using Contracts.BindingModels;
using Contracts.SearchModels;
using Contracts.StorageContracts;
using Contracts.ViewModels;
using DatabaseImplement.Models;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DatabaseImplement.Implements
{
	public class PurchaseStorage : IPurchaseStorage
	{
		public PurchaseViewModel? Delete(PurchaseSearchModel model)
		{
            using var context = new Database();
            var element = context.Purchases.FirstOrDefault(rec => rec.Id == model.Id);
            if (element != null)
            {
                context.Purchases.Remove(element);
                context.SaveChanges();
                return element.GetViewModel;
            }
            return null;
        }

		public PurchaseViewModel? GetElement(PurchaseSearchModel model)
		{
            if (!model.Id.HasValue)
            {
                return null;
            }
            using var context = new Database();
            return context.Purchases
            .Include(x => x.Products)
            .ThenInclude(x => x.Product)
            .FirstOrDefault(x => (model.Id.HasValue && x.Id == model.Id))?.GetViewModel;
        }

		public List<PurchaseViewModel> GetFullList(PurchaseSearchModel? model)
		{
            using var context = new Database();
            return context.Purchases
            .Include(x => x.Products)
            .ThenInclude(x => x.Product)
            .ToList()
            .Select(x => x.GetViewModel)
            .ToList();
        }
        public List<PurchaseViewModel> GetFilteredList(PurchaseSearchModel? model)
        {
            using var context = new Database();
            if (!model.CostFrom.HasValue && !model.CostTo.HasValue && !model.DateTo.HasValue && !model.DateFrom.HasValue && !model.Status.HasValue)
            {
                return new();
            }

            if (model.CostFrom.HasValue && model.CostTo.HasValue)
            {
                return context.Purchases
                .Where(x => x.Cost <= model.CostTo && x.Cost >= model.CostFrom)
                .ToList()
                .Select(x => x.GetViewModel)
                .ToList();
            }
            if (model.CostFrom.HasValue)
            {
                return context.Purchases
                .Where(x => x.Cost >= model.CostFrom)
                .ToList()
                .Select(x => x.GetViewModel)
                .ToList();
            }
            if (model.CostTo.HasValue)
            {
                return context.Purchases
                .Where(x => x.Cost <= model.CostTo)
                .ToList()
                .Select(x => x.GetViewModel)
                .ToList();
            }
            if (model.DateFrom.HasValue && model.DateTo.HasValue)
            {
                return context.Purchases
                .Where(x => x.DatePurchase <= model.DateTo && x.DatePurchase >= model.DateFrom)
                .ToList()
                .Select(x => x.GetViewModel)
                .ToList();
            }
            if (model.DateFrom.HasValue)
            {
                return context.Purchases
                .Where(x => x.DatePurchase >= model.DateFrom)
                .ToList()
                .Select(x => x.GetViewModel)
                .ToList();
            }
            if (model.DateTo.HasValue)
            {
                return context.Purchases
                .Where(x => x.DatePurchase <= model.DateTo)
                .ToList()
                .Select(x => x.GetViewModel)
                .ToList();
            }
            return context.Purchases
            .Include(x => x.Products)
            .ThenInclude(x => x.Product)
            .ToList()
            .Select(x => x.GetViewModel)
            .ToList();
        }

        public PurchaseViewModel? Insert(PurchaseBindingModel model)
		{
            using var context = new Database();
            var purchase = Purchase.Create(context, model);
            if (purchase == null)
                return null;
            context.Purchases.Add(purchase);
            context.SaveChanges();
            return purchase.GetViewModel;
        }

		public PurchaseViewModel? Update(PurchaseBindingModel model)
		{
            using var context = new Database();
            using var transaction = context.Database.BeginTransaction();
            try
            {
                var purchase = context.Purchases.FirstOrDefault(rec =>
                rec.Id == model.Id);
                if (purchase == null)
                {
                    return null;
                }
                purchase.Update(model);
                context.SaveChanges();
                purchase.UpdateProducts(context, model);
                transaction.Commit();
                return purchase.GetViewModel;
            }
            catch
            {
                transaction.Rollback();
                throw;
            }
        }
        public PurchaseViewModel? AddProducts(PurchaseSearchModel purchaseModel, ProductSearchModel productModel, int count) 
        {         
            using var context = new Database();
            using var transaction = context.Database.BeginTransaction();
            try
            {
                var purchase = context.Purchases.FirstOrDefault(rec =>
                rec.Id == purchaseModel.Id);

                var product = context.Products.FirstOrDefault(rec =>
                rec.Id == productModel.Id);

                if (purchase == null)
                    return null;

                if (product == null)
                    return null;

                if (count <= 0)
                    return null;

                context.PurchaseProducts.Add(new PurchaseProducts
                {
                    Purchase = purchase,
                    Product = product,
                    Count = count
                });
                context.SaveChanges();
                return purchase.GetViewModel;
            }
            catch { transaction.Rollback(); throw; }
            
        }

        public Dictionary<Guid, int> GetProducts(PurchaseSearchModel model)
        {
            Dictionary<Guid, int> productsDict = new();
            using var context = new Database();

            var purchase = context.Purchases.FirstOrDefault(rec =>
                rec.Id == model.Id);

            if (purchase == null)
            {
                return null;
            }

            var purchaseProducts = context.PurchaseProducts
               .Where(x => x.PurchaseId == model.Id)
               .ToList();

            foreach (var purchaseProduct in purchaseProducts)
            {
                productsDict.Add(purchaseProduct.ProductId, purchaseProduct.Count);
            }

            return productsDict;
        }

    }
}