using System.Data;

using Vitorm.Sql;
using Vitorm.Sql.Transaction;
using Vitorm.Transaction;

using SqlTransaction = Microsoft.Data.Sqlite.SqliteTransaction;

namespace Vitorm.Sqlite
{
    // sqlite/transactions  https://learn.microsoft.com/en-us/dotnet/standard/data/sqlite/transactions  
    public class SqlTransactionManager : Vitorm.Sql.Transaction.SqlTransactionManager
    {
        int savePointCount = 0;
        public Sql.Transaction.SqlTransaction CreateTransactionSavePoint(IDbTransaction originalTransaction)
        {
            var savePointName = "tran" + savePointCount++;
            return new TransactionSavePoint(originalTransaction, savePointName);
        }
        public SqlTransactionManager(SqlDbContext dbContext) : base(dbContext)
        {
        }

        public override ITransaction BeginTransaction()
        {
            Sql.Transaction.SqlTransaction transaction;
            IDbTransaction originalTransaction = GetDbTransaction();
            if (originalTransaction == null)
            {
                var dbConnection = dbContext.dbConnection;
                if (dbConnection.State != ConnectionState.Open) dbConnection.Open();
                originalTransaction = dbConnection.BeginTransaction();

                transaction = new Sql.Transaction.SqlTransaction(originalTransaction);
            }
            else
            {
                transaction = CreateTransactionSavePoint(originalTransaction);
            }

            transactions.Push(transaction);
            return transaction;
        }

    }

    public class TransactionSavePoint : Sql.Transaction.SqlTransaction
    {
        public SqlTransaction sqlTran => (SqlTransaction)originalTransaction;
        readonly string savePointName;
        public TransactionSavePoint(IDbTransaction transaction, string savePointName) : base(transaction)
        {
            this.savePointName = savePointName;
            sqlTran.Save(savePointName);
        }

        public override void Commit()
        {
            sqlTran.Release(savePointName);
            TransactionState = ETransactionState.Committed;
        }

        public override void Dispose()
        {
            if (TransactionState == ETransactionState.Active)
                sqlTran.Rollback(savePointName);
            TransactionState = ETransactionState.Disposed;
        }

        public override void Rollback()
        {
            sqlTran.Rollback(savePointName);
            TransactionState = ETransactionState.RolledBack;
        }
    }
}