using Biskilog_Accounting.Server.POSModels;
using Biskilog_Accounting.Shared.CustomModels;
using Biskilog_Accounting.Shared.Interfaces;
using Biskilog_Accounting.Shared.POSModels;
using Microsoft.EntityFrameworkCore;
using System.Data.Entity;
using System.Runtime.CompilerServices;
using static Microsoft.EntityFrameworkCore.DbLoggerCategory;

namespace Biskilog_Accounting.Server.Services
{
    /// <summary>
    /// Gets the KPIs/ Analysis of operations made with the software
    /// </summary>
    public class AnalyticalService : IAnalytics
    {
        private readonly BiskAcdbContext m_context;
        private bool m_comparisonMode;
        private string m_activeBranch;
        public AnalyticalService(BiskAcdbContext a_context, bool a_comparisonMode, string a_activeBranchId)
        {
            m_context = a_context;
            m_comparisonMode = a_comparisonMode;
            m_activeBranch = a_activeBranchId;
        }
        public IEnumerable<CancelledSales> GetCancelledSales(DateTime a_start, DateTime a_end)
        {
            //If in comparison mode, the list is fetched from all branchid of the business
            if (m_comparisonMode)
            {
                return from cSale in m_context.Tblcancelledtransactions
                       join aSale in m_context.Tblcarts on cSale.Transno equals aSale.Transno into activeSale
                       join cPurchase in m_context.Tblcustomerpurchases on cSale.Transno equals cPurchase.TransactionId into customerSales
                       from c in customerSales.DefaultIfEmpty()
                       join customer in m_context.Tblcustomers on c.CustomerId equals customer.CustomerId into Customers
                       from cc in Customers.DefaultIfEmpty()
                       where cSale.DateCancelled >= a_start && cSale.DateCancelled <= a_end
                       select new CancelledSales
                       {
                           CancelledTransaction = cSale,
                           Value = activeSale.Sum(s => s.Total),
                           Customer = !String.IsNullOrEmpty(cc.CustomerId) ? $"{cc.Firstname} {cc.Surname}" : "Walk-IN Purchase"
                       };
            }
            else
            {
                return from cSale in m_context.Tblcancelledtransactions
                       join aSale in m_context.Tblcarts on cSale.Transno equals aSale.Transno into activeSale
                       join cPurchase in m_context.Tblcustomerpurchases on cSale.Transno equals cPurchase.TransactionId into customerSales
                       from c in customerSales.DefaultIfEmpty()
                       join customer in m_context.Tblcustomers on c.CustomerId equals customer.CustomerId into Customers
                       from cc in Customers.DefaultIfEmpty()
                       where cSale.DateCancelled >= a_start && cSale.DateCancelled <= a_end && cSale.BranchId == m_activeBranch
                       select new CancelledSales
                       {
                           CancelledTransaction = cSale,
                           Value = (from a in activeSale where a.BranchId == m_activeBranch select a.Total).Sum(),
                           Customer = !String.IsNullOrEmpty(cc.CustomerId) ? $"{cc.Firstname} {cc.Surname}" : "Walk-IN Purchase"
                       };

            }
        }

        public IEnumerable<Dictionary<string, List<Tblcart>>> GetEmployeeSales(DateTime a_start, DateTime a_end)
        {
            throw new NotImplementedException();
        }

        public IEnumerable<InDebtCustomers> GetInDebtCustomers()
        {
            if (m_comparisonMode)
            {
                return from c in m_context.Tblcustomers
                       join a in m_context.Customeraccounts on c.CustomerId equals a.CustomerId into CustomerAccounts
                       from ac in CustomerAccounts.OrderByDescending(ac => ac.Date).Take(1).DefaultIfEmpty()
                       where ac.Balance < 0
                       orderby ac.Date descending
                       select new InDebtCustomers
                       {
                           Customer = c,
                           Debt = ac != null ? ac.Balance : 0
                       };

            }
            else
            {
                return null;
            }
        }

        public IEnumerable<ProductItem> GetMostPurchasedItem(DateTime a_start, DateTime a_end)
        {
            throw new NotImplementedException();
        }

        public IEnumerable<ProductItem> GetOutOfStockItems()
        {
            //if (m_comparisonMode)
            //{
            //    return from r in m_context.Restocklevels
            //           join i in m_context.Tblinventories on r.ProductId equals i.Pcode
            //           join p in m_context.Tblproducts on i.Pcode equals p.Pcode
            //           where i.Quantity == r.WarnLevel
            //           select new ProductItem
            //           {
            //               Product = p,
            //               Stock = i,
            //               Unitofmeasure = 
            //           }
            //}
            //else { 
            //}
            return null;
        }

        public IEnumerable<ProductPriceChange> GetPriceChanges(DateTime a_start, DateTime a_end)
        {
            if (m_comparisonMode)
            {
                return from change in m_context.Tblpricechanges
                       join p in m_context.Tblproducts on change.Pcode equals p.Pcode
                       where change.ChangeDate <= a_start && change.ChangeDate >= a_end
                       select new ProductPriceChange
                       {
                           BranchId = change.BranchId,
                           ChangeDate = change.ChangeDate,
                           Pcode = change.Pcode,
                           CountId = change.CountId,
                           CurrentPrice = change.CurrentPrice,
                           PreviousPrice = change.PreviousPrice,
                           ProductName = p.ProductName
                       };
            }
            else
            {
                return from change in m_context.Tblpricechanges
                       join p in m_context.Tblproducts on change.Pcode equals p.Pcode
                       where change.ChangeDate <= a_start && change.ChangeDate >= a_end && change.BranchId == m_activeBranch
                       select new ProductPriceChange
                       {
                           BranchId = change.BranchId,
                           ChangeDate = change.ChangeDate,
                           Pcode = change.Pcode,
                           CountId = change.CountId,
                           CurrentPrice = change.CurrentPrice,
                           PreviousPrice = change.PreviousPrice,
                           ProductName = p.ProductName
                       };
            }
        }

        public IEnumerable<Tblcart> GetSalesTransaction(DateTime a_start, DateTime a_end)
        {
            //If in comparison mode, the list is fetched from all branchid of the business
            if (m_comparisonMode)
            {
                return m_context.Tblcarts.Where(t => t.Date >= a_start && t.Date <= a_end);
            }
            else
            {
                return m_context.Tblcarts.Where(t => t.Date >= a_start && t.Date <= a_end && t.BranchId == m_activeBranch);
            }
        }
    }
}