using System.Collections.Generic;
using UnityEngine;
using BaseGames.Core;
using BaseGames.Core.Events;
using BaseGames.Core.Save;

namespace BaseGames.Progression
{
    /// <summary>
    /// 图鉴追踪服务（仿 <see cref="BaseGames.Equipment.EquipmentManager"/> 的 ISaveable + ServiceLocator 模式）。
    /// 订阅 EVT_EnemyDied(payload=enemyId)，记录已发现敌人与击杀次数，持久化到 <see cref="SaveData.Journal"/>。
    /// 仅依赖字符串 enemyId 与事件频道，不引用敌人程序集（asmdef 解耦）；敌人代码零改动。
    /// 挂在 Persistent 的 [GameManagers] 下，OnEnable 注册 IBestiaryService 与 ISaveableRegistry。
    /// </summary>
    public class BestiaryService : MonoBehaviour, ISaveable, IBestiaryService
    {
        [Header("事件频道")]
        [Tooltip("EVT_EnemyDied：payload = enemyId。敌人 / Boss 死亡时由 EnemyBase 广播。")]
        [SerializeField] private StringEventChannelSO _onEnemyDied;
        [Tooltip("EVT_BestiaryUpdated：payload = enemyId。新发现 / 击杀计数更新时广播，驱动图鉴 UI 实时刷新。")]
        [SerializeField] private StringEventChannelSO _onBestiaryUpdated;

        private readonly HashSet<string>           _discovered = new();
        private readonly Dictionary<string, int>   _killCounts = new();
        private readonly CompositeDisposable        _subs       = new();

        // ── IBestiaryService ─────────────────────────────────────────────────
        public int DiscoveredCount => _discovered.Count;

        public bool IsDiscovered(string enemyId)
            => !string.IsNullOrEmpty(enemyId) && _discovered.Contains(enemyId);

        public int GetKillCount(string enemyId)
            => !string.IsNullOrEmpty(enemyId) && _killCounts.TryGetValue(enemyId, out var n) ? n : 0;

        // ── 生命周期 ──────────────────────────────────────────────────────────
        private void OnEnable()
        {
            ServiceLocator.Register<IBestiaryService>(this);
            ServiceLocator.GetOrDefault<ISaveableRegistry>()?.Register(this);
            _onEnemyDied?.Subscribe(OnEnemyDied).AddTo(_subs);
        }

        private void OnDisable()
        {
            ServiceLocator.Unregister<IBestiaryService>(this);
            ServiceLocator.GetOrDefault<ISaveableRegistry>()?.Unregister(this);
            _subs.Clear();
        }

        // ── 解锁处理 ──────────────────────────────────────────────────────────
        private void OnEnemyDied(string enemyId)
        {
            if (string.IsNullOrEmpty(enemyId)) return;
            _discovered.Add(enemyId);
            _killCounts.TryGetValue(enemyId, out var n);
            _killCounts[enemyId] = n + 1;
            _onBestiaryUpdated?.Raise(enemyId);
        }

        // ── ISaveable ─────────────────────────────────────────────────────────
        public void OnSave(SaveData data)
        {
            var j = data.Journal;
            j.DiscoveredEnemyIds.Clear();
            foreach (var id in _discovered) j.DiscoveredEnemyIds.Add(id);
            j.EnemyKillCounts.Clear();
            foreach (var kv in _killCounts) j.EnemyKillCounts[kv.Key] = kv.Value;
        }

        public void OnLoad(SaveData data)
        {
            _discovered.Clear();
            _killCounts.Clear();
            var j = data.Journal;
            if (j == null) return;
            if (j.DiscoveredEnemyIds != null)
                foreach (var id in j.DiscoveredEnemyIds) _discovered.Add(id);
            if (j.EnemyKillCounts != null)
                foreach (var kv in j.EnemyKillCounts) _killCounts[kv.Key] = kv.Value;
        }
    }
}