namespace EgwCoreLib.Lux.Data.Repository.Supplier
{
    public class BuyOrderRepository : BaseRepository, IBuyOrderRepository
    {
        #region Public Constructors

        public BuyOrderRepository(IDbContextFactory<DataLayerContext> ctxFactory) : base(ctxFactory)
        {
        }

        #endregion Public Constructors

        #region Public Methods

        /// <inheritdoc />
        public async Task<bool> AddAsync(BuyOrderModel entity)
        {
            await using var dbCtx = await CreateContextAsync();
            await dbCtx.DbSetBuyOrder.AddAsync(entity);
            return await dbCtx.SaveChangesAsync() > 0;
        }

        /// <inheritdoc />
        public async Task<bool> DeleteAsync(BuyOrderModel entity)
        {
            await using var dbCtx = await CreateContextAsync();
            dbCtx.DbSetBuyOrder.Remove(entity);
            return await dbCtx.SaveChangesAsync() > 0;
        }

        /// <inheritdoc />
        public async Task<List<BuyOrderModel>> GetAllAsync()
        {
            await using var dbCtx = await CreateContextAsync();
            return await dbCtx.DbSetBuyOrder
                                .Include(c => c.SupplierNav)
                                .Include(o => o.BuyOrderRowNav)
                                    .ThenInclude(s => s.ItemNav)
                                .Include(m => m.BuyOrderRowNav)
                                    .ThenInclude(s => s.MatReqNav)
                                .AsNoTracking()
                                .ToListAsync();
        }

        /// <inheritdoc />
        public async Task<BuyOrderModel> GenerateFromSelectionAsync(Dictionary<string, List<int>> currSelDict)
        {
            if (currSelDict == null) throw new ArgumentNullException(nameof(currSelDict));
            if (currSelDict.Values.Any(l => l == null || l.Count == 0))
                throw new ArgumentException("La selezione contiene valori null o vuoti.");

            await using var dbCtx = await CreateContextAsync();

            // 1. Avvia transazione per garantire atomicità
            await using var tx = await dbCtx.Database.BeginTransactionAsync();

            try
            {
                // 2. Calcola il prossimo RefNum per l'anno corrente
                int nextRefNum = await GetNextRefNumAsync(DateTime.Today.Year);

                // 3. Crea il nuovo ordine padre
                var newOrder = new BuyOrderModel
                {
                    RefYear = DateTime.Today.Year,
                    RefNum = nextRefNum,
                    RefRev = 1,
                    Description = $"Acquisto raggruppato - {DateTime.Now:yyyy-MM-dd HH:mm}",
                    BuyOrderRowNav = new List<BuyOrderRowModel>()
                };

                dbCtx.DbSetBuyOrder.Add(newOrder);
                await dbCtx.SaveChangesAsync(); // Necessario per generare BuyOrderID

                // 4. Recupera in BATCH tutti i MatReq selezionati (Anti-N+1)
                var allSelectedIds = currSelDict.Values.SelectMany(ids => ids).Distinct().ToList();
                var matReqLookup = await dbCtx.DbSetMaterialReq
                                                .Where(m => allSelectedIds.Contains(m.MatReqID))
                                                .ToListAsync();
                //.Select(m => new { m.MatReqID, m.ItemID, m.TotQty, m.CodGroup })
                //.ToDictionaryAsync(m => m.MatReqID);

                // 5. Costruisci righe e join table
                int rowCounter = 1;
                foreach (var matReqIds in currSelDict.Values)
                {
                    foreach (var matReqId in matReqIds)
                    {
                        var matReqInfo = matReqLookup.FirstOrDefault(x => x.MatReqID == matReqId);
                        if (matReqInfo == null) continue;

                        var row = new BuyOrderRowModel
                        {
                            BuyOrderID = newOrder.BuyOrderID,
                            ItemID = matReqInfo.ItemID,
                            RowNum = rowCounter++,
                            ClassCode = matReqInfo.CodGroup,
                            ItemCode = matReqInfo.ItemCode,
                            DescriptionCode = matReqInfo.Description
                        };

                        var join = new BuyOrderRow2MatReqModel
                        {
                            MatReqID = matReqId,
                            Qty = matReqInfo.TotQty,
                            // BuyOrderRowID verrà popolato automaticamente da EF Core al SaveChanges
                        };

                        // segno processato
                        matReqInfo.Processed = true;

                        // EF Core gestisce le relazioni attraverso le collection
                        row.MatReqNav.Add(join);
                        newOrder.BuyOrderRowNav.Add(row);
                    }
                }

                await dbCtx.SaveChangesAsync();
                await tx.CommitAsync();

                return newOrder;
            }
            catch
            {
                await tx.RollbackAsync();
                throw;
            }
        }

        /// <summary>
        /// Helper calcolo del nuovo refNum dell'ordine
        /// </summary>
        /// <param name="year"></param>
        /// <returns></returns>
        private async Task<int> GetNextRefNumAsync(int year)
        {
            await using var dbCtx = await CreateContextAsync();

            var max = await dbCtx.DbSetBuyOrder
                                    .Where(o => o.RefYear == year)
                                    .MaxAsync(o => (int?)o.RefNum);
            return (max ?? 0) + 1;
        }

        /// <inheritdoc />
        public async Task<BuyOrderModel?> GetByIdAsync(int recId)
        {
            await using var dbCtx = await CreateContextAsync();
            return await dbCtx.DbSetBuyOrder
                                .Where(x => x.BuyOrderID == recId)
                                .Include(c => c.SupplierNav)
                                .Include(o => o.BuyOrderRowNav)
                                    .ThenInclude(s => s.ItemNav)
                                .Include(m => m.BuyOrderRowNav)
                                    .ThenInclude(s => s.MatReqNav)
                                .FirstOrDefaultAsync();
        }

        /// <inheritdoc />
        public async Task<List<BuyOrderModel>> GetFiltAsync(DateTime inizio, DateTime fine)
        {
            await using var dbCtx = await CreateContextAsync();
            return await dbCtx.DbSetBuyOrder
                                .Where(x => x.Inserted >= inizio && x.Inserted <= fine)
                                .Include(c => c.SupplierNav)
                                .Include(o => o.BuyOrderRowNav)
                                    .ThenInclude(s => s.ItemNav)
                                .Include(m => m.BuyOrderRowNav)
                                    .ThenInclude(s => s.MatReqNav)
                                .AsNoTracking()
                                .ToListAsync();
        }

        /// <inheritdoc />
        public async Task<List<BuyOrderRowModel>> GetRowsAsync(int recId)
        {
            await using var dbCtx = await CreateContextAsync();
            return await dbCtx.DbSetBuyOrderRow
                                .Where(x => x.BuyOrderID == recId)
                                .ToListAsync();
        }

        /// <inheritdoc />
        public async Task<bool> SaveRowsAsync(List<BuyOrderRowModel> rows)
        {
            // Add validation for null or empty list
            if (rows == null || rows.Count == 0) return false;

            await using var dbCtx = await CreateContextAsync();

            // Wrap in transaction for atomicity (batch update multiple rows)
            await using var tx = await dbCtx.Database.BeginTransactionAsync();
            try
            {
                foreach (var row in rows)
                    dbCtx.Entry(row).State = EntityState.Modified;

                bool done = await dbCtx.SaveChangesAsync() > 0;

                if (done)
                    await tx.CommitAsync();

                return done;
            }
            catch
            {
                await tx.RollbackAsync();
                throw;
            }
        }

        /// <inheritdoc />
        public async Task<bool> UpdateAsync(BuyOrderModel entity)
        {
            await using var dbCtx = await CreateContextAsync();
            // Recuperiamo l'entità tracciata dal context
            var trackedEntity = await dbCtx.DbSetBuyOrder.FirstOrDefaultAsync(x => x.BuyOrderID == entity.BuyOrderID);

            if (trackedEntity != null)
            {
                // Aggiorna i valori dell'entità tracciata con quelli della nuova
                dbCtx.Entry(trackedEntity).CurrentValues.SetValues(entity);
            }
            else
            {
                dbCtx.DbSetBuyOrder.Update(entity);
            }
            return await dbCtx.SaveChangesAsync() > 0;
        }

        #endregion Public Methods
    }
}