using Microsoft.EntityFrameworkCore.Storage;
using SPMS.Domain.Interfaces;

namespace SPMS.Infrastructure.Persistence;

public class UnitOfWork : IUnitOfWork
{
    private readonly AppDbContext _context;
    private IDbContextTransaction? _transaction;

    public UnitOfWork(AppDbContext context)
    {
        _context = context;
    }

    public async Task<int> SaveChangesAsync(CancellationToken cancellationToken = default)
        => await _context.SaveChangesAsync(cancellationToken);

    public async Task<IDisposable> BeginTransactionAsync(CancellationToken cancellationToken = default)
    {
        _transaction = await _context.Database.BeginTransactionAsync(cancellationToken);
        return _transaction;
    }

    public async Task CommitTransactionAsync(CancellationToken cancellationToken = default)
    {
        if (_transaction is null)
            throw new InvalidOperationException("Transaction has not been started.");

        await _transaction.CommitAsync(cancellationToken);
        await _transaction.DisposeAsync();
        _transaction = null;
    }

    public async Task RollbackTransactionAsync(CancellationToken cancellationToken = default)
    {
        if (_transaction is null)
            throw new InvalidOperationException("Transaction has not been started.");

        await _transaction.RollbackAsync(cancellationToken);
        await _transaction.DisposeAsync();
        _transaction = null;
    }

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