fix: arxiv year

docs/storage-layout.md

@@ -53,16 +53,21 @@ papers/arxiv/YEAR/arxiv-NORMALIZED_ID/
 ```
 
 Where:
-- `YEAR` is extracted from the arXiv ID (e.g., `2212.06340` → `2022`)
+- `YEAR` is extracted from the arXiv ID (e.g., `2212.06340` → `2022`, `0001.12345` → `2000`)
 - `NORMALIZED_ID` replaces dots and version numbers with underscores
   - `2212.06340` → `arxiv-2212_06340`
   - `2212.06340v2` → `arxiv-2212_06340v2`
 
+The year extraction follows arXiv's YYMM.NNNNN format:
+- Years 00-89 map to 2000-2089
+- Years 90-99 map to 1990-1999
+
 **Examples:**
 ```
-papers/arxiv/2022/arxiv-2212_06340/
-papers/arxiv/2023/arxiv-2301_12345v1/
-papers/arxiv/2024/arxiv-2405_98765/
+papers/arxiv/2022/arxiv-2212_06340/    # 2212.06340 -> year 2022
+papers/arxiv/2023/arxiv-2301_12345v1/  # 2301.12345v1 -> year 2023  
+papers/arxiv/2000/arxiv-0001_98765/    # 0001.98765 -> year 2000
+papers/arxiv/1999/arxiv-9912_12345/    # 9912.12345 -> year 1999
 ```
 
 ### Local Papers

src/paperlib/storage/manager.py

@@ -43,10 +43,15 @@ class PaperStorageManager:
         if source_type == SourceType.ARXIV:
             # Extract year from arXiv ID pattern (e.g., "2212.06340" -> "2022")
             arxiv_id = paper_id.replace("arxiv-", "").replace("_", ".")
-            year_part = arxiv_id[:4]
+            year_part = arxiv_id[:2]  # Get YY part
             # Modern arXiv format: YYMM.NNNNN
-            if len(year_part) == 4 and year_part.isdigit():
-                year = year_part
+            if len(year_part) == 2 and year_part.isdigit():
+                # Convert 2-digit year to 4-digit year
+                yy = int(year_part)
+                if yy >= 90:  # 90-99 maps to 1990-1999
+                    year = str(1900 + yy)
+                else:  # 00-89 maps to 2000-2089
+                    year = str(2000 + yy)
             else:
                 # Fallback to current year for older formats
                 year = str(datetime.now().year)

tests/test_arxiv_year_fix.py

@@ -0,0 +1,139 @@
+"""Test for arXiv year extraction bug fix."""
+
+import shutil
+from pathlib import Path
+
+import pytest
+
+from paperlib.config import LibraryPaths
+from paperlib.models import SourceType
+from paperlib.storage import PaperStorageManager
+
+
+class TestArxivYearFix:
+    """Test the arXiv year extraction fix."""
+
+    @pytest.fixture
+    def temp_library(self):
+        """Create a temporary library for testing."""
+        temp_dir = Path("./.tmp") / f"test_arxiv_year_{hash(self)}"
+        temp_dir.mkdir(parents=True, exist_ok=True)
+        library_paths = LibraryPaths.from_root(temp_dir)
+        library_paths.create_directories()
+
+        yield library_paths
+
+        # Cleanup
+        if temp_dir.exists():
+            shutil.rmtree(temp_dir)
+
+    @pytest.fixture
+    def storage_manager(self, temp_library):
+        """Create a storage manager for testing."""
+        return PaperStorageManager(temp_library)
+
+    def test_arxiv_year_extraction_2022(self, storage_manager):
+        """Test year extraction for 2022 paper (2212.06340)."""
+        paper_dir = storage_manager.get_paper_directory(
+            "arxiv-2212_06340", SourceType.ARXIV
+        )
+
+        # Should extract year 2022 from 2212.06340
+        expected = (
+            storage_manager.library_paths.papers_dir
+            / "arxiv"
+            / "2022"
+            / "arxiv-2212_06340"
+        )
+        assert paper_dir == expected
+
+    def test_arxiv_year_extraction_2023(self, storage_manager):
+        """Test year extraction for 2023 paper (2301.12345)."""
+        paper_dir = storage_manager.get_paper_directory(
+            "arxiv-2301_12345", SourceType.ARXIV
+        )
+
+        # Should extract year 2023 from 2301.12345
+        expected = (
+            storage_manager.library_paths.papers_dir
+            / "arxiv"
+            / "2023"
+            / "arxiv-2301_12345"
+        )
+        assert paper_dir == expected
+
+    def test_arxiv_year_extraction_2020(self, storage_manager):
+        """Test year extraction for 2020 paper (2005.67890)."""
+        paper_dir = storage_manager.get_paper_directory(
+            "arxiv-2005_67890", SourceType.ARXIV
+        )
+
+        # Should extract year 2020 from 2005.67890
+        expected = (
+            storage_manager.library_paths.papers_dir
+            / "arxiv"
+            / "2020"
+            / "arxiv-2005_67890"
+        )
+        assert paper_dir == expected
+
+    def test_arxiv_year_extraction_1999(self, storage_manager):
+        """Test year extraction for 1999 paper (9912.12345)."""
+        paper_dir = storage_manager.get_paper_directory(
+            "arxiv-9912_12345", SourceType.ARXIV
+        )
+
+        # Should extract year 1999 from 9912.12345 (99 -> 1999)
+        expected = (
+            storage_manager.library_paths.papers_dir
+            / "arxiv"
+            / "1999"
+            / "arxiv-9912_12345"
+        )
+        assert paper_dir == expected
+
+    def test_arxiv_year_extraction_2000(self, storage_manager):
+        """Test year extraction for 2000 paper (0001.12345)."""
+        paper_dir = storage_manager.get_paper_directory(
+            "arxiv-0001_12345", SourceType.ARXIV
+        )
+
+        # Should extract year 2000 from 0001.12345 (00 -> 2000)
+        expected = (
+            storage_manager.library_paths.papers_dir
+            / "arxiv"
+            / "2000"
+            / "arxiv-0001_12345"
+        )
+        assert paper_dir == expected
+
+    def test_arxiv_id_with_version(self, storage_manager):
+        """Test year extraction with version number."""
+        paper_dir = storage_manager.get_paper_directory(
+            "arxiv-2212_06340v1", SourceType.ARXIV
+        )
+
+        # Should extract year 2022 from 2212.06340v1
+        expected = (
+            storage_manager.library_paths.papers_dir
+            / "arxiv"
+            / "2022"
+            / "arxiv-2212_06340v1"
+        )
+        assert paper_dir == expected
+
+    def test_existing_storage_test_still_passes(self, storage_manager):
+        """Ensure we didn't break the existing test case."""
+        # This matches the test case in test_storage.py
+        paper_dir = storage_manager.get_paper_directory(
+            "arxiv-2212_06340", SourceType.ARXIV
+        )
+
+        # The old test expected papers/arxiv/2212/ but should now be papers/arxiv/2022/
+        expected = (
+            storage_manager.library_paths.papers_dir
+            / "arxiv"
+            / "2022"
+            / "arxiv-2212_06340"
+        )
+        assert paper_dir == expected

tests/test_storage.py

@@ -72,10 +72,11 @@ class TestPaperStorageManager:
             "arxiv-2212_06340", SourceType.ARXIV
         )
 
+        # Should extract year 2022 from 2212.06340 (22 -> 2022)
         expected = (
             storage_manager.library_paths.papers_dir
             / "arxiv"
-            / "2212"
+            / "2022"
             / "arxiv-2212_06340"
         )
         assert paper_dir == expected