"""Integration: host-metrics read paths (DISTINCT ON latest + SQL date_bin history).

Validates the two host_agent query helpers that back the slow host views, against
a live Postgres: the latest-per-(resource,metric) lookup and the bucket-averaged
history (which now aggregates in SQL instead of shipping raw rows to Python).
Requires STEWARD_DATABASE_URL.
"""
from __future__ import annotations

import asyncio
import os
import uuid
from datetime import datetime, timedelta, timezone

import pytest

pytestmark = pytest.mark.integration

_NEEDS_DB = pytest.mark.skipif(
    not os.environ.get("STEWARD_DATABASE_URL"),
    reason="integration test needs a live Postgres (STEWARD_DATABASE_URL)",
)


@pytest.fixture
def app():
    if not os.environ.get("STEWARD_DATABASE_URL"):
        pytest.skip("needs Postgres")
    from steward.app import create_app
    return create_app(testing=False)


@_NEEDS_DB
def test_latest_distinct_on_and_sql_bucketed_history(app):
    from sqlalchemy import text
    from steward.models.metrics import PluginMetric
    from plugins.host_agent.metrics_query import (
        SOURCE_MODULE, _history_for_host, _latest_metrics_for_host,
    )

    now = datetime.now(timezone.utc)
    hostname = "metrics-host-" + uuid.uuid4().hex[:8]

    async def _go():
        async with app.db_sessionmaker() as s:
            async with s.begin():
                await s.execute(
                    text("DELETE FROM plugin_metrics WHERE resource_name LIKE :p"),
                    {"p": hostname + "%"},
                )
                rows = []
                # Host-level CPU samples, oldest → newest (10, 20, 30).
                for i, val in enumerate([10.0, 20.0, 30.0]):
                    rows.append(PluginMetric(
                        source_module=SOURCE_MODULE, resource_name=hostname,
                        metric_name="cpu_pct", value=val,
                        recorded_at=now - timedelta(minutes=30 - i * 10),
                    ))
                # A sub-resource (root mount) to exercise the host:% match.
                rows.append(PluginMetric(
                    source_module=SOURCE_MODULE, resource_name=hostname + ":/",
                    metric_name="disk_used_pct", value=80.0,
                    recorded_at=now - timedelta(minutes=5),
                ))
                s.add_all(rows)

            latest = await _latest_metrics_for_host(s, hostname)
            hist = await _history_for_host(s, hostname, now - timedelta(hours=1))
            return latest, hist

    latest, hist = asyncio.run(_go())

    # DISTINCT ON returns the newest sample per (resource, metric).
    assert latest[hostname]["cpu_pct"] == 30.0
    assert latest[hostname + ":/"]["disk_used_pct"] == 80.0

    # SQL date_bin aggregation returns cpu_pct buckets; averages stay in range.
    cpu = hist["cpu_pct"]
    assert cpu, "expected bucketed cpu_pct history"
    assert all(10.0 <= v <= 30.0 for _, v in cpu)