felhom-controller/controller/internal/notify/notifier.go

package notify

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"strings"
	"sync"
	"time"

	"gitea.dooplex.hu/admin/felhom-controller/internal/settings"
)

// Notifier sends structured events to the hub via /api/v1/event.
// Non-blocking: fires requests in goroutines, logs errors but doesn't retry aggressively.
// Cooldown logic is handled by the Hub — the controller sends all events unconditionally.
// EventHistoryEntry records a sent event for the debug page.
type EventHistoryEntry struct {
	Timestamp time.Time `json:"timestamp"`
	EventType string    `json:"event_type"`
	Severity  string    `json:"severity"`
	Message   string    `json:"message"`
	HubStatus int       `json:"hub_status"`
	HubError  string    `json:"hub_error,omitempty"`
}

type Notifier struct {
	hubURL     string
	apiKey     string
	customerID string
	httpClient *http.Client
	logger     *log.Logger
	enabled    bool
	debug      bool
	settings   *settings.Settings

	mu               sync.Mutex
	prevHealthStatus string // tracks previous health check status for change detection

	// oomSeen (R-514) remembers container runs already reported as OOM-killed.
	oomSeen map[string]bool
	// appDown tracks which deployed apps are currently in the DOWN state so app_start_failed fires
	// ONCE per running→down transition, not every health cycle (fix-3 anti-spam). In-memory: a
	// controller restart re-notifies once (acceptable — better than missing). The hub owns the real
	// cooldown; the controller must not add its own timer.
	appDown map[string]bool

	// pushFn is a test seam for the transition-emitting notifiers (fix-3). nil → the real async
	// PushEvent; tests inject a synchronous recorder.
	pushFn func(eventType, severity, message string, details interface{})

	// Event history ring buffer (debug page)
	historyMu sync.RWMutex
	history   [50]EventHistoryEntry
	histPos   int
	histFull  bool
}

// New creates a new Notifier. Returns a no-op notifier if hub is not enabled.
func New(hubURL, apiKey, customerID string, sett *settings.Settings, logger *log.Logger, debug bool) *Notifier {
	enabled := hubURL != "" && apiKey != ""
	if enabled {
		logger.Printf("[INFO] Notifier enabled (hub: %s)", hubURL)
	} else {
		logger.Printf("[INFO] Notifier disabled (hub not configured)")
	}

	return &Notifier{
		hubURL:     hubURL,
		apiKey:     apiKey,
		customerID: customerID,
		httpClient: &http.Client{Timeout: 10 * time.Second},
		logger:     logger,
		enabled:    enabled,
		debug:      debug,
		settings:   sett,
	}
}

// IsEnabled returns whether the notifier has a configured hub connection.
func (n *Notifier) IsEnabled() bool {
	return n.enabled
}

// ── Detail structs ───────────────────────────────────────────────────

// BackupDetails holds structured data for backup events.
type BackupDetails struct {
	DriveCount  int    `json:"drive_count,omitempty"`
	SnapshotID  string `json:"snapshot_id,omitempty"`
	DurationSec int    `json:"duration_sec,omitempty"`
	DataAdded   string `json:"data_added,omitempty"`
	Error       string `json:"error,omitempty"`
}

// WholeGuestBackupDetails carries the TIER for a whole-guest (vzdump) backup event (R-97a).
//
// The `tier` field is load-bearing beyond display: the hub's operator cooldown is keyed
// `customerID:eventType` plus this tier when present, so `local` failing does not get swallowed by
// `felhom-pbs` having failed within the same hour. Rename it and the two tiers silently share one
// cooldown again.
type WholeGuestBackupDetails struct {
	Tier  string `json:"tier"`
	Error string `json:"error,omitempty"`
}

// DBDumpDetails holds structured data for DB dump events.
type DBDumpDetails struct {
	DatabaseCount int    `json:"database_count,omitempty"`
	TotalSize     string `json:"total_size,omitempty"`
	DurationSec   int    `json:"duration_sec,omitempty"`
	Error         string `json:"error,omitempty"`
}

// DiskDetails holds structured data for disk warning/critical events.
type DiskDetails struct {
	Mount        string  `json:"mount,omitempty"`
	UsagePercent float64 `json:"usage_percent,omitempty"`
	Label        string  `json:"label,omitempty"`
}

// HealthDetails holds structured data for health events.
type HealthDetails struct {
	PreviousStatus string   `json:"previous_status,omitempty"`
	CurrentStatus  string   `json:"current_status,omitempty"`
	Issues         []string `json:"issues,omitempty"`
	Warnings       []string `json:"warnings,omitempty"`
}

// StorageDetails holds structured data for storage events.
type StorageDetails struct {
	DrivePath   string   `json:"drive_path,omitempty"`
	Label       string   `json:"label,omitempty"`
	StoppedApps []string `json:"stopped_apps,omitempty"`
}

// UpdateDetails holds structured data for controller update events.
type UpdateDetails struct {
	FromVersion string `json:"from_version,omitempty"`
	ToVersion   string `json:"to_version,omitempty"`
	Error       string `json:"error,omitempty"`
}

// AppDetails holds structured data for app lifecycle events.
type AppDetails struct {
	StackName   string `json:"stack_name,omitempty"`
	DisplayName string `json:"display_name,omitempty"`
}

// CrossDriveDetails holds structured data for cross-drive backup events.
type CrossDriveDetails struct {
	StackName string `json:"stack_name,omitempty"`
	Method    string `json:"method,omitempty"`
	DestPath  string `json:"dest_path,omitempty"`
	Duration  string `json:"duration,omitempty"`
	Error     string `json:"error,omitempty"`
}

// ── Core event push ──────────────────────────────────────────────────

// eventRequest is the JSON payload sent to /api/v1/event.
type eventRequest struct {
	CustomerID string          `json:"customer_id"`
	EventType  string          `json:"event_type"`
	Severity   string          `json:"severity"`
	Message    string          `json:"message"`
	Details    json.RawMessage `json:"details,omitempty"`
}

// PushEvent sends a structured event to the hub's /api/v1/event endpoint.
// Non-blocking (goroutine). Retries twice with 3s backoff.
// details may be nil (omitted from JSON) or a struct that marshals to JSON.
func (n *Notifier) PushEvent(eventType, severity, message string, details interface{}) {
	if !n.enabled {
		return
	}

	var detailsJSON json.RawMessage
	if details != nil {
		b, err := json.Marshal(details)
		if err != nil {
			n.logger.Printf("[WARN] PushEvent: failed to marshal details for %s: %v", eventType, err)
		} else {
			detailsJSON = b
		}
	}

	payload := eventRequest{
		CustomerID: n.customerID,
		EventType:  eventType,
		Severity:   severity,
		Message:    message,
		Details:    detailsJSON,
	}

	jsonData, err := json.Marshal(payload)
	if err != nil {
		n.logger.Printf("[ERROR] PushEvent: marshal failed for %s: %v", eventType, err)
		return
	}

	go func() {
		url := n.hubURL + "/api/v1/event"
		if n.debug {
			n.logger.Printf("[DEBUG] PushEvent: type=%s severity=%s url=%s", eventType, severity, url)
		}
		var lastErr error
		for attempt := 0; attempt < 3; attempt++ {
			if attempt > 0 {
				time.Sleep(3 * time.Second)
			}

			req, err := http.NewRequest("POST", url, bytes.NewReader(jsonData))
			if err != nil {
				lastErr = err
				continue
			}
			req.Header.Set("Authorization", "Bearer "+n.apiKey)
			req.Header.Set("Content-Type", "application/json")

			resp, err := n.httpClient.Do(req)
			if err != nil {
				lastErr = err
				continue
			}
			io.Copy(io.Discard, resp.Body)
			resp.Body.Close()

			if resp.StatusCode >= 200 && resp.StatusCode < 300 {
				if n.debug {
					n.logger.Printf("[DEBUG] PushEvent: %s pushed OK (HTTP %d)", eventType, resp.StatusCode)
				}
				n.logger.Printf("[INFO] Event pushed: %s (%s) — %s", eventType, severity, message)
				n.recordHistory(eventType, severity, message, resp.StatusCode, "")
				return
			}
			lastErr = fmt.Errorf("HTTP %d", resp.StatusCode)
		}
		n.logger.Printf("[WARN] Event push failed after 3 attempts (%s/%s): %v", eventType, severity, lastErr)
		errMsg := ""
		if lastErr != nil {
			errMsg = lastErr.Error()
		}
		n.recordHistory(eventType, severity, message, 0, errMsg)
	}()
}

// ── Convenience methods ──────────────────────────────────────────────

// NotifyHealthChange checks if health status changed and sends appropriate events.
// Detects both degradation (ok→warn, ok→fail, warn→fail) and recovery (fail→ok, warn→ok, fail→warn).
func (n *Notifier) NotifyHealthChange(status string, issues, warnings []string) {
	if !n.enabled {
		return
	}

	n.mu.Lock()
	prev := n.prevHealthStatus
	n.prevHealthStatus = status
	n.mu.Unlock()

	if prev == "" {
		return // First run, just record status
	}
	if status == prev {
		return
	}

	details := HealthDetails{
		PreviousStatus: prev,
		CurrentStatus:  status,
		Issues:         issues,
		Warnings:       warnings,
	}

	prevRank := statusRank(prev)
	newRank := statusRank(status)

	if newRank > prevRank {
		// Degradation
		if status == "fail" {
			n.PushEvent("health_critical", "error",
				fmt.Sprintf("Rendszer állapot kritikus (volt: %s)", prev), details)
		} else if status == "warn" {
			n.PushEvent("health_degraded", "warning",
				fmt.Sprintf("Rendszer állapot romlott (volt: %s)", prev), details)
		}
	} else {
		// Recovery
		n.PushEvent("health_recovered", "info",
			fmt.Sprintf("Rendszer állapot helyreállt: %s (volt: %s)", status, prev), details)
	}
}

// NotifyBackupFailed sends a backup failure event.
func (n *Notifier) NotifyBackupFailed(message, errMsg string) {
	n.PushEvent("backup_failed", "error", message, BackupDetails{Error: errMsg})
}

// RecoveryUnitFailureDetails is the machine-readable tail of a Tier-1 capture failure. App NAMES and
// byte figures only — never an env value (§9.5).
type RecoveryUnitFailureDetails struct {
	App         string  `json:"app"`
	Error       string  `json:"error"`
	TargetPath  string  `json:"target_path,omitempty"`
	UsedGB      float64 `json:"used_gb,omitempty"`
	AvailGB     float64 `json:"avail_gb,omitempty"`
	TotalGB     float64 `json:"total_gb,omitempty"`
	UsedPercent float64 `json:"used_percent,omitempty"`
	// SpaceKnown distinguishes "we read the filesystem and it says these numbers" from "we could not
	// read it". Without it, an unreadable target is indistinguishable from an empty one — the
	// presence-is-not-success trap, in the other direction.
	SpaceKnown bool `json:"space_known"`
}

// NotifyRecoveryUnitCaptureFailed sends the OPERATOR-TIER alert for a per-app Tier-1 recovery-unit
// capture failure (R-158, D-c's operator half).
//
// DELIBERATELY NOT `backup_failed`. That type carries a `customerMessages` entry AND sits in
// `settings.DefaultEnabledEvents`, so reusing it would email the customer, in Hungarian, that their
// backup failed — an event they can take no action on. It is exactly the mistake R-97a avoided by
// minting `whole_guest_backup_failed`, and the reasoning is written into the hub's handler.go.
// R-158's original proposal named `backup_failed`; decision D-c routes this to the operator, and
// where the two disagree D-c wins.
//
// Operator-only is enforced by the hub's `notify.operatorOnlyEvents` register, NOT by the absence of
// a customerMessages entry — v0.78.0 claimed the latter and was wrong.
func (n *Notifier) NotifyRecoveryUnitCaptureFailed(message string, d RecoveryUnitFailureDetails) {
	n.PushEvent("recovery_unit_capture_failed", "error", message, d)
}

// RunFailureDetail is one app's failed leg inside a backup run digest.
type RunFailureDetail struct {
	App    string `json:"app"`
	Leg    string `json:"leg"`
	Reason string `json:"reason"`
}

// BackupRunFailuresDetails is the per-RUN digest payload (R-182). App NAMES, leg names, reasons and
// byte figures only — never an env value (§9.4).
type BackupRunFailuresDetails struct {
	// RunID makes the hub's 1-hour operator cooldown unable to collapse two real runs into one
	// e-mail. EMPTY on the periodic refresh sweep, deliberately: that path can fire on every status
	// poll, so it must fall under the ordinary cooldown instead.
	RunID       string             `json:"run_id,omitempty"`
	RunKind     string             `json:"run_kind"`
	Failed      int                `json:"failed"`
	Attempted   int                `json:"attempted"`
	TargetPath  string             `json:"target_path,omitempty"`
	UsedGB      float64            `json:"used_gb,omitempty"`
	AvailGB     float64            `json:"avail_gb,omitempty"`
	TotalGB     float64            `json:"total_gb,omitempty"`
	UsedPercent float64            `json:"used_percent,omitempty"`
	SpaceKnown  bool               `json:"space_known"`
	Apps        []RunFailureDetail `json:"apps"`
}

// NotifyBackupRunFailures sends the ONE operator digest for a backup run in which something failed
// (R-182). It is the NOTIFICATION; the per-app `recovery_unit_capture_failed` events are the RECORD,
// and the hub routes those record-only so they never compete for an e-mail slot.
//
// OPERATOR-TIER, and for the same reason as its per-app sibling: a customer can act on a full disk
// (that is the fill warning, which fires first and IS customer-facing) but not on a list of which
// apps' backups failed and why. `notify.operatorOnlyEvents` in the hub enforces that — NOT the
// absence of a customerMessages entry, which is a fallback rather than a block (v0.78.0).
func (n *Notifier) NotifyBackupRunFailures(message string, d BackupRunFailuresDetails) {
	n.PushEvent("backup_run_failures", "error", message, d)
}

// NotifyOffboxEnlargeBlocked sends a WARNING (not a failure) when an app's enlarged offsite push was
// refused by the pre-push quota gate — its config+DB were still saved. Customer-facing (Hungarian
// body). NOTE: the event type "offbox_enlarge_blocked" must be added to the hub's allowedEventTypes +
// customerMessages for delivery (a hub-side task, flagged — until then the hub 400s/drops it and the
// in-dashboard LastWarning + /backups/remote note carry the message).
func (n *Notifier) NotifyOffboxEnlargeBlocked(message string) {
	n.PushEvent("offbox_enlarge_blocked", "warning", message, nil)
}

// (NotifyBackupCompleted removed 2026-06-16 — the backup_completed event had no callers
// since slice 8C moved whole-guest backup to the agent. The hub's backup-deadline check
// now reads the agent host-report's PBS snapshots instead of this event. DB-dump events
// below are still emitted and consumed.)

// NotifyDBDumpFailed sends a DB dump failure event.
func (n *Notifier) NotifyDBDumpFailed(message, errMsg string) {
	n.PushEvent("db_dump_failed", "error", message, DBDumpDetails{Error: errMsg})
}

// NotifyDBDumpCompleted sends a DB dump success event.
func (n *Notifier) NotifyDBDumpCompleted(details DBDumpDetails) {
	n.PushEvent("db_dump_completed", "info", "Adatbázis mentés elkészült", details)
}

// NotifyIntegrityFailed sends a backup integrity check failure event.
func (n *Notifier) NotifyIntegrityFailed(message, errMsg string) {
	n.PushEvent("backup_integrity_failed", "error", message, &BackupDetails{Error: errMsg})
}

// NotifyOffsiteProofEmpty (R-87) reports that the nightly off-site proof found a backup that is
// READABLE and holds none of the app's data.
//
// SEVERITY `error`, from the hub's exact vocabulary {info, warning, error, critical}. Anything else
// is silently coerced to `info` and mailed to nobody — that shipped twice (R-328 on
// `disk_health_degraded`, R-329 on `app_start_failed`, 91 events stored and zero delivered), and
// `r329_severity_contract_test.go` walks this file to keep it from shipping a third time.
//
// A SEPARATE TYPE FROM `backup_integrity_failed`, and that is the point rather than an oversight: the
// integrity check says THE STORE IS DAMAGED; this says the store is sound and the CONTENT is absent.
// The customer's action differs and so must the sentence.
//
// The message is passed through, not templated hub-side, so it can name the app and what is missing.
func (n *Notifier) NotifyOffsiteProofEmpty(message, detail string) {
	n.PushEvent("offsite_proof_empty", "error", message, &BackupDetails{Error: detail})
}

// NotifyIntegrityOK sends a backup integrity check success event.
func (n *Notifier) NotifyIntegrityOK(message string) {
	n.PushEvent("backup_integrity_ok", "info", message, nil)
}

// NotifyControllerUpdated sends a controller update event.
func (n *Notifier) NotifyControllerUpdated(fromVer, toVer string, success bool) {
	severity := "info"
	msg := fmt.Sprintf("Controller frissítve: %s → %s", fromVer, toVer)
	details := UpdateDetails{FromVersion: fromVer, ToVersion: toVer}
	if !success {
		severity = "error"
		msg = fmt.Sprintf("Controller frissítés sikertelen: %s → %s", fromVer, toVer)
	}
	n.PushEvent("controller_updated", severity, msg, details)
}

// NotifyControllerStarted sends a controller startup event.
// details may include self-test summary (e.g., {"selftest_pass": 8, "selftest_warn": 1, "selftest_fail": 0}).
func (n *Notifier) NotifyControllerStarted(version string, details map[string]interface{}) {
	n.PushEvent("controller_started", "info",
		fmt.Sprintf("Controller elindult (%s)", version), details)
}

// NotifyStorageDisconnected sends a drive disconnection event.
func (n *Notifier) NotifyStorageDisconnected(label string, stoppedApps []string) {
	msg := fmt.Sprintf("Meghajtó váratlanul leválasztva: %s", label)
	n.PushEvent("storage_disconnected", "error", msg, StorageDetails{
		Label:       label,
		StoppedApps: stoppedApps,
	})
}

// NotifyBackupTargetAbsent (E-2) reports that the drive holding the WHOLE-GUEST backup is gone.
//
// Distinct from NotifyStorageDisconnected on purpose. That one means "a drive went away and some apps
// may have stopped"; this means "the thing that makes your backup survive a disk failure is gone" —
// a different customer action and a different operator urgency. Before E-2 this had NO prompt signal
// at all: the tier stays DUE (targetStoragePresent checks name presence, never reachability), so the
// only evidence was its own failure at the next due cycle, up to ~24 h away on the daily local tier.
func (n *Notifier) NotifyBackupTargetAbsent(label, target string) {
	n.PushEvent("backup_target_absent", "error",
		fmt.Sprintf("A rendszermentés meghajtója nem érhető el: %s (%s)", label, target),
		StorageDetails{Label: label})
}

// NotifyBackupTargetRestored is the paired recovery. info severity — the existing recovery pattern;
// severityNotifies is deliberately NOT widened.
func (n *Notifier) NotifyBackupTargetRestored(label, target string) {
	n.PushEvent("backup_target_restored", "info",
		fmt.Sprintf("A rendszermentés meghajtója újra elérhető: %s (%s)", label, target),
		StorageDetails{Label: label})
}

// NotifyStorageReconnected sends a drive reconnection event.
func (n *Notifier) NotifyStorageReconnected(label string) {
	n.PushEvent("storage_reconnected", "info",
		fmt.Sprintf("Meghajtó újra csatlakoztatva: %s", label), StorageDetails{Label: label})
}

// AgentChannelDetails carries the classified reason for a controller→agent channel-down event.
type AgentChannelDetails struct {
	Reason string `json:"reason"`
}

// NotifyAgentChannelDown sends an OPERATOR-facing controller→agent channel-down event (the message is
// English — the customer can't act on "the agent re-keyed", so this never reaches them: the event type
// is not a customer notification toggle, same as the host_* operator events). eventType/severity/
// message come from the channelhealth classifier (spike Q1 map).
func (n *Notifier) NotifyAgentChannelDown(reason, eventType, severity, message string) {
	n.PushEvent(eventType, severity, message, AgentChannelDetails{Reason: reason})
}

// NotifyAgentChannelRecovered sends the recovery event (info → logged, no email, mirrors
// storage_reconnected).
func (n *Notifier) NotifyAgentChannelRecovered() {
	n.PushEvent("agent_channel_recovered", "info",
		"Controller→agent channel recovered — local-API reachable again.", nil)
}

// NotifyEndpointDrift reports a local_api endpoint divergence (R-77). Operator-only English, its
// OWN event type — deliberately not folded into agent_channel_*, because during the 2026-07-25
// outage the generic channel alert was the only signal and it hid a specific, fixable config fault.
// severity=error: unlike a transient unreachable, drift never self-heals.
//
// NOTE: the hub validates event_type against allowedEventTypes and 400s an unknown one, so this
// type MUST exist there too (hub handler.go) or the alert is silently inert.
func (n *Notifier) NotifyEndpointDrift(message string, fingerprintAgrees bool) {
	n.PushEvent("local_api_endpoint_drift", "error", message,
		EndpointDriftDetails{FingerprintAgrees: fingerprintAgrees})
}

// EndpointDriftDetails carries NO addresses and NO secrets — the endpoints are in the message, and
// the pin is a boolean by design.
type EndpointDriftDetails struct {
	FingerprintAgrees bool `json:"fingerprint_agrees"`
}

// NotifyAppDeployed sends an app deployment event.
func (n *Notifier) NotifyAppDeployed(stackName, displayName string) {
	n.PushEvent("app_deployed", "info",
		fmt.Sprintf("Alkalmazás telepítve: %s", displayName),
		AppDetails{StackName: stackName, DisplayName: displayName})
}

// AppRunState is one deployed app's running state for the fix-3 start-failure notifier: Down=true
// when the app is deployed but its containers are not running.
type AppRunState struct {
	Name        string
	DisplayName string
	Down        bool
	// IntentUnknown is set when this app is STOPPED and no customer intent was ever recorded, so the
	// alarm was suppressed by the §4 fallback rather than by a decision anyone made (R-386).
	//
	// It rides here rather than being a third return value or a logger parameter so that the log line
	// and the suppression come from the SAME computation — a separately-derived log is a second
	// source of truth, and the two drift. `classifyRunStates` stays pure and its signature does not
	// move, which is what lets its existing tests keep testing what they were written to test.
	IntentUnknown bool
}

// NotifyAppStartFailures fires an `app_start_failed` hub event ONCE per running→down transition
// (fix-3). It is called each health cycle with the CURRENT deployed-app run states; the per-app
// transition tracking (n.appDown) makes down→down cycles silent, so a persistently-dead app does not
// spam. down→running clears the tracker (no event — the dashboard banner self-clears; a recovery
// event is deliberately omitted to keep the operator inbox quiet). The hub applies its own cooldown.
func (n *Notifier) NotifyAppStartFailures(apps []AppRunState) {
	n.mu.Lock()
	if n.appDown == nil {
		n.appDown = map[string]bool{}
	}
	var newlyDown []AppRunState
	seen := map[string]bool{}
	for _, a := range apps {
		seen[a.Name] = true
		was := n.appDown[a.Name]
		if a.Down && !was {
			newlyDown = append(newlyDown, a) // running→down (or first-seen-down after the boot grace)
		}
		n.appDown[a.Name] = a.Down
	}
	// Forget apps no longer reported (removed/undeployed) so a later redeploy re-notifies cleanly.
	for name := range n.appDown {
		if !seen[name] {
			delete(n.appDown, name)
		}
	}
	n.mu.Unlock()

	for _, a := range newlyDown {
		name := a.DisplayName
		if name == "" {
			name = a.Name
		}
		// R-329: "warning", NOT "warn". The hub's vocabulary is exactly
		// {info, warning, error, critical} and it COERCES anything else to "info" at ingest, silently
		// — after which severityNotifies drops it and NEITHER leg runs. See DiskAlertKind.Severity's
		// doc comment, which records the same mistake shipping once before (v0.215.0). This one was
		// worse: it was invisible for months because R-384's ordering defect meant the event could
		// not fire at all, so a broken severity had nothing to break.
		// Pinned by TestR329_EveryEmittedSeverityIsInTheHubVocabulary (AST walk over this package).
		n.emit("app_start_failed", "warning",
			fmt.Sprintf("Telepített alkalmazás nem fut: %s", name),
			AppDetails{StackName: a.Name, DisplayName: a.DisplayName})
	}
}

// NotifyAppOOM — R-514 (v0.243.0). A process inside a running app container was killed by the memory
// limit (Docker State.OOMKilled). Fires ONCE per container run (keyed by StartedAt), so a container
// that stays OOM-marked does not repeat. "warning" — the hub vocabulary (R-329). Operator-only
// hub-side (hub >= v0.114.0 registers it): the household sees the dashboard tag.
func (n *Notifier) NotifyAppOOM(stack, container, startedAt string) {
	key := container + "|" + startedAt
	n.mu.Lock()
	if n.oomSeen == nil {
		n.oomSeen = map[string]bool{}
	}
	if n.oomSeen[key] {
		n.mu.Unlock()
		return
	}
	n.oomSeen[key] = true
	n.mu.Unlock()
	n.emit("app_oom", "warning",
		fmt.Sprintf("Alkalmazás memóriája elfogyott: %s (%s) — egy folyamatát a memóriakorlát leállította", stack, container),
		AppDetails{StackName: stack, DisplayName: container})
}

// DiskHealthDetails is the event-detail payload for disk_health_degraded.
type DiskHealthDetails struct {
	Disk       string   `json:"disk"`
	Attributes []string `json:"attributes,omitempty"`
	Critical   bool     `json:"critical"`
}

// DiskAlertKind selects the customer-facing message shape. A customer's ACTION differs by kind —
// "back up and call us for a replacement" is not "check the ventilation" — so the kind travels with
// the alert rather than being flattened into a single sentence.
type DiskAlertKind int

const (
	DiskAlertWarn             DiskAlertKind = iota // Figyelmeztetés — worth keeping an eye on
	DiskAlertFailSelfReported                      // Hiba — the drive's own SMART verdict says FAILING
	DiskAlertFailSectors                           // Hiba — reached from unreadable-sector counters
	DiskAlertFailTemperature                       // Hiba — reached from heat
	DiskAlertFailWorsened                          // Hiba — already reported, and still getting worse
)

// DiskAlert is the payload for one disk-health alert. It carries enough for the notifier to pick a
// message shape and fill in the counts; message CONSTRUCTION stays here because the notifier owns
// customer copy, and moving it to the caller would scatter Hungarian across packages.
type DiskAlert struct {
	Label        string   // customer-facing disk label (device model where known)
	Attributes   []string // Hungarian attribute names behind the verdict (nil for a self-reported FAILING)
	Kind         DiskAlertKind
	Sectors      int // max(pending, offline_uncorrectable) — quoted in the sector/worsened shapes
	TemperatureC int // °C — quoted in the temperature shape
}

// Severity is the hub-accepted severity string for this alert.
//
// THE VOCABULARY IS EXACT AND IT IS THE HUB'S, NOT OURS. The hub accepts only
// {"info","warning","error","critical"} and silently COERCES anything else to "info"
// (felhom.eu/hub/internal/api/handler.go, the severity switch in the event-ingest handler); "info" is
// then dropped by severityNotifies (felhom.eu/hub/internal/notify/dispatcher.go), which routes only
// warning/error/critical. So a severity outside that set is stored and emailed to NOBODY — neither
// the customer nor the operator leg.
//
// Exported so any caller — and any test in any package — can check the contract against the two
// named hub locations instead of duplicating the literal.
//
// Until v0.215.0 this function emitted "warn", which is not in the set. Every Figyelmeztetés-level
// disk alert the product ever produced was filed as an informational notice and delivered to no one.
func (k DiskAlertKind) Severity() string {
	if k == DiskAlertWarn {
		return "warning"
	}
	return "critical"
}

// NotifyDiskHealthDegraded fires a disk_health_degraded hub event. The controller's periodic check
// owns the decision to call this at all (transitions, flap damping, the re-alert cooldown) — never
// first-run, never recovery, never UNKNOWN.
//
// The hub applies its own per-event-type cooldown ON TOP of ours. NOTE: the event type
// "disk_health_degraded" MUST be in the hub's allowedEventTypes (else the hub 400s the POST) — it is.
func (n *Notifier) NotifyDiskHealthDegraded(a DiskAlert) {
	critical := a.Kind != DiskAlertWarn
	var msg string
	switch a.Kind {
	case DiskAlertFailSelfReported:
		msg = fmt.Sprintf("Lemez állapot romlás: %s — a lemez SMART önellenőrzése hibát jelez. Kérjük, mentse az adatait, és vegye fel velünk a kapcsolatot.", a.Label)
	case DiskAlertFailSectors:
		msg = fmt.Sprintf("Lemez hiba: %s — a meghajtón %d olvashatatlan szektor van. Mentse az adatait, és keressen meg minket a meghajtó cseréjéhez.", a.Label, a.Sectors)
	case DiskAlertFailTemperature:
		msg = fmt.Sprintf("Lemez hiba: %s — a meghajtó túlmelegedett (%d °C). Ellenőrizze a gép szellőzését, és keressen meg minket.", a.Label, a.TemperatureC)
	case DiskAlertFailWorsened:
		msg = fmt.Sprintf("Lemez hiba: %s — a meghajtó állapota tovább romlott, már %d olvashatatlan szektor van. Ha még nem tette meg, mentse az adatait.", a.Label, a.Sectors)
	default: // DiskAlertWarn
		if len(a.Attributes) > 0 {
			msg = fmt.Sprintf("Lemez állapot romlás: %s — romló érték: %s. Javasolt figyelemmel kísérni.", a.Label, strings.Join(a.Attributes, ", "))
		} else {
			msg = fmt.Sprintf("Lemez állapot romlás: %s — a lemez állapota romlott. Javasolt figyelemmel kísérni.", a.Label)
		}
	}
	n.emit("disk_health_degraded", a.Kind.Severity(), msg,
		DiskHealthDetails{Disk: a.Label, Attributes: a.Attributes, Critical: critical})
}

// emit sends an event through the test seam if set, else the real async PushEvent.
func (n *Notifier) emit(eventType, severity, message string, details interface{}) {
	if n.pushFn != nil {
		n.pushFn(eventType, severity, message, details)
		return
	}
	n.PushEvent(eventType, severity, message, details)
}

// NotifyAppRemoved sends an app removal event.
func (n *Notifier) NotifyAppRemoved(stackName, displayName string) {
	n.PushEvent("app_removed", "info",
		fmt.Sprintf("Alkalmazás eltávolítva: %s", displayName),
		AppDetails{StackName: stackName, DisplayName: displayName})
}

// NotifyCrossDriveCompleted sends a cross-drive backup success event.
func (n *Notifier) NotifyCrossDriveCompleted(details CrossDriveDetails) {
	n.PushEvent("crossdrive_completed", "info",
		fmt.Sprintf("Másodlagos mentés elkészült: %s", details.StackName), details)
}

// NotifyCrossDriveFailed sends a cross-drive backup failure event.
func (n *Notifier) NotifyCrossDriveFailed(details CrossDriveDetails) {
	n.PushEvent("crossdrive_failed", "error",
		fmt.Sprintf("Másodlagos mentés sikertelen: %s", details.StackName), details)
}

// NotifyDRStarted sends a disaster recovery start event.
func (n *Notifier) NotifyDRStarted(appCount int) {
	n.PushEvent("disaster_recovery_started", "warning",
		fmt.Sprintf("Katasztrófa helyreállítás elindítva (%d alkalmazás)", appCount), nil)
}

// NotifyDRCompleted sends a disaster recovery completion event.
func (n *Notifier) NotifyDRCompleted(successCount, failCount int) {
	severity := "info"
	if failCount > 0 {
		severity = "warning"
	}
	n.PushEvent("disaster_recovery_completed", severity,
		fmt.Sprintf("Katasztrófa helyreállítás befejezve (%d sikeres, %d sikertelen)", successCount, failCount), nil)
}

// ── Preferences sync ─────────────────────────────────────────────────

type preferencesRequest struct {
	CustomerID    string   `json:"customer_id"`
	Email         string   `json:"email"`
	EnabledEvents []string `json:"enabled_events"`
	CooldownHours int      `json:"cooldown_hours,omitempty"`
}

// SyncPreferences pushes the current notification preferences to the hub.
// Synchronous — returns error for the handler to display to the user.
func (n *Notifier) SyncPreferences(email string, enabledEvents []string, cooldownHours int) error {
	if !n.enabled {
		return fmt.Errorf("hub nem konfigurált")
	}

	payload := preferencesRequest{
		CustomerID:    n.customerID,
		Email:         email,
		EnabledEvents: enabledEvents,
		CooldownHours: cooldownHours,
	}

	jsonData, err := json.Marshal(payload)
	if err != nil {
		return fmt.Errorf("marshal: %w", err)
	}

	url := n.hubURL + "/api/v1/preferences"
	if n.debug {
		n.logger.Printf("[DEBUG] SyncPreferences: url=%s email=%s events=%v cooldown=%dh",
			url, email, enabledEvents, cooldownHours)
	}
	req, err := http.NewRequest("POST", url, bytes.NewReader(jsonData))
	if err != nil {
		return fmt.Errorf("request: %w", err)
	}
	req.Header.Set("Authorization", "Bearer "+n.apiKey)
	req.Header.Set("Content-Type", "application/json")

	resp, err := n.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("hub elérhetetlen: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode >= 400 {
		body, _ := io.ReadAll(io.LimitReader(resp.Body, 512))
		return fmt.Errorf("hub hiba (%d): %s", resp.StatusCode, string(body))
	}

	if n.debug {
		n.logger.Printf("[DEBUG] SyncPreferences: response HTTP %d", resp.StatusCode)
	}
	n.logger.Printf("[INFO] Notification preferences synced to hub: email=%s, events=%v, cooldown=%dh", email, enabledEvents, cooldownHours)
	return nil
}

// ── Test notification ────────────────────────────────────────────────

// SendTest sends a test event for verifying the notification flow (synchronous).
func (n *Notifier) SendTest() error {
	if !n.enabled {
		return fmt.Errorf("notifications not enabled (hub not configured)")
	}

	payload := eventRequest{
		CustomerID: n.customerID,
		EventType:  "test",
		Severity:   "info",
		Message:    "Teszt értesítés a Felhom rendszerből",
	}

	jsonData, err := json.Marshal(payload)
	if err != nil {
		return fmt.Errorf("marshal: %w", err)
	}

	url := n.hubURL + "/api/v1/event"
	req, err := http.NewRequest("POST", url, bytes.NewReader(jsonData))
	if err != nil {
		return fmt.Errorf("request: %w", err)
	}
	req.Header.Set("Authorization", "Bearer "+n.apiKey)
	req.Header.Set("Content-Type", "application/json")

	resp, err := n.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("send: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode >= 400 {
		return fmt.Errorf("hub returned %d", resp.StatusCode)
	}

	return nil
}

// ── Debug event testing ───────────────────────────────────────────────

// PushTestEventSync sends a test event synchronously and returns the Hub HTTP status code.
// Used by the debug page for event testing with configurable type/severity.
func (n *Notifier) PushTestEventSync(eventType, severity, message string) (statusCode int, err error) {
	if !n.enabled {
		return 0, fmt.Errorf("hub nem konfigurált")
	}

	payload := eventRequest{
		CustomerID: n.customerID,
		EventType:  eventType,
		Severity:   severity,
		Message:    message,
	}

	jsonData, err := json.Marshal(payload)
	if err != nil {
		return 0, fmt.Errorf("marshal: %w", err)
	}

	url := n.hubURL + "/api/v1/event"
	req, err := http.NewRequest("POST", url, bytes.NewReader(jsonData))
	if err != nil {
		return 0, fmt.Errorf("request: %w", err)
	}
	req.Header.Set("Authorization", "Bearer "+n.apiKey)
	req.Header.Set("Content-Type", "application/json")

	resp, err := n.httpClient.Do(req)
	if err != nil {
		n.recordHistory(eventType, severity, message, 0, err.Error())
		return 0, fmt.Errorf("send: %w", err)
	}
	io.Copy(io.Discard, resp.Body)
	resp.Body.Close()

	if resp.StatusCode >= 400 {
		n.recordHistory(eventType, severity, message, resp.StatusCode, fmt.Sprintf("HTTP %d", resp.StatusCode))
		return resp.StatusCode, fmt.Errorf("hub returned %d", resp.StatusCode)
	}

	n.recordHistory(eventType, severity, message, resp.StatusCode, "")
	return resp.StatusCode, nil
}

// GetEventHistory returns the last N event history entries (newest first).
func (n *Notifier) GetEventHistory(limit int) []EventHistoryEntry {
	n.historyMu.RLock()
	defer n.historyMu.RUnlock()

	total := n.histPos
	if n.histFull {
		total = len(n.history)
	}
	if limit <= 0 || limit > total {
		limit = total
	}

	result := make([]EventHistoryEntry, 0, limit)
	for i := 0; i < limit; i++ {
		idx := n.histPos - 1 - i
		if idx < 0 {
			idx += len(n.history)
		}
		result = append(result, n.history[idx])
	}
	return result
}

// recordHistory appends an entry to the event history ring buffer.
func (n *Notifier) recordHistory(eventType, severity, message string, hubStatus int, hubError string) {
	n.historyMu.Lock()
	defer n.historyMu.Unlock()
	n.history[n.histPos] = EventHistoryEntry{
		Timestamp: time.Now(),
		EventType: eventType,
		Severity:  severity,
		Message:   message,
		HubStatus: hubStatus,
		HubError:  hubError,
	}
	n.histPos++
	if n.histPos >= len(n.history) {
		n.histPos = 0
		n.histFull = true
	}
}

// ── Backward compatibility ───────────────────────────────────────────

// notifyRequest is the JSON payload for the legacy /api/v1/notify endpoint.
type notifyRequest struct {
	CustomerID string `json:"customer_id"`
	EventType  string `json:"event_type"`
	Severity   string `json:"severity"`
	Message    string `json:"message"`
	Details    string `json:"details,omitempty"`
}

// Notify sends a legacy notification to /api/v1/notify (backward compat).
// Kept for old Hub instances that don't support /api/v1/event yet.
// No local cooldown — Hub handles cooldowns.
func (n *Notifier) Notify(eventType, severity, message, details string) {
	if !n.enabled {
		return
	}

	go func() {
		payload := notifyRequest{
			CustomerID: n.customerID,
			EventType:  eventType,
			Severity:   severity,
			Message:    message,
			Details:    details,
		}

		jsonData, err := json.Marshal(payload)
		if err != nil {
			n.logger.Printf("[ERROR] Failed to marshal notification: %v", err)
			return
		}

		url := n.hubURL + "/api/v1/notify"
		req, err := http.NewRequest("POST", url, bytes.NewReader(jsonData))
		if err != nil {
			return
		}
		req.Header.Set("Authorization", "Bearer "+n.apiKey)
		req.Header.Set("Content-Type", "application/json")

		resp, err := n.httpClient.Do(req)
		if err != nil {
			return
		}
		io.Copy(io.Discard, resp.Body)
		resp.Body.Close()
	}()
}

// ── Helpers ──────────────────────────────────────────────────────────

func statusRank(status string) int {
	switch status {
	case "ok":
		return 0
	case "warn":
		return 1
	case "fail":
		return 2
	default:
		return 0
	}
}

// NotifyWholeGuestBackupFailed / ...Recovered — R-97a, the WHOLE-GUEST (vzdump) backup tier.
//
// OPERATOR-TIER ONLY, and that is why these are NOT `backup_failed`. `backup_failed` and
// `backup_completed` both carry `customerMessages` entries in the hub AND sit in demo-felhom's live
// `enabled_events`, so reusing them would email the CUSTOMER, in Hungarian, that their backup failed
// — while it is still retrying behind the R-88 breaker. A customer can take no action on a failed
// whole-guest backup; that is the same harm R-97b removes, re-introduced through the front door.
//
// Operator-only is enforced hub-side by `notify.operatorOnlyEvents` (hub >= v0.79.0, R-97c), NOT by
// the absence of a `customerMessages` entry — v0.177.0 claimed the latter and was WRONG: the hub
// falls back to the raw message when the entry is missing, and the only customer gate is
// `prefs.EnabledEvents`, which is configuration. Adding a type to the allowlist does NOT make it
// operator-only; it must go in that register too.
//
// HUB DEPENDENCY: both types MUST be present in the hub's allowedEventTypes or POST /event 400s
// (the recorded allowlist gotcha). Do not deploy this controller ahead of that hub change.
func (n *Notifier) NotifyWholeGuestBackupFailed(tier, message, errMsg string) {
	n.PushEvent("whole_guest_backup_failed", "error", message,
		WholeGuestBackupDetails{Tier: tier, Error: errMsg})
}

// NotifyBackupTierSkipped — R-518 (v0.243.0). A whole-guest tier was not attempted because its
// storage does not exist on the host. Operator-only hub-side (hub >= v0.114.0 registers the type in
// allowedEventTypes AND operatorOnlyEvents): the household can do nothing about an unprovisioned DR tier.
func (n *Notifier) NotifyBackupTierSkipped(tier, message string) {
	n.PushEvent("backup_tier_skipped", "warning", message, WholeGuestBackupDetails{Tier: tier})
}

func (n *Notifier) NotifyWholeGuestBackupRecovered(tier, message string) {
	n.PushEvent("whole_guest_backup_recovered", "info", message,
		WholeGuestBackupDetails{Tier: tier})
}