"""No external API calls or engine dependencies: verify the shared-state boundary."""
import ast
import inspect
from concurrent.futures import ThreadPoolExecutor
from pathlib import Path
from threading import Barrier, Lock
from time import sleep

import pytest
from calculation_lock import serialize_calculation


def test_mixed_chart_requests_do_not_interleave_shared_settings():
    start = Barrier(8)
    state = {"profile": None, "active": 0, "max_active": 0}
    stats_lock = Lock()

    @serialize_calculation
    def western(profile):
        state["profile"] = profile
        with stats_lock:
            state["active"] += 1
            state["max_active"] = max(state["max_active"], state["active"])
        sleep(0.003)
        assert state["profile"] == profile
        with stats_lock:
            state["active"] -= 1
        return profile

    @serialize_calculation
    def vedic(profile):
        # Reentrant calls share the same lock, including engine helpers.
        return western(profile)

    def request(index):
        start.wait()
        return (western if index % 2 else vedic)(str(index))

    with ThreadPoolExecutor(max_workers=8) as pool:
        assert list(pool.map(request, range(8))) == list(map(str, range(8)))
    assert state["max_active"] == 1


def test_errors_release_the_calculation_lock_and_preserve_signature():
    @serialize_calculation
    def calculate(value: str) -> str:
        if value == "invalid":
            raise ValueError("invalid")
        return value

    with pytest.raises(ValueError):
        calculate("invalid")
    assert str(inspect.signature(calculate)) == "(value: str) -> str"
    with ThreadPoolExecutor(max_workers=1) as pool:
        assert pool.submit(calculate, "next request").result(timeout=1) == "next request"


def test_every_shared_engine_entry_point_is_serialized():
    tree = ast.parse(Path(__file__).with_name("app.py").read_text())
    routes = {node.name: node for node in tree.body if isinstance(node, ast.FunctionDef)}
    for name in ["calculate_chart", "generate_chart_svg", "calculate_vedic_chart"]:
        assert any(isinstance(d, ast.Name) and d.id == "serialize_calculation" for d in routes[name].decorator_list)
    assert "COPY app.py calculation_lock.py ./" in Path(__file__).with_name("Dockerfile").read_text()