using System;
using System.Threading;
using System.Threading.Tasks;
using CellularManagement.Domain.Services;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace CellularManagement.Infrastructure.Services;

/// <summary>
/// 密钥轮换后台服务
/// </summary>
public sealed class KeyRotationBackgroundService : BackgroundService
{
    private readonly IKeyRotationService _keyRotationService;
    private readonly ILogger<KeyRotationBackgroundService> _logger;
    private readonly TimeSpan _checkInterval;

    /// <summary>
    /// 构造函数
    /// </summary>
    public KeyRotationBackgroundService(
        IKeyRotationService keyRotationService,
        ILogger<KeyRotationBackgroundService> logger)
    {
        _keyRotationService = keyRotationService;
        _logger = logger;
        _checkInterval = TimeSpan.FromHours(1); // 每小时检查一次
    }

    /// <inheritdoc />
    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        try
        {
            // 初始化密钥轮换服务
            await _keyRotationService.InitializeAsync();

            while (!stoppingToken.IsCancellationRequested)
            {
                try
                {
                    // 检查是否需要轮换密钥
                    if (_keyRotationService.ShouldRotateKey())
                    {
                        _logger.LogInformation("开始轮换密钥");
                        await _keyRotationService.RotateKeyAsync();
                        _logger.LogInformation("密钥轮换完成");
                    }
                }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "密钥轮换检查失败: {Message}", ex.Message);
                }

                // 等待下一次检查
                await Task.Delay(_checkInterval, stoppingToken);
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "密钥轮换后台服务失败: {Message}", ex.Message);
            throw;
        }
    }
}