using IRaCIS.Core.Application.Helper;
using IRaCIS.Core.Application.Service;
using IRaCIS.Core.Domain.Models;
using IRaCIS.Core.Infra.EFCore;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using System;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace IRaCIS.Core.API.HostService;


public class SyncFileRecoveryService(IServiceScopeFactory _scopeFactory, FileSyncQueue _fileSyncQueue) : BackgroundService
{

    private readonly int _pageSize = 500;

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        using var scope = _scopeFactory.CreateScope();
        var fileUploadRecordRepository = scope.ServiceProvider.GetRequiredService<IRepository<FileUploadRecord>>();

        // 延迟启动，保证主机快速启动
        await Task.Delay(5000, stoppingToken);

        int page = 0;


        while (!stoppingToken.IsCancellationRequested)
        {
            // 分页获取未入队任务
            var pending = await fileUploadRecordRepository
                .Where(x => x.IsNeedSync == true && (x.IsSync == false || x.IsSync == null))
                .OrderByDescending(x => x.Priority)
                .Select(t => new { t.Id, t.Priority })
                .Skip(page * _pageSize)
                .Take(_pageSize)
                .ToListAsync(stoppingToken);

            if (!pending.Any())
                break; // 扫描完毕，退出循环

            foreach (var file in pending)
            {
                //file.IsQueued = true;      // 避免重复入队
                _fileSyncQueue.Enqueue(file.Id, file.Priority ?? 0);  // 放入队列
            }

            page++;                       // 下一页
            await Task.Delay(200, stoppingToken); // 缓解数据库压力
        }
    }
}

public class FileSyncWorker(IServiceScopeFactory _scopeFactory, ILogger<FileSyncWorker> _logger, FileSyncQueue _fileSyncQueue) : BackgroundService
{

    // ⭐ 自动根据服务器CPU
    private readonly int _workerCount = Math.Max(1, Environment.ProcessorCount - 1);



    protected override Task ExecuteAsync(CancellationToken stoppingToken)
    {
        for (int i = 0; i < _workerCount; i++)
            Task.Run(() => WorkerLoop(stoppingToken));

        return Task.CompletedTask;
    }


    private async Task WorkerLoop(CancellationToken stoppingToken)
    {
        while (!stoppingToken.IsCancellationRequested)
        {
            var id = await _fileSyncQueue.DequeueAsync(stoppingToken);

            try
            {
                using var scope = _scopeFactory.CreateScope();
                var _fileUploadRecordRepository = scope.ServiceProvider.GetRequiredService<IRepository<FileUploadRecord>>();
                var _uploadFileSyncRecordRepository = scope.ServiceProvider.GetRequiredService<IRepository<UploadFileSyncRecord>>();
                var oss = scope.ServiceProvider.GetRequiredService<IOSSService>();

                var file = await _fileUploadRecordRepository.FirstOrDefaultAsync(t => t.Id == id);

                if (file == null || file.IsNeedSync != true)
                    return;

                var log = new UploadFileSyncRecord
                {
                    FileUploadRecordId = id,
                    StartTime = DateTime.Now,
                    JobState = jobState.RUNNING
                };

                await _uploadFileSyncRecordRepository.AddAsync(log);
                await _uploadFileSyncRecordRepository.SaveChangesAsync(stoppingToken);

                try
                {
                    await oss.SyncFileAsync(file.Path.TrimStart('/'), file.UploadRegion == "CN" ? ObjectStoreUse.AliyunOSS : ObjectStoreUse.AWS, file.UploadRegion == "CN" ? ObjectStoreUse.AWS : ObjectStoreUse.AliyunOSS);

                    file.IsSync = true;
                    file.SyncFinishedTime = DateTime.UtcNow;

                    log.JobState = jobState.SUCCESS;
                }
                catch (Exception ex)
                {
                    log.JobState = jobState.FAILED;

                    log.Msg = ex.Message[..300];
                }

                log.EndTime = DateTime.UtcNow;

                await _uploadFileSyncRecordRepository.SaveChangesAsync(stoppingToken);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Sync failed {Id}", id);
            }
        }


    }
}