<?php
// ═══════════════════════════════════════════════════════════════════════════════════════════════
// PURPOSE
//   Watchdog data endpoint. Every watchdog's current state for every node in one document —
//   resource, docker, system, storage, network and stability — together with the thresholds
//   each one is judging against, for the watchdog tab's poll.
//
// DESIGN PRINCIPLES
//   Thin transport. State-file parsing and threshold resolution live in
//   include/watchdog.php; this file only sets the content type and encodes.
//
//   Thresholds ship with the state, not separately.
//       vv_wd_all() resolves every threshold from master.conf into the same payload as the
//       counters they apply to. A strike count means nothing without the limit it is counted
//       against, so the page never has to fetch the two independently and risk mismatching
//       them across a conf edit.
//
//   No parameters. Which watchdogs exist is fixed by the codebase, not by the request.
//
// OPERATIONAL SAFEGUARDS
//   Read-only. Nothing here clears a strike, lifts a skip-list entry, restarts a container,
//   or cancels a pending reboot. The watchdogs own their own state; this endpoint reports it.
//
//   Absent counters are reported quiet, not alarming.
//       A watchdog that has not yet written state reads as zero rather than unknown, so a
//       fresh boot does not light the page up with false strikes.
//
//   Thresholds fall back to the shipped defaults.
//       Every vv_wd_scalar() lookup has a ?: default, so a master.conf that is mid-edit or
//       missing a key still yields a coherent payload instead of comparing counters against
//       zero and declaring everything critical.
//
//   Remote collection degrades per node — one unreachable partner drops that node's card and
//   leaves the local host and every other partner intact.
//
//   Served from cache, collected only on a miss.
//       vv_wd_all() SSHes to every configured partner, so its cost is set by the slowest node
//       rather than by how much data there is. Measured at 8.3s on this host with HOST2 down —
//       paid by every visitor, every 30 seconds, because the tab polls. The cache check happens
//       before the heavy include, so a hit costs one file read and no SSH at all.
//
//       The window is deliberately wider than the poll. Watchdog state only changes when the
//       orchestrator runs, which is every 15 minutes; polling it every 30 seconds was never
//       reading anything new, it was just re-paying for the same answer.
//
// REQUEST
//   GET             served from the 300s cache when one is present
//   GET ?live       bypass the cache and collect everything fresh
//
// RESPONSE
//   vv_wd_all() verbatim — per-node watchdog state plus the resolved threshold set
//
// DEPENDS ON
//   include/config.php          vv_cache_read()
//   include/watchdog.php        vv_wd_all()   — required only on a miss
//   Tools/api_cache_writer.php  writes the cache this endpoint normally serves
// ═══════════════════════════════════════════════════════════════════════════════════════════════
header('Content-Type: application/json');
require_once dirname(__DIR__) . '/include/config.php';

if (!isset($_GET['live'])) {
    $_vv_cached = vv_cache_read('watchdog', 300);
    if ($_vv_cached !== null) { echo json_encode($_vv_cached); exit; }
    unset($_vv_cached);
}

require_once dirname(__DIR__) . '/include/watchdog.php';
$_vv_wd = vv_wd_all();
// Written on the miss as well as by the background writer. Without this the first visitor after
// a restart pays the full collection and so does the next one, until the writer's next minute
// happens to land.
vv_cache_write('watchdog', $_vv_wd);
echo json_encode($_vv_wd);
