import tempfile
import unittest
from pathlib import Path
from unittest.mock import patch

from B03_FileInput.B03_FileInput_Engine import (
    resolve_upload_destination,
    save_upload_stream,
)
from B03_FileInput.B03_FileInput_Schema import FileUploadDescriptor


class ResolveUploadDestinationTest(unittest.TestCase):
    def test_resolve_upload_destination(self) -> None:
        with tempfile.TemporaryDirectory() as temporary_directory:
            descriptor = FileUploadDescriptor(
                original_filename="cloud_merged.LAS",
                size_bytes=1024,
            )

            destination = resolve_upload_destination(temporary_directory, descriptor)

            self.assertEqual(
                destination,
                Path(temporary_directory).resolve()
                / "B03_FileInput"
                / "input"
                / "las"
                / "cloud_merged.LAS",
            )
            self.assertTrue(destination.parent.is_dir())


class SaveUploadStreamTest(unittest.IsolatedAsyncioTestCase):
    async def test_save_upload_stream(self) -> None:
        class FakeUpload:
            def __init__(self, chunks: list[bytes]) -> None:
                self.chunks = iter(chunks)

            async def read(self, _size: int) -> bytes:
                return next(self.chunks, b"")

        with tempfile.TemporaryDirectory() as temporary_directory:
            destination = Path(temporary_directory) / "cloud.las"
            upload = FakeUpload([b"abc", b"def"])

            written_bytes = await save_upload_stream(upload, destination)  # type: ignore[arg-type]

            self.assertEqual(written_bytes, 6)
            self.assertEqual(destination.read_bytes(), b"abcdef")
            self.assertEqual(list(destination.parent.glob("*.upload")), [])

            with patch("B03_FileInput.B03_FileInput_Engine.UPLOAD_MAX_MB", 0):
                with self.assertRaises(ValueError):
                    await save_upload_stream(  # type: ignore[arg-type]
                        FakeUpload([b"too-large"]),
                        destination,
                    )