// (c) Copyright Ascensio System SIA 2010-2022
//
// This program is a free software product.
// You can redistribute it and/or modify it under the terms
// of the GNU Affero General Public License (AGPL) version 3 as published by the Free Software
// Foundation. In accordance with Section 7(a) of the GNU AGPL its Section 15 shall be amended
// to the effect that Ascensio System SIA expressly excludes the warranty of non-infringement of
// any third-party rights.
//
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// of MERCHANTABILITY or FITNESS FOR A PARTICULAR  PURPOSE. For details, see
// the GNU AGPL at: http://www.gnu.org/licenses/agpl-3.0.html
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// International. See the License terms at http://creativecommons.org/licenses/by-sa/4.0/legalcode

namespace ASC.Data.Backup.Services;

[Singletone]
public sealed class BackupSchedulerService : BackgroundService
{
    private readonly TimeSpan _backupSchedulerPeriod;
    private readonly ILog _logger;

    private readonly CoreBaseSettings _coreBaseSettings;
    private readonly IServiceScopeFactory _scopeFactory;
    private readonly IEventBus _eventBus;

    public BackupSchedulerService(
        ILog<BackupSchedulerService> logger,
        IServiceScopeFactory scopeFactory,
        ConfigurationExtension configuration,
        CoreBaseSettings coreBaseSettings,
        IEventBus eventBus)
    {
        _logger = logger;
        _coreBaseSettings = coreBaseSettings;
        _backupSchedulerPeriod = configuration.GetSetting<BackupSettings>("backup").Scheduler.Period;
        _scopeFactory = scopeFactory;
        _eventBus = eventBus ?? throw new ArgumentNullException(nameof(eventBus));
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        _logger.LogDebug("BackupSchedulerService is starting.");

        stoppingToken.Register(() => _logger.LogDebug("#1 BackupSchedulerService background task is stopping."));

        while (!stoppingToken.IsCancellationRequested)
        {
            using var serviceScope = _scopeFactory.CreateScope();

            var registerInstanceService = serviceScope.ServiceProvider.GetService<IRegisterInstanceManager<BackupSchedulerService>>();

            if (!await registerInstanceService.IsActive(RegisterInstanceWorkerService<BackupSchedulerService>.InstanceId))
            {
                _logger.LogDebug($"BackupSchedulerService background task with instance id {RegisterInstanceWorkerService<BackupSchedulerService>.InstanceId} is't active.");

                await Task.Delay(1000, stoppingToken);

                continue;
            }

            _logger.LogDebug("BackupSchedulerService background task is doing background work.");

            ExecuteBackupScheduler(stoppingToken);

            await Task.Delay(_backupSchedulerPeriod, stoppingToken);
        }

        _logger.LogDebug("BackupSchedulerService background task is stopping.");
    }

    private void ExecuteBackupScheduler(CancellationToken stoppingToken)
    {
        using var serviceScope = _scopeFactory.CreateScope();

        var paymentManager = serviceScope.ServiceProvider.GetRequiredService<PaymentManager>();
        var backupRepository = serviceScope.ServiceProvider.GetRequiredService<BackupRepository>(); ;
        var backupSchedule = serviceScope.ServiceProvider.GetRequiredService<Schedule>();
        var tenantManager = serviceScope.ServiceProvider.GetRequiredService<TenantManager>();

        _logger.LogDebug("started to schedule backups");

        var backupsToSchedule = backupRepository.GetBackupSchedules().Where(schedule => backupSchedule.IsToBeProcessed(schedule)).ToList();

        _logger.LogDebug("{0} backups are to schedule", backupsToSchedule.Count);

        foreach (var schedule in backupsToSchedule)
        {
            if (stoppingToken.IsCancellationRequested)
            {
                return;
            }

            try
            {
                if (_coreBaseSettings.Standalone || tenantManager.GetTenantQuota(schedule.TenantId).AutoBackup)
                {
                    var tariff = paymentManager.GetTariff(schedule.TenantId);

                    if (tariff.State < TariffState.Delay)
                    {
                        schedule.LastBackupTime = DateTime.UtcNow;

                        backupRepository.SaveBackupSchedule(schedule);

                        _logger.LogDebug("Start scheduled backup: {0}, {1}, {2}, {3}", schedule.TenantId, schedule.BackupMail, schedule.StorageType, schedule.StorageBasePath);

                        _eventBus.Publish(new BackupRequestIntegrationEvent(
                                                 tenantId: schedule.TenantId,
                                                 storageBasePath: schedule.StorageBasePath,
                                                 storageParams: JsonConvert.DeserializeObject<Dictionary<string, string>>(schedule.StorageParams),
                                                 storageType: schedule.StorageType,
                                                 backupMail: schedule.BackupMail,
                                                 createBy: ASC.Core.Configuration.Constants.CoreSystem.ID,
                                                 isScheduled: true,
                                                 backupsStored: schedule.BackupsStored
                                          ));
                    }
                    else
                    {
                        _logger.LogDebug("Skip portal {0} not paid", schedule.TenantId);
                    }
                }
                else
                {
                    _logger.LogDebug("Skip portal {0} haven't access", schedule.TenantId);
                }
            }
            catch (Exception error)
            {
                _logger.LogError(error, "error while scheduling backups: {0}");
            }
        }
    }
}