using System;
using System.Collections.Generic;
using System.Collections.Concurrent;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


using Newtonsoft.Json;
using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.Model;
using Amazon.DynamoDBv2.DocumentModel;
using Amazon.Runtime;
using StackExchange.Redis;




using ServerCore; using ServerBase;
using ServerCommon.BusinessLogDomain;



using DYNAMO_DB_TABLE_NAME = System.String;
using SESSION_ID = System.Int32;
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
{
    public class DBQEntityWriteAfterRead<TDoc> : QueryExecutorBase
        where TDoc : DynamoDbDocBase, new()
    {
        private string m_combination_key_for_pk = string.Empty;
        private string m_combination_key_for_sk = string.Empty;

        private string m_pk = string.Empty;
        private string m_sk = string.Empty;

        private List<TDoc>? m_read_docs_nullable;

        public delegate Task<Result> FnEntityWrite(List<TDoc> readDocs);

        private FnEntityWrite m_fn_entity_write;

        public DBQEntityWriteAfterRead( string combinationKeyForPK, string combinationKeyForSK
                                      , FnEntityWrite fnEntityWrite )
            : base(typeof(DBQEntityWriteAfterRead<TDoc>).Name)
        {
            m_combination_key_for_pk = combinationKeyForPK;
            m_combination_key_for_sk = combinationKeyForSK;

            m_fn_entity_write = fnEntityWrite;
        }

        //=====================================================================================
        // DB 쿼리 직전에 준비해야 할 로직들을 작성한다.
        //=====================================================================================
        public override async Task<Result> onPrepareQuery()
        {
            var result = new Result();
            var err_msg = string.Empty;

            var owner = getOwner();
            NullReferenceCheckHelper.throwIfNull(owner, () => $"owner is null !!!");

            var doc = new TDoc();

            doc.setCombinationKeyForPKSK(m_combination_key_for_pk, m_combination_key_for_sk);

            var error_code = doc.onApplyPKSK();
            if(error_code.isFail())
            {
                err_msg = $"Failed to onApplyPKSK() !!! : {error_code.toBasicString()} - {toBasicString()}, {owner.toBasicString()}";
                result.setFail(error_code, err_msg);
                Log.getLogger().error(result.toBasicString());
                return result;
            }

            m_pk = doc.getPK();
            m_sk = doc.getSK();

            return await Task.FromResult(result);
        }

        //=====================================================================================
        // onPrepareQuery()를 성공할 경우 호출된다.
        //=====================================================================================
        public override async Task<Result> onQuery()
        {
            var result = new Result();
            var err_msg = string.Empty;

            var owner = getOwner();
            NullReferenceCheckHelper.throwIfNull(owner, () => $"owner is null !!!");

            var query_batch = getQueryBatch();
            NullReferenceCheckHelper.throwIfNull(query_batch, () => $"query_batch is null !!! - {owner.toBasicString()}");
            var query_runner = query_batch.getQueryRunner();
            NullReferenceCheckHelper.throwIfNull(query_runner, () => $"query_runner is null !!! - {owner.toBasicString()}");
            var dynamo_db_connector = query_batch.getDynamoDbConnector();

            QueryOperationConfig? query_config = null;
            if (true == m_sk.isNullOrWhiteSpace())
            {
                query_config = dynamo_db_connector.makeQueryConfigForReadByPKSK(m_pk);
            }
            else
            {
                query_config = dynamo_db_connector.makeQueryConfigForReadByPKSK(m_pk, m_sk);
            }

            (result, var read_docs) = await dynamo_db_connector.simpleQueryDocTypesWithQueryOperationConfig<TDoc>(query_config, eventTid: query_batch.getTransId());
            if(result.isFail())
            {
                return result;
            }

            m_read_docs_nullable = read_docs;

            var read_msg = $"{this.getTypeName()} : readCount:{read_docs.Count}, isUseTransact:{query_batch.isUseTransact()} - TransId:{query_batch.getTransId()}";
            Log.getLogger().info(read_msg);

            result = await m_fn_entity_write.Invoke(m_read_docs_nullable);
            if(result.isFail()) 
            {
                return result;
            }

            var query_batch_with_document = query_batch as QueryBatch<QueryRunnerWithDocument>;
            NullReferenceCheckHelper.throwIfNull(query_batch_with_document, () => $"query_batch_with_document is null !!! - {owner.toBasicString()}");

            foreach (var to_write_doc in m_read_docs_nullable)
            {
                (result, var query_context) = await query_runner.tryCreateQueryContext(to_write_doc);
                if (result.isFail())
                {
                    return result;
                }
                NullReferenceCheckHelper.throwIfNull(query_context, () => $"query_context is null !!! - {owner.toBasicString()}");

                result = await query_runner.tryRegisterQueryContext(query_context);
                if (result.isFail())
                {
                    return result;
                }
            }

            var write_msg = $"{this.getTypeName()} : tryWriteCount:{m_read_docs_nullable.Count}, isUseTransact:{query_batch.isUseTransact()} - TransId:{query_batch.getTransId()}";
            Log.getLogger().info(write_msg);

            return result;
        }

        public List<TDoc>? getReadDocs() => m_read_docs_nullable;

        //=====================================================================================
        // DB 쿼리를 성공하고, doFnCommit()가 QueryResultType.NotCalledQueryFunc를 반환할 경우 호출된다.
        //=====================================================================================
        public override async Task onQueryResponseCommit()
        {
            await Task.CompletedTask;
            return;
        }

        //=====================================================================================
        // DB 쿼리를 실패하고, doFnRollback()가 QueryResultType.NotCalledQueryFunc를 반환할 경우 호출된다.
        //=====================================================================================
        public override async Task onQueryResponseRollback(Result errorResult)
        {
            await Task.CompletedTask;
            return;
        }
    }
}