mypy strict support!

bcao.py

@@ -16,7 +16,7 @@ from os import path
 from base64 import b64encode
 from zipfile import ZipFile
 from pathlib import Path
-from typing import Optional, Union, List, Dict
+from typing import Optional, Union, List, Dict, Any
 
 # pycharm tells me some of these classes shouldn't be imported because they're not declared in __all__.
 # however, the mutagen docs show example code where someone creates a mutagen.flac.Picture by referring to it as
@@ -37,6 +37,7 @@ fully_supported: List[str] = ["ogg", "flac", "mp3", "m4a", "wav"]
 MutagenFile = Union[MP3, FLAC, OggVorbis, mutagen.FileType]
 MutagenTags = Union[mutagen.id3.ID3Tags, mutagen.mp4.Tags, mutagen.oggvorbis.OggVCommentDict]
 args: argparse.Namespace
+tmp_dir: tempfile.TemporaryDirectory[Any]
 
 class SongInfo:
 	tag_lookup: Dict[str, Dict[str, str]] = {
@@ -46,6 +47,7 @@ class SongInfo:
 		"album":        {"id3": "TALB", "m4a": "©alb", "vorbis": "album"},
 		"album_artist": {"id3": "TPE2", "m4a": "aART", "vorbis": "albumartist"}
 	}
+
 	format_lookup: Dict[str, str] = {
 		"mp3": "id3",
 		"m4a": "m4a",
@@ -110,10 +112,10 @@ class SongInfo:
 				self.tags[standard_name] = value_list[0]
 				self.list_tags[standard_name] = value_list
 
-	def get_target_name(self, zeroes: int):
+	def get_target_name(self, zeroes: int) -> str:
 		return f"{self.tags['track'].zfill(zeroes)} {self.tags['title']}.{self.format}"
 
-	def has_cover(self):
+	def has_cover(self) -> bool:
 		if self.format == "ogg":
 			return "metadata_block_picture" in self.m_tags and len(self.m_tags["metadata_block_picture"]) != 0
 
@@ -132,7 +134,7 @@ class SongInfo:
 
 		raise NotImplementedError("Song format not yet implemented.")
 
-	def set_cover(self, to_embed: Union[Picture, APIC, MP4Cover]):
+	def set_cover(self, to_embed: Union[Picture, APIC, MP4Cover]) -> None:
 		# embed cover art
 		if self.format == "ogg":
 			self.m_tags["metadata_block_picture"] = [b64encode(to_embed.write()).decode("ascii")]
@@ -146,43 +148,26 @@ class SongInfo:
 
 		self.m_file.save()
 
-	def __getitem__(self, item):
+	def __getitem__(self, item: str) -> str:
 		return self.tags[item]
 
-def log(message: str, importance: int = 0):
+def log(message: str, importance: int = 0) -> None:
 	if not args.quiet or importance > 0:
 		print(message)
 
-def die(message: str, code: int = 1):
+def die(message: str, code: int = 1) -> None:
 	print(message)
 	sys.exit(code)
 
-def has_cover(mut_song: MutagenFile):
-	if isinstance(mut_song, OggVorbis):
-		return "metadata_block_picture" in mut_song and len(mut_song["metadata_block_picture"]) != 0
-
-	if isinstance(mut_song, FLAC):
-		return len(mut_song.pictures) != 0
-
-	if isinstance(mut_song, MP3):
-		apics: List[APIC] = mut_song.tags.getall("APIC")
-		for apic in apics:
-			if apic.type == PictureType.COVER_FRONT:
-				return True
-		return False
-
-	if isinstance(mut_song, MP4):
-		return 'covr' in mut_song and len(mut_song['covr']) != 0
-
-	raise NotImplementedError("Song format not yet implemented.")
-
 def sanitise(in_str: str) -> str:
 	if args.sanitise:
 		return re.sub(r"[?\\/:|*\"<>]", "_", in_str)
 	return in_str
 
 
-def main():
+def main() -> None:
+	global args, tmp_dir
+
 	# noinspection PyTypeChecker
 	parser = argparse.ArgumentParser(usage='%(prog)s zip [options]',
 		formatter_class=argparse.RawTextHelpFormatter,
@@ -203,7 +188,6 @@ def main():
 	parser.add_argument('-t', '--threshold', dest='threshold', nargs=1, default=300,
 		help="Maximum acceptable file size for cover art, in kilobytes.\nDefault: %(default)s")
 
-	global args
 	args = parser.parse_args()
 	# convert args.threshold to bytes
 	args.threshold *= 1024
@@ -212,7 +196,7 @@ def main():
 		die(f"Couldn't find {args.zip}.", 2)
 
 	log("Extracting...")
-	tmp_dir: tempfile.TemporaryDirectory = tempfile.TemporaryDirectory()
+	tmp_dir = tempfile.TemporaryDirectory()
 	tmp: str = tmp_dir.name
 	cover: Optional[str] = None
 	song_names: List[str] = []
@@ -327,7 +311,7 @@ def main():
 			)
 
 	artists: List[str] = []
-	album: Optional[str] = None
+	album: str = "Unknown album" # it SHOULD be impossible for this value to ever appear
 	songs: Dict[str, str] = {}
 	zeroes = min(len(song_names), 2)
 	first_loop: bool = True