download

type Config struct {
	// FileName
	FilePath string
	// SegmentSize
	SegmentSize int
	// TmpDir
	TmpDir string
	//
	IsRangesDisabled bool
}

type Downloader struct {
	// URL is the url to download
	URL string
	// FileDir represents the directory to store the downloaded file
	FileDir string
	// FileName represents the file name
	FileName string
	// FileExt represents the file extension
	FileExt string
	// HeadHeaders represents the headers of the head file response
	HeadHeaders http.Header
	// ContentType represents the content type of the file
	ContentType string
	// ContentLength represents the content length of the file
	ContentLength int64
	// Hash represents the file info hash, use for temp dir
	Hash string
	// IsSupportRange represents if the server supports the range header
	IsSupportRange bool
	// SegmentSize represents the size of each segment, default is 10 Mb
	SegmentSize int
	// Ranges represents the ranges of the file
	Ranges []*Range
	// FileParts represents the file parts by ranges
	FileParts []*FilePart
	// TmpDir represents the temporary directory to store file parts
	TmpDir string
	//
	IsRangesDisabled bool
}

type FilePart struct {
	// Name of the file.
	// format <file_name>.<file_ext>.part.<part_index>.<range_start>.<range_end>
	Name string
	// FilePath concats the TmpDir and Hash.
	Path string
	//
	FileName   string
	FileExt    string
	Index      int
	RangeStart int
	RangeEnd   int
}

type Range struct {
	Start int
	End   int
}