"""Release metadata and installer integrity checks."""

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

from packaging.version import Version

from app_version import CHECKSUM_ASSET_NAME, INSTALLER_ASSET_NAME
from modules.release_updater import (
    ReleaseInfo,
    UpdateError,
    download_installer,
    get_latest_release,
    update_available,
)


HOST = "https://git.robotail.pro"


class FakeResponse:
    def __init__(self, *, status=200, url=HOST, data=None, text="", chunks=()):
        self.status_code = status
        self.url = url
        self.data = data
        self.text = text
        self.chunks = chunks

    def raise_for_status(self):
        if self.status_code >= 400:
            raise ValueError(f"HTTP {self.status_code}")

    def json(self):
        return self.data

    def iter_content(self, chunk_size):
        return iter(self.chunks)

    def __enter__(self):
        return self

    def __exit__(self, *_):
        return False


class FakeSession:
    def __init__(self, responses):
        self.responses = iter(responses)

    def get(self, *_args, **_kwargs):
        return next(self.responses)


def release_data(installer_url=HOST + "/download/setup"):
    return {
        "tag_name": "v1.2.0",
        "body": "Исправления и новые возможности",
        "html_url": HOST + "/Robotail/BUH_bot/releases/tag/v1.2.0",
        "assets": [
            {"name": INSTALLER_ASSET_NAME, "browser_download_url": installer_url, "size": 7},
            {"name": CHECKSUM_ASSET_NAME, "browser_download_url": HOST + "/download/sha", "size": 90},
        ],
    }


class ReleaseUpdaterTests(unittest.TestCase):
    def test_no_published_release(self):
        self.assertIsNone(get_latest_release(FakeSession([FakeResponse(status=404)])))

    def test_newer_release_with_assets(self):
        release = get_latest_release(FakeSession([FakeResponse(data=release_data())]))
        self.assertEqual(release.version, Version("1.2.0"))
        self.assertTrue(update_available(release))

    def test_rejects_untrusted_installer_host(self):
        with self.assertRaises(UpdateError):
            get_latest_release(FakeSession([FakeResponse(data=release_data("https://evil.example/setup"))]))

    def test_rejects_missing_checksum(self):
        data = release_data()
        data["assets"].pop()
        with self.assertRaises(UpdateError):
            get_latest_release(FakeSession([FakeResponse(data=data)]))

    def test_download_and_verify(self):
        payload = b"installer"
        digest = hashlib.sha256(payload).hexdigest()
        release = ReleaseInfo(
            "v1.2.0", Version("1.2.0"), "", HOST + "/release",
            HOST + "/download/setup", HOST + "/download/sha", len(payload),
        )
        session = FakeSession([
            FakeResponse(url=release.checksum_url, text=f"{digest}  {INSTALLER_ASSET_NAME}"),
            FakeResponse(url=release.installer_url, chunks=[payload[:3], payload[3:]]),
        ])
        with tempfile.TemporaryDirectory() as directory, patch(
            "modules.release_updater.tempfile.gettempdir", return_value=directory
        ):
            target = download_installer(release, session)
            self.assertEqual(target.read_bytes(), payload)

    def test_rejects_corrupt_installer(self):
        payload = b"corrupt"
        release = ReleaseInfo(
            "v1.2.0", Version("1.2.0"), "", HOST + "/release",
            HOST + "/download/setup", HOST + "/download/sha", len(payload),
        )
        session = FakeSession([
            FakeResponse(url=release.checksum_url, text="0" * 64),
            FakeResponse(url=release.installer_url, chunks=[payload]),
        ])
        with tempfile.TemporaryDirectory() as directory, patch(
            "modules.release_updater.tempfile.gettempdir", return_value=directory
        ):
            with self.assertRaises(UpdateError):
                download_installer(release, session)
            self.assertFalse((Path(directory) / "MoySkladGenerator" / "v1.2.0" / INSTALLER_ASSET_NAME).exists())


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