Add download_checklist function

tubesync/sync/models/media__tasks.py

@@ -1,6 +1,52 @@
+from common.logger import log
+from common.errors import (
+    NoMetadataException,
+)
 from django.utils import timezone
 
 
+def download_checklist(self, skip_checks=False):
+    media = self
+    if skip_checks:
+        return True
+
+    if not media.source.download_media:
+        log.warn(f'Download task triggered for media: {media} (UUID: {media.pk}) but '
+                 f'the source {media.source} has since been marked to not download, '
+                 f'not downloading')
+        return False
+    if media.skip or media.manual_skip:
+        # Media was toggled to be skipped after the task was scheduled
+        log.warn(f'Download task triggered for media: {media} (UUID: {media.pk}) but '
+                 f'it is now marked to be skipped, not downloading')
+        return False
+    # metadata is required to generate the proper filepath
+    if not media.has_metadata:
+        raise NoMetadataException('Metadata is not yet available.')
+    downloaded_file_exists = (
+        media.downloaded and
+        media.has_metadata and
+        (
+            media.media_file_exists or
+            media.filepath.exists()
+        )
+    )
+    if downloaded_file_exists:
+        # Media has been marked as downloaded before the download_media task was fired,
+        # skip it
+        log.warn(f'Download task triggered for media: {media} (UUID: {media.pk}) but '
+                 f'it has already been marked as downloaded, not downloading again')
+        return False
+    max_cap_age = media.source.download_cap_date
+    published = media.published
+    if max_cap_age and published:
+        if published <= max_cap_age:
+            log.warn(f'Download task triggered media: {media} (UUID: {media.pk}) but '
+                     f'the source has a download cap and the media is now too old, '
+                     f'not downloading')
+            return False
+
+
 def wait_for_premiere(self):
     hours = lambda td: 1+int((24*td.days)+(td.seconds/(60*60)))