from __future__ import annotations

import sys
import unittest
from pathlib import Path
from unittest import mock


META_ROOT = Path(__file__).resolve().parents[1]
RELEASE_ROOT = META_ROOT / "tools" / "release"
if str(RELEASE_ROOT) not in sys.path:
    sys.path.insert(0, str(RELEASE_ROOT))

from govoplan_release.http_fetch import (  # noqa: E402
    DEFAULT_MAX_RESPONSE_BYTES,
    fetch_http,
)


class ReleaseHttpFetchTests(unittest.TestCase):
    def test_content_length_over_default_limit_blocks_before_read(self) -> None:
        response = FakeResponse(
            body=b"ignored",
            headers={"Content-Length": str(DEFAULT_MAX_RESPONSE_BYTES + 1)},
        )

        with mock.patch(
            "govoplan_release.http_fetch.urllib.request.urlopen",
            return_value=response,
        ):
            with self.assertRaisesRegex(ValueError, "exceeds the configured size"):
                fetch_http("https://example.invalid/catalog.json", timeout=1)

        self.assertEqual([], response.read_sizes)

    def test_streamed_body_is_capped_when_length_is_absent(self) -> None:
        response = FakeResponse(body=b"x" * 9, headers={})

        with mock.patch(
            "govoplan_release.http_fetch.urllib.request.urlopen",
            return_value=response,
        ):
            with self.assertRaisesRegex(ValueError, "exceeds the configured size"):
                fetch_http(
                    "https://example.invalid/catalog.json",
                    timeout=1,
                    max_response_bytes=8,
                )

        self.assertEqual([9], response.read_sizes)


class FakeResponse:
    def __init__(self, *, body: bytes, headers: dict[str, str]) -> None:
        self.status = 200
        self.headers = headers
        self.body = body
        self.read_sizes: list[int] = []

    def __enter__(self) -> FakeResponse:
        return self

    def __exit__(self, *args: object) -> None:
        return None

    def read(self, size: int) -> bytes:
        self.read_sizes.append(size)
        return self.body[:size]


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