using System;
using System.Collections.Generic;
using AppleHills.Data.CardSystem;
using Core;
using UnityEngine;

namespace Data.CardSystem
{
    /// <summary>
    /// Manages the player's card collection, booster packs, and related operations.
    /// Uses a singleton pattern for global access.
    /// </summary>
    public class CardSystemManager : MonoBehaviour
    {
        private static CardSystemManager _instance;
        private static bool _isQuitting = false;

        public static CardSystemManager Instance
        {
            get
            {
                if (_instance == null && Application.isPlaying && !_isQuitting)
                {
                    _instance = FindAnyObjectByType<CardSystemManager>();
                    if (_instance == null)
                    {
                        var go = new GameObject("CardSystemManager");
                        _instance = go.AddComponent<CardSystemManager>();
                        DontDestroyOnLoad(go);
                    }
                }
                return _instance;
            }
        }
        
        [Header("Card Collection")]
        [SerializeField] private List<CardDefinition> availableCards = new List<CardDefinition>();
        
        // Runtime data - will be serialized for save/load
        [SerializeField] private CardInventory playerInventory = new CardInventory();
        
        // Dictionary to quickly look up card definitions by ID
        private Dictionary<string, CardDefinition> _definitionLookup = new Dictionary<string, CardDefinition>();
        
        // Event callbacks using System.Action
        public event Action<List<CardData>> OnBoosterOpened;
        public event Action<CardData> OnCardCollected;
        public event Action<CardData> OnCardRarityUpgraded;
        public event Action<int> OnBoosterCountChanged;

        private void Awake()
        {
            if (_instance != null && _instance != this)
            {
                Destroy(gameObject);
                return;
            }
            
            _instance = this;
            DontDestroyOnLoad(gameObject);
            
            // Build lookup dictionary
            BuildDefinitionLookup();
        }

        private void OnApplicationQuit()
        {
            _isQuitting = true;
        }
        
        /// <summary>
        /// Builds a lookup dictionary for quick access to card definitions by ID
        /// </summary>
        private void BuildDefinitionLookup()
        {
            _definitionLookup.Clear();
            
            foreach (var cardDef in availableCards)
            {
                if (cardDef != null && !string.IsNullOrEmpty(cardDef.Id))
                {
                    _definitionLookup[cardDef.Id] = cardDef;
                }
            }
            
            // Link existing card data to their definitions
            foreach (var cardData in playerInventory.CollectedCards.Values)
            {
                if (!string.IsNullOrEmpty(cardData.DefinitionId) && 
                    _definitionLookup.TryGetValue(cardData.DefinitionId, out CardDefinition def))
                {
                    cardData.SetDefinition(def);
                }
            }
        }

        /// <summary>
        /// Adds a booster pack to the player's inventory
        /// </summary>
        public void AddBoosterPack(int count = 1)
        {
            playerInventory.BoosterPackCount += count;
            OnBoosterCountChanged?.Invoke(playerInventory.BoosterPackCount);
            Logging.Debug($"[CardSystemManager] Added {count} booster pack(s). Total: {playerInventory.BoosterPackCount}");
        }

        /// <summary>
        /// Opens a booster pack and returns the newly obtained cards
        /// </summary>
        public List<CardData> OpenBoosterPack()
        {
            if (playerInventory.BoosterPackCount <= 0)
            {
                Logging.Warning("[CardSystemManager] Attempted to open a booster pack, but none are available.");
                return new List<CardData>();
            }

            playerInventory.BoosterPackCount--;
            OnBoosterCountChanged?.Invoke(playerInventory.BoosterPackCount);
            
            // Draw 3 cards based on rarity distribution
            List<CardData> drawnCards = DrawRandomCards(3);
            
            // Add cards to the inventory
            foreach (var card in drawnCards)
            {
                AddCardToInventory(card);
            }
            
            // Notify listeners
            OnBoosterOpened?.Invoke(drawnCards);
            
            Logging.Debug($"[CardSystemManager] Opened a booster pack and obtained {drawnCards.Count} cards. Remaining boosters: {playerInventory.BoosterPackCount}");
            return drawnCards;
        }

        /// <summary>
        /// Adds a card to the player's inventory, handles duplicates
        /// </summary>
        private void AddCardToInventory(CardData card)
        {
            // Check if the player already has this card type (definition)
            if (playerInventory.HasCard(card.DefinitionId))
            {
                CardData existingCard = playerInventory.GetCard(card.DefinitionId);
                existingCard.CopiesOwned++;
                
                // Check if the card can be upgraded
                if (existingCard.TryUpgradeRarity())
                {
                    OnCardRarityUpgraded?.Invoke(existingCard);
                }
                
                Logging.Debug($"[CardSystemManager] Added duplicate card '{card.Name}'. Now have {existingCard.CopiesOwned} copies.");
            }
            else
            {
                // Add new card
                playerInventory.AddCard(card);
                OnCardCollected?.Invoke(card);
                
                Logging.Debug($"[CardSystemManager] Added new card '{card.Name}' to collection.");
            }
        }

        /// <summary>
        /// Draws random cards based on rarity distribution
        /// </summary>
        private List<CardData> DrawRandomCards(int count)
        {
            List<CardData> result = new List<CardData>();
            
            if (availableCards.Count == 0)
            {
                Debug.LogError("[CardSystemManager] No available cards defined!");
                return result;
            }
            
            // Simple weighted random selection based on rarity
            for (int i = 0; i < count; i++)
            {
                // Determine card rarity first
                CardRarity rarity = DetermineRandomRarity();
                
                // Filter cards by the selected rarity
                List<CardDefinition> cardsOfRarity = availableCards.FindAll(c => c.Rarity == rarity);
                
                if (cardsOfRarity.Count > 0)
                {
                    // Select a random card of this rarity
                    int randomIndex = UnityEngine.Random.Range(0, cardsOfRarity.Count);
                    CardDefinition selectedDef = cardsOfRarity[randomIndex];
                    
                    // Create card data from definition
                    CardData newCard = selectedDef.CreateCardData();
                    result.Add(newCard);
                }
                else
                {
                    // Fallback if no cards of the selected rarity
                    Logging.Warning($"[CardSystemManager] No cards of rarity {rarity} available, selecting a random card instead.");
                    int randomIndex = UnityEngine.Random.Range(0, availableCards.Count);
                    CardDefinition randomDef = availableCards[randomIndex];
                    
                    CardData newCard = randomDef.CreateCardData();
                    result.Add(newCard);
                }
            }
            
            return result;
        }

        /// <summary>
        /// Determines a random card rarity with appropriate weighting
        /// </summary>
        private CardRarity DetermineRandomRarity()
        {
            // Simple weighted random - can be adjusted for better distribution
            float rand = UnityEngine.Random.value;
            
            if (rand < 0.6f) return CardRarity.Common;
            if (rand < 0.85f) return CardRarity.Uncommon;
            if (rand < 0.95f) return CardRarity.Rare;
            if (rand < 0.99f) return CardRarity.Epic;
            return CardRarity.Legendary;
        }
        
        /// <summary>
        /// Returns all cards from the player's collection
        /// </summary>
        public List<CardData> GetAllCollectedCards()
        {
            return playerInventory.GetAllCards();
        }
        
        /// <summary>
        /// Returns cards from a specific zone
        /// </summary>
        public List<CardData> GetCardsByZone(CardZone zone)
        {
            return playerInventory.GetCardsByZone(zone);
        }
        
        /// <summary>
        /// Returns cards of a specific rarity
        /// </summary>
        public List<CardData> GetCardsByRarity(CardRarity rarity)
        {
            return playerInventory.GetCardsByRarity(rarity);
        }
        
        /// <summary>
        /// Returns the number of booster packs the player has
        /// </summary>
        public int GetBoosterPackCount()
        {
            return playerInventory.BoosterPackCount;
        }
        
        /// <summary>
        /// Returns whether a specific card definition has been collected
        /// </summary>
        public bool IsCardCollected(string definitionId)
        {
            return playerInventory.HasCard(definitionId);
        }
        
        /// <summary>
        /// Gets total unique card count
        /// </summary>
        public int GetUniqueCardCount()
        {
            return playerInventory.GetUniqueCardCount();
        }
        
        /// <summary>
        /// Gets completion percentage for a specific zone (0-100)
        /// </summary>
        public float GetZoneCompletionPercentage(CardZone zone)
        {
            // Count available cards in this zone
            int totalInZone = availableCards.FindAll(c => c.Zone == zone).Count;
            if (totalInZone == 0) return 0;
            
            // Count collected cards in this zone
            int collectedInZone = playerInventory.GetCardsByZone(zone).Count;
            
            return (float)collectedInZone / totalInZone * 100f;
        }
    }
}