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


using Newtonsoft.Json;
using Amazon.Runtime;
using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.DocumentModel;
using Amazon.DynamoDBv2.Model;
using Axion.Collections.Concurrent;



using DYNAMO_DB_TABLE_NAME = System.String;
using DYNAMO_DB_TABLE_FULL_NAME = System.String;
using MongoDB.Driver.Core.Configuration;


namespace ServerCore;

public abstract class DynamoDbConnectorBase
{
    // 하나의 아이템 최대 저장 크기 : PK + SK + ITEM <= ITEM_MAX_SIZE_BYTES
    public static readonly UInt32 ITEM_MAX_SIZE_BYTES = 400 * 1024;

    private AmazonDynamoDBClient? m_db_client;
    private ConcurrentDictionary<DYNAMO_DB_TABLE_NAME, DYNAMO_DB_TABLE_FULL_NAME> m_to_load_table_names = new();

    private string m_access_key = string.Empty;
    private string m_secret_key = string.Empty;
    private AmazonDynamoDBConfig? m_db_config;

    private ConcurrentDictionary<DYNAMO_DB_TABLE_FULL_NAME, Table> m_loaded_tables = new();

    public bool connectToDb(string accessKey, string secretKey, AmazonDynamoDBConfig dbConfig)
    {
        m_access_key = accessKey;
        m_secret_key = secretKey;
        m_db_config = dbConfig;

        try
        {
            m_db_client = new AmazonDynamoDBClient(accessKey, secretKey, dbConfig);
        }
        catch (Exception e)
        {
            Log.getLogger().error($"Exception !!!, Failed to perform in DynamoDbConnectorBase.connectToDb() !!! : exception:{e}, AccessKey:{accessKey}, SecretKey:{secretKey} - {toBasicString()}");
            return false;
        }

        return true;
    }

    public async Task<bool> isExistTable(string tableName)
    {
        try
        {
            if (m_db_client == null)
            {
                return false;
            }

            var loaded_tables = await m_db_client.ListTablesAsync();
            return loaded_tables.TableNames.Contains(tableName);
        }
        catch (Exception e)
        {
            Log.getLogger().fatal($"Exception !!!, Failed to perform in DynamoDbConnectorBase.isExistTable() !!! : exception:{e}, toFindTableName{tableName}");
            return false;
        }
    }

    public static async Task<bool> createTable( AmazonDynamoDBClient dbClient, DYNAMO_DB_TABLE_FULL_NAME tableFullName
                                              , UpdateTimeToLiveRequest ttlUpdate
                                              , List<AttributeDefinition> tableAttributes
                                              , List<KeySchemaElement> tableKeySchema )
    {
        var request = new CreateTableRequest
        {
            TableName = tableFullName,
            AttributeDefinitions = tableAttributes,
            KeySchema = tableKeySchema,
            BillingMode = BillingMode.PAY_PER_REQUEST
        };

        try
        {
            var new_table = await dbClient.CreateTableAsync(request);
            Log.getLogger().info($"Created DynamoDB Table : {new_table.TableDescription.TableName}");

            var ttl_res = await dbClient.UpdateTimeToLiveAsync(ttlUpdate);
            if (System.Net.HttpStatusCode.OK != ttl_res.HttpStatusCode)
            {
                Log.getLogger().fatal($"Failed to UpdateTimeToLiveAsync() !!!, not configured TTL : {ttlUpdate.TimeToLiveSpecification.AttributeName}, toCreateTableName{tableFullName}");
                return false;
            }

            var ttl_status_res = await dbClient.DescribeTimeToLiveAsync(new DescribeTimeToLiveRequest { TableName = tableFullName });
            if (TimeToLiveStatus.ENABLED != ttl_status_res.TimeToLiveDescription.TimeToLiveStatus)
            {
                Log.getLogger().fatal($"Failed to check configured TTL !!! : ttlName:{ttlUpdate.TimeToLiveSpecification.AttributeName}, toCreateTableName{tableFullName}");
                return false;
            }
        }
        catch (Exception e)
        {
            Log.getLogger().fatal($"Exception !!!, Failed to perform in DynamoDbConnectorBase.createTable() !!! : exception:{e}, toCreateTableName{tableFullName}");
            return false;
        }

        return true;
    }

    public static bool checkItemSizeLimit(string itemString)
    {
        var bytes = Encoding.UTF8.GetBytes(itemString);
        if (bytes.Length > ITEM_MAX_SIZE_BYTES)
        {
            return false;
        }

        return true;
    }

    public async Task<bool> createTable( DYNAMO_DB_TABLE_FULL_NAME tableFullName
                                       , List<AttributeDefinition> tableAttributes
                                       , List<KeySchemaElement> tableKeySchema
                                       , List<GlobalSecondaryIndex> globalSecondaryIndexes)
    {
        

        var request = new CreateTableRequest
        {
            TableName = tableFullName,
            AttributeDefinitions = tableAttributes,
            KeySchema = tableKeySchema,
            GlobalSecondaryIndexes = globalSecondaryIndexes,
            BillingMode = BillingMode.PAY_PER_REQUEST
        };

        try
        {
            if (m_db_client == null)
            {
                return false;
            }

            var new_table = await m_db_client.CreateTableAsync(request);

            Log.getLogger().info($"Created DynamoDB Table : {new_table.TableDescription.TableName}");
        }
        catch (Exception e)
        {
            Log.getLogger().fatal($"Exception !!!, Failed to perform in DynamoDbConnectorBase.createTable() !!! : exception:{e}, toCreateTableName{tableFullName}");
            return false;
        }

        return true;
    }

    public async Task<bool> deleteTables(List<DYNAMO_DB_TABLE_FULL_NAME> tableFullNames)
    {
        
        foreach(var table_full_name in tableFullNames)
        {
            var request = new DeleteTableRequest
            {
                TableName = table_full_name,
            };

            try
            {
                if (m_db_client == null)
                {
                    return false;
                }

                var deleted_table = await m_db_client.DeleteTableAsync(request);
            }
            catch (Exception e)
            {
                Log.getLogger().fatal($"Exception !!!, Failed to perform in DynamoDbConnectorBase.deleteTables() !!! : exception:{e}, toDeleteTableName{table_full_name}");
                return false;
            }
        }

        return true;
    }

    public async Task<TableDescription?> getTableDescription(DYNAMO_DB_TABLE_FULL_NAME tableFullName)
    {
        try
        {
            if (m_db_client == null)
            {
                return null;
            }

            var response = await m_db_client.DescribeTableAsync(tableFullName);
            return response.Table;
        }
        catch (Exception e)
        {
            Log.getLogger().fatal($"Exception !!!, Failed to perform in DynamoDbConnectorBase.getTableDescription() !!! : exception:{e}, TableName{tableFullName}");
            return null;
        }
    }

    public Table getTableByName(DYNAMO_DB_TABLE_NAME tableName) 
    {
        m_to_load_table_names.TryGetValue(tableName, out var table_full_name);
        NullReferenceCheckHelper.throwIfNull(table_full_name, () => $"table_full_name is null !!! : tableName:{tableName}");
        
        m_loaded_tables.TryGetValue(table_full_name, out var table);
        NullReferenceCheckHelper.throwIfNull(table, () => $"table is null !!!, Not found DynamoDb Table !!! : tableFullName:{table_full_name}");
        return table;
    }

    public Table getTableByFullName(DYNAMO_DB_TABLE_FULL_NAME tableFullName)
    {
        m_loaded_tables.TryGetValue(tableFullName, out var table);
        NullReferenceCheckHelper.throwIfNull(table, () => $"table is null !!!, Not found DynamoDb Table !!! : tableFullName:{tableFullName}");
        return table;
    }

    public bool addTable(DYNAMO_DB_TABLE_FULL_NAME tableFullName, Table loadedTable)
    {
        return m_loaded_tables.TryAdd(tableFullName, loadedTable);
    }

    public bool hasTableName(DYNAMO_DB_TABLE_NAME tableName) => m_to_load_table_names.ContainsKey(tableName);

    public DYNAMO_DB_TABLE_FULL_NAME getTableFullName(DYNAMO_DB_TABLE_NAME tableName)
    {
        m_to_load_table_names.TryGetValue(tableName, out var table_full_name);
        NullReferenceCheckHelper.throwIfNull(table_full_name, () => $"table_full_name is null !!! : tableName:{tableName}");
        return table_full_name;
    }

    public ConcurrentDictionary<DYNAMO_DB_TABLE_NAME, DYNAMO_DB_TABLE_FULL_NAME> getTableNames() => m_to_load_table_names;

    protected bool addTableFullName(DYNAMO_DB_TABLE_NAME tableName, DYNAMO_DB_TABLE_FULL_NAME tableFullName) => m_to_load_table_names.TryAdd(tableName, tableFullName);

    public string toConnectionKeyString()
    {
        return $"AccessKey:{m_access_key}, SecretKey:{m_secret_key}";
    }

    public string toBasicString()
    {
        return $"ServerUrl:{m_db_config?.ServiceURL}, RegionEndPoint:{m_db_config?.RegionEndpoint}";
    }

    public AmazonDynamoDBClient? getDbClient() => m_db_client;
}