using System.Collections.Generic;
using UnityEngine;

#if UNITY_EDITOR
using UnityEditor;
#endif

public static class EquipmentSkillGroupLibrary
{
    private static readonly string[] SpecialResourcesPaths =
    {
        "so/skill_equipSkills/mmrEffectSkills",
        "so/skill_equipSkills/\u8bb0\u5fc6\u7279\u6548\u6280\u80fd"
    };

    private static readonly string[] IllusionResourcesPaths =
    {
        "so/skill_equipSkills/illusionSkills",
        "so/skill_equipSkills/\u5e7b\u5316\u6280\u80fd"
    };

#if UNITY_EDITOR
    private static readonly string[] SpecialAssetFolders =
    {
        "Assets/Resources/so/skill_equipSkills/mmrEffectSkills",
        "Assets/Resources/so/skill_equipSkills/\u8bb0\u5fc6\u7279\u6548\u6280\u80fd"
    };

    private static readonly string[] IllusionAssetFolders =
    {
        "Assets/Resources/so/skill_equipSkills/illusionSkills",
        "Assets/Resources/so/skill_equipSkills/\u5e7b\u5316\u6280\u80fd"
    };
#endif

    public static SkillGroup ResolveSpecialSkillGroup(int skillGroupId)
    {
        return ResolveSkillGroup(skillGroupId, EquipmentSkillGroupSO.EquipmentSkillCategory.Special);
    }

    public static SkillGroup ResolveIllusionSkillGroup(int skillGroupId)
    {
        return ResolveSkillGroup(skillGroupId, EquipmentSkillGroupSO.EquipmentSkillCategory.Illusion);
    }

    public static SkillGroup ResolveSkillGroup(int skillGroupId)
    {
        SkillGroup group = ResolveSpecialSkillGroup(skillGroupId);
        if (group != null)
        {
            return group;
        }

        return ResolveIllusionSkillGroup(skillGroupId);
    }

    public static SkillGroup ResolveSkillGroup(int skillGroupId, EquipmentSkillGroupSO.EquipmentSkillCategory category)
    {
        if (skillGroupId <= 0)
        {
            return null;
        }

        EquipmentSkillGroupSO asset = FindAsset(skillGroupId, category);
        return asset != null ? asset.skillGroup : null;
    }

    // --- Runtime cache -------------------------------------------------------
    // Equipment skill-group assets are static config loaded from Resources and never
    // mutated at runtime, so both the per-category asset list and the id->asset resolution
    // are memoized during play mode. This turns a per-note/per-trigger Resources.LoadAll +
    // collection-allocation storm into O(1) dictionary lookups. The editor (!isPlaying)
    // path stays uncached so asset edits are always reflected; the cache is cleared on
    // play-mode start via RuntimeInitializeOnLoadMethod so a fresh session never sees stale
    // entries from a prior play session (domain-reload-disabled projects).
    private static readonly Dictionary<EquipmentSkillGroupSO.EquipmentSkillCategory, List<EquipmentSkillGroupSO>> s_assetsByCategory =
        new Dictionary<EquipmentSkillGroupSO.EquipmentSkillCategory, List<EquipmentSkillGroupSO>>();
    // Keyed by (category, skillGroupId); caches both hits and misses (null value = confirmed miss).
    private static readonly Dictionary<long, EquipmentSkillGroupSO> s_findAssetCache = new Dictionary<long, EquipmentSkillGroupSO>();

    [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
    private static void ResetRuntimeCache()
    {
        s_assetsByCategory.Clear();
        s_findAssetCache.Clear();
    }

    private static long MakeFindKey(int skillGroupId, EquipmentSkillGroupSO.EquipmentSkillCategory category)
    {
        return ((long)category << 32) | (uint)skillGroupId;
    }

    public static EquipmentSkillGroupSO FindAsset(int skillGroupId, EquipmentSkillGroupSO.EquipmentSkillCategory category)
    {
        if (skillGroupId <= 0)
        {
            return null;
        }

        bool useCache = Application.isPlaying;
        long findKey = 0;
        if (useCache)
        {
            findKey = MakeFindKey(skillGroupId, category);
            if (s_findAssetCache.TryGetValue(findKey, out EquipmentSkillGroupSO cached))
            {
                return cached;
            }
        }

        var assets = LoadAssets(category);
        EquipmentSkillGroupSO resolved = null;
        for (int i = 0; i < assets.Count; i++)
        {
            EquipmentSkillGroupSO asset = assets[i];
            if (asset == null || asset.skillGroup == null)
            {
                continue;
            }

            if (asset.skillGroup.skillGroupID == skillGroupId)
            {
                resolved = asset;
                break;
            }
        }

        if (useCache)
        {
            // Cache hits AND misses (null) so repeated unmatched ids don't re-scan.
            s_findAssetCache[findKey] = resolved;
        }

        return resolved;
    }

    public static List<EquipmentSkillGroupSO> LoadAssets(EquipmentSkillGroupSO.EquipmentSkillCategory category)
    {
        // Play mode: build the per-category list once (from Resources) and reuse it.
        if (Application.isPlaying && s_assetsByCategory.TryGetValue(category, out var cachedList))
        {
            return cachedList;
        }

        var results = new List<EquipmentSkillGroupSO>();

#if UNITY_EDITOR
        if (!Application.isPlaying)
        {
            string[] folders = category == EquipmentSkillGroupSO.EquipmentSkillCategory.Special ? SpecialAssetFolders : IllusionAssetFolders;
            var dedupe = new HashSet<string>();
            for (int folderIndex = 0; folderIndex < folders.Length; folderIndex++)
            {
                if (!AssetDatabase.IsValidFolder(folders[folderIndex]))
                {
                    continue;
                }

                string[] guids = AssetDatabase.FindAssets("t:EquipmentSkillGroupSO", new[] { folders[folderIndex] });
                for (int i = 0; i < guids.Length; i++)
                {
                    string path = AssetDatabase.GUIDToAssetPath(guids[i]);
                    if (!dedupe.Add(path))
                    {
                        continue;
                    }

                    EquipmentSkillGroupSO asset = AssetDatabase.LoadAssetAtPath<EquipmentSkillGroupSO>(path);
                    if (asset != null)
                    {
                        results.Add(asset);
                    }
                }
            }

            return results;
        }
#endif

        string[] resourcePaths = category == EquipmentSkillGroupSO.EquipmentSkillCategory.Special ? SpecialResourcesPaths : IllusionResourcesPaths;
        var seen = new HashSet<EquipmentSkillGroupSO>();
        for (int i = 0; i < resourcePaths.Length; i++)
        {
            EquipmentSkillGroupSO[] loaded = Resources.LoadAll<EquipmentSkillGroupSO>(resourcePaths[i]);
            if (loaded == null || loaded.Length == 0)
            {
                continue;
            }

            for (int j = 0; j < loaded.Length; j++)
            {
                if (loaded[j] != null && seen.Add(loaded[j]))
                {
                    results.Add(loaded[j]);
                }
            }
        }

        if (Application.isPlaying)
        {
            s_assetsByCategory[category] = results;
        }

        return results;
    }
}