using UnityEngine;
using BaseGames.Core.Events;
using BaseGames.Core.Save;
using BaseGames.Player.States;

namespace BaseGames.Equipment
{
    /// <summary>
    /// 工具槽管理器（架构 09_ProgressionModule §7.5）。
    /// 管理玩家的 2 个工具槽（装备、使用、冷却）。
    /// 实现 ISaveable 以持久化槽位状态。
    /// </summary>
    public class ToolSlotManager : MonoBehaviour, ISaveable
    {
        private const int SlotCount = 2;

        [SerializeField] private ToolCatalogSO            _toolCatalog;
        [SerializeField] private ToolSO[]                _slots         = new ToolSO[SlotCount];
        [SerializeField] private int[]                   _remainingUses = new int[SlotCount];  // -1 = 无限
        [SerializeField] private ToolUsedEventChannelSO  _onToolUsed;

        private readonly float[] _cooldowns = new float[SlotCount];

        private void Awake()
        {
            Debug.Assert(_toolCatalog != null, "[ToolSlotManager] _toolCatalog 未赋值，请在 Inspector 中指定 ToolCatalogSO。", this);
        }

        // ── 装备 ─────────────────────────────────────────────────────────────
        public void EquipTool(int slotIndex, ToolSO tool)
        {
            if (slotIndex < 0 || slotIndex >= SlotCount) return;
            _slots[slotIndex]         = tool;
            _remainingUses[slotIndex] = tool != null ? tool.maxUses : 0;
            _cooldowns[slotIndex]     = 0f;
        }

        // ── 使用 ─────────────────────────────────────────────────────────────
        public bool TryUseTool(int slotIndex, PlayerController player)
        {
            if (slotIndex < 0 || slotIndex >= SlotCount) return false;
            var tool = _slots[slotIndex];
            if (tool == null)                       return false;
            if (_cooldowns[slotIndex] > 0f)         return false;
            if (_remainingUses[slotIndex] == 0)     return false;  // 已耗尽（-1 = 无限不触发）

            tool.effect?.Use(player);

            if (_remainingUses[slotIndex] > 0) _remainingUses[slotIndex]--;
            _cooldowns[slotIndex] = tool is IToolCooldown tc ? tc.CooldownDuration : 0f;

            _onToolUsed?.Raise(new ToolUsedPayload
            {
                SlotIndex = slotIndex,
                ToolId    = tool.toolId
            });
            return true;
        }

        private void Update()
        {
            for (int i = 0; i < SlotCount; i++)
                if (_cooldowns[i] > 0f) _cooldowns[i] -= Time.deltaTime;
        }

        // ── 查询 ─────────────────────────────────────────────────────────────
        public ToolSO GetTool(int slotIndex)          => _slots[slotIndex];
        public int    GetRemainingUses(int slotIndex) => _remainingUses[slotIndex];
        public float  GetCooldownRatio(int slotIndex)
        {
            if (_slots[slotIndex] is IToolCooldown tc && tc.CooldownDuration > 0f)
                return _cooldowns[slotIndex] / tc.CooldownDuration;
            return 0f;
        }

        // ── ISaveable ────────────────────────────────────────────────────────
        public void OnSave(SaveData data)
        {
            data.Tools.ToolSlot0 = _slots[0]?.toolId;
            data.Tools.ToolSlot1 = _slots[1]?.toolId;
        }

        public void OnLoad(SaveData data)
        {
            _cooldowns[0] = _cooldowns[1] = 0f;

            EquipTool(0, _toolCatalog.Find(data.Tools.ToolSlot0));
            EquipTool(1, _toolCatalog.Find(data.Tools.ToolSlot1));
        }
    }
}