[FEATURE] Automatically handle playlists ordered in reverse

src/ytdl_sub/entries/script/custom_functions.py

@@ -1,11 +1,14 @@
 import os
 import posixpath
+from typing import List
 
 from yt_dlp.utils import sanitize_filename
 
+from ytdl_sub.downloaders.ytdlp import YTDLP
 from ytdl_sub.script.functions import Functions
 from ytdl_sub.script.types.map import Map
 from ytdl_sub.script.types.resolvable import AnyArgument
+from ytdl_sub.script.types.resolvable import Boolean
 from ytdl_sub.script.types.resolvable import Integer
 from ytdl_sub.script.types.resolvable import ReturnableArgument
 from ytdl_sub.script.types.resolvable import String
@@ -21,6 +24,51 @@ _days_in_month = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
 
 
 class CustomFunctions:
+    @staticmethod
+    def is_playlist_ordered_by_newest(url: String) -> Boolean:
+        """
+        Queries a playlist-based URL using yt-dlp to see if it is ordered from newest
+        (lower playlist number) to oldest.
+        """
+        info_only_kwargs = {
+            "skip_download": True,
+            "writethumbnail": False,
+            "writeinfojson": False,
+            "ignoreerrors": True,
+            "extract_flat": "discard",
+            "playlist_items": "0:5",
+        }
+        try:
+            url_info = YTDLP.extract_info(
+                ytdl_options_overrides=info_only_kwargs,
+                url=url.value,
+            )
+
+            if (
+                not isinstance(url_info, dict)
+                or not isinstance(url_info.get("entries"), list)
+                or not len(url_info["entries"])
+            ):
+                return Boolean(False)
+
+            upload_dates: List[str] = []
+            for entry in url_info["entries"]:
+                if entry.get("uploader_id") and entry.get("url"):
+                    full_entry = YTDLP.extract_info(
+                        ytdl_options_overrides=info_only_kwargs, url=entry.get("url")
+                    )
+                    if isinstance(full_entry.get("upload_date"), str):
+                        upload_dates.append(full_entry["upload_date"])
+
+            for idx in range(1, len(upload_dates)):
+                if upload_dates[idx - 1] < upload_dates[idx]:
+                    return Boolean(False)
+
+            return Boolean(True)
+
+        except Exception:
+            return Boolean(False)
+
     @staticmethod
     def legacy_bracket_safety(value: ReturnableArgument) -> ReturnableArgument:
         """
@@ -170,6 +218,7 @@ class CustomFunctions:
         Register Custom functions once and only once
         """
         if not Functions.is_built_in("sanitize"):
+            Functions.register_function(CustomFunctions.is_playlist_ordered_by_newest)
             Functions.register_function(CustomFunctions.legacy_bracket_safety)
             Functions.register_function(CustomFunctions.truncate_filepath_if_too_long)
             Functions.register_function(CustomFunctions.to_native_filepath)

tests/e2e/entries/script/test_custom_functions.py

@@ -0,0 +1,22 @@
+from unit.script.conftest import single_variable_output
+
+
+class TestCustomFunctions:
+    def test_is_playlist_ordered_by_newest_true(self):
+        assert (
+            single_variable_output(
+                "{%is_playlist_ordered_by_newest('https://www.youtube.com/playlist?list=PL5BC0FC26BECA5A35')}"
+            )
+            is True
+        )
+
+    def test_is_playlist_ordered_by_newest_false(self):
+        assert (
+            single_variable_output(
+                "{%is_playlist_ordered_by_newest('https://www.youtube.com/playlist?list=PL2KvlCGf4yFftX466OnFS8wvuSosBfUgm')}"
+            )
+            is False
+        )
+
+    def test_is_playlist_ordered_by_newest_defaults_false(self):
+        assert single_variable_output("{%is_playlist_ordered_by_newest('aaaaaa')}") is False