using System.Collections.Concurrent;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Volo.Abp.DependencyInjection;
using Volo.Abp.Uow;
using Yi.Framework.TenantManagement.Application.Contracts;

namespace FoodLabeling.Th.Application.MultiTenancy;

/// <summary>
/// 使用独立 DI Scope 在后台执行 <see cref="ITenantService.InitAsync"/>，避免阻塞 HTTP 请求。
/// </summary>
public class ThTenantDatabaseBackgroundInitializer
    : IThTenantDatabaseBackgroundInitializer, ISingletonDependency
{
    private readonly IServiceScopeFactory _scopeFactory;
    private readonly ILogger<ThTenantDatabaseBackgroundInitializer> _logger;
    private static readonly ConcurrentDictionary<Guid, byte> Running = new();

    public ThTenantDatabaseBackgroundInitializer(
        IServiceScopeFactory scopeFactory,
        ILogger<ThTenantDatabaseBackgroundInitializer> logger)
    {
        _scopeFactory = scopeFactory;
        _logger = logger;
    }

    /// <inheritdoc />
    public void Enqueue(Guid tenantId)
    {
        if (!Running.TryAdd(tenantId, 0))
        {
            _logger.LogInformation("租户 {TenantId} 业务库初始化已在进行中，跳过重复入队", tenantId);
            return;
        }

        _ = Task.Run(() => RunInitAsync(tenantId));
    }

    private async Task RunInitAsync(Guid tenantId)
    {
        try
        {
            _logger.LogInformation("租户 {TenantId} 业务库后台初始化开始", tenantId);

            using var scope = _scopeFactory.CreateScope();
            var uowManager = scope.ServiceProvider.GetRequiredService<IUnitOfWorkManager>();
            var tenantService = scope.ServiceProvider.GetRequiredService<ITenantService>();

            using var uow = uowManager.Begin(requiresNew: true, isTransactional: false);
            await tenantService.InitAsync(tenantId);
            await uow.CompleteAsync();

            _logger.LogInformation("租户 {TenantId} 业务库后台初始化完成", tenantId);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "租户 {TenantId} 业务库后台初始化失败", tenantId);
        }
        finally
        {
            Running.TryRemove(tenantId, out _);
        }
    }
}