package web

import (
	"net/http"
)

// Agent-backed host metrics (slice 9).
//
// The de-privileged controller (slice 8C) sees only its own cgroup, so it cannot read host
// health itself. This thin proxy forwards GET /api/host-metrics to the agent's GET /host/metrics
// and returns the host-wide view (cpu%/mem/load/uptime/cpu-temp + per-storage capacity) for the
// monitoring page. It reuses the same pinned agentapi.Client + {ok,data,error} envelope as the
// disk proxy (agent_disk_handlers.go). Read-only; no CSRF mutation.

// ServeHostMetricsAPI proxies GET /api/host-metrics → agent GET /host/metrics.
// Wired in main.go behind RequireAuth.
func (s *Server) ServeHostMetricsAPI(w http.ResponseWriter, r *http.Request) {
	if s.isDebug() {
		s.logger.Printf("[DEBUG] [web] ServeHostMetricsAPI: %s %s from %s", r.Method, r.URL.Path, r.RemoteAddr)
	}
	if r.Method != http.MethodGet {
		writeDiskJSON(w, http.StatusMethodNotAllowed, false, "method not allowed", nil)
		return
	}
	client, err := s.agentClient()
	if err != nil {
		// Unprovisioned guest / no local API configured — the UI shows "host metrics unavailable".
		writeDiskJSON(w, http.StatusServiceUnavailable, false, err.Error(), nil)
		return
	}
	resp, err := client.HostMetrics(r.Context())
	if err != nil {
		s.logger.Printf("[ERROR] [web] host metrics via agent failed: %v", err)
		writeDiskJSON(w, http.StatusBadGateway, false, err.Error(), nil)
		return
	}
	writeDiskJSON(w, http.StatusOK, true, "", resp)
}