from __future__ import annotations

import io
import unittest
from unittest.mock import MagicMock, PropertyMock, patch

from govoplan_files.backend.storage.backends import S3StorageBackend, StorageBackendError


def _backend() -> S3StorageBackend:
    return S3StorageBackend(
        bucket="files",
        endpoint_url="https://objects.example.test",
        region_name="test",
        access_key_id="access",
        secret_access_key="secret",
    )


class S3StorageBackendTests(unittest.TestCase):
    def test_get_bytes_rejects_declared_oversize_object_without_reading(self) -> None:
        body = MagicMock()
        client = MagicMock()
        client.get_object.return_value = {"ContentLength": 6, "Body": body}
        with patch.dict("os.environ", {"GOVOPLAN_CONNECTOR_MAX_FILE_TRANSFER_BYTES": "5"}), patch.object(
            S3StorageBackend,
            "client",
            new_callable=PropertyMock,
            return_value=client,
        ), self.assertRaisesRegex(StorageBackendError, "deployment limit"):
            _backend().get_bytes("large.bin")
        body.read.assert_not_called()
        body.close.assert_called_once_with()

    def test_iter_bytes_rejects_undeclared_oversize_object(self) -> None:
        client = MagicMock()
        client.get_object.return_value = {"Body": io.BytesIO(b"123456")}
        with patch.dict("os.environ", {"GOVOPLAN_CONNECTOR_MAX_FILE_TRANSFER_BYTES": "5"}), patch.object(
            S3StorageBackend,
            "client",
            new_callable=PropertyMock,
            return_value=client,
        ), self.assertRaisesRegex(StorageBackendError, "deployment limit"):
            list(_backend().iter_bytes("large.bin", chunk_size=3))

    def test_iter_bytes_closes_streaming_body_when_consumer_stops_early(self) -> None:
        body = MagicMock()
        body.read.side_effect = (b"123", b"456", b"")
        client = MagicMock()
        client.get_object.return_value = {"ContentLength": 6, "Body": body}
        with patch.dict("os.environ", {"GOVOPLAN_CONNECTOR_MAX_FILE_TRANSFER_BYTES": "10"}), patch.object(
            S3StorageBackend,
            "client",
            new_callable=PropertyMock,
            return_value=client,
        ):
            chunks = _backend().iter_bytes("object.bin", chunk_size=3)
            self.assertEqual(b"123", next(chunks))
            chunks.close()
        body.close.assert_called_once_with()


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