using InnovEnergy.App.Backend.DataTypes;
using InnovEnergy.App.Backend.DataTypes.Methods;
using InnovEnergy.App.Backend.Relations;
namespace InnovEnergy.App.Backend.Database;

public static partial class Db 
{
    //Since we do not want to stress the memory in the VM a lot, we make a snapshot of the database every 100 transactions.
    private static int _backupCounter = 0;
    private static void Backup()
    {
        _backupCounter++;
        if (_backupCounter > 100)
        {
            _backupCounter = 0;
            BackupDatabase();
        }
    }
    public static Boolean Delete(Folder folder)
    {
        var deleteSuccess= RunTransaction(DeleteFolderAndAllItsDependencies);
        if (deleteSuccess)
        {
            Backup();
        }

        return deleteSuccess;

        Boolean DeleteFolderAndAllItsDependencies()
        {
            return folder
                  .DescendantFoldersAndSelf()
                  .All(DeleteDescendantFolderAndItsDependencies);
        }
        
        Boolean DeleteDescendantFolderAndItsDependencies(Folder f)
        {
            FolderAccess  .Delete(r => r.FolderId == f.Id);
            Installations.Delete(r => r.ParentId == f.Id);
            var delete = Folders.Delete(r => r.Id == f.Id);            
            
            return delete>0;
        }
    }
    
    public static Boolean Delete(Error errorToDelete)
    {
        var deleteSuccess = RunTransaction(DeleteError);
        
        if (deleteSuccess)
            Backup();
        return deleteSuccess;
        
        
        Boolean DeleteError()
        {
            return Errors.Delete(error => error.Id == errorToDelete.Id) >0;
        }
    }
    
    public static Boolean Delete(UserAction actionToDelete)
    {
        var deleteSuccess = RunTransaction(DeleteAction);
        
        
        if (deleteSuccess)
            Backup();
        return deleteSuccess;
        
        
        Boolean DeleteAction()
        {
            return UserActions.Delete(action => action.Id == actionToDelete.Id) >0;
            
        }
    }
    
    public static Boolean Delete(Warning warningToDelete)
    {
        var deleteSuccess = RunTransaction(DeleteWarning);
        if (deleteSuccess)
            Backup();
        return deleteSuccess;
        
        
        Boolean DeleteWarning()
        {
            return Warnings.Delete(warning => warning.Id == warningToDelete.Id) >0;
        }
    }
    
    public static Boolean Delete(Installation installation)
    {
        var deleteSuccess = RunTransaction(DeleteInstallationAndItsDependencies);
        if (deleteSuccess)
            Backup();
        return deleteSuccess;
        
        
        Boolean DeleteInstallationAndItsDependencies()
        {
            InstallationAccess.Delete(i => i.InstallationId == installation.Id);
            if (installation.Product == (int)ProductType.Salimax)
            {
                //For Salimax, delete the OrderNumber2Installation entries associated with this installation id.
                OrderNumber2Installation.Delete(i => i.InstallationId == installation.Id);
            }
            
            return Installations.Delete(i => i.Id == installation.Id) > 0;
        }
    }

    public static Boolean Delete(User user)
    {
        var deleteSuccess = RunTransaction(DeleteUserAndHisDependencies);
        if (deleteSuccess)
            Backup();
        return deleteSuccess;
        
        Boolean DeleteUserAndHisDependencies()
        {
            FolderAccess      .Delete(u => u.UserId == user.Id);
            InstallationAccess.Delete(u => u.UserId == user.Id);
            return Users.Delete(u => u.Id == user.Id) > 0;
        }
    }
    
    
    #pragma warning disable CS0618
    
    // private!!
    private static Boolean Delete(Session session)
    {
        var delete = Sessions.Delete(s => s.Id == session.Id) > 0;
        if (delete) 
            Backup();
        return delete;
    }

    public static void Delete(OrderNumber2Installation relation)
    {
        OrderNumber2Installation.Delete(s => s.InstallationId == relation.InstallationId && s.OrderNumber == relation.OrderNumber);
    }

    public static void DeleteWeeklyReportsForMonth(Int64 installationId, Int32 year, Int32 month)
    {
        var monthStart = $"{year:D4}-{month:D2}-01";
        var monthEnd   = month == 12 ? $"{year + 1:D4}-01-01" : $"{year:D4}-{month + 1:D2}-01";

        // SQLite-net doesn't support string comparison in Delete lambda,
        // so fetch matching IDs first, then delete by ID.
        var ids = WeeklyReports
            .Where(r => r.InstallationId == installationId)
            .ToList()
            .Where(r => String.Compare(r.PeriodStart, monthStart, StringComparison.Ordinal) >= 0
                     && String.Compare(r.PeriodStart, monthEnd,   StringComparison.Ordinal) <  0)
            .Select(r => r.Id)
            .ToList();

        foreach (var id in ids)
            WeeklyReports.Delete(r => r.Id == id);

        if (ids.Count > 0) Backup();
    }

    public static void DeleteMonthlyReportsForYear(Int64 installationId, Int32 year)
    {
        MonthlyReports.Delete(r => r.InstallationId == installationId && r.Year == year);
        Backup();
    }

    public static void DeleteMonthlyReport(Int64 installationId, Int32 year, Int32 month)
    {
        var count = MonthlyReports.Delete(r => r.InstallationId == installationId && r.Year == year && r.Month == month);
        if (count > 0) Backup();
    }

    public static void DeleteYearlyReport(Int64 installationId, Int32 year)
    {
        var count = YearlyReports.Delete(r => r.InstallationId == installationId && r.Year == year);
        if (count > 0) Backup();
    }

    /// <summary>
    /// Deletes all report records older than 1 year. Called annually on Jan 2
    /// after yearly reports are created. Uses fetch-then-delete for string-compared
    /// date fields (SQLite-net doesn't support string comparisons in Delete lambdas).
    /// </summary>
    public static void CleanupOldData()
    {
        var cutoff   = DateOnly.FromDateTime(DateTime.UtcNow).AddYears(-1).ToString("yyyy-MM-dd");
        var prevYear = DateTime.UtcNow.Year - 1;

        // Daily records older than 1 year
        var oldDailyIds = DailyRecords
            .ToList()
            .Where(r => String.Compare(r.Date, cutoff, StringComparison.Ordinal) < 0)
            .Select(r => r.Id)
            .ToList();
        foreach (var id in oldDailyIds)
            DailyRecords.Delete(r => r.Id == id);

        // Weekly summaries older than 1 year
        var oldWeeklyIds = WeeklyReports
            .ToList()
            .Where(r => String.Compare(r.PeriodEnd, cutoff, StringComparison.Ordinal) < 0)
            .Select(r => r.Id)
            .ToList();
        foreach (var id in oldWeeklyIds)
            WeeklyReports.Delete(r => r.Id == id);

        // Monthly summaries older than 1 year
        var oldMonthlyIds = MonthlyReports
            .ToList()
            .Where(r => String.Compare(r.PeriodEnd, cutoff, StringComparison.Ordinal) < 0)
            .Select(r => r.Id)
            .ToList();
        foreach (var id in oldMonthlyIds)
            MonthlyReports.Delete(r => r.Id == id);

        // Yearly summaries — keep current and previous year only
        YearlyReports.Delete(r => r.Year < prevYear);

        // AI insight cache entries older than 1 year
        var oldCacheIds = AiInsightCaches
            .ToList()
            .Where(c => String.Compare(c.CreatedAt, cutoff, StringComparison.Ordinal) < 0)
            .Select(c => c.Id)
            .ToList();
        foreach (var id in oldCacheIds)
            AiInsightCaches.Delete(c => c.Id == id);

        Backup();
        Console.WriteLine($"[Db] Cleanup: {oldDailyIds.Count} daily, {oldWeeklyIds.Count} weekly, {oldMonthlyIds.Count} monthly, {oldCacheIds.Count} insight cache records deleted (cutoff {cutoff}).");
    }
}