using System;
using System.Data;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Storage;

namespace IRaCIS.Core.Infra.EFCore
{
    public class EFUnitOfWork<TDbContext> :
        IEFUnitOfWork<TDbContext> where TDbContext : DbContext
        , IDisposable
    {
        public DbContext DbContext { get; }
        // https://docs.microsoft.com/en-us/ef/core/saving/transactions
        private  IDbContextTransaction _transaction;

        public EFUnitOfWork(TDbContext dbContext)
        {
            DbContext = dbContext;
        }

 
        public void BeginTransaction(IsolationLevel isolationLevel = IsolationLevel.ReadCommitted)
        {
            if (DbContext.Database.IsRelational())
            {
                _transaction = DbContext.Database.BeginTransaction(isolationLevel);
            }
        }

        public async Task BeginTransactionAsync(IsolationLevel isolationLevel = IsolationLevel.ReadCommitted)
        {
            if (DbContext.Database.IsRelational())
            {
                _transaction = await DbContext.Database.BeginTransactionAsync(isolationLevel);
            }
        }

        //失败 自动回退
        public virtual void Commit()
        {
            DbContext.SaveChanges();
            _transaction?.Commit();
        }

        public virtual async Task CommitAsync(CancellationToken cancellationToken)
        {
            await DbContext.SaveChangesAsync(cancellationToken);

            await _transaction?.CommitAsync(cancellationToken);

        }

        public virtual void Dispose()
        {
            _transaction?.Dispose();
        }

       
    }
}