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


using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.DocumentModel;
using Amazon.DynamoDBv2.Model;



using ServerCore; using ServerBase;


using LINK_PKSK = System.String;


namespace ServerBase;

/*=============================================================================================
  DynamoDb 정보 관리 흐름도

  # 읽기는 Document Only, 쓰기는 Document + ItemRequest 로 처리는 하는 것이 적절하다 !!!
 
  1. Document Only 시퀀스
      
    * 읽기 => 쓰기
      DB => Document => Attrib => Doc => EntityAttribute => Doc => Attrib => Document => DB

  2. ItemRequest Only 시퀀스
      
    * 읽기 => 쓰기
      DB => ItemRequest => EntityAttribute => ItemRequest => DB
   
  3. Document + ItemRequest 시퀀스

    * 읽기 => 쓰기
      DB => ItemRequest => Document => Attrib => Doc => Attrib => Document => ItemRequest => DB
    
                                                                                     - kangms
//===========================================================================================*/


//=============================================================================================
// DynamoDB의 쿼리의 종류를 정의 한다.
// 
//                                                                                   - kangms
//=============================================================================================

public enum QueryType
{
    None = 0,

    // 일반 쿼리
    Select,         // 조회 한다.
    Insert,         // 존재하지 않은 경우만 추가 한다.
    Update,         // 존재하는 경우만 업데이트 한다.
    Upsert,         // 존재하지 않으면 추가하고, 있으면 업데이트 한다.
    Delete,         // 존재하는 경우 삭제 한다.

    // 특수 쿼리
    ExistsDelete,   // 존재하지 않을 경우, 삭제되기 전 모든 속성을 반환 한다.
}

//=============================================================================================
// DynamoDB의 PrimaryKey를 설정하는 클래스 이다.
// 
//                                                                                   - kangms
//=============================================================================================

public class PrimaryKey
{
    public const string PK_Define = "PK";
    public const string SK_Define = "SK";

    [JsonProperty(PK_Define)]
    public string PK { get; private set; } = string.Empty;
    [JsonProperty(SK_Define)]
    public string SK { get; private set; } = string.Empty;

    public PrimaryKey()
    { }

    public PrimaryKey(string partitionKey)
    {
        PK = partitionKey;
    }
    public PrimaryKey(string partitionKey, string sortKey)
    {
        PK = partitionKey;
        SK = sortKey;
    }

    public bool isFilledPK()
    {
        if (true == PK.isNullOrWhiteSpace())
        {
            return false;
        }

        return true;
    }

    public bool isFilledSK()
    {
        if (true == SK.isNullOrWhiteSpace())
        {
            return false;
        }

        return true;
    }

    public void fillUpPrimaryKey(string partitionKey, string sortKey)
    {
        PK = partitionKey;
        SK = sortKey;
    }
    public void fillUpPK(string partitionKey)
    {
        PK = partitionKey;
    }
    public void fillUpSK(string sortKey)
    {
        SK = sortKey;
    }

    public void setEmptySK()
    {
        SK = DynamoDbClient.SK_EMPTY;
    }

    public string toPKSK()
    {
        return $"{PK_Define}:{PK}-{SK_Define}:{SK})";
    }

    //=====================================================================================
    // LINK_PKSK : "PK-SK"
    //=====================================================================================
    public static (Result, PrimaryKey?) parseLinkPKSK(LINK_PKSK linkPKSK)
    {
        var result = new Result();
        var err_msg = string.Empty;

        var pksk_parts = linkPKSK.Split('-');
        if (pksk_parts.Length != 2)
        {
            err_msg = $"Invalid length of LinkPKSK !!! : 2 == length:{pksk_parts.Length}";
            result.setFail(ServerErrorCode.DynamoDbDocLinkPkSkInvalid, err_msg);
            Log.getLogger().error(result.toBasicString());

            return (result, null);
        }

        return (result, new PrimaryKey(pksk_parts[0], pksk_parts[1]));
    }

    public string toBasicString()
    {
        return $"PrimaryKey({PK_Define}:{PK}, {SK_Define}:{SK})";
    }
}

//=============================================================================================
// DynamoDB의 Document Model에서 쿼리할때 옵션을 설정하는 클래스 이다.
// 
//                                                                                   - kangms
//=============================================================================================

public static class DynamoDbQueryOperationOptionConfig
{
    private static GetItemOperationConfig m_get_item_config = new();

    private static TransactWriteItemOperationConfig m_transact_write_config_for_exist_primary_key = new();
    private static TransactWriteItemOperationConfig m_transact_write_config_for_not_exist_primary_key = new ();

    // Select 쿼리후 반환되는 필드 선택 설정
    private static TransactGetItemOperationConfig m_transact_get_config = new();
    public static void configure()
    {

        {
            m_get_item_config.ConsistentRead = true;
        }

        {
            var expression = new Amazon.DynamoDBv2.DocumentModel.Expression();
            expression.ExpressionStatement = $"attribute_exists(#{PrimaryKey.PK_Define}) AND attribute_exists(#{PrimaryKey.SK_Define})";
            expression.ExpressionAttributeNames[$"#{PrimaryKey.PK_Define}"] = PrimaryKey.PK_Define;
            expression.ExpressionAttributeNames[$"#{PrimaryKey.SK_Define}"] = PrimaryKey.SK_Define;

            m_transact_write_config_for_exist_primary_key.ConditionalExpression = expression;
            m_transact_write_config_for_exist_primary_key.ReturnValuesOnConditionCheckFailure = Amazon.DynamoDBv2.DocumentModel.ReturnValuesOnConditionCheckFailure.AllOldAttributes;
        }

        {
            var expression = new Amazon.DynamoDBv2.DocumentModel.Expression();
            expression.ExpressionStatement = $"attribute_not_exists(#{PrimaryKey.PK_Define}) AND attribute_not_exists(#{PrimaryKey.SK_Define})";
            expression.ExpressionAttributeNames[$"#{PrimaryKey.PK_Define}"] = PrimaryKey.PK_Define;
            expression.ExpressionAttributeNames[$"#{PrimaryKey.SK_Define}"] = PrimaryKey.SK_Define;

            m_transact_write_config_for_not_exist_primary_key.ConditionalExpression = expression;
            m_transact_write_config_for_not_exist_primary_key.ReturnValuesOnConditionCheckFailure = Amazon.DynamoDBv2.DocumentModel.ReturnValuesOnConditionCheckFailure.AllOldAttributes;
        }
    }

    public static TransactWriteItemOperationConfig getTransactWriteConfigForExistKey() => m_transact_write_config_for_exist_primary_key;
    public static TransactWriteItemOperationConfig getTransactWriteConfigForNotExistKey() => m_transact_write_config_for_not_exist_primary_key;

    public static GetItemOperationConfig getItemConfig() => m_get_item_config;
}