using UnityEngine;
using BaseGames.Core;
using BaseGames.Core.Events;
using BaseGames.World;

namespace BaseGames.Enemies
{
    /// <summary>
    /// 战利品解算器（静态工具类）。
    /// 根据 <see cref="LootTableSO"/> 和当前难度决定掉落内容。
    /// </summary>
    public static class LootResolver
    {
        /// <summary>
        /// 解算并执行战利品掉落。
        /// <para>保底 LingZhu：直接加入玩家（通过事件频道）或在 <paramref name="worldPosition"/> 生成拾取物。</para>
        /// <para>随机物品：加权随机后通过 CollectibleSpawner 实例化拾取物。</para>
        /// </summary>
        public static void Resolve(LootTableSO table, Vector2 worldPosition)
        {
            if (table == null) return;

            // 保底 LingZhu
            int guaranteedLingZhu = Random.Range(table.GuaranteedLingZhuMin, table.GuaranteedLingZhuMax + 1);
            ApplyDifficultyLingZhuScale(ref guaranteedLingZhu);
            if (guaranteedLingZhu > 0)
                CollectibleSpawner.SpawnLingZhu(worldPosition, guaranteedLingZhu);

            // 加权随机物品掉落
            if (table.Entries == null || table.Entries.Length == 0) return;

            var dm = ServiceLocator.GetOrDefault<IDifficultyService>();
            bool isHard = dm != null &&
                          (int)dm.CurrentLevel >= (int)DifficultyLevel.Hard;

            float totalWeight = 0f;
            foreach (var entry in table.Entries)
            {
                float w = entry.BaseWeight;
                if (isHard && entry.ScaleWithDifficulty) w *= 1.5f;
                totalWeight += w;
            }

            if (totalWeight <= 0f) return;

            float roll = Random.Range(0f, totalWeight);
            float accum = 0f;
            foreach (var entry in table.Entries)
            {
                float w = entry.BaseWeight;
                if (isHard && entry.ScaleWithDifficulty) w *= 1.5f;
                accum += w;
                if (roll <= accum)
                {
                    if (!string.IsNullOrEmpty(entry.ItemId))
                        CollectibleSpawner.SpawnItem(worldPosition, entry.ItemId);
                    else if (entry.LingZhuAmount > 0)
                        CollectibleSpawner.SpawnLingZhu(worldPosition, entry.LingZhuAmount);
                    return;
                }
            }
        }

        private static void ApplyDifficultyLingZhuScale(ref int lingZhu)
        {
            var dm = ServiceLocator.GetOrDefault<IDifficultyService>();
            if (dm?.CurrentScaler == null) return;
            float mult = dm.CurrentScaler.LingZhuDropMultiplier;
            lingZhu = Mathf.RoundToInt(lingZhu * mult);
        }
    }
}