/* call processNextArchiveEntry in some kind of loop! */
- (int)processNextArchiveEntry:(struct archive *)archive
{
    struct archive_entry *entry = NULL;
    int result = ARCHIVE_OK;

    result = archive_read_next_header(archive, &entry);

    if (result == ARCHIVE_OK)
    {
        if (archive_entry_filetype(entry) == AE_IFDIR)
        {
            result = [self processDirectory:entry inArchive:archive];
        }
        else if (archive_entry_filetype(entry) == AE_IFREG)
        {
            result = [self processFile:entry inArchive:archive];
        }
    }

    return result;
}


- (int)processDirectory:(struct archive_entry *)entry inArchive:(struct archive *)archive
{
    NSString *path = nil;
    NSError *error = nil;
    BOOL exists, isDirectory;
    BOOL ok = NO;

    path = [self fullDestinationPathForEntry:entry];
    exists = [fileManager fileExistsAtPath:path isDirectory:&isDirectory];

    if (!exists)
    {
        ok = [fileManager createDirectoryAtPath:path withIntermediateDirectories:YES attributes:nil error:&error];
    }
    else if (exists && isDirectory)
    {
        // we allow users to re-download content, in which case this can happen.
        ok = YES;
    }

    return ok ? ARCHIVE_OK : ARCHIVE_FATAL;
}


- (int)processFile:(struct archive_entry *)entry inArchive:(struct archive *)archive
{
    NSFileHandle *file = nil;
    NSString *path = nil;
    BOOL ok = NO;
    int result = ARCHIVE_FAILED;

    path = [self fullDestinationPathForEntry:entry];

    ok = [fileManager createFileAtPath:path contents:nil attributes:nil];

    if (ok)
    {
        file = [NSFileHandle fileHandleForWritingAtPath:path];
    }

    if(file != nil)
    {
        result = archive_read_data_into_fd(archive, [file fileDescriptor]);
        [file closeFile];
    }

    return result;
}


- (NSString *)fullDestinationPathForEntry:(struct archive_entry *)entry
{
    NSString *path = nil;
    const char *entry_path = NULL;

    entry_path = archive_entry_pathname(entry);

    if (entry_path != NULL)
    {
        path = [fileManager stringWithFileSystemRepresentation:entry_path length:strlen(entry_path)];
    }

    if (path != nil)
    {
        path = [tempDirectory stringByAppendingPathComponent:path];
    }

    return path;
}