using System.Collections.Generic;
using UnityEngine;
using Northbound.Data;

namespace Northbound
{
    /// <summary>
    /// 업그레이드 데이터를 자동으로 로드하고 관리하는 싱글톤
    /// Resources 폴더에서 모든 UpgradeData를 자동으로 로드
    /// </summary>
    public class UpgradeDatabase : MonoBehaviour
    {
        private static UpgradeDatabase _instance;
        public static UpgradeDatabase Instance => _instance;

        // Resources에서 자동 로드된 데이터
        private List<UpgradeData> _upgradeDataList = new List<UpgradeData>();

        // 조회용 딕셔너리
        private Dictionary<int, UpgradeData> _upgradeById = new Dictionary<int, UpgradeData>();
        private Dictionary<string, List<UpgradeData>> _upgradesByCategory = new Dictionary<string, List<UpgradeData>>();

        // Resources 경로
        private const string UPGRADE_RESOURCES_PATH = "Data/ScriptableObjects/Upgrade";

        private void Awake()
        {
            if (_instance != null && _instance != this)
            {
                Destroy(gameObject);
                return;
            }

            _instance = this;
            LoadUpgradeData();
            BuildLookupTables();
        }

        /// <summary>
        /// Resources에서 모든 UpgradeData 자동 로드
        /// </summary>
        private void LoadUpgradeData()
        {
            _upgradeDataList.Clear();

            var upgrades = Resources.LoadAll<UpgradeData>(UPGRADE_RESOURCES_PATH);
            _upgradeDataList.AddRange(upgrades);

            Debug.Log($"[UpgradeDatabase] {_upgradeDataList.Count}개의 업그레이드 데이터를 로드했습니다.");
        }

        /// <summary>
        /// 조회용 테이블 구축
        /// </summary>
        private void BuildLookupTables()
        {
            _upgradeById.Clear();
            _upgradesByCategory.Clear();

            foreach (var upgrade in _upgradeDataList)
            {
                if (upgrade == null) continue;

                // ID로 조회
                if (!_upgradeById.ContainsKey(upgrade.id))
                {
                    _upgradeById[upgrade.id] = upgrade;
                }

                // 카테고리로 조회
                string category = upgrade.upgradeCategory;
                if (!_upgradesByCategory.ContainsKey(category))
                {
                    _upgradesByCategory[category] = new List<UpgradeData>();
                }
                _upgradesByCategory[category].Add(upgrade);
            }
        }

        /// <summary>
        /// 데이터 다시 로드 (에디터에서 데이터 변경 시 호출)
        /// </summary>
        public void ReloadData()
        {
            LoadUpgradeData();
            BuildLookupTables();
        }

        #region Getters

        /// <summary>
        /// ID로 업그레이드 데이터 조회
        /// </summary>
        public UpgradeData GetUpgradeById(int id)
        {
            if (_upgradeById.TryGetValue(id, out var upgrade))
            {
                return upgrade;
            }
            Debug.LogWarning($"[UpgradeDatabase] ID {id}에 해당하는 업그레이드를 찾을 수 없습니다.");
            return null;
        }

        /// <summary>
        /// 카테고리로 업그레이드 목록 조회
        /// </summary>
        public List<UpgradeData> GetUpgradesByCategory(string category)
        {
            if (_upgradesByCategory.TryGetValue(category, out var upgrades))
            {
                return new List<UpgradeData>(upgrades);
            }
            return new List<UpgradeData>();
        }

        /// <summary>
        /// 개인 업그레이드 목록 조회
        /// </summary>
        public List<UpgradeData> GetPersonalUpgrades()
        {
            var result = new List<UpgradeData>();
            foreach (var upgrade in _upgradeDataList)
            {
                if (upgrade != null && upgrade.upgradeTarget == "person")
                {
                    result.Add(upgrade);
                }
            }
            return result;
        }

        /// <summary>
        /// 팀 업그레이드 목록 조회
        /// </summary>
        public List<UpgradeData> GetTeamUpgrades()
        {
            var result = new List<UpgradeData>();
            foreach (var upgrade in _upgradeDataList)
            {
                if (upgrade != null && upgrade.upgradeTarget == "share")
                {
                    result.Add(upgrade);
                }
            }
            return result;
        }

        /// <summary>
        /// 모든 업그레이드 데이터 반환
        /// </summary>
        public List<UpgradeData> GetAllUpgrades()
        {
            return new List<UpgradeData>(_upgradeDataList);
        }

        /// <summary>
        /// 선행 업그레이드 조건 충족 여부 확인
        /// </summary>
        public bool ArePrerequisitesMet(int upgradeId, HashSet<int> ownedUpgradeIds)
        {
            var upgrade = GetUpgradeById(upgradeId);
            if (upgrade == null) return false;

            foreach (int requiredId in upgrade.requireUpgradeId)
            {
                if (!ownedUpgradeIds.Contains(requiredId))
                {
                    return false;
                }
            }

            return true;
        }

        #endregion
    }
}