GH-31: Analyse the code quality using codacy (GH-32)

* Fix the names to correspond to the functionality
* Clean-up - use attribute delegate
* Make the FileFormatter abstract base class
* Fix the critical code quality issues

Author: ArtyomVancyan

thumbnails/__init__.py

@@ -6,8 +6,8 @@
 
 from PIL import Image
 
+from .formatter import FileFormatter
 from .formatter import FormatterFactory
-from .formatter import ThumbnailFormat
 from .thumbnails import Thumbnails
 from .thumbnails import arange
 
@@ -17,34 +17,33 @@
 DEFAULT_BASEPATH = ""
 
 
-def register_format(typename):
-    """Register a new thumbnail format to the factory."""
+def register_formatter(typename):
+    """Register a new thumbnail formatter to the factory."""
 
-    def _registrator(cls):
-        if not issubclass(cls, ThumbnailFormat):
-            raise ValueError("Thumbnail format must implement"
-                             "the ThumbnailFormat interface.")
+    def _register_factory(cls):
+        if not issubclass(cls, FileFormatter):
+            raise ValueError("The formatter must implement the FileFormatter interface.")
 
         cls.extension = typename
         FormatterFactory.thumbnails[typename] = cls
         return cls
 
-    return _registrator
+    return _register_factory
 
 
-@register_format("vtt")
-class VTT(ThumbnailFormat):
+@register_formatter("vtt")
+class VTTFormatter(FileFormatter):
     """Implements the methods for generating thumbnails in the WebVTT format."""
 
     def __init__(self, video):
         super().__init__(video)
         self._master_name = self.filename + ".png"
 
     def prepare_thumbnails(self):
-        _thumbnails = self.video.thumbnails(True)
+        _thumbnails = self.thumbnails(True)
         master = Image.new(mode="RGBA", size=next(_thumbnails))
 
-        for frame, start, end, x, y in self.video.thumbnails():
+        for frame, start, end, x, y in self.thumbnails():
             with Image.open(frame) as image:
                 image = image.resize((self.width, self.height), Image.ANTIALIAS)
                 master.paste(image, (x, y))
@@ -60,19 +59,19 @@ def _format_time(secs):
         _lines = ["WEBVTT\n\n"]
         _img_src = self.basepath + self._master_name
 
-        for frame, start, end, x, y in self.video.thumbnails():
+        for frame, start, end, x, y in self.thumbnails():
             _thumbnail = "%s --> %s\n%s#xywh=%d,%d,%d,%d\n\n" % (
                 _format_time(start), _format_time(end),
                 _img_src, x, y, self.width, self.height
             )
             _lines.append(_thumbnail)
 
-        with open(self.output_format, "w") as fp:
+        with open(self.thumbnail_file, "w") as fp:
             fp.writelines(_lines)
 
 
-@register_format("json")
-class JSON(ThumbnailFormat):
+@register_formatter("json")
+class JSONFormatter(FileFormatter):
     """Implements the methods for generating thumbnails in the JSON format."""
 
     def __init__(self, video):
@@ -88,7 +87,7 @@ def prepare_thumbnails(self):
     def generate(self):
         _content = {}
 
-        for frame, start, end, x, y in self.video.thumbnails():
+        for frame, start, end, x, y in self.thumbnails():
             frame = self._outdir + os.sep + os.path.split(frame)[1]
             with Image.open(frame) as image:
                 image.resize((self.width, self.height), Image.ANTIALIAS).save(frame)
@@ -98,16 +97,16 @@ def generate(self):
                 }
                 _content[int(start)] = _thumbnail
 
-        with open(self.output_format, "w") as fp:
+        with open(self.thumbnail_file, "w") as fp:
             json.dump(_content, fp, indent=2)
 
 
 __version__ = "v1.0"
 __all__ = (
-    FormatterFactory,
-    register_format,
-    ThumbnailFormat,
-    Thumbnails,
-    JSON,
-    VTT,
+    "register_formatter",
+    "FormatterFactory",
+    "FileFormatter",
+    "JSONFormatter",
+    "VTTFormatter",
+    "Thumbnails",
 )

thumbnails/__main__.py

@@ -33,9 +33,12 @@ def format_usage(self, ctx, formatter):
         formatter.write_usage(ctx.command_path, "\n\t\t\t".join(usages), prefix="Usages: ")
 
 
+# This defines a set of supported values for the particular option of the CLI.
+_type = click.Choice(FormatterFactory.thumbnails.keys(), case_sensitive=False)
+
+
 @click.command(cls=_ThumbnailsCLI)
-@click.option("--as", "-F", default=DEFAULT_AS, help="Output format. Default is %s." % DEFAULT_AS,
-              type=click.Choice(FormatterFactory.thumbnails.keys(), case_sensitive=False))
+@click.option("--as", "-F", default=DEFAULT_AS, type=_type, help="Output format. Default is %s." % DEFAULT_AS)
 @click.option("--compress", "-C", default=DEFAULT_COMPRESS, help="The image scale coefficient. A number from 0 to 1.")
 @click.option("--interval", "-I", default=DEFAULT_INTERVAL, help="The interval between neighbor thumbnails in seconds.")
 @click.option("--basepath", "-B", default=DEFAULT_BASEPATH, help="The prefix of the thumbnails path can be customized.")

thumbnails/formatter.py

@@ -1,5 +1,8 @@
-class ThumbnailFormat:
-    """The interface of the thumbnails' final output format generator."""
+from abc import ABCMeta, abstractmethod
+
+
+class FileFormatter(metaclass=ABCMeta):
+    """Any thumbnail describing format should implement the base Formatter."""
 
     extension = None
 
@@ -11,16 +14,17 @@ def __getattr__(self, item):
         return getattr(self.video, item)
 
     @property
-    def output_format(self):
+    def thumbnail_file(self):
+        """Return the name of the thumbnail file."""
         return "%s.%s" % (self.filename, self.extension)
 
+    @abstractmethod
     def prepare_thumbnails(self):
         """Prepare the thumbnails before generating the output."""
-        raise NotImplementedError
 
+    @abstractmethod
     def generate(self):
         """Generate the thumbnails for the given video."""
-        raise NotImplementedError
 
 
 class FormatterFactory:
@@ -29,9 +33,9 @@ class FormatterFactory:
     thumbnails = {}
 
     @classmethod
-    def create_formatter(cls, typename, *args, **kwargs) -> ThumbnailFormat:
+    def create_formatter(cls, typename, *args, **kwargs) -> FileFormatter:
         """Create a new thumbnail formatter by the given typename."""
         try:
             return cls.thumbnails[typename](*args, **kwargs)
         except KeyError:
-            raise ValueError("Thumbnail format '%s' is not supported." % typename)
+            raise ValueError("The formatter type '%s' is not registered." % typename)