using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using LCU.Shared.Collections.RepoApiLib.Formatting;
using LCU.Shared.Collections.RepoApiLib.Models.Reporting.Responses;

namespace LCU.API.Collections.RepoApi.Factories
{
    public enum ReportSumType { WholeNumber, Currency, WholeNumberAvg, CurrencyAvg, PercentageAvg }

    public static class ReportTableFactory
    {

        public static ReportTable CreateHistoricalSummationTable<T>(
            ReportSumType reportType,
            IEnumerable<T> dataRows,
            string pluralEntityName,
            DateTime lowDateTime,
            DateTime highDateTime,
            Func<T, decimal?> cellValue,
            Func<T, string> uniqueRowDisplay,
            Func<T, DateTime?> dateTimeField,
            Func<T, object> rowKey,
            bool showAbsenceRow = true
        )
        {
            var totalMonths = CalculateTotalMonths(lowDateTime, highDateTime);
            var rows = CreateUniqueRowNames(dataRows, uniqueRowDisplay, pluralEntityName, showAbsenceRow);

            var reportTable = new ReportTable()
            {
                Headers = CreateMonthHeaders(lowDateTime, highDateTime, new string[] { "" }, new string[] { "Total" }),
                Cells = new ReportCell[rows.Count(), totalMonths + 2]
            };

            // Build the Report Table Values
            var uniqueRowIdentifiers = new List<object>();
            var rawValueTableLengths = new int[rows.Count(), totalMonths + 1];
            var rawValueTable = new decimal[rows.Count(), totalMonths + 1];
            foreach (var currentDataRow in dataRows)
            {
                var rowDisplay = uniqueRowDisplay(currentDataRow);
                var currentKey = rowKey(currentDataRow);
                var currentValue = cellValue(currentDataRow);
                var currentDateOfRow = dateTimeField(currentDataRow);

                if (currentDateOfRow != null &&
                    currentValue != null &&
                    !uniqueRowIdentifiers.Contains(currentKey))
                {
                    uniqueRowIdentifiers.Add(currentKey);

                    var monthIndex = CalculateMonthOffset(lowDateTime, currentDateOfRow.Value);
                    var currentItemIndex = FindUniqueRowIndex(rows, rowDisplay);

                    // "All Entities" Value
                    rawValueTable[0, monthIndex] += currentValue.Value; // Totals for Month
                    rawValueTable[0, totalMonths] += currentValue.Value; // Totals for All

                    // "All Entities" Length
                    rawValueTableLengths[0, monthIndex] += 1; // Totals for Month
                    rawValueTableLengths[0, totalMonths] += 1; // Totals for All

                    // Current Auction Row
                    if (currentItemIndex != 0)
                    {
                        rawValueTable[currentItemIndex, monthIndex] += currentValue.Value; // Total for Month
                        rawValueTable[currentItemIndex, totalMonths] += currentValue.Value; // Total for Auction House.

                        rawValueTableLengths[currentItemIndex, monthIndex] += 1; // Total for Month
                        rawValueTableLengths[currentItemIndex, totalMonths] += 1; // Total for Auction House.
                    }

                }
            }

            // Convert Report Table into ReportCells
            for (var i = 0; i < rawValueTable.GetLength(0); i++)
            {
                for (var j = 0; j < rawValueTable.GetLength(1); j++)
                {
                    var rawValue = rawValueTable[i, j];
                    var columnIndex = j + 1; // Add 1 to compensate for Row Display Column

                    if (reportType == ReportSumType.WholeNumberAvg ||
                        reportType == ReportSumType.PercentageAvg ||
                        reportType == ReportSumType.CurrencyAvg)
                    {
                        var rawValueLength = rawValueTableLengths[i, j];
                        if (rawValueLength != 0)
                        {
                            rawValue = rawValue / rawValueLength;
                        }
                    }

                    switch(reportType)
                    {
                        case ReportSumType.WholeNumberAvg:
                        case ReportSumType.WholeNumber:
                            reportTable.Cells[i, columnIndex] = ReportCellFormatting.CreateIntCell(Convert.ToInt32(rawValue));
                            break;
                        case ReportSumType.Currency:
                        case ReportSumType.CurrencyAvg:
                            reportTable.Cells[i, columnIndex] = ReportCellFormatting.CreateCurrencyCell(rawValue);
                            break;
                        case ReportSumType.PercentageAvg:
                            reportTable.Cells[i, columnIndex] = ReportCellFormatting.CreatePercentageCell(rawValue);
                            break;
                    }
                }
            }

            // Add Auction Names to Left Column
            for (var i = 0; i < rows.Count(); i++)
            {
                reportTable.Cells[i, 0] = ReportCellFormatting.CreateStringCell(rows.ElementAt(i));
            }

            return reportTable;
        }

        public static int FindUniqueRowIndex(IEnumerable<string> uniqueRows, string columnName)
        {
            if (columnName != null)
            {
                foreach (var item in uniqueRows.Select((value, index) => new { index, value }))
                {
                    if (item.value == columnName)
                    {
                        return item.index;
                    }
                }
            }

            return uniqueRows.Count() - 1;
        }

        private static IEnumerable<string> CreateUniqueRowNames<T>(IEnumerable<T> reportData, Func<T, string> uniqueRowDisplay, string pluralEntityName, bool showAbsenceRow = true)
        {
            var list = new List<string>();
            list.Add("All " + pluralEntityName);

            if (uniqueRowDisplay != null)
            {
                foreach (var row in reportData)
                {
                    var rowName = uniqueRowDisplay(row);
                    if (rowName != null)
                    {
                        if (!list.Contains(rowName))
                        {
                            list.Add(rowName);
                        }
                    }
                }
            }

            if (showAbsenceRow)
            {
                list.Add("No " + pluralEntityName);
            }
            return list;
        }

        private static string[] CreateMonthHeaders(DateTime lowDateTime, DateTime highDateTime, string[] preHeaders = null, string[] postHeaders = null)
        {
            var totalMonths = CalculateTotalMonths(lowDateTime, highDateTime);
            var preHeadersLength = preHeaders?.Length ?? 0;
            var postHeadersLength = postHeaders?.Length ?? 0;
            string[] monthHeaders = new string[totalMonths + preHeadersLength + postHeadersLength];

            for (var i = 0; i < preHeadersLength; i++)
            {
                monthHeaders[i] = preHeaders[i];
            }

            for (var i = 0; i < totalMonths; i++)
            {
                var currentDate = lowDateTime.AddMonths(i);
                monthHeaders[preHeadersLength + i] = $"{currentDate.ToString("MMM", CultureInfo.InvariantCulture)} {currentDate.Year}";
            }

            for (var i = 0; i < postHeadersLength; i++)
            {
                monthHeaders[preHeadersLength + totalMonths + i] = postHeaders[i];
            }

            return monthHeaders;
        }

        private static int CalculateTotalMonths(DateTime lowDateTime, DateTime highDateTime)
        {
            return CalculateMonthOffset(lowDateTime, highDateTime) + 1;
        }

        private static int CalculateMonthOffset(DateTime lowDateTime, DateTime highDateTime)
        {
            return (((highDateTime.Year - lowDateTime.Year) * 12) + highDateTime.Month - lowDateTime.Month);
        }
    }
}