"""A check_history row must say which task produced it.

On 2026-08-11 a 425 MB probe task and the 5 GB nightly backup both ran through
config_backup_executor. The probe failed, and the row it wrote was
indistinguishable from a nightly-backup failure — same `source`, same `domain`,
nothing naming the task. The health record could not answer which job broke,
which is most of what a health record is for.

Executors are called as `execute(config, settings)` and are never told which
task they are, so the name travels in a ContextVar. These tests pin the three
properties that makes safe: it reaches the reporter, it survives the worker
thread T-74 introduced, and concurrent executions cannot read each other's.
"""
import asyncio
import json

import pytest
from unittest.mock import AsyncMock, MagicMock, patch

from src.config import Settings
from src.executors import health_report
from src.task_context import current_task_name, task_scope
from src.tasks.executor import TaskExecutor


@pytest.fixture
def captured_row(monkeypatch):
    """Capture the JSON payload report() would insert, without a database."""
    box = {}
    conn, cur = MagicMock(), MagicMock()

    def execute(sql, params):
        box['result'] = json.loads(params[4])

    cur.execute.side_effect = execute
    conn.cursor.return_value.__enter__ = MagicMock(return_value=cur)
    conn.cursor.return_value.__exit__ = MagicMock(return_value=None)
    conn.__enter__ = MagicMock(return_value=conn)
    conn.__exit__ = MagicMock(return_value=None)
    monkeypatch.setattr(health_report.psycopg2, 'connect', lambda **kw: conn)
    return box


def _report(settings, **kw):
    health_report.report(
        settings, domain="backup", status=health_report.OK,
        source="scheduler/config_backup_executor", metrics={}, **kw
    )


@pytest.mark.unit
class TestAttribution:

    def test_the_row_names_the_task(self, test_settings: Settings, captured_row):
        with task_scope("backup_docker_configs_daily"):
            _report(test_settings)
        assert captured_row['result']['task'] == "backup_docker_configs_daily"

    def test_source_still_names_the_code(self, test_settings: Settings, captured_row):
        """Task and source answer different questions; both are needed.

        `source` says which code wrote the row, `task` says which schedule
        invoked it. Replacing one with the other loses a distinction.
        """
        with task_scope("t74_loop_probe"):
            _report(test_settings)
        r = captured_row['result']
        assert r['source'] == "scheduler/config_backup_executor"
        assert r['task'] == "t74_loop_probe"

    def test_the_field_is_omitted_rather_than_nulled(self, test_settings: Settings, captured_row):
        """report() is callable from a script with no task around it.

        A null would claim there was a task and it had no name. Absence says the
        question does not apply.
        """
        _report(test_settings)
        assert 'task' not in captured_row['result']

    @pytest.mark.asyncio
    async def test_attribution_survives_the_worker_thread(
        self, test_settings: Settings, captured_row
    ):
        """T-74 moved reporting into asyncio.to_thread. Attribution has to follow.

        If the context did not propagate, every row written by a real executor
        would silently lose its task while the tests above still passed.
        """
        with task_scope("backup_portainer_daily"):
            await health_report.report_async(
                test_settings, domain="backup", status=health_report.OK,
                source="scheduler/portainer_backup_executor", metrics={},
            )
        assert captured_row['result']['task'] == "backup_portainer_daily"


@pytest.mark.unit
class TestAttributionIsolation:
    """MAX_CONCURRENT_TASKS is 5, so mixing values between them is a live risk."""

    def _executor_with_db(self, test_settings):
        executor = TaskExecutor(test_settings)
        conn, cur = MagicMock(), MagicMock()
        cur.fetchone.return_value = [1]
        conn.cursor.return_value.__enter__ = MagicMock(return_value=cur)
        conn.cursor.return_value.__exit__ = MagicMock(return_value=None)
        conn.__enter__ = MagicMock(return_value=conn)
        conn.__exit__ = MagicMock(return_value=None)
        return executor, patch.object(executor, 'get_db_connection', return_value=conn)

    def _task(self, name):
        return {'id': hash(name) % 1000, 'task_name': name, 'executor': 'x',
                'service': 'scheduler', 'priority': 5, 'timeout_seconds': 60}

    @pytest.mark.asyncio
    async def test_the_engine_names_the_task_and_clears_it_after(
        self, test_settings: Settings
    ):
        executor, db = self._executor_with_db(test_settings)
        seen = {}

        async def fake_run(name, task, timeout):
            seen['during'] = current_task_name()
            return "done", None

        with db, patch.object(executor, '_run_executor', new=fake_run):
            await executor.execute_task(self._task("nightly_backup"))

        assert seen['during'] == "nightly_backup", "executor ran unattributed"
        assert current_task_name() is None, "attribution leaked past the execution"

    @pytest.mark.asyncio
    async def test_concurrent_executions_do_not_see_each_other(
        self, test_settings: Settings
    ):
        executor, db = self._executor_with_db(test_settings)
        seen = {}

        async def fake_run(name, task, timeout):
            who = task['task_name']
            # Yield mid-flight so the executions genuinely interleave; without
            # this they would run to completion one at a time and the test would
            # pass even with a shared global.
            await asyncio.sleep(0.01 if who == "slow_one" else 0)
            seen[who] = current_task_name()
            return "done", None

        with db, patch.object(executor, '_run_executor', new=fake_run):
            await asyncio.gather(
                executor.execute_task(self._task("slow_one")),
                executor.execute_task(self._task("fast_one")),
            )

        assert seen == {"slow_one": "slow_one", "fast_one": "fast_one"}