using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Application.Services.Database.MongoDB;

namespace Infrastructure.BackgroundServices;

public class AppointmentCleanupService(
    IAppointmentsMongoDbService appointmentsMongoDbService,
    ILogger<AppointmentCleanupService> logger)
    : BackgroundService
{
    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        logger.LogInformation("Appointment Cleanup Service started.");

        while (!stoppingToken.IsCancellationRequested)
        {
            await CheckAndDeletePastAppointments();
            await Task.Delay(TimeSpan.FromMinutes(1), stoppingToken);
        }
    }

    private async Task CheckAndDeletePastAppointments()
    {
        // Get the current UTC time and adjust it to the local timezone (GMT +3)
        var currentUtcDate = DateTime.UtcNow;
        var currentDate = TimeZoneInfo.ConvertTimeBySystemTimeZoneId(currentUtcDate, "E. Europe Standard Time"); // Adjust to GMT +3
        logger.LogInformation("Checking for past appointments as of local time {CurrentDate}.", currentDate);

        var appointments = await appointmentsMongoDbService.GetAllAppointments(CancellationToken.None);
        int updatedCount = 0, deletedCount = 0;

        foreach (var appointment in appointments)
        {
            // Filter out past appointments based on the adjusted current date
            appointment.AppointmentsList.RemoveAll(date => date < currentDate);

            if (appointment.AppointmentsList.Count > 0)
            {
                await appointmentsMongoDbService.UpdateAppointment(appointment, CancellationToken.None);
                updatedCount++;
                logger.LogInformation("Updated appointment {AppointmentId} by removing past dates.", appointment.Id);
            }
            else
            {
                await appointmentsMongoDbService.DeleteAppointment(appointment.Id, CancellationToken.None);
                deletedCount++;
                logger.LogInformation("Deleted appointment {AppointmentId} because all dates were in the past.", appointment.Id);
            }
        }

        logger.LogInformation("Finished checking appointments. Updated: {UpdatedCount}, Deleted: {DeletedCount}.", updatedCount, deletedCount);
    }

}