-mkInfo :: BVal -> Maybe Info
-mkInfo (Bdict m) = let (Bint pieceLength') = m ! "piece length"
- (Bstr pieces') = m ! "pieces"
- private' = Nothing
- (Bstr name') = m ! "name"
- (Bint length') = m ! "length"
- md5sum' = Nothing
- in Just Info { pieceLength = pieceLength'
- , pieces = pieces'
- , private = private'
- , name = unpack name'
- , lengthInBytes = length'
- , md5sum = md5sum'}
-mkInfo _ = Nothing
+bvalToInfo :: BVal -> Maybe Info
+bvalToInfo (Bdict m) = let (Bint pieceLength') = m ! "piece length"
+ (Bstr pieces') = m ! "pieces"
+ private' = Nothing
+ (Bstr name') = m ! "name"
+ -- is the key "files" present? If so, it is a multi-file torrent
+ -- if not, it is a single file torrent.
+ filesIfMulti = lookup "files" m
+ partialInfo = Info { pieceLength = pieceLength'
+ , pieces = pieces'
+ , private = private'
+ , name = unpack name'
+ , filemeta = []
+ }
+ in
+ case filesIfMulti of
+ Nothing -> let (Bint length') = m ! "length"
+ filemeta' = FileMeta { lengthInBytes = length'
+ , md5sum = Nothing
+ , path = unpack name' }
+ in Just (partialInfo { filemeta = [filemeta'] })
+ Just (Blist files) -> mapM toFileMeta files >>=
+ \filemeta' ->
+ Just partialInfo { filemeta = filemeta' }
+bvalToInfo _ = Nothing
+
+toFileMeta :: BVal -> Maybe FileMeta
+toFileMeta (Bdict fm) = let (Bint length) = fm ! "length"
+ (Blist pathElems) = fm ! "path"
+ pathStrings = fmap bstrToString pathElems
+ in
+ sequence pathStrings >>=
+ \pathList -> let path' = concat $ intersperse "/" pathList
+ in Just (FileMeta { lengthInBytes = length
+ , md5sum = Nothing
+ , path = path' })
+toFileMeta _ = Nothing
+
+mkMetaInfo :: BVal -> Either String Metainfo
+mkMetaInfo (Bdict m) =
+ let info' = bvalToInfo $ m ! "info"
+ announce' = lookup "announce" m
+ announceList' = lookup "announce-list" m
+ creationDate' = lookup "creation date" m
+ comment' = lookup "comment" m
+ createdBy' = lookup "created by" m
+ encoding' = lookup "encoding" m
+ in Right Metainfo {
+ info = info'
+ , announceList = maybeToList (announce' >>= bstrToString)
+ ++ getAnnounceList announceList'
+ , creationDate = bValToInteger =<< creationDate'
+ , comment = bstrToString =<< comment'
+ , createdBy = bstrToString =<< createdBy'
+ , encoding = bstrToString =<< encoding'
+ , infoHash = hash . encode $ (m ! "info")
+ }
+mkMetaInfo _ = Left "mkMetaInfo: expect an input dict"