using ClosedXML.Excel;
using System.Data;
using System.Data.OleDb;

namespace AiQ_GUI
{
    internal class StatsExcel
    {
        private const string exportPath = @"G:\Shared drives\MAV Production GUI's\AiQ\GUI's\AiQ_Test_Stats.xlsx";

        public void ExportDatabaseToExcel()
        {
            try
            {
                MainForm.Instance.AddToActionsList("=== ExportDatabaseToExcel START ===");

                using OleDbConnection conn = new(Access.connString);
                conn.Open();
                MainForm.Instance.AddToActionsList("Connected to Access database.");
                DateTime now = DateTime.Now;

                // Read LastStatsRun from UniversalData (if any)
                DateTime? lastStatsRun = null;
                try
                {
                    using (OleDbCommand cmdPeriod = new OleDbCommand("SELECT LastStatsRun FROM UniversalData", conn))
                    {
                        object res = cmdPeriod.ExecuteScalar();
                        if (res != null && res != DBNull.Value)
                            lastStatsRun = (DateTime)res;
                    }
                    MainForm.Instance.AddToActionsList($"Fetched LastStatsRun: {(lastStatsRun.HasValue ? lastStatsRun.Value.ToString("yyyy-MM-dd HH:mm:ss") : "none")}");
                }
                catch (Exception periodEx)
                {
                    MainForm.Instance.AddToActionsList($"Warning: could not read LastStatsRun. Details: {periodEx.Message}");
                }

                // ==================== MAIN STATS EXPORT ====================
                string selectColumns = @"
                                ModelNumber,
                                [Total Tests Run],
                                [Pre Tests Passed],
                                [Pre Tests Failed],
                                [Final Tests Passed],
                                [Final Tests Failed],
                                [RMA Total Tests Run],
                                [RMA Pre Tests Passed],
                                [RMA Pre Tests Failed],
                                [RMA Final Tests Passed], 
                                [RMA Final Tests Failed],
                                [Diagnostic Failure],
                                [Failed To Set Model Or Serial Number],
                                [Camera Not In Test Tube],
                                [Could Not Zoom Modules To 8000],
                                [Could Not Zoom Modules To Full Wide],
                                [Please Get RMA Number From Operations Team Before Continuing],
                                [Please Get A Valid Vaxtor Product Key Before Continuing],  
                                [Visual Test Fail - Sleeve Not Aligned],  
                                [Visual Test Fail - Not All Front Screws Fitted],
                                [Visual Test Fail - Not All Rear Screws Fitted],
                                [Visual Test Fail - Unit rattles]";

                string query = $@"
                        SELECT 
                            {selectColumns}
                        FROM AiQ";

                OleDbDataAdapter adapter = new(query, conn);
                DataTable dataTable = new();
                adapter.Fill(dataTable);

                if (dataTable.Rows.Count == 0)
                {
                    MainForm.Instance.AddToActionsList("No data found in AiQ table.");
                    return;
                }

                string monthName = now.ToString("MMMM");
                string sheetName = $"{monthName} Stats";

                MainForm.Instance.AddToActionsList($"Adding sheet: {sheetName}");

                XLWorkbook workbook;
                if (File.Exists(exportPath))
                {
                    workbook = new XLWorkbook(exportPath);
                    MainForm.Instance.AddToActionsList("Opened existing workbook.");
                }
                else
                {
                    workbook = new XLWorkbook();
                    MainForm.Instance.AddToActionsList("Created new workbook (file not found).");
                }

                if (workbook.Worksheets.Contains(sheetName))
                {
                    workbook.Worksheet(sheetName).Delete();
                    MainForm.Instance.AddToActionsList($"Deleted old sheet: {sheetName}");
                }

                IXLWorksheet ws = workbook.Worksheets.Add(sheetName);
                ws.Cell(1, 1).InsertTable(dataTable, "AiQ_Stats", true);
                ws.Columns().AdjustToContents();

                // Write Data Period label and computed period string to the right of the table
                int infoCol = dataTable.Columns.Count + 2;
                ws.Cell(1, infoCol).Value = "Data Period";

                string periodText;
                if (lastStatsRun.HasValue)
                {
                    periodText = $"{lastStatsRun.Value:yyyy-MM-dd HH:mm:ss} - {now:yyyy-MM-dd HH:mm:ss}";
                }
                else
                {
                    periodText = $"Up to {now:yyyy-MM-dd HH:mm:ss}";
                }

                ws.Cell(2, infoCol).Value = periodText;

                // ==================== DIAGS STATS EXPORT (CURRENT MONTH ONLY) ====================
                MainForm.Instance.AddToActionsList("Exporting DiagsStats for current month...");

                DateTime monthStart = new(now.Year, now.Month, 1);
                DateTime nextMonth = monthStart.AddMonths(1);

                string diagsQuery = @"
                        SELECT 
                            [Date],
                            [Model],
                            [Red Diags Labels],
                            [RhTxBxActions Contents],
                            [IsRma],
                            [RMA]
                        FROM DiagsStats
                        WHERE [Date] >= ? AND [Date] < ?";

                using (OleDbCommand diagsCmd = new OleDbCommand(diagsQuery, conn))
                {
                    diagsCmd.Parameters.Add(new OleDbParameter { OleDbType = OleDbType.Date, Value = monthStart });
                    diagsCmd.Parameters.Add(new OleDbParameter { OleDbType = OleDbType.Date, Value = nextMonth });

                    using (OleDbDataAdapter diagsAdapter = new OleDbDataAdapter(diagsCmd))
                    {
                        DataTable diagsTable = new();
                        diagsAdapter.Fill(diagsTable);

                        if (diagsTable.Rows.Count > 0)
                        {
                            int startRow = (ws.LastRowUsed()?.RowNumber() ?? 0) + 3;

                            ws.Cell(startRow, 1).Value = "Diags Stats (Current Month)";
                            ws.Cell(startRow, 1).Style.Font.Bold = true;
                            ws.Cell(startRow, 1).Style.Font.FontSize = 12;

                            ws.Cell(startRow + 1, 1).InsertTable(diagsTable, "Diags_Stats", true);
                            ws.Columns().AdjustToContents();

                            MainForm.Instance.AddToActionsList($"Added DiagsStats ({diagsTable.Rows.Count} rows) starting at row {startRow}.");
                        }
                    }
                }

                // ==================== SAVE MAIN SHEET ====================
                workbook.SaveAs(exportPath);
                MainForm.Instance.AddToActionsList($"Added {sheetName} to workbook: {exportPath}");

                workbook.Dispose();

                // ==================== BACKUP TABLE (ALWAYS, BEFORE RESET) ====================
                string ts = now.ToString("yyyyMMdd_HHmmss");
                string backupTableName = $"Ztats_{ts}";

                if (backupTableName.Length > 64)
                    backupTableName = backupTableName.Substring(0, 64);

                string backupSql = $@"
                        SELECT
                            {selectColumns}
                        INTO [{backupTableName}]
                        FROM AiQ";
                try
                {
                    using (OleDbCommand cmdBackup = new(backupSql, conn))
                    {
                        cmdBackup.ExecuteNonQuery();
                    }
                    MainForm.Instance.AddToActionsList($"Created backup table: [{backupTableName}]");
                }
                catch (Exception backupEx)
                {
                    MainForm.Instance.AddToActionsList($"ERROR creating backup table [{backupTableName}]. Aborting reset to protect data. Details: {backupEx.Message}");
                    MainForm.Instance.AddToActionsList("=== ExportDatabaseToExcel END (backup failed, no reset) ===");
                    return;
                }

                using (OleDbTransaction tx = conn.BeginTransaction())
                {
                    try
                    {
                        string resetSql = @"
                                UPDATE AiQ SET
                                    [Total Tests Run] = 0,
                                    [Pre Tests Passed] = 0,
                                    [Pre Tests Failed] = 0,
                                    [Final Tests Passed] = 0,
                                    [Final Tests Failed] = 0,
                                    [RMA Total Tests Run] = 0,
                                    [RMA Pre Tests Passed] = 0,
                                    [RMA Pre Tests Failed] = 0,
                                    [RMA Final Tests Passed] = 0,
                                    [RMA Final Tests Failed] = 0,
                                    [Diagnostic Failure] = 0,
                                    [Failed To Set Model Or Serial Number] = 0,
                                    [Camera Not In Test Tube] = 0,
                                    [Could Not Zoom Modules To 8000] = 0,
                                    [Could Not Zoom Modules To Full Wide] = 0,
                                    [Please Get RMA Number From Operations Team Before Continuing] = 0,
                                    [Please Get A Valid Vaxtor Product Key Before Continuing] = 0,
                                    [Visual Test Fail - Sleeve Not Aligned] = 0,
                                    [Visual Test Fail - Not All Front Screws Fitted] = 0,
                                    [Visual Test Fail - Not All Rear Screws Fitted] = 0,
                                    [Visual Test Fail - Unit rattles] = 0;";

                        using (OleDbCommand cmdReset = new(resetSql, conn, tx))
                        {
                            int affected = cmdReset.ExecuteNonQuery();
                            MainForm.Instance.AddToActionsList($"Zeroed counters on AiQ rows: {affected} row(s).");
                        }

                        int updatedRows;
                        using (OleDbCommand cmdUpd = new("UPDATE UniversalData SET LastStatsRun = ?", conn, tx))
                        {
                            cmdUpd.Parameters.Add(new OleDbParameter { OleDbType = OleDbType.Date, Value = now });
                            updatedRows = cmdUpd.ExecuteNonQuery();
                        }

                        if (updatedRows == 0)
                        {
                            using OleDbCommand cmdIns = new("INSERT INTO UniversalData (LastStatsRun) VALUES (?)", conn, tx);
                            cmdIns.Parameters.Add(new OleDbParameter { OleDbType = OleDbType.Date, Value = now });
                            cmdIns.ExecuteNonQuery();
                            MainForm.Instance.AddToActionsList("Inserted LastStatsRun row.");
                        }
                        else
                        {
                            MainForm.Instance.AddToActionsList("Updated LastStatsRun successfully.");
                        }

                        tx.Commit();
                        MainForm.Instance.AddToActionsList("Reset committed.");
                    }
                    catch (Exception resetEx)
                    {
                        tx.Rollback();
                        MainForm.Instance.AddToActionsList($"ERROR during reset, rolled back. Details: {resetEx.Message}");
                    }

                    conn.Close();
                }

                MainForm.Instance.AddToActionsList("=== ExportDatabaseToExcel END ===");
            }
            catch (Exception ex)
            {
                MainForm.Instance.AddToActionsList($"ERROR exporting stats: {ex.Message}");
                MainForm.Instance.AddToActionsList($"Stack Trace: {ex.StackTrace}");
            }
        }
    }
}