"""Run the actual installer functions against a real disposable Python venv."""
import json
import os
import shutil
import subprocess
import sys
from pathlib import Path

import pytest

SOURCE = Path(__file__).resolve().parents[1] / 'scripts/install.ps1'
PS = shutil.which('powershell') or shutil.which('pwsh')
pytestmark = pytest.mark.skipif(os.name != 'nt' or not PS, reason='Windows installer runtime test')


def function(source, name):
    start = source.index('function ' + name + ' {')
    opening = source.index('{', start)
    depth = 0
    for index in range(opening, len(source)):
        if source[index] == '{': depth += 1
        elif source[index] == '}': depth -= 1
        if depth == 0: return source[start:index + 1]
    raise AssertionError(name)


@pytest.fixture(scope='module')
def runtime(tmp_path_factory):
    root = tmp_path_factory.mktemp('installer-reuse')
    subprocess.run([sys.executable, '-m', 'venv', '--without-pip', str(root / 'venv')], check=True)
    return root


def run(runtime, body):
    text = SOURCE.read_text(encoding='utf-8-sig')
    script = runtime / 'probe.ps1'
    prefix = "$ErrorActionPreference = 'Stop'\n"
    prefix += function(text, 'Test-ReusableManagedVenv') + '\n'
    prefix += function(text, 'Install-Venv') + '\n'
    prefix += "$InstallDir = '" + str(runtime).replace("'", "''") + "'\n"
    prefix += "$BasePython = '" + sys._base_executable.replace("'", "''") + "'\n"
    prefix += "$Version = '" + str(sys.version_info.major) + '.' + str(sys.version_info.minor) + "'\n"
    script.write_text(prefix + body, encoding='utf-8-sig')
    result = subprocess.run([PS, '-NoProfile', '-File', str(script)], capture_output=True, text=True, timeout=40)
    assert result.returncode == 0, result.stdout + result.stderr
    return result.stdout


def test_healthy_update_keeps_live_python_and_never_reaches_kill_sweep(runtime):
    python = runtime / 'venv/Scripts/python.exe'
    live = subprocess.Popen([str(python), '-c', 'import time;time.sleep(90)'])
    try:
        output = run(runtime, r'''
function Resolve-AvailablePythonVersion { return @{Path=$BasePython;Version=$Version} }
function Write-Success { param($Message); Write-Output $Message }
function Write-Info { throw 'Unexpected venv recreation/kill path' }
function taskkill { throw 'Live process must not be killed' }
Install-Venv
''')
        assert 'Reusing healthy' in output
        assert live.poll() is None
        assert python.is_file()
    finally:
        live.terminate();live.wait(timeout=10)


def test_wrong_version_or_foreign_interpreter_does_not_reuse(runtime):
    output = run(runtime, r'''
$venvPath = Join-Path $InstallDir 'venv'
$results = @(
  (Test-ReusableManagedVenv $venvPath $BasePython '0.0'),
  (Test-ReusableManagedVenv $venvPath (Join-Path $InstallDir 'other-python.exe') $Version),
  (Test-ReusableManagedVenv (Join-Path $InstallDir 'missing') $BasePython $Version)
)
ConvertTo-Json -Compress -InputObject $results
''')
    assert json.loads(output) == [False, False, False]