.Singleton.GetPurchasedIcons(),
                    MonetizationManager.Singleton.GetPurchasedFrames(),
                    MonetizationManager.Singleton.GetPurchasedShopItems(),
                    purchasedItems
                );
            }

            // 3) Save this single item as well
            if (BackendManager.Singleton.CheckInitialized() && foundItem != null)
            {
                await BackendManager.Singleton.SavePurchasedInventoryItemAsync(foundItem);
            }
        }

        /// <summary>
        /// Gets the item upgrade level from local data, returns 0 if not found.
        /// </summary>
        /// <param name="uniqueItemGuid">GUID of the purchased item.</param>
        /// <returns>The upgrade level, or 0 if not found.</returns>
        public static int GetItemUpgradeLevel(string uniqueItemGuid)
        {
            return PlayerSave.GetItemUpgradeLevel(uniqueItemGuid);
        }

        /// <summary>
        /// Equips an item (assigns a GUID) in the given character's slot, saving to Firestore if needed.
        /// If uniqueItemGuid is empty, it means unequip and calls RemoveCharacterItemAsync.
        /// </summary>
        public static async void SetEquippedItemForSlot(int characterId, string slotName, string uniqueItemGuid)
        {
            // 1) Store locally
            PlayerSave.SetCharacterSlotItem(characterId, slotName, uniqueItemGuid);

            // 2) If empty, remove from Firestore
            if (string.IsNullOrEmpty(uniqueItemGuid))
            {
                if (BackendManager.Singleton.CheckInitialized())
                {
                    await BackendManager.Singleton.RemoveCharacterItemAsync(characterId, slotName, "the-doc-id");
                }
                return;
            }

            // 3) Otherwise, find the purchased item data
            var purchasedItems = MonetizationManager.Singleton.GetPurchasedInventoryItems();
            var foundItem = purchasedItems.Find(i => i.uniqueItemGuid == uniqueItemGuid);

            if (foundItem != null && BackendManager.Singleton.CheckInitialized())
            {
                await BackendManager.Singleton.SaveCharacterItemAsync(
                    characterId,
                    slotName,
                    uniqueItemGuid,
                    foundItem.itemId,
                    foundItem.itemLevel
                );
            }
        }

        /// <summary>
        /// Returns the unique item GUID equipped in a specific slot for a given character,
        /// or empty string if none is equipped.
        /// </summary>
        public static string GetEquippedItemForSlot(int characterId, string slotName)
        {
            return PlayerSave.GetCharacterSlotItem(characterId, slotName) ?? "";
        }

        /// <summary>
        /// Deletes local references of this item, removing any equipped data.
        /// Does not remove from Firebase or MonetizationManager by itself.
        /// Call DeletePurchasedItemAsync if you want full removal.
        /// </summary>
        public static async void DeleteLocalItemData(string uniqueItemGuid)
        {
            // If you used PlayerSave for equipping, you might want to find which slot used it
            // But for now, just remove the level key
            PlayerPrefs.DeleteKey($"{uniqueItemGuid}_equipped");
            PlayerPrefs.DeleteKey($"{uniqueItemGuid}_level");
            PlayerPrefs.Save();

            UIInventoryMenu.Singleton.UpdateInventoryUI();
            await BackendManager.Singleton.DeletePurchasedInventoryItemAsync(uniqueItemGuid);
        }
    }
}