package hostapi

import (
	"context"
	"encoding/json"
	"errors"
	"net/http"
	"time"

	"github.com/itworx/pulse/internal/auth"
	"github.com/itworx/pulse/internal/host"
	"github.com/itworx/pulse/internal/problem"
)

type Handler struct{ Provider host.Provider }

func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet || r.URL.Path != "/api/v1/host" {
		http.NotFound(w, r)
		return
	}
	if _, ok := auth.PrincipalFromContext(r.Context()); !ok {
		problem.Write(w, r, http.StatusUnauthorized, "UNAUTHORIZED", "Authentication required", "Authentication is required to read host telemetry.", nil)
		return
	}
	if err := r.Context().Err(); err != nil {
		return
	}
	var snapshot host.Snapshot
	var err error
	if h.Provider == nil {
		snapshot = host.UnknownSnapshot(time.Now().UTC(), "host", "agent", "source_unavailable")
	} else {
		snapshot, err = h.Provider.Snapshot(r.Context())
	}
	if err != nil {
		if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) || errors.Is(r.Context().Err(), context.Canceled) {
			return
		}
		problem.Write(w, r, http.StatusServiceUnavailable, "HOST_UNAVAILABLE", "Hosttelemetrie niet beschikbaar", "De hosttelemetrie kon niet worden gelezen.", nil)
		return
	}
	w.Header().Set("Content-Type", "application/json")
	w.Header().Set("Cache-Control", "private, max-age=5")
	_ = json.NewEncoder(w).Encode(snapshot)
}