"""Keep the public availability figure honest about what it measured."""

import json
from pathlib import Path

import yaml


REPO_ROOT = Path(__file__).resolve().parents[2]

# On 2026-08-18 the metrics volume filled and the availability pipeline failed
# in both directions at once: the stale yearly sample silently fell back to a
# one-hour Traefik ratio wearing the 365d title, and the 34-hour telemetry gap
# vanished from the yearly ratio as if it had been measured. These guardrails
# pin the corrections.


def _overview_panels() -> list[dict]:
    """Return the generated Overview dashboard's top-level panels."""
    dashboard = json.loads(
        (REPO_ROOT / "services/monitoring/dashboards/atlas-overview.json").read_text()
    )
    return dashboard["panels"]


def _panel(title_prefix: str) -> dict:
    return next(
        panel
        for panel in _overview_panels()
        if str(panel.get("title", "")).startswith(title_prefix)
    )


def _panel_exprs(panel: dict) -> str:
    return " ".join(target.get("expr", "") for target in panel.get("targets", []))


def _alert_rules() -> dict[str, dict]:
    """Return every provisioned Grafana alert rule keyed by uid."""
    manifest = next(
        document
        for document in yaml.safe_load_all(
            (REPO_ROOT / "services/monitoring/grafana-alerting-config.yaml").read_text()
        )
        if document
    )
    groups = yaml.safe_load(manifest["data"]["rules.yaml"])["groups"]
    return {rule["uid"]: rule for group in groups for rule in group["rules"]}


def test_availability_panel_never_swaps_measurements() -> None:
    """A stale yearly rollup must render empty, not a 1h ratio in disguise."""
    panel = _panel("Atlas Availability")
    exprs = _panel_exprs(panel)
    assert "atlas:availability:ratio_365d" in exprs
    assert "traefik_entrypoint_requests_total" not in exprs


def test_availability_coverage_is_disclosed() -> None:
    """The overview must state how many days the yearly figure rests on."""
    panel = _panel("Availability Coverage")
    assert "atlas:availability:coverage_days_365d" in _panel_exprs(panel)


def test_stale_availability_rollup_pages() -> None:
    """A silent rollup once hid 34 hours of lost publishes; staleness must page."""
    rules = _alert_rules()
    stale = rules["atlas-availability-rollup-stale"]
    assert "atlas:availability:ratio_365d" in stale["data"][0]["model"]["expr"]
    assert stale["noDataState"] == "Alerting"
    assert stale["execErrState"] == "Alerting"
    assert stale["labels"]["severity"] == "warning"


def test_rollup_proves_its_publish_survived() -> None:
    """A read-only store accepts imports and drops them; the job must read back."""
    source = (
        REPO_ROOT / "services/monitoring/scripts/availability_rollup.py"
    ).read_text()
    assert "def verify_stored" in source
    assert "verify_stored(OUTPUT_METRIC" in source
    assert "atlas:availability:coverage_days_365d" in source