using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Transactions;

namespace bnhtrade.Core.Logic.Export
{
    public class AmazonSettlement
    {
        private Logic.Log.LogEvent log = new Logic.Log.LogEvent();
        private List<string> lineItemCodeList = new List<string>();

        public AmazonSettlement()
        {
        }

        public void ToInvoice()
        {
            log.LogInformation("Starting processing of Amazon settlement data into export invoice table...");

            // check settlement reports consistancy
            var consistencyCheck = new Data.Database.Consistency.ImportAmazonSettlement().PeriodDateGaps();
            if (consistencyCheck == false)
            { return; }

            // get list of unprocssed settlement reports to export
            var settlementData = new Data.Database.Import.AmazonSettlementRead();
            var settlementList = settlementData.AllUnprocessed();
            settlementData = null;

            if (settlementList == null)
            {
                log.LogInformation("No new settlements to process, exiting import...");
                return;
            }

            // create list of settlement ids
            var settlementIdList = new List<string>();
            for (int i = 0; i < settlementList.Count(); i++)
            {
                settlementIdList.Add(settlementList[i].SettlementId);
            }

            // test marketplace-name has been sucsessfully entered into settlement table -- 
            // as this is not supplied in the original report from Amazon and has to be inferred from settlement line data
            // this is not picked up in validate stage as null value is valid
            for (int i = 0; i < settlementList.Count(); i++)
            {
                if (!settlementList[i].MarketPlaceNameIsSet)
                {
                    log.LogError(
                        "Action required: Enter market place name for settlelment report id " + settlementList[i].SettlementId + "."
                        , "Unable to process settlement data from one settlement report '" + settlementList[i].SettlementId +
                        "'. Report header table requires a market place name, which is not supplied in original " +
                        "report from Amazon. This is useually inferred from settlement lines. " +
                        "However, in this case, it was not not possible. Manual edit/entry for database table required."
                        );
                }
            }

            // validate settlelments
            var validate = new Logic.Validate.AmazonSettlement();
            for (int i = 0; i < settlementList.Count(); i++)
            {
                if (!validate.IsValid(settlementList[i]))
                {
                    log.LogError("Error procesing Amazon Settlement data for export.", validate.ValidationResultListToString());
                }
            }
            if (validate.IsValidResult == false) { return; }

            // get dictionary of sku-number to taxcodeId
            Console.Write("\rBuilding SKU list... ");
            var skuList = new List<string>();
            foreach (var settlement in settlementList)
            {
                if (settlement.SettlementLineListIsSet)
                {
                    foreach (var line in settlement.SettlementLineList)
                    {
                        if (line.SkuIsSet
                            && !string.IsNullOrWhiteSpace(line.Sku))
                        {
                            skuList.Add(line.Sku);
                        }
                    }
                }
            }
            var taxCodeBySkuNumer = new Logic.Account.GetTaxCodeInfo().GetBySkuNumber(skuList);

            // loop through each settlement and build list of invoices to export
            Console.Write("\rBuilding invoices to export... ");
            var invoiceList = new List<Model.Account.SalesInvoice>();
            for (int i = 0; i < settlementList.Count(); i++)
            {
                // split settlement line list into months
                // List<Model.Account.SalesInvoice.InvoiceLine>
                var monthList = settlementList[i].SettlementLineList
                    .GroupBy(x => new DateTime(x.PostDateTime.Year, x.PostDateTime.Month, 1, 0, 0, 0, x.PostDateTime.Kind));
                //.GroupBy(x => string.Format("{0}-{1}", x.PostDateTime.Year, x.PostDateTime.Month));
                //.GroupBy(x => new { x.PostDateTime.Month, x.PostDateTime.Year });

                int monthCount = 0;
                foreach (var month in monthList)
                {
                    monthCount++;
                    var itemCodeTotal = new Dictionary<string, decimal>();
                    foreach (var line in month)
                    {
                        string itemCode = BuildLineItemCode(taxCodeBySkuNumer, line.Sku, line.TransactionType, line.AmountType, line.AmountDescription);
                        if (itemCodeTotal.ContainsKey(itemCode))
                        {
                            itemCodeTotal[itemCode] += line.Amount;
                        }
                        else
                        {
                            itemCodeTotal.Add(itemCode, line.Amount);
                        }
                    }

                    // create invoice, one for each month
                    var invoice = new Model.Account.SalesInvoice();

                    // create invoice lines forsy
                    invoice.InvoiceLineList = new List<Model.Account.SalesInvoice.InvoiceLine>();
                    decimal lineNetTotal = 0m;
                    decimal lineTaxTotal = 0m;
                    foreach (var item in itemCodeTotal)
                    {
                        var line = new Model.Account.SalesInvoice.InvoiceLine(invoice.UnitAmountIsTaxExclusive);
                        line.ItemCode = item.Key;
                        line.Quantity = 1;
                        line.UnitAmount = item.Value;
                        lineNetTotal += item.Value;
                        lineTaxTotal += 0;
                        invoice.InvoiceLineList.Add(line);
                    }

                    invoice.ContactName = settlementList[i].MarketPlaceName;
                    invoice.InvoiceCurrencyCode = settlementList[i].CurrencyCode;
                    if (monthList.Count() == 1 || monthList.Count() == monthCount)
                    { invoice.InvoiceDate = settlementList[i].EndDate; }
                    else
                    { invoice.InvoiceDate = new DateTime(month.Key.Year, month.Key.Month, 1, 0, 0, 0, DateTimeKind.Utc).AddMonths(1).AddDays(-1); }
                    invoice.InvoiceDueDate = settlementList[i].DepositDate;
                    invoice.InvoiceReference = settlementList[i].SettlementId;
                    invoice.InvoiceTotalAmount = lineNetTotal + lineTaxTotal;
                    if (invoice.InvoiceTotalAmount < 0) { invoice.IsCreditNote = true; }
                    else { invoice.IsCreditNote = false; }

                    // invoice complete, add to list
                    invoiceList.Add(invoice);
                }
            }

            // sort list of invoices
            invoiceList = invoiceList.OrderBy(x => x.InvoiceReference).ThenBy(x => x.InvoiceDate).ToList();

            // check invoice total against settlement totals
            var invoiceTotal = new Dictionary<string, decimal>();
            for (int i = 0; i < invoiceList.Count(); i++)
            {
                if (invoiceTotal.ContainsKey(invoiceList[i].InvoiceReference))
                {
                    invoiceTotal[invoiceList[i].InvoiceReference] += invoiceList[i].InvoiceTotalAmount.GetValueOrDefault();
                }
                else
                {
                    invoiceTotal.Add(invoiceList[i].InvoiceReference, invoiceList[i].InvoiceTotalAmount.GetValueOrDefault());
                }
            }
            for (int i = 0; i < settlementList.Count(); i++)
            {
                if (settlementList[i].TotalAmount != invoiceTotal[settlementList[i].SettlementId])
                {
                    throw new Exception("invoice totals does not match settlement total.");
                }
            }
            if (settlementIdList.Count != invoiceTotal.Count())
            {
                log.LogError("Stopping Settlement export. Not all settlements have been transposed into invoices.");
                return;
            }

            // add invoice item code data to lines 
            // also clean invoices of any disabled lines (remove lines and possibly invoices)
            var getLineItemInfo = new Logic.Account.GetInvoiceLineItem();
            getLineItemInfo.InsertNewOnNoMatch = true;
            getLineItemInfo.CacheFill(lineItemCodeList);
            bool newTypeFound = false;
            string newTypeText = null;

            for (int i = 0; i < invoiceList.Count(); i++)
            {
                for (int j = 0; j < invoiceList[i].InvoiceLineList.Count(); j++)
                {
                    var itemCode = getLineItemInfo.ByItemCode(invoiceList[i].InvoiceLineList[j].ItemCode);
                    // error! itemCode should never be null
                    if (itemCode == null)
                    {
                        throw new Exception("Item code is null");
                    }
                    // flag new type and throw exception further on
                    else if (itemCode.IsNewReviewRequired)
                    {
                        newTypeFound = true;
                        if (string.IsNullOrWhiteSpace(itemCode.ItemCode))
                        {
                            newTypeText = itemCode.Name;
                        }
                        else
                        {
                            newTypeText = itemCode.ItemCode;
                        }
                    }
                    // clean invoices of any disabled lines (remove lines and possibly invoices)
                    else if (itemCode.InvoiceLineEntryEnabled == false)
                    {
                        // remove line
                        invoiceList[i].InvoiceTotalAmount = invoiceList[i].InvoiceTotalAmount - invoiceList[i].InvoiceLineList[j].LineTotalAmount;
                        invoiceList[i].InvoiceLineList.RemoveAt(j);
                        j = j - 1;

                        // remove invoice?
                        if (invoiceList[i].InvoiceLineList.Count == 0)
                        {
                            invoiceList.RemoveAt(i);
                            if (i > 0)
                            {
                                i = i - 1;
                            }
                        }
                    }
                    // get here add info to lines
                    else
                    {
                        invoiceList[i].InvoiceLineList[j].AccountCode = itemCode.DefaultAccountCode;
                        invoiceList[i].InvoiceLineList[j].Description = itemCode.Name;
                        invoiceList[i].InvoiceLineList[j].ItemCode = itemCode.ItemCode;
                        invoiceList[i].InvoiceLineList[j].TaxCode = itemCode.DefaultTaxCode;
                    }
                }
            }

            if (newTypeFound)
            {
                if (newTypeFound)
                {
                    throw new Exception("Parameters required for Invoice line item code '"+ newTypeText + "'. Set in tblAccountInvoiceLineItem.");
                }
                return;
            }

            // postfix invoices references that span multiple months with -n
            if (invoiceList.Count > 1)
            {
                string lastRef = invoiceList[0].InvoiceReference;
                int countRef = 1;
                for (int i = 1; i < invoiceList.Count(); i++)
                {
                    if (invoiceList[i].InvoiceReference == lastRef)
                    {
                        if (countRef == 1)
                        {
                            invoiceList[i - 1].InvoiceReference = lastRef + "-" + countRef;
                        }
                        invoiceList[i].InvoiceReference = lastRef + "-" + (countRef += 1);
                    }
                    else
                    {
                        // shouldn't normally be more than 2 date ranges, log and move on.
                        if (countRef > 2)
                        {
                            log.LogError(
                                countRef + " invoices where created from Amazon Settlement Id" + lastRef + "."
                                , "Settlement period appears to span more 3 months or more. Whilst this is possible, it is unsual. Confirm his is correct.");
                        }

                        lastRef = invoiceList[i].InvoiceReference;
                        countRef = 1;
                    }
                }
            }

            Console.Write("\rWriting to database... ");
            using (TransactionScope scope = new TransactionScope())
            {
                try
                {
                    var saveInv = new Logic.Export.SalesInvoice();
                    // add temp invoice numbers
                    saveInv.AddTempInvoiceNumber(invoiceList, true);

                    // write to the database (gets validated there)
                    saveInv.SaveSalesInvoice(invoiceList);

                    // set settlements to isprocessed
                    new Data.Database.Import.AmazonSettlementUpdate().SetIsProcessedTrue(settlementIdList);

                    scope.Complete();
                }
                catch (Exception ex)
                {
                    scope.Dispose();
                    log.LogError("Exeception caught while writing Amazon settlement invoices to DB. Changes were rolled back."
                        , ex.Message);
                    return;
                }
            }
            Console.Write("\r");
            log.LogInformation("\rFinished processing of Amazon settlement data. " + invoiceList.Count() + " invoices created from " + settlementIdList.Count() + " Amazon settlement reports.");
        }

        private string BuildLineItemCode(Dictionary<string, Model.Account.TaxCodeInfo> taxCodeBySkuNumer, string skuNumber, string transactionType, string amountType, string amountDescription)
        {
            // build the match string
            // NB special case for global accounting sale and refunds (also note Goodlwill is included) and sku's where tax is included
            string match01 = transactionType;
            string match02 = amountType;
            string match03 = amountDescription;
            string matchString = "<AmazonReport><SettlementReportLine><" + match01 + "><" + match02 + "><" + match03 + ">";

            // add tax info if required
            if ((match01 == "Order" || match01 == "Refund")
                && (match02 == "ItemPrice" || match02 == "Promotion" || match02 == "ItemWithheldTax"))
            {
                if (taxCodeBySkuNumer.ContainsKey(skuNumber))
                {
                    matchString = matchString + "<TaxCode=" + taxCodeBySkuNumer[skuNumber].TaxCode + ">";
                }
                else
                {
                    throw new Exception("Sku#" + skuNumber + " tax info not found in dictionary list.");
                }
            }

            // add to list of generated line item codes
            lineItemCodeList.Add(matchString);

            // return value
            return matchString;
        }
    }
}