# plugins/host_agent/__init__.py
from __future__ import annotations
from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from quart import Quart

_app: "Quart | None" = None


def setup(app: "Quart") -> None:
    global _app
    _app = app
    # A host's CPU, memory and load per core learn their normal (#5742), each
    # with its floor from Settings → Thresholds. Parts don't: a host's CPU has
    # a normal, each of its cores doesn't. Disks stay on their fixed cutoffs:
    # a nearly full disk is a failure whatever its history (System 182).
    from steward.core.norms import floor_setting, learn_normal
    learn_normal("host_agent", "cpu_pct", floor_setting(app, "host_cpu_pct"), parts=False)
    learn_normal("host_agent", "mem_used_pct", floor_setting(app, "host_mem_pct"), parts=False)
    learn_normal("host_agent", "load_pct", floor_setting(app, "host_load_pct"), parts=False)
    # "Agent offline" speaks for everything the agent carries: while it is
    # firing, the host's other rules going silent isn't emailed (#5721).
    from steward.core.alerts import agent_fed, agent_heartbeat
    from steward.hosts.service import agent_stale_after_seconds
    agent_heartbeat("host_agent", "seconds_since_seen", lambda: agent_stale_after_seconds(app.config))
    agent_fed("host_agent", lambda resource: resource.split(":", 1)[0])
    # A reboot the agent announced is silence with a reason, for a while (#5756).
    from datetime import datetime, timezone
    from steward.core.alerts import agents_away
    from .downtime import hosts_away, restart_grace_seconds
    agents_away(lambda session: hosts_away(session, datetime.now(timezone.utc),
                                           restart_grace_seconds(app.config)))
    from steward.core.cleanup import prune_by_age
    from .models import HostDowntime
    prune_by_age(HostDowntime.started_at)


def get_scheduled_tasks() -> list:
    from .scheduler import make_task
    return [make_task(_app)]


def get_blueprint():
    from .routes import host_agent_bp
    return host_agent_bp


def register_mcp_tools(register) -> None:
    from .mcp_tools import register_tools
    register_tools(register)


async def mcp_overview(db) -> list[dict]:
    from .mcp_tools import mcp_overview as findings
    return await findings(db)


def get_alert_metrics() -> dict[str, list[str]]:
    """Host metrics ingest records for alert rules (resource = the host name;
    disk_used_pct per mount, resource "<host>:<mount>"). seconds_since_seen
    comes from the scheduler, not the agent: "agent offline" is > 180.
    clock_off_secs is how far the host's clock is from Steward's, either way
    (agent ≥ 1.12.0): "clock drifting" is > 30. load_pct is load_1m as a %
    of the host's cores. inodes_used_pct is per mount (agent ≥ 1.13.0), and
    disk_used_pct_worst is the fullest mount by space or inodes."""
    return {"host_agent": [
        "cpu_pct", "mem_used_pct", "mem_available_bytes", "swap_used_bytes",
        "disk_used_pct_worst", "disk_used_pct", "inodes_used_pct", "load_1m", "load_5m", "load_15m",
        "load_pct",
        "uptime_secs", "seconds_since_seen", "clock_off_secs",
    ]}