using System;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.DependencyInjection;
using Parking_space_WebAPI.Services;

// 讓ExcelGenerationService執行每日固定存取
namespace Parking_space_WebAPI.BackgroundServices
{
    public class DailyExcelGenerationService : IHostedService, IDisposable
    {
        private readonly ILogger<DailyExcelGenerationService> _logger;
        private readonly IServiceProvider _serviceProvider;
        private Timer _timer;

        public DailyExcelGenerationService(ILogger<DailyExcelGenerationService> logger, IServiceProvider serviceProvider)
        {
            _logger = logger;
            _serviceProvider = serviceProvider;
        }

        public Task StartAsync(CancellationToken cancellationToken)
        {
            TimeSpan scheduledTime = new TimeSpan(0, 23, 59);     //設定固定每天存取的時間
            var now = DateTime.Now;
            var nextRunTime = DateTime.Today.Add(scheduledTime);

            if (now > nextRunTime)
            {
                nextRunTime = nextRunTime.AddDays(1);
            }

            var timeToGo = nextRunTime - now;

            _timer = new Timer(GenerateExcel, null, timeToGo, TimeSpan.FromDays(1));
            return Task.CompletedTask;
        }

        private async void GenerateExcel(object state)
        {
            try
            {
               
                using (var scope = _serviceProvider.CreateScope()) 
                {
                    var excelGenerationService = scope.ServiceProvider.GetRequiredService<ExcelGenerationService>();
                    await excelGenerationService.GenerateDailyExcel(); 
                }
                _logger.LogInformation("每日 Excel 檔案已生成。");
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "生成 Excel 檔案時出錯。");
            }
        }

        public Task StopAsync(CancellationToken cancellationToken)
        {
            _timer?.Change(Timeout.Infinite, 0);
            return Task.CompletedTask;
        }

        public void Dispose()
        {
            _timer?.Dispose();
        }
    }
}