using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Fake.UnitOfWork;

namespace Oms.Application.Messaging;

/// <summary>
/// 把创单/预报之后的副作用延后到当前事务提交成功再执行，每一步单独提交。
/// </summary>
internal static class OmsAfterCommit
{
    public static Task ScheduleAsync(IUnitOfWorkManager unitOfWorkManager, Func<Task> action)
    {
        var current = unitOfWorkManager.Current;
        if (current != null && !current.IsCompleted)
        {
            // OnCompleted 仍处在创单事务里，此时再写 Outbox 征用不到连接，事件会丢。
            // 等工作单元释放后再开独立事务。
            EventHandler<UnitOfWorkEventArgs> handler = null!;
            handler = (_, _) =>
            {
                current.Disposed -= handler;
                _ = Task.Run(action);
            };
            current.Disposed += handler;
            return Task.CompletedTask;
        }

        return action();
    }

    /// <summary>
    /// 新开独立事务执行一步。失败只记日志，不抛回调用方。
    /// </summary>
    public static async Task<bool> RunStepAsync(
        IServiceScopeFactory scopeFactory,
        ILogger logger,
        string step,
        Func<IServiceProvider, Task> work)
    {
        try
        {
            using var scope = scopeFactory.CreateScope();
            var unitOfWorkManager = scope.ServiceProvider.GetRequiredService<IUnitOfWorkManager>();
            using var unitOfWork = unitOfWorkManager.Begin(OmsOutboxUnitOfWork.Independent());
            await OmsIntegrationEventPublisher.EnsureOutboxDbContextAsync(unitOfWorkManager);
            await work(scope.ServiceProvider);
            await unitOfWork.CompleteAsync();
            return true;
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "订单后置步骤失败 Step={Step}", step);
            return false;
        }
    }
}