[BUGFIX] Handle truncating file names if too long (#524)

* [BUGFIX] Handle truncating file names if too long

* always import os

* test fix

* fix for windows

* lint

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

@@ -2,11 +2,19 @@ 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
 
+if IS_WINDOWS:
+    _MAX_FILE_NAME_BYTES = 255
+else:
+    _MAX_FILE_NAME_BYTES = os.pathconf("/", "PC_NAME_MAX")
+
 
 class FFmpegFileValidator(StringValidator):
     _expected_value_type_name = "ffmpeg dependency"
@@ -34,9 +42,45 @@ class FFprobeFileValidator(FFmpegFileValidator):
 class StringFormatterFilePathValidator(StringFormatterValidator):
     _expected_value_type_name = "filepath"
 
+    @classmethod
+    def _is_file_name_too_long(cls, file_name: str) -> bool:
+        return 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)
+
+        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 = 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 str(file_path)
 
 
 class OverridesStringFormatterValidatorFilePathValidator(OverridesStringFormatterValidator):

tests/unit/validators/test_file_path_validators.py

@@ -0,0 +1,42 @@
+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-US.{ext}" for ext in SUBTITLE_EXTENSIONS],
+    )
+    @pytest.mark.parametrize("file_name_char", ["a", "𒃀"])
+    @pytest.mark.parametrize("file_name_len", [10, 10000])
+    def test_truncates_file_name_successfully(
+        self, ext: str, file_name_char: str, file_name_len: int
+    ):
+        ext = f".{ext}"  # pytest args with . in the beginning act weird
+        with tempfile.TemporaryDirectory() as temp_dir:
+            file_name = (file_name_char * file_name_len) + 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"):
+                # Make sure the file is actually in the directory
+                dir_paths = list(Path(temp_dir).rglob("*"))
+
+                assert len(dir_paths) == 1
+                assert Path(truncated_file_path) == dir_paths[0]