"""Unified check dispatcher: Monitor -> normalised MonitorResult fields.

One entry point, `run_monitor`, dispatches on Monitor.type to the per-type
probes (ping/dns/http) and returns a dict with every MonitorResult field so the
scheduler can persist a row uniformly regardless of type.
"""
from __future__ import annotations
import logging

from steward.models.monitors import Monitor, MonitorType
from .ping import tcp_check, icmp_check, DEFAULT_TCP_PORT
from .dns import dns_check
from .http import http_check

logger = logging.getLogger(__name__)

# Every result carries these keys; type-specific probes fill the relevant ones.
_BLANK = {
    "is_up": False,
    "response_ms": None,
    "status_code": None,
    "resolved_ip": None,
    "content_matched": None,
    "tls_expires_at": None,
    "error_msg": None,
}


async def run_monitor(monitor: Monitor) -> dict:
    """Run one monitor's check and return a full MonitorResult field dict."""
    cfg = monitor.config
    result = dict(_BLANK)
    try:
        if monitor.type == MonitorType.icmp.value:
            result.update(await icmp_check(monitor.target))
        elif monitor.type == MonitorType.tcp.value:
            result.update(await tcp_check(monitor.target, int(cfg.get("port") or DEFAULT_TCP_PORT)))
        elif monitor.type == MonitorType.dns.value:
            result.update(await dns_check(monitor.target, cfg.get("expected_ip") or None))
        elif monitor.type == MonitorType.http.value:
            result.update(await http_check(
                url=monitor.target,
                method=cfg.get("method", "GET"),
                expected_status=int(cfg.get("expected_status", 200) or 200),
                content_match=cfg.get("content_match", "") or "",
                headers=cfg.get("headers") or {},
                timeout_seconds=int(cfg.get("timeout_seconds", 10) or 10),
                follow_redirects=bool(cfg.get("follow_redirects", True)),
                verify_ssl=bool(cfg.get("verify_ssl", True)),
            ))
        else:
            result["error_msg"] = f"Unknown monitor type {monitor.type!r}"
    except Exception as exc:  # a probe should never take the scheduler down
        logger.exception("Monitor %r (%s) check raised", monitor.name, monitor.type)
        result["error_msg"] = str(exc)[:512]
    return result