Refactor Candidate class in fetchart.py to improve

validation and resizing logic

beetsplug/fetchart.py

@@ -67,10 +67,15 @@ class Candidate:
         self.match = match
         self.size = size
 
-    def _validate(self, plugin):
+    def _validate(self, plugin, skip_check_for=None):
         """Determine whether the candidate artwork is valid based on
         its dimensions (width and ratio).
 
+        `skip_check_for` is a check or list of checks to skip. This is used to
+        avoid redundant checks when the candidate has already been
+        validated for a particular operation without changing
+        plugin configuration.
+
         Return `CANDIDATE_BAD` if the file is unusable.
         Return `CANDIDATE_EXACT` if the file is usable as-is.
         Return `CANDIDATE_DOWNSCALE` if the file must be rescaled.
@@ -82,6 +87,11 @@ class Candidate:
         if not self.path:
             return self.CANDIDATE_BAD
 
+        if skip_check_for is None:
+            skip_check_for = []
+        if isinstance(skip_check_for, int):
+            skip_check_for = [skip_check_for]
+
         if not (
             plugin.enforce_ratio
             or plugin.minwidth
@@ -180,30 +190,51 @@ class Candidate:
                     plugin.cover_format,
                 )
 
-        if downscale:
+        if downscale and (not self.CANDIDATE_DOWNSCALE in skip_check_for):
             return self.CANDIDATE_DOWNSCALE
-        elif downsize:
+        if reformat and (not self.CANDIDATE_REFORMAT in skip_check_for):
-            return self.CANDIDATE_DOWNSIZE
-        elif plugin.deinterlace:
-            return self.CANDIDATE_DEINTERLACE
-        elif reformat:
             return self.CANDIDATE_REFORMAT
-        else:
+        if plugin.deinterlace and (
-            return self.CANDIDATE_EXACT
+            not self.CANDIDATE_DEINTERLACE in skip_check_for
+        ):
+            return self.CANDIDATE_DEINTERLACE
+        if downsize and (not self.CANDIDATE_DOWNSIZE in skip_check_for):
+            return self.CANDIDATE_DOWNSIZE
+        return self.CANDIDATE_EXACT
 
-    def validate(self, plugin):
+    def validate(self, plugin, skip_check_for=None):
-        self.check = self._validate(plugin)
+        self.check = self._validate(plugin, skip_check_for)
         return self.check
 
     def resize(self, plugin):
-        if self.check == self.CANDIDATE_DOWNSCALE:
+        """Resize the candidate artwork according to the plugin's
+        configuration until it is valid or no further resizing is
+        possible.
+        """
+        # validate the candidate in case it hasn't been done yet
+        current_check = self.validate(plugin)
+        checks_performed = []
+
+        # we don't want to resize the image if it's valid or bad
+        while current_check not in [self.CANDIDATE_BAD, self.CANDIDATE_EXACT]:
+            self._resize(plugin, current_check)
+            checks_performed.append(current_check)
+            current_check = self.validate(
+                plugin, skip_check_for=checks_performed
+            )
+
+    def _resize(self, plugin, check=None):
+        """Resize the candidate artwork according to the plugin's
+        configuration and the specified check.
+        """
+        if check == self.CANDIDATE_DOWNSCALE:
             self.path = ArtResizer.shared.resize(
                 plugin.maxwidth,
                 self.path,
                 quality=plugin.quality,
                 max_filesize=plugin.max_filesize,
             )
-        elif self.check == self.CANDIDATE_DOWNSIZE:
+        elif check == self.CANDIDATE_DOWNSIZE:
             # dimensions are correct, so maxwidth is set to maximum dimension
             self.path = ArtResizer.shared.resize(
                 max(self.size),
@@ -211,9 +242,9 @@ class Candidate:
                 quality=plugin.quality,
                 max_filesize=plugin.max_filesize,
             )
-        elif self.check == self.CANDIDATE_DEINTERLACE:
+        elif check == self.CANDIDATE_DEINTERLACE:
             self.path = ArtResizer.shared.deinterlace(self.path)
-        elif self.check == self.CANDIDATE_REFORMAT:
+        elif check == self.CANDIDATE_REFORMAT:
             self.path = ArtResizer.shared.reformat(
                 self.path,
                 plugin.cover_format,