from __future__ import annotations

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

from uvm.config import Settings
from uvm.domain import VmRecord
from uvm.errors import FirecrackerError
from uvm.firecracker.process import FirecrackerProcessManager


def make_vm(pid: int | None, start_time: str | None) -> VmRecord:
    return VmRecord(
        id="vm-test",
        cpu=1,
        ram_mib=512,
        guest_ip="10.42.0.2",
        gateway="10.42.0.1",
        tap="uvm-test",
        mac="02:fc:00:00:00:01",
        socket="/tmp/uvm-missing.sock",
        config="/tmp/config.json",
        log="/tmp/firecracker.log",
        pid=pid,
        process_start_time=start_time,
    )


class FirecrackerProcessSafetyTests(unittest.TestCase):
    def test_refuses_to_signal_an_unidentified_legacy_pid(self) -> None:
        manager = FirecrackerProcessManager(Settings())
        vm = make_vm(pid=12345, start_time=None)

        with patch("uvm.firecracker.process.os.kill") as kill:
            with self.assertRaises(FirecrackerError):
                manager.terminate(vm)

        kill.assert_called_once_with(12345, 0)

    def test_allows_cleanup_when_an_unidentified_legacy_pid_is_already_gone(self) -> None:
        manager = FirecrackerProcessManager(Settings())
        vm = make_vm(pid=12345, start_time=None)

        with patch("uvm.firecracker.process.os.kill", side_effect=ProcessLookupError):
            manager.terminate(vm)

    def test_rejects_non_positive_pids_without_signaling(self) -> None:
        manager = FirecrackerProcessManager(Settings())
        vm = make_vm(pid=0, start_time="42")

        with patch("uvm.firecracker.process.os.kill") as kill:
            with self.assertRaises(FirecrackerError):
                manager.terminate(vm)

        kill.assert_not_called()

    def test_interrupt_during_startup_terminates_the_child_process(self) -> None:
        class FakePopen:
            pid = 12345

            def poll(self) -> int | None:
                return None

        with tempfile.TemporaryDirectory() as temporary_directory:
            settings = Settings(base=Path(temporary_directory), terminate_timeout_s=0)
            manager = FirecrackerProcessManager(settings, popen=lambda *_args, **_kwargs: FakePopen())
            manager._wait_for_socket = lambda *_args: (_ for _ in ()).throw(KeyboardInterrupt)
            vm = make_vm(pid=None, start_time=None)
            vm.log = str(Path(temporary_directory) / "firecracker.log")
            vm.socket = str(Path(temporary_directory) / "firecracker.sock")

            with patch("uvm.firecracker.process.os.kill") as kill:
                with self.assertRaises(KeyboardInterrupt):
                    manager.start(vm)

        self.assertEqual(kill.call_count, 2)