[BUGFIX] Handle truncating file names if too long

src/ytdl_sub/plugins/subtitles.py

@@ -2,7 +2,6 @@ from pathlib import Path
 from typing import Dict
 from typing import List
 from typing import Optional
-from typing import Set
 
 from ytdl_sub.downloaders.ytdl_options_builder import YTDLOptionsBuilder
 from ytdl_sub.entries.entry import Entry
@@ -11,15 +10,13 @@ from ytdl_sub.plugins.plugin import PluginOptions
 from ytdl_sub.utils.file_handler import FileHandler
 from ytdl_sub.utils.file_handler import FileMetadata
 from ytdl_sub.utils.logger import Logger
+from ytdl_sub.utils.subtitles import SUBTITLE_EXTENSIONS
 from ytdl_sub.validators.file_path_validators import StringFormatterFilePathValidator
 from ytdl_sub.validators.string_formatter_validators import StringFormatterValidator
 from ytdl_sub.validators.string_select_validator import StringSelectValidator
 from ytdl_sub.validators.validators import BoolValidator
 from ytdl_sub.validators.validators import StringListValidator
 
-SUBTITLE_EXTENSIONS: Set[str] = {"srt", "vtt", "ass", "lrc"}
-
-
 logger = Logger.get(name="subtitles")
 
 

src/ytdl_sub/utils/subtitles.py

@@ -0,0 +1,3 @@
+from typing import Set
+
+SUBTITLE_EXTENSIONS: Set[str] = {"srt", "vtt", "ass", "lrc"}

src/ytdl_sub/validators/file_path_validators.py

@@ -1,12 +1,25 @@
-import os
 from pathlib import Path
 from typing import Any
 from typing import Dict
+from typing import Tuple
 
+from ytdl_sub.utils.subtitles import SUBTITLE_EXTENSIONS
+from ytdl_sub.utils.system import IS_WINDOWS
 from ytdl_sub.validators.string_formatter_validators import OverridesStringFormatterValidator
 from ytdl_sub.validators.string_formatter_validators import StringFormatterValidator
 from ytdl_sub.validators.validators import StringValidator
 
+_MAX_FILE_NAME_LEN: int = 0
+_MAX_FILE_NAME_BYTES: int = 0
+if IS_WINDOWS:
+    from ctypes.wintypes import MAX_PATH
+
+    _MAX_FILE_NAME_LEN = MAX_PATH
+else:
+    import os
+
+    _MAX_FILE_NAME_BYTES = os.pathconf("/", "PC_NAME_MAX")
+
 
 class FFmpegFileValidator(StringValidator):
     _expected_value_type_name = "ffmpeg dependency"
@@ -34,9 +47,50 @@ class FFprobeFileValidator(FFmpegFileValidator):
 class StringFormatterFilePathValidator(StringFormatterValidator):
     _expected_value_type_name = "filepath"
 
+    @classmethod
+    def _is_file_name_too_long(cls, file_name: str) -> bool:
+        return (_MAX_FILE_NAME_LEN and len(file_name) > _MAX_FILE_NAME_LEN) or (
+            _MAX_FILE_NAME_BYTES and len(file_name.encode("utf-8")) > _MAX_FILE_NAME_BYTES
+        )
+
+    @classmethod
+    def _get_extension_split(cls, file_name: str) -> Tuple[str, str]:
+        if file_name.endswith(".info.json"):
+            ext = "info.json"
+        elif any(file_name.endswith(f".{subtitle_ext}") for subtitle_ext in SUBTITLE_EXTENSIONS):
+            file_name_split = file_name.split(".")
+            ext = file_name_split[-1]
+
+            # Try to capture .lang.ext
+            if len(file_name_split) > 2 and len(file_name_split[-2]) < 6:
+                ext = f"{file_name_split[-2]}.{file_name_split[-1]}"
+        else:
+            ext = file_name.rsplit(".", maxsplit=1)[-1]
+
+        return file_name[: -len(ext)], ext
+
+    @classmethod
+    def _truncate_file_name(cls, file_name: str) -> str:
+        file_sub_name, file_ext = cls._get_extension_split(file_name)
+        if _MAX_FILE_NAME_LEN:
+            to_trim = len(file_name) - _MAX_FILE_NAME_LEN + 1
+            file_sub_name = file_sub_name[:-to_trim]
+        elif _MAX_FILE_NAME_BYTES:
+            desired_size = _MAX_FILE_NAME_BYTES - len(file_ext.encode("utf-8")) - 1
+            while len(file_sub_name.encode("utf-8")) > desired_size:
+                file_sub_name = file_sub_name[:-1]
+
+        return f"{file_sub_name}.{file_ext}"
+
     def apply_formatter(self, variable_dict: Dict[str, str]) -> str:
         """Turn into a Path, then a string, to get correct directory separators"""
-        return str(Path(super().apply_formatter(variable_dict)))
+        file_path = str(Path(super().apply_formatter(variable_dict)))
+        file_directory, file_name = os.path.split(Path(file_path))
+
+        if self._is_file_name_too_long(file_name):
+            return str(Path(file_directory) / self._truncate_file_name(file_name))
+
+        return file_path
 
 
 class OverridesStringFormatterValidatorFilePathValidator(OverridesStringFormatterValidator):

tests/unit/validators/test_file_path_validators.py

@@ -0,0 +1,34 @@
+import tempfile
+from pathlib import Path
+
+import pytest
+
+from ytdl_sub.utils.subtitles import SUBTITLE_EXTENSIONS
+from ytdl_sub.validators.file_path_validators import StringFormatterFilePathValidator
+
+
+class TestStringFormatterFilePathValidator:
+    @pytest.mark.parametrize(
+        "ext",
+        [
+            ".mp4",
+            ".info.json",
+        ]
+        + [f".en.{ext}" for ext in SUBTITLE_EXTENSIONS],
+    )
+    def test_truncates_file_name_successfully(self, ext: str):
+        ext = ".info.json"
+        with tempfile.TemporaryDirectory() as temp_dir:
+            file_name = ("a" * 10000) + ext
+            file_path = str(Path(temp_dir) / file_name)
+
+            formatter = StringFormatterFilePathValidator(name="test", value=str(file_path))
+            truncated_file_path = formatter.apply_formatter({})
+
+            assert truncated_file_path.count(".") == ext.count(".")
+            assert str(Path(temp_dir)) in truncated_file_path
+            assert ext in truncated_file_path
+
+            # Ensure it can actually open the file
+            with open(truncated_file_path, "w", encoding="utf-8"):
+                pass