using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Volo.Abp.DependencyInjection;
using Volo.Abp.Threading;

namespace Sanhe.Abp.Notifications;

/// <summary>
/// 通知发布提供者抽象类
/// </summary>
public abstract class NotificationPublishProvider : INotificationPublishProvider, ITransientDependency
{
    public abstract string Name { get; }

    protected IServiceProvider ServiceProvider { get; }

    protected readonly object ServiceProviderLock = new();

    public ILoggerFactory LoggerFactory => LazyGetRequiredService(ref _loggerFactory);
    private ILoggerFactory _loggerFactory;

    protected ILogger Logger => LazyLogger.Value;
    private Lazy<ILogger> LazyLogger => new(() => LoggerFactory?.CreateLogger(GetType().FullName) ?? NullLogger.Instance, true);


    protected TService LazyGetRequiredService<TService>(ref TService reference)
    {
        if (reference == null)
        {
            lock (ServiceProviderLock)
            {
                if (reference == null)
                {
                    reference = ServiceProvider.GetRequiredService<TService>();
                }
            }
        }

        return reference;
    }

    public ICancellationTokenProvider CancellationTokenProvider { get; set; }

    protected NotificationPublishProvider(IServiceProvider serviceProvider)
    {
        ServiceProvider = serviceProvider;
        CancellationTokenProvider = NullCancellationTokenProvider.Instance;
    }

    public async Task PublishAsync(NotificationInfo notification, IEnumerable<UserIdentifier> identifiers)
    {
        await PublishAsync(notification, identifiers, CancellationTokenProvider.Token);
    }

    /// <summary>
    /// 重写实现通知发布
    /// </summary>
    /// <param name="notification"></param>
    /// <param name="identifiers"></param>
    /// <param name="cancellationToken"></param>
    /// <returns></returns>
    protected abstract Task PublishAsync(NotificationInfo notification, IEnumerable<UserIdentifier> identifiers, CancellationToken cancellationToken = default);
}