using System;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.Data.SqlClient;
using Microsoft.AspNetCore.Http;
using Volo.Abp;
using Volo.Abp.DependencyInjection;
using Volo.Abp.Identity;
using Volo.Abp.MultiTenancy;
using Volo.Abp.Security.Claims;
using Volo.Abp.Uow;

namespace Sozsoft.Platform.Identity;

public class PlatformSessionValidationMiddleware : IMiddleware, ITransientDependency
{
    private readonly IIdentitySessionRepository sessionRepository;
    private readonly ICurrentTenant currentTenant;
    private readonly IUnitOfWorkManager unitOfWorkManager;

    public PlatformSessionValidationMiddleware(
        IIdentitySessionRepository sessionRepository,
        ICurrentTenant currentTenant,
        IUnitOfWorkManager unitOfWorkManager)
    {
        this.sessionRepository = sessionRepository;
        this.currentTenant = currentTenant;
        this.unitOfWorkManager = unitOfWorkManager;
    }

    public async Task InvokeAsync(HttpContext context, RequestDelegate next)
    {
        if (context.Request.Path.StartsWithSegments("/api/setup"))
        {
            await next(context);
            return;
        }

        if (context.User.Identity?.IsAuthenticated != true)
        {
            await next(context);
            return;
        }

        var userIdValue = context.User.FindFirst(AbpClaimTypes.UserId)?.Value;
        var sessionId = context.User.FindFirst(PlatformClaimTypes.SessionId.Key)?.Value;

        if (!Guid.TryParse(userIdValue, out var userId) || sessionId.IsNullOrWhiteSpace())
        {
            await next(context);
            return;
        }

        var tenantId = ParseTenantId(context.User.FindFirst(AbpClaimTypes.TenantId)?.Value);
        using (currentTenant.Change(tenantId))
        {
            try
            {
                using var uow = unitOfWorkManager.Begin(requiresNew: true, isTransactional: false);
                var sessions = await sessionRepository.GetListAsync(userId: userId);
                var isCurrentSession = sessions.Any(session => session.SessionId == sessionId);
                await uow.CompleteAsync();

                if (!isCurrentSession)
                {
                    context.Response.StatusCode = StatusCodes.Status401Unauthorized;
                    return;
                }
            }
            catch (Exception ex) when (IsDatabaseUnavailableException(ex))
            {
                context.Response.StatusCode = StatusCodes.Status503ServiceUnavailable;
                return;
            }
        }

        await next(context);
    }

    private static Guid? ParseTenantId(string value)
    {
        return !string.IsNullOrWhiteSpace(value) && Guid.TryParse(value, out var id) ? id : null;
    }

    private static bool IsDatabaseUnavailableException(Exception exception)
    {
        return exception is SqlException ||
               exception is TimeoutException ||
               exception is TaskCanceledException ||
               exception is InvalidOperationException && exception.InnerException != null &&
                   IsDatabaseUnavailableException(exception.InnerException);
    }
}