from __future__ import annotations

import tempfile
import unittest
from concurrent.futures import ThreadPoolExecutor
from pathlib import Path

from web.routers.files import _numbered_upload_name, _replace_upload, _write_upload_without_overwrite


class FileUploadConflictTests(unittest.TestCase):
    def test_number_is_inserted_before_complete_extension(self):
        self.assertEqual(_numbered_upload_name("data.tar.gz", 2), "data (2).tar.gz")
        self.assertEqual(_numbered_upload_name("报告", 1), "报告 (1)")
        self.assertEqual(_numbered_upload_name(".env", 1), ".env (1)")

    def test_existing_file_is_preserved(self):
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            (root / "报告.pdf").write_bytes(b"old")
            saved = _write_upload_without_overwrite(root, "报告.pdf", b"new")
            self.assertEqual(saved.name, "报告 (1).pdf")
            self.assertEqual((root / "报告.pdf").read_bytes(), b"old")
            self.assertEqual(saved.read_bytes(), b"new")

    def test_concurrent_uploads_get_distinct_names(self):
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            with ThreadPoolExecutor(max_workers=4) as pool:
                saved = list(pool.map(
                    lambda i: _write_upload_without_overwrite(root, "same.txt", str(i).encode()),
                    range(4),
                ))
            self.assertEqual(len({path.name for path in saved}), 4)
            self.assertEqual(len(list(root.glob("same*.txt"))), 4)

    def test_explicit_replace_changes_only_target(self):
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            target = root / "target.txt"
            target.write_bytes(b"old")
            _replace_upload(target, b"new")
            self.assertEqual(target.read_bytes(), b"new")
            self.assertFalse(list(root.glob(".zcbot-upload-*")))


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