Downloader.m

#import "Downloader.h"
#import "RNFSManager.h"

@implementation RNFSDownloadParams

@end

@interface RNFSDownloader()

@property (copy) RNFSDownloadParams* params;

@property (retain) NSURLSession* session;
@property (retain) NSURLSessionTask* task;
@property (retain) NSNumber* statusCode;
@property (retain) NSNumber* lastProgressValue;
@property (retain) NSNumber* contentLength;
@property (retain) NSNumber* bytesWritten;
@property (retain) NSString* sessionIdentifier;

@property (retain) NSFileHandle* fileHandle;
@property (retain) NSMutableDictionary* responseData;
@end

@implementation RNFSDownloader

- (void)downloadFile:(RNFSDownloadParams*)params
{
  _params = params;

  _bytesWritten = 0;

  NSURL* url = [NSURL URLWithString:_params.fromUrl];
  NSURL* logURLWithoutQuery = [[NSURL alloc] initWithScheme:[url scheme] host:[url host] path:[url path]];
  [[NSFileManager defaultManager] createFileAtPath:_params.toFile contents:nil attributes:nil];
  _fileHandle = [NSFileHandle fileHandleForWritingAtPath:_params.toFile];

  if (!_fileHandle) {
    NSError* error = [NSError errorWithDomain:@"Downloader" code:NSURLErrorFileDoesNotExist
                              userInfo:@{NSLocalizedDescriptionKey: [NSString stringWithFormat: @"Failed to create target file at path: %@", _params.toFile]}];

    return _params.errorCallback(error);
  } else {
    [_fileHandle closeFile];
  }

  NSURLSessionConfiguration *config;
  if (_params.background) {
    _sessionIdentifier = [[NSUUID UUID] UUIDString];
    NSLog(@"---CREATING BG DOWNLOAD of %@ in session %@", [logURLWithoutQuery absoluteString], _sessionIdentifier);
    config = [NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:_sessionIdentifier];
    config.sessionSendsLaunchEvents = YES;
  } else {
    NSLog(@"---CREATING FG DOWNLOAD %@", [logURLWithoutQuery absoluteString]);
    config = [NSURLSessionConfiguration defaultSessionConfiguration];
  }

  config.HTTPAdditionalHeaders = _params.headers;

  _session = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:nil];
  _task = [_session downloadTaskWithURL:url];
  [_task resume];
}

- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite
{
  NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)downloadTask.response;
  if (!_statusCode) {
    _statusCode = [NSNumber numberWithLong:httpResponse.statusCode];
    _contentLength = [NSNumber numberWithLong:httpResponse.expectedContentLength];
    return _params.beginCallback(_statusCode, _contentLength, httpResponse.allHeaderFields);
  }

  if ([_statusCode isEqualToNumber:[NSNumber numberWithInt:200]]) {
    _bytesWritten = @(totalBytesWritten);

    if (_params.progressDivider.integerValue <= 0) {
      return _params.progressCallback(_contentLength, _bytesWritten);
    } else {
      double doubleBytesWritten = (double)[_bytesWritten longValue];
      double doubleContentLength = (double)[_contentLength longValue];
      double doublePercents = doubleBytesWritten / doubleContentLength * 100;
      NSNumber* progress = [NSNumber numberWithUnsignedInt: floor(doublePercents)];
      if ([progress unsignedIntValue] % [_params.progressDivider integerValue] == 0) {
        if (([progress unsignedIntValue] != [_lastProgressValue unsignedIntValue]) || ([_bytesWritten unsignedIntegerValue] == [_contentLength longValue])) {
          NSLog(@"---Progress callback EMIT--- %zu", [progress unsignedIntValue]);
          _lastProgressValue = [NSNumber numberWithUnsignedInt:[progress unsignedIntValue]];
          return _params.progressCallback(_contentLength, _bytesWritten);
        }
      }
    }
  }
}

- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location
{

  NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)downloadTask.response;
  if (!_statusCode) {
      _statusCode = [NSNumber numberWithLong:httpResponse.statusCode];
      //@TODO: fetch _bytesWritten
  }

  NSURL *destURL = [NSURL fileURLWithPath:_params.toFile];
  NSFileManager *fm = [NSFileManager defaultManager];
  NSError *error = nil;
  [fm removeItemAtURL:destURL error:nil];       // Remove file at destination path, if it exists
  [fm moveItemAtURL:location toURL:destURL error:&error];
  if (error) {
    NSLog(@"RNFS download: unable to move tempfile to destination. %@, %@", error, error.userInfo);
    return _params.errorCallback(error);
  }
  NSMutableData *responseForTask = [_responseData objectForKey:@(downloadTask.taskIdentifier)];
  NSString *body = @"";
  if (responseForTask) {
    body = [[NSString alloc] initWithData:responseForTask encoding:NSUTF8StringEncoding];
    NSLog(@"---WITH DATA---");
    [_responseData removeObjectForKey:@(downloadTask.taskIdentifier)];
  }
  if(!_statusCode || ![_statusCode isEqualToNumber:[NSNumber numberWithInt:200]]){
    NSString *errorDescription = [NSString stringWithFormat:@"Status Code: %d. Body: %@",
                                      _statusCode != nil ? [_statusCode integerValue] : 0,
                                      body];
    NSString *errorDomain = [RNFSManager getErrorDomain];
    NSMutableDictionary *userInfo = [[NSMutableDictionary alloc] init];
    [userInfo setObject:errorDescription forKey:NSLocalizedDescriptionKey];
    NSError *serverError = [NSError errorWithDomain:errorDomain code:500 userInfo:userInfo];
    return _params.errorCallback(serverError);
  }
  return _params.completeCallback(_statusCode, _bytesWritten);
}

- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionTask *)downloadTask didCompleteWithError:(NSError *)error
{
    NSLog(@"didCompleteWithError");

  return _params.errorCallback(error);
}

- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {
    NSLog(@"---RECEIVED DATA---");
    NSMutableData *responseData = [_responseData objectForKey:@(dataTask.taskIdentifier)];
    if (!responseData) {
        responseData = [NSMutableData dataWithData:data];
        [_responseData setObject:responseData forKey:@(dataTask.taskIdentifier)];
    } else {
        [responseData appendData:data];
    }
}

- (void)stopDownload
{
  [_task cancel];

  NSError *error = [NSError errorWithDomain:@"RNFS"
                                       code:@"Aborted"
                                   userInfo:@{
                                     NSLocalizedDescriptionKey: @"Download has been aborted"
                                   }];

  return _params.errorCallback(error);
}

- (void)URLSessionDidFinishEventsForBackgroundURLSession:(NSURLSession *)session
{
    [RNFSManager URLSessionDidFinishEventsForBackgroundURLSession:session];
}

@end