"""Tests for copy_lib.py - library copying with dependencies."""

import contextlib
import pathlib
import tempfile
import unittest


class TestCopySingle(unittest.TestCase):
    """Tests for _copy_single helper function."""

    def test_copies_file(self):
        """Test copying a single file."""
        from update_lib.cmd_copy_lib import _copy_single

        with tempfile.TemporaryDirectory() as tmpdir:
            tmpdir = pathlib.Path(tmpdir)

            src = tmpdir / "source.py"
            src.write_text("content")
            dst = tmpdir / "dest.py"

            _copy_single(src, dst, verbose=False)

            self.assertTrue(dst.exists())
            self.assertEqual(dst.read_text(), "content")

    def test_copies_directory(self):
        """Test copying a directory."""
        from update_lib.cmd_copy_lib import _copy_single

        with tempfile.TemporaryDirectory() as tmpdir:
            tmpdir = pathlib.Path(tmpdir)

            src = tmpdir / "source_dir"
            src.mkdir()
            (src / "file.py").write_text("content")
            dst = tmpdir / "dest_dir"

            _copy_single(src, dst, verbose=False)

            self.assertTrue(dst.exists())
            self.assertTrue((dst / "file.py").exists())

    def test_removes_existing_before_copy(self):
        """Test that existing destination is removed before copy."""
        from update_lib.cmd_copy_lib import _copy_single

        with tempfile.TemporaryDirectory() as tmpdir:
            tmpdir = pathlib.Path(tmpdir)

            src = tmpdir / "source.py"
            src.write_text("new content")
            dst = tmpdir / "dest.py"
            dst.write_text("old content")

            _copy_single(src, dst, verbose=False)

            self.assertEqual(dst.read_text(), "new content")

    def test_directory_copy_excludes_bytecode_cache_directories(self):
        from update_lib.cmd_copy_lib import _copy_single

        with tempfile.TemporaryDirectory() as tmpdir:
            root = pathlib.Path(tmpdir)
            src = root / "source"
            dst = root / "destination"
            for relative in ("__pycache__", "package/__pycache__", "assets"):
                (src / relative).mkdir(parents=True)
            files = {
                "__init__.py": b"source\n",
                "package/module.py": b"nested source\n",
                "assets/data.bin": b"\x00\xffasset",
                "assets/__pycache__": b"ordinary file, not a directory",
                "assets/fixture.pyc": b"canonical bytecode fixture",
                "__pycache__/module.cpython-315.pyc": b"stale cache",
                "package/__pycache__/module.cpython-315.pyc": b"nested cache",
            }
            for relative, content in files.items():
                (src / relative).write_bytes(content)

            _copy_single(src, dst, verbose=False)

            expected = {
                relative: content
                for relative, content in files.items()
                if "__pycache__" not in pathlib.Path(relative).parts[:-1]
            }
            actual = {
                path.relative_to(dst).as_posix(): path.read_bytes()
                for path in dst.rglob("*")
                if path.is_file()
            }
            self.assertEqual(actual, expected)
            self.assertFalse((dst / "__pycache__").exists())
            self.assertFalse((dst / "package/__pycache__").exists())
            for relative, content in files.items():
                self.assertEqual((src / relative).read_bytes(), content)


class TestCopyLib(unittest.TestCase):
    """Tests for copy_lib function."""

    def test_nested_data_file_preserves_siblings(self):
        from update_lib.cmd_copy_lib import copy_lib

        for name in ("hierarchy.txt", "fixture.bin", "README"):
            with self.subTest(name=name), tempfile.TemporaryDirectory() as tmpdir:
                root = pathlib.Path(tmpdir)
                source = root / "cpython/Lib/test/data" / name
                source.parent.mkdir(parents=True)
                source.write_bytes(b"canonical\x00\xff\n")
                (source.parent / "other.txt").write_bytes(b"unselected source")
                target = root / "Lib/test/data" / name
                target.parent.mkdir(parents=True)
                target.write_bytes(b"old")
                sibling = root / "Lib/test/test_local.py"
                sibling.write_bytes(b"local guards\n")
                with contextlib.chdir(root):
                    copy_lib(source, verbose=False)
                self.assertEqual(target.read_bytes(), source.read_bytes())
                self.assertEqual(sibling.read_bytes(), b"local guards\n")
                self.assertFalse((target.parent / "other.txt").exists())

    def test_missing_data_file_does_not_copy_containing_package(self):
        from update_lib.cmd_copy_lib import copy_lib

        with tempfile.TemporaryDirectory() as tmpdir:
            root = pathlib.Path(tmpdir)
            source = root / "cpython/Lib/test/missing.txt"
            source.parent.mkdir(parents=True)
            (source.parent / "other.py").write_text("unselected source")
            sibling = root / "Lib/test/test_local.py"
            sibling.parent.mkdir(parents=True)
            sibling.write_bytes(b"local guards\n")
            with contextlib.chdir(root), self.assertRaises(FileNotFoundError):
                copy_lib(source, verbose=False)
            self.assertEqual(sibling.read_bytes(), b"local guards\n")
            self.assertFalse((sibling.parent / "other.py").exists())

    def test_python_module_still_copies_hard_dependencies(self):
        from update_lib.cmd_copy_lib import copy_lib

        with tempfile.TemporaryDirectory() as tmpdir:
            root = pathlib.Path(tmpdir)
            source = root / "cpython/Lib"
            source.mkdir(parents=True)
            for name in ("pickle.py", "_compat_pickle.py"):
                (source / name).write_text(name)
            with contextlib.chdir(root):
                copy_lib(source / "pickle.py", verbose=False)
            for name in ("pickle.py", "_compat_pickle.py"):
                self.assertEqual((root / "Lib" / name).read_text(), name)

    def test_package_still_copies_directory(self):
        from update_lib.cmd_copy_lib import copy_lib

        with tempfile.TemporaryDirectory() as tmpdir:
            root = pathlib.Path(tmpdir)
            source = root / "cpython/Lib/json"
            source.mkdir(parents=True)
            for name in ("__init__.py", "decoder.py"):
                (source / name).write_text(name)
            with contextlib.chdir(root):
                copy_lib(source, verbose=False)
            for name in ("__init__.py", "decoder.py"):
                self.assertEqual((root / "Lib/json" / name).read_text(), name)

    def test_raises_on_path_without_lib(self):
        """Test that copy_lib raises ValueError when path doesn't contain /Lib/."""
        from update_lib.cmd_copy_lib import copy_lib

        with self.assertRaises(ValueError) as ctx:
            copy_lib(pathlib.Path("some/path/without/lib.py"))

        self.assertIn("/Lib/", str(ctx.exception))


if __name__ == "__main__":
    unittest.main()