using Microsoft.Extensions.Options;
using Tiku.Application.Jobs;
using Tiku.Application.PlatformBilling;
using Tiku.Application.Security;
using Tiku.Application.Tenancy;
using Tiku.Infrastructure.Messaging;

namespace Tiku.Worker;

internal abstract class PeriodicWorkerService(
    ILogger logger,
    TimeSpan interval) : BackgroundService
{
    protected abstract Task<int> ProcessAsync(CancellationToken cancellationToken);

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        while (!stoppingToken.IsCancellationRequested)
        {
            try
            {
                var processed = await ProcessAsync(stoppingToken);
                if (processed > 0)
                {
                    logger.LogInformation("{Worker} processed {Count} items.", GetType().Name, processed);
                }
            }
            catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
            {
                break;
            }
            catch (Exception exception)
            {
                logger.LogError(exception, "{Worker} iteration failed.", GetType().Name);
            }

            await Task.Delay(interval, stoppingToken);
        }
    }

    protected static void InitializeSystem(IServiceProvider services, string reason) =>
        services.GetRequiredService<ITenantContextInitializer>().InitializeSystem(null, reason);
}

internal sealed class TenantDomainWorker(
    IServiceScopeFactory scopeFactory,
    IOptions<DomainLifecycleOptions> options,
    ILogger<TenantDomainWorker> logger)
    : PeriodicWorkerService(logger, TimeSpan.FromSeconds(Math.Clamp(options.Value.PollSeconds, 10, 3600)))
{
    protected override async Task<int> ProcessAsync(CancellationToken cancellationToken)
    {
        await using var scope = scopeFactory.CreateAsyncScope();
        InitializeSystem(scope.ServiceProvider, "Tenant domain DNS and TLS lifecycle worker");
        return await scope.ServiceProvider.GetRequiredService<ITenantDomainLifecycleService>()
            .ProcessPendingAsync(cancellationToken);
    }
}

internal sealed class SaasSubscriptionWorker(
    IServiceScopeFactory scopeFactory,
    ILogger<SaasSubscriptionWorker> logger)
    : PeriodicWorkerService(logger, TimeSpan.FromSeconds(60))
{
    protected override async Task<int> ProcessAsync(CancellationToken cancellationToken)
    {
        await using var scope = scopeFactory.CreateAsyncScope();
        InitializeSystem(scope.ServiceProvider, "SaaS subscription lifecycle discovery worker");
        return await scope.ServiceProvider.GetRequiredService<ISaasSubscriptionLifecycleService>()
            .ProcessDueAsync(cancellationToken: cancellationToken);
    }
}

internal sealed class FeatureUsageWorker(
    IServiceScopeFactory scopeFactory,
    IOptions<FeatureUsageReconciliationOptions> options,
    ILogger<FeatureUsageWorker> logger)
    : PeriodicWorkerService(logger, TimeSpan.FromMinutes(Math.Clamp(options.Value.IntervalMinutes, 1, 1440)))
{
    protected override async Task<int> ProcessAsync(CancellationToken cancellationToken)
    {
        await using var scope = scopeFactory.CreateAsyncScope();
        InitializeSystem(scope.ServiceProvider, "Tenant feature usage reconciliation worker");
        return await scope.ServiceProvider.GetRequiredService<IFeatureUsageReconciliationService>()
            .ProcessDueAsync(cancellationToken);
    }
}

internal sealed class BackgroundJobsWorker(
    IServiceScopeFactory scopeFactory,
    MessagingOptions messagingOptions,
    ILogger<BackgroundJobsWorker> logger)
    : PeriodicWorkerService(logger, TimeSpan.FromSeconds(2))
{
    private readonly string workerId = $"{Environment.MachineName}:{Guid.NewGuid():N}";

    protected override async Task<int> ProcessAsync(CancellationToken cancellationToken)
    {
        var workers = Enumerable.Range(0, 4).Select(index => ProcessPartitionAsync(index, cancellationToken));
        return (await Task.WhenAll(workers)).Sum();
    }

    private async Task<int> ProcessPartitionAsync(int index, CancellationToken cancellationToken)
    {
        await using var scope = scopeFactory.CreateAsyncScope();
        InitializeSystem(scope.ServiceProvider, "Background job lease worker");
        return await scope.ServiceProvider.GetRequiredService<IBackgroundJobService>()
            .ProcessPendingAsync(
                $"{workerId}:{index}",
                5,
                includeImmediateJobs: !messagingOptions.IsConfigured,
                cancellationToken: cancellationToken);
    }
}