using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Diagnostics.Eventing.Reader;
using System.Runtime.CompilerServices;


using Newtonsoft.Json;
using Pipelines.Sockets.Unofficial.Buffers;
using Amazon.DynamoDBv2.Model;



using ServerCore;
using ServerBase;


using META_ID = System.UInt32;
using ENTITY_GUID = System.String;
using ACCOUNT_ID = System.String;
using OWNER_GUID = System.String;
using USER_GUID = System.String;
using CHARACTER_GUID = System.String;
using ITEM_GUID = System.String;



namespace ServerCommon;

//===========================================================================================
// Meta 관련 각종 지원 함수
//
// author : kangms
// 
//===========================================================================================

public static partial class MetaHelper
{
    public static bool isTestAccount(this string accountId)
    {
        var err_msg = string.Empty;

        // 1. TestUserCreateData Meta 파일에서 특정 계정 정보가 존재하는 지 체크 한다.
        if (true == MetaData.Instance.m_test_user_create_meta_datas.ContainsKey(accountId))
        {
            return true;
        }

        return false;
    }

    public static async Task<(Result, MetaAssets.TestUserCreateMetaData?)> getTestUserCreateDataByAccountId(string accountId)
    {
        await Task.CompletedTask;

        var result = new Result();
        var err_msg = string.Empty;

        // 1. TestUserCreateData Meta 파일에서 특정 계정 정보가 존재하는 지 체크 한다.
        if (false == MetaData.Instance.m_test_user_create_meta_datas.TryGetValue(accountId, out var found_test_user_create_data))
        {
            err_msg = $"Not found TestUserCreateData !!! : accountId:{accountId}";
            Log.getLogger().warn(err_msg);

            // 1.1. TestUserCreateData Meta 파일에서 기본 계정 정보가 존재하는 지 체크 한다.
            if (false == MetaData.Instance.m_test_user_create_meta_datas.TryGetValue(MetaHelper.GameConfigMeta.DefaultTestAccountId, out found_test_user_create_data))
            {
                err_msg = $"Not found TestUserCreateData !!! : DefaultTestId:{MetaHelper.GameConfigMeta.DefaultTestAccountId} - accountId:{accountId}";
                result.setFail(ServerErrorCode.MetaDataNotFoundByTestUserId, err_msg);
                Log.getLogger().error(result.toBasicString());

                return (result, null);
            }
        }

        return (result, found_test_user_create_data);
    }

    public static async Task<(Result, MetaAssets.UserCreateMetaData?)> getUserCreateDataByAccountId(META_ID userCreateMetaId, string accountId)
    {
        await Task.CompletedTask;

        var result = new Result();
        var err_msg = string.Empty;

        // 1. UserCreateData Meta 파일에서 특정 계정 정보가 존재하는 지 체크 한다.
        if (false == MetaData.Instance.m_user_create_meta_datas.TryGetValue((int)userCreateMetaId, out var found_user_create_data))
        {
            err_msg = $"Not found UserCreateData !!! : metaId:{userCreateMetaId} - accountId:{accountId}";
            Log.getLogger().error(err_msg);

            return (result, null);
        }

        return (result, found_user_create_data);
    }

    public static async Task<(Result, AccountBaseDoc?)> fillupAccountBaseDocForAccountCreate(UserBase userBase, string accountId)
    {
        await Task.CompletedTask;

        var result = new Result();
        var err_msg = string.Empty;

        // 1. AccountAttribute 기본 생성 정보를 설정 한다.
        var account_attribute = userBase.getEntityAttribute<AccountAttribute>();
        NullReferenceCheckHelper.throwIfNull(account_attribute, () => $"account_attribute is null !!! - {userBase.toBasicString()}");

        account_attribute.AccountId = accountId;
        account_attribute.AccountCreationType = (accountId.isContainsBotId() == false ? AccountCreationType.Normal : AccountCreationType.Bot);
        account_attribute.newUserGuid(); // LoginCache 및 Game 시스템에서 유저 식별을 할 수 있도록 여기서 UserGuid를 미리 발급해 둔다 !!! - kangms
        account_attribute.LanguageType = LanguageType.Ko;
        account_attribute.newEntityAttribute();

        // 2. AccountBaseDoc를 생성 한다.
        (result, var new_account_base_doc) = await account_attribute.toDocBase();
        if (result.isFail())
        {
            return (result, null);
        }
        NullReferenceCheckHelper.throwIfNull(new_account_base_doc, () => $"new_account_base_doc is null !!! - {userBase.toBasicString()}");

        var account_base_attrib = new_account_base_doc.getAttrib<AccountBaseAttrib>();
        NullReferenceCheckHelper.throwIfNull(account_base_attrib, () => $"account_base_attrib is null - {userBase.toBasicString()}");
        account_base_attrib.CreatedDateTime = DateTimeHelper.Current;

        return (result, new_account_base_doc as AccountBaseDoc);
    }

    public static async Task<(Result, AccountBaseDoc?)> fillupAccountBaseDocByTestUserCreateData(UserBase userBase, string accountId)
    {
        var result = new Result();
        var err_msg = string.Empty;

        AccountBaseDoc? new_account_base_doc;

        try
        {
            // 1. TestUserCreateData Meta 파일에서 특정 계정 정보가 존재하는 지 체크 한다.
            (result, var found_test_user_create_data) = await getTestUserCreateDataByAccountId(accountId);
            if (result.isFail() || null == found_test_user_create_data)
            {
                err_msg = $"Not found TestUserCreateData for Account Create !!! : {result.toBasicString()} - accountId:{accountId}";
                Log.getLogger().error(err_msg);

                return (result, null);
            }

            // 1. AccountAttribute 기본 생성 정보를 설정 한다.
            var account_attribute = userBase.getEntityAttribute<AccountAttribute>();
            NullReferenceCheckHelper.throwIfNull(account_attribute, () => $"account_attribute is null !!! - {userBase.toBasicString()}");

            account_attribute.AccountId = accountId;
            account_attribute.AccountCreationType = (accountId.isContainsBotId() == false ? AccountCreationType.Test : AccountCreationType.Bot);
            account_attribute.newUserGuid();// LoginCache 및 Game 시스템에서 유저 식별을 할 수 있도록 여기서 UserGuid를 미리 발급해 둔다 !!! - kangms
            account_attribute.newEntityAttribute();

            if (false == account_attribute.copyEntityAttributeFromMeta(found_test_user_create_data))
            {
                err_msg = $"Failed to copyEntityAttributeFromMeta() !!! : to:{account_attribute.getTypeName()}, from:{found_test_user_create_data.getTypeName()} - accountId:{accountId}";
                result.setFail(ServerErrorCode.MetaDataCopyToEntityAttributeFailed, err_msg);
                Log.getLogger().error(err_msg);

                return (result, null);
            }

            // 2. AccountBaseDoc를 생성 한다.
            (result, var maked_doc) = await account_attribute.toDocBase();
            if (result.isFail())
            {
                return (result, null);
            }
            new_account_base_doc = maked_doc as AccountBaseDoc;
            NullReferenceCheckHelper.throwIfNull(new_account_base_doc, () => $"new_account_base_doc is null - {userBase.toBasicString()}");
            var account_base_attrib = new_account_base_doc.getAttrib<AccountBaseAttrib>();
            NullReferenceCheckHelper.throwIfNull(account_base_attrib, () => $"account_base_attrib is null - {userBase.toBasicString()}");
            account_base_attrib.CreatedDateTime = DateTimeHelper.Current;

            // 3. AccountBaseDoc를 추가로 구성한다.
            // - TestUserCreateData => AccountBaseDoc 에 선택적으로 복사한다.
            result = await DataCopyHelper.copyDocFromMetas(new_account_base_doc, new List<MetaAssets.IMetaData>() { found_test_user_create_data });
            if (result.isFail())
            {
                err_msg = $"Failed to copyDocFromMetas() !!! : accountId:{accountId}";
                Log.getLogger().error(err_msg);
                return (result, null);
            }
        }
        catch (Exception e)
        {
            err_msg = $"Failed to fillupAccountBaseDocByTestUserCreateData() !!! : Exception:{e} - accountId:{accountId}";
            result.setFail(ServerErrorCode.DotNetException, err_msg);
            Log.getLogger().error(result.toBasicString());

            return (result, null);
        }

        return (result, new_account_base_doc);
    }

    public static async Task<(Result, UserBaseDoc?)> fillupUserBaseDocBy(UserBase userBase, AccountBaseDoc accountBaseDoc)
    {
        ArgumentNullReferenceCheckHelper.throwIfNull(userBase, () => $"userBase is null !!!");
        ArgumentNullReferenceCheckHelper.throwIfNull(accountBaseDoc, () => $"accountBaseDoc is null !!! - {userBase.toBasicString()}");

        var result = new Result();
        var err_msg = string.Empty;

        var owner = userBase;

        var account_attribute = owner.getEntityAttribute<AccountAttribute>();
        NullReferenceCheckHelper.throwIfNull(account_attribute, () => $"account_attribute is null !!! - {userBase.toBasicString()}");

        var account_id = account_attribute.AccountId;

        var user_attribute = owner.getEntityAttribute<UserAttribute>();
        NullReferenceCheckHelper.throwIfNull(user_attribute, () => $"user_attribute is null !!! - {userBase.toBasicString()}");
        user_attribute.GameLoginDateTime = owner.getLoginStartTime();
        user_attribute.newEntityAttribute();

        UserBaseDoc? user_base_doc_nullable;
        
        try
        {
            if (false == user_attribute.copyEntityAttributeFromAccountBaseDoc(accountBaseDoc))
            {
                err_msg = $"Failed to copyEntityAttributeFromAccountBaseDoc() !!! : {accountBaseDoc.toBasicString()}";
                result.setFail(ServerErrorCode.DynamoDbDocCopyToEntityAttributeFailed, err_msg);
                Log.getLogger().error(err_msg);

                return (result, null);
            }

            (result, var user_doc_base) = await user_attribute.toDocBase();
            if (result.isFail())
            {
                err_msg = $"Failed to toDocBase() !!! : {result.toBasicString()} - {user_attribute.toBasicString()}";
                Log.getLogger().error(err_msg);

                return (result, null);
            }
            user_base_doc_nullable = user_doc_base as UserBaseDoc;
            NullReferenceCheckHelper.throwIfNull(user_base_doc_nullable, () => $"user_base_doc_nullable is null - {userBase.toBasicString()}");
        }
        catch (Exception e)
        {
            err_msg = $"Failed to fillupUserBaseDocBy() !!! : Exception:{e} - userGuid:{user_attribute.UserGuid}, accountId:{account_id}";
            result.setFail(ServerErrorCode.DotNetException, err_msg);
            Log.getLogger().error(result.toBasicString());

            return (result, null);
        }

        return (result, user_base_doc_nullable);
    }

    public static async Task<(Result, CharacterBaseDoc?)> fillupCharacterBaseDocByTestUserCreateData(UserAttribute userAttribute, CharacterAttribute characterAttribute)
    {
        ArgumentNullReferenceCheckHelper.throwIfNull(userAttribute, () => $"userAttribute is null !!!");

        var owner = userAttribute.getOwner();
        NullReferenceCheckHelper.throwIfNull(owner, () => $"owner is null !!!");
        ArgumentNullReferenceCheckHelper.throwIfNull(characterAttribute, () => $"characterAttribute is null !!! - {owner.toBasicString()}");

        var result = new Result();
        var err_msg = string.Empty;

        var account_id = userAttribute.AccountId;
        var user_guid = userAttribute.UserGuid;

        var new_character_base_doc = new CharacterBaseDoc();

        try
        {
            // 1. TestUserCreateData Meta 파일에서 특정 계정 정보가 존재하는 지 체크 한다.
            (result, var found_test_user_create_data) = await getTestUserCreateDataByAccountId(account_id);
            if (result.isFail())
            {
                err_msg = $"Not found TestUserCreateData for Character Create !!! : {result.toBasicString()} - accountId:{account_id}";
                Log.getLogger().error(err_msg);

                return (result, null);
            }
            NullReferenceCheckHelper.throwIfNull(found_test_user_create_data, () => $"found_test_user_create_data is null !!! - {owner.toBasicString()}");

            // 2. CharacterBaseDoc 를 구성 한다.
            if (false == characterAttribute.copyEntityAttributeFromMeta(found_test_user_create_data))
            {
                err_msg = $"Failed to copyEntityAttributeFromMeta() !!!, to:{characterAttribute.getTypeName()}, from:{found_test_user_create_data.getTypeName()}";
                result.setFail(ServerErrorCode.MetaDataCopyToEntityAttributeFailed, err_msg);
                Log.getLogger().error(result.toBasicString());

                return (result, null);
            }

            characterAttribute.newEntityAttribute();

            (result, var character_doc) = await characterAttribute.toDocBase();
            if (result.isFail())
            {
                return (result, null);
            }
            new_character_base_doc = character_doc as CharacterBaseDoc;
            NullReferenceCheckHelper.throwIfNull(new_character_base_doc, () => $"new_character_base_doc is null !!! - {owner.toBasicString()}");
        }
        catch (Exception e)
        {
            err_msg = $"Failed to fillupCharacterBaseDocByTestUserCreateData() !!! : Exception:{e} - accountId:{account_id}, userGuid:{user_guid}";
            result.setFail(ServerErrorCode.DotNetException, err_msg);
            Log.getLogger().error(result.toBasicString());

            return (result, null);
        }

        return (result, new_character_base_doc);
    }

    public static async Task<(Result, CharacterBaseDoc?)> fillupCharacterBaseDocByUserCreateData( META_ID userCreateMetaId
                                                                                                , UserAttribute userAttribute, CharacterAttribute characterAttribute)
    {
        ArgumentNullReferenceCheckHelper.throwIfNull(userAttribute, () => $"userAttribute is null !!!");

        var owner = userAttribute.getOwner();
        NullReferenceCheckHelper.throwIfNull(owner, () => $"owner is null !!!");
        ArgumentNullReferenceCheckHelper.throwIfNull(characterAttribute, () => $"characterAttribute is null !!! - {owner.toBasicString()}");

        var result = new Result();
        var err_msg = string.Empty;

        var account_id = userAttribute.AccountId;
        var user_guid = userAttribute.UserGuid;

        var new_character_base_doc = new CharacterBaseDoc();

        try
        {
            // 1. UserCreateData Meta 파일에서 특정 계정 정보가 존재하는 지 체크 한다.
            (result, var found_user_create_data) = await getUserCreateDataByAccountId(userCreateMetaId, account_id);
            if (result.isFail())
            {
                err_msg = $"Not found serCreateData for Character Create !!! : {result.toBasicString()} - accountId:{account_id}";
                Log.getLogger().error(err_msg);

                return (result, null);
            }
            NullReferenceCheckHelper.throwIfNull(found_user_create_data, () => $"found_user_create_data is null !!! - {owner.toBasicString()}");

            // 2. CharacterBaseDoc 를 구성 한다.
            if (false == characterAttribute.copyEntityAttributeFromMeta(found_user_create_data))
            {
                err_msg = $"Failed to copyEntityAttributeFromMeta() !!!, to:{characterAttribute.getTypeName()}, from:{found_user_create_data.getTypeName()}";
                result.setFail(ServerErrorCode.MetaDataCopyToEntityAttributeFailed, err_msg);
                Log.getLogger().error(result.toBasicString());

                return (result, null);
            }

            characterAttribute.newEntityAttribute();

            (result, var character_doc) = await characterAttribute.toDocBase();
            if (result.isFail())
            {
                return (result, null);
            }
            new_character_base_doc = character_doc as CharacterBaseDoc;
            NullReferenceCheckHelper.throwIfNull(new_character_base_doc, () => $"new_character_base_doc is null !!! - {owner.toBasicString()}");
        }
        catch (Exception e)
        {
            err_msg = $"Failed to fillupCharacterBaseDocByUserCreateData() !!! : Exception:{e} - accountId:{account_id}, userGuid:{user_guid}";
            result.setFail(ServerErrorCode.DotNetException, err_msg);
            Log.getLogger().error(result.toBasicString());

            return (result, null);
        }

        return (result, new_character_base_doc);
    }

    public static ClothInfo toClothInfo(this MetaAssets.TestUserCreateMetaData testUserCreateData, string userId)
    {
        var err_msg = string.Empty;
        var cloth_info = new ClothInfo();

        if (testUserCreateData.WearingItems == null)
        {
            return cloth_info;
        }

        foreach (var item_meta_id in testUserCreateData.WearingItems)
        {
            MetaData.Instance._ItemTable.TryGetValue(item_meta_id, out var found_item_meta);
            if (null == found_item_meta)
            {
                err_msg = $"Not found Cloth Item in ItemData !!! : ItemMetaId:{item_meta_id} - userId:{userId}";
                Log.getLogger().error(err_msg);
                continue;
            }

            var meta_id = (uint)found_item_meta.ItemId;

            var error_code = found_item_meta.fillupClothInfo(ref cloth_info, userId);
            if (ServerErrorCode.Success != error_code)
            {
                err_msg = $"Failed to fillup ClothInfo !!! : errorCode:{error_code}, ItemMetaId:{item_meta_id} - TestUserCreateMetaId:{testUserCreateData.MetaId}, userId:{userId}";
                Log.getLogger().error(err_msg);
                continue;
            }
        }

        return cloth_info;
    }

    public static ServerErrorCode fillupClothInfo(this MetaAssets.ItemMetaData metaData, ref ClothInfo clothInfo, string userId)
    {
        ArgumentNullReferenceCheckHelper.throwIfNull(clothInfo, () => $"clothInfo is null !!!");

        var err_msg = string.Empty;

        if (null == clothInfo)
        {
            err_msg = $"Function param is null, ClothInfo !!! : ItemMetaId:{metaData.ItemId} - userId:{userId}";
            Log.getLogger().error(err_msg);
            return ServerErrorCode.FunctionParamNull;
        }

        var meta_id = (uint)metaData.ItemId;

        if (false == metaData.TypeLarge.isClothType())
        {
            err_msg = $"Not EItemLargeType of Cloth !!! : EItemLargeType.Cloth == {metaData.TypeLarge}, ItemMetaId:{meta_id} - userId:{userId}";
            Log.getLogger().error(err_msg);
            return ServerErrorCode.ItemClothInvalidLargeType;
        }

        if (false == metaData.TypeSmall.isClothType())
        {
            err_msg = $"Not EItemSmallType of Cloth !!! : EItemSmallType:{metaData.TypeSmall}, ItemMetaId:{meta_id} - userId:{userId}";
            Log.getLogger().error(err_msg);
            return ServerErrorCode.ItemClothInvalidSmallType;
        }

        clothInfo.setClothInfo(metaData, userId);

        return ServerErrorCode.Success;
    }

    public static bool isClothType(this MetaAssets.ItemMetaData itemMeta)
    {
        if (true == itemMeta.TypeLarge.isClothType()
           && true == itemMeta.TypeSmall.isClothType())
        {
            return true;
        }

        return false;
    }

    public static bool isClothType(this MetaAssets.EItemLargeType itemLargeType)
    {
        if (MetaAssets.EItemLargeType.CLOTH == itemLargeType)
        {
            return true;
        }

        return false;
    }

    public static bool isClothType(this MetaAssets.EItemSmallType itemSmallType)
    {
        switch (itemSmallType)
        {
            case MetaAssets.EItemSmallType.CAP:
            case MetaAssets.EItemSmallType.MASK:
            case MetaAssets.EItemSmallType.GLASSES:
            case MetaAssets.EItemSmallType.EARRING:
            case MetaAssets.EItemSmallType.NECKLACE:
            case MetaAssets.EItemSmallType.SHIRT:
            case MetaAssets.EItemSmallType.DRESS:
            case MetaAssets.EItemSmallType.PANTS:
            case MetaAssets.EItemSmallType.SOCKS:
            case MetaAssets.EItemSmallType.ANKLET:
            case MetaAssets.EItemSmallType.GLOVES:
            case MetaAssets.EItemSmallType.BRACELET:
            case MetaAssets.EItemSmallType.RING:
            case MetaAssets.EItemSmallType.SHOES:
            case MetaAssets.EItemSmallType.OUTER:
            case MetaAssets.EItemSmallType.BACKPACK:
            case MetaAssets.EItemSmallType.BAG:
            case MetaAssets.EItemSmallType.SHOULDERBAG:
                break;

            default:
                return false;
        }

        return true;
    }

    public static bool setClothInfo(this ClothInfo clothInfo, MetaAssets.ItemMetaData itemMeta, string userId)
    {
        ArgumentNullReferenceCheckHelper.throwIfNull(itemMeta, () => $"itemMeta is null !!!");

        var meta_id = (uint)itemMeta.ItemId;

        var err_msg = string.Empty;

        switch (itemMeta.TypeSmall)
        {
            case MetaAssets.EItemSmallType.CAP:
                clothInfo.ClothHeadwear = meta_id;
                break;
            case MetaAssets.EItemSmallType.MASK:
            case MetaAssets.EItemSmallType.GLASSES:
                clothInfo.ClothMask = meta_id;
                break;
            case MetaAssets.EItemSmallType.EARRING:
                clothInfo.ClothEarrings = meta_id;
                break;
            case MetaAssets.EItemSmallType.NECKLACE:
                clothInfo.ClothNeckless = meta_id;
                break;
            case MetaAssets.EItemSmallType.SHIRT:
            case MetaAssets.EItemSmallType.DRESS:
                clothInfo.ClothTops = meta_id;
                break;
            case MetaAssets.EItemSmallType.PANTS:
                clothInfo.ClothBottoms = meta_id;
                break;
            case MetaAssets.EItemSmallType.SOCKS:
            case MetaAssets.EItemSmallType.ANKLET:
                clothInfo.ClothSocks = meta_id;
                break;
            case MetaAssets.EItemSmallType.GLOVES:
            case MetaAssets.EItemSmallType.BRACELET:
            case MetaAssets.EItemSmallType.RING:
                clothInfo.ClothGloves = meta_id;
                break;
            case MetaAssets.EItemSmallType.SHOES:
                clothInfo.ClothShoes = meta_id;
                break;
            case MetaAssets.EItemSmallType.OUTER:
                clothInfo.ClothOuter = meta_id;
                break;
            case MetaAssets.EItemSmallType.BACKPACK:
            case MetaAssets.EItemSmallType.BAG:
            case MetaAssets.EItemSmallType.SHOULDERBAG:
                clothInfo.ClothBag = meta_id;
                break;

            default:
                err_msg = $"No EItemSmallType in ClothInfo !!! : EItemSmallType:{itemMeta.TypeSmall}, ItemMetaId:{meta_id} - userId:{userId}";
                Log.getLogger().warn(err_msg);
                return false;
        }

        return true;
    }

    public static bool isTattooType(this MetaAssets.ItemMetaData itemMeta)
    {
        if (true == itemMeta.TypeLarge.isTattooType())
        {
            return true;
        }

        return false;
    }

    public static bool isTattooType(this MetaAssets.EItemLargeType itemLargeType)
    {
        if (itemLargeType == MetaAssets.EItemLargeType.TATTOO)
        {
            return true;
        }

        return false;
    }

    public static CurrencyType toCurrencyType(this EntityDeltaType deltaType)
    {
        return deltaType switch
        {
            EntityDeltaType.MoneyGold => CurrencyType.Gold,
            EntityDeltaType.MoneySaphire => CurrencyType.Sapphire,
            EntityDeltaType.MoneyCalium => CurrencyType.Calium,
            EntityDeltaType.MoneyBeam => CurrencyType.Beam,
            EntityDeltaType.MoneyRuby => CurrencyType.Ruby,
            _ => CurrencyType.None
        };
    }
    
    public static CurrencyType intToCurrencyType(int currencyType)
    {
        return currencyType switch
        {
            1 => CurrencyType.Gold,
            2 => CurrencyType.Sapphire,
            3 => CurrencyType.Calium,
            4 => CurrencyType.Beam,
            5 => CurrencyType.Ruby,
            _ => CurrencyType.None
        };
    }

    public static bool isBalanceWithinMaxCurrency(this CurrencyType currencyType, double currencyValue)
    {
        var err_msg = string.Empty;

        // 해당 CurrencyType 으로 등록되어 있지 않아도 실패 처리 한다. !!!
        if (MetaData.Instance._CurrencyMetaTableByCurrencyType.TryGetValue(currencyType, out var currencyMetaData) == false)
        {
            err_msg = $"Not found CurrencyMetaData !!! : currencyType:{currencyType}";
            Log.getLogger().error(err_msg);

            return false;
        }

        // 제한 크기를 초과하면 실패 처리 한다. !!!
        if(currencyMetaData.MaxCount < currencyValue)
        {
            return false;
        }

        return true;
    }

    public static List<MailItem> toMailItems(List<MetaAssets.GachaMetaData> gachaMetaDatas)
    {
        ArgumentNullReferenceCheckHelper.throwIfNull(gachaMetaDatas, () => $"gachaMetaDatas is null !!!");

        var mail_items = new List<MailItem>();

        foreach(var gachaMetaData in gachaMetaDatas)
        {
            NullReferenceCheckHelper.throwIfNull(gachaMetaData, () => $"gachaMetaData is null !!!");
            NullReferenceCheckHelper.throwIfNull(gachaMetaData.Reward, () => $"gachaMetaData.Reward is null !!!");

            if (gachaMetaData.Reward.Item is MetaAssets.ItemReward reward_item)
            {
                var mail_item = new MailItem();
                mail_item.ItemId = (META_ID)reward_item.Id;
                mail_item.Count = reward_item.Count;

                mail_items.Add(mail_item);
            }
            else 
            {
                object? reward_type = null;
                if (gachaMetaData.Reward.Currency is MetaAssets.CurrencyReward reward_currency) 
                { 
                    reward_type = reward_currency; 
                }
                
                Log.getLogger().error($"Not supported RewardType in Mail !!! : {reward_type?.getTypeName() ?? string.Empty} - gachaMetaId:{gachaMetaData.Id}");
            }
        }

        return mail_items;
    }
}