using Core;
using DataProviders;
using DataProviders.Buckets;
using DomainResults.Common;
using FileSecurityService;

namespace WeatherForecast.Services {

  /// <summary>
  /// 
  /// </summary>
  public interface IFileService {

    /// <summary>
    /// 
    /// </summary>
    /// <param name="siteId"></param>
    /// <param name="userId"></param>
    /// <param name="file"></param>
    /// <returns></returns>
    (Guid?, IDomainResult) Post(Guid siteId, Guid userId, IFormFile file);

    /// <summary>
    /// 
    /// </summary>
    /// <param name="siteId"></param>
    /// <param name="userId"></param>
    /// <param name="fileId"></param>
    /// <returns></returns>
    (BucketFile?, IDomainResult) Get(Guid siteId, Guid userId, Guid fileId);
    
    /// <summary>
    /// 
    /// </summary>
    /// <param name="siteId"></param>
    /// <param name="userId"></param>
    /// <param name="fileId"></param>
    /// <returns></returns>
    IDomainResult Delete(Guid siteId, Guid userId, Guid fileId);
  }

  /// <summary>
  /// 
  /// </summary>
  public class FileService : IFileService {

    private readonly ILogger<FilesService> _logger;
    private readonly IFileSecurityService _fileSecurityService;
    private readonly IImagesBucketDataProvider _imageBucketDataProvider;

    /// <summary>
    /// 
    /// </summary>
    /// <param name="logger"></param>
    /// <param name="fileSecurityService"></param>
    /// <param name="imageBucketDataProvider"></param>
    public FileService(
      ILogger<FilesService> logger,
      IFileSecurityService fileSecurityService,
      IImagesBucketDataProvider imageBucketDataProvider
    ) {
      _logger = logger;
      _fileSecurityService = fileSecurityService;
      _imageBucketDataProvider = imageBucketDataProvider;
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="siteId"></param>
    /// <param name="userId"></param>
    /// <param name="file"></param>
    /// <returns></returns>
    public (Guid?, IDomainResult) Post(Guid siteId, Guid userId, IFormFile file) {
      try {
        if (!(file.Length > 0))
          return IDomainResult.Failed<Guid?>();

        using var ms = new MemoryStream();
        file.CopyTo(ms);
        var bytes = ms.ToArray();

        var (fileCategory, signatureResult) = _fileSecurityService.CheckFileSignature(file.FileName, bytes, file.ContentType);
        if(!signatureResult.IsSuccess || fileCategory == null)
          return IDomainResult.Failed<Guid?>();

        var bucketFile = new BucketFile(file.FileName, bytes, file.ContentType);

        IDomainResult result;
        Guid? fileId;

        switch (fileCategory) {
          case FileCategory.Image:
            (fileId, result) = _imageBucketDataProvider.Upload(siteId, userId, bucketFile);
            break;
          default:
            return IDomainResult.Failed<Guid?>();
        }

        if (!result.IsSuccess || fileId == null)
          return IDomainResult.Failed<Guid?>();

        return IDomainResult.Success(fileId);
      }
      catch (Exception ex) {
        _logger.LogError(ex, "Unhandled exception");
        return IDomainResult.Failed<Guid?>(ex.Message);
      }
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="siteId"></param>
    /// <param name="userId"></param>
    /// <param name="fileId"></param>
    /// <returns></returns>
    public (BucketFile?, IDomainResult) Get(Guid siteId, Guid userId, Guid fileId) {
      try {
        var (file, result) = _imageBucketDataProvider.Download(siteId, userId, fileId);
        if (!result.IsSuccess || file == null)
          return (null, result);

        return IDomainResult.Success(file);
      }
      catch (Exception ex) {
        _logger.LogError(ex, "Unhandled exception");
        return IDomainResult.Failed<BucketFile?>(ex.Message);
      }
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="siteId"></param>
    /// <param name="userId"></param>
    /// <param name="fileId"></param>
    /// <returns></returns>
    public IDomainResult Delete(Guid siteId, Guid userId, Guid fileId) {
      try {
        return _imageBucketDataProvider.DeleteOne(siteId, userId, fileId);
      }
      catch (Exception ex) {
        _logger.LogError(ex, "Unhandled exception");
        return IDomainResult.Failed(ex.Message);
      }
    }
  }
}