ananke/internal/cluster/orchestrator.go

package cluster

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"sort"
	"strconv"
	"strings"
	"sync"
	"time"

	"scm.bstein.dev/bstein/hecate/internal/config"
	"scm.bstein.dev/bstein/hecate/internal/execx"
	"scm.bstein.dev/bstein/hecate/internal/state"
)

type Orchestrator struct {
	cfg    config.Config
	runner *execx.Runner
	store  *state.Store
	log    *log.Logger
}

type StartupOptions struct {
	ForceFluxBranch    string
	SkipLocalBootstrap bool
	Reason             string
}

type ShutdownOptions struct {
	SkipEtcdSnapshot bool
	SkipDrain        bool
	Reason           string
}

type startupWorkload struct {
	Namespace string
	Kind      string
	Name      string
}

type workloadScaleEntry struct {
	Namespace string `json:"namespace"`
	Kind      string `json:"kind"`
	Name      string `json:"name"`
	Replicas  int    `json:"replicas"`
}

type workloadScaleSnapshot struct {
	GeneratedAt time.Time            `json:"generated_at"`
	Entries     []workloadScaleEntry `json:"entries"`
}

var criticalStartupWorkloads = []startupWorkload{
	{Namespace: "flux-system", Kind: "deployment", Name: "source-controller"},
	{Namespace: "flux-system", Kind: "deployment", Name: "kustomize-controller"},
	{Namespace: "flux-system", Kind: "deployment", Name: "helm-controller"},
	{Namespace: "flux-system", Kind: "deployment", Name: "notification-controller"},
	{Namespace: "harbor", Kind: "statefulset", Name: "harbor-redis"},
	{Namespace: "harbor", Kind: "deployment", Name: "harbor-registry"},
	{Namespace: "vault", Kind: "statefulset", Name: "vault"},
	{Namespace: "postgres", Kind: "statefulset", Name: "postgres"},
	{Namespace: "gitea", Kind: "deployment", Name: "gitea"},
}

func New(cfg config.Config, runner *execx.Runner, store *state.Store, logger *log.Logger) *Orchestrator {
	return &Orchestrator{cfg: cfg, runner: runner, store: store, log: logger}
}

func (o *Orchestrator) Startup(ctx context.Context, opts StartupOptions) (err error) {
	unlock, err := state.AcquireLock(o.cfg.State.LockPath)
	if err != nil {
		return err
	}
	defer unlock()

	record := state.RunRecord{
		ID:        fmt.Sprintf("startup-%d", time.Now().UnixNano()),
		Action:    "startup",
		Reason:    opts.Reason,
		StartedAt: time.Now().UTC(),
	}
	defer o.finalizeRecord(&record, &err)

	if !o.runner.DryRun {
		currentIntent, readErr := state.ReadIntent(o.cfg.State.IntentPath)
		if readErr != nil {
			return fmt.Errorf("read startup intent: %w", readErr)
		}
		if currentIntent.State == state.IntentShuttingDown {
			return fmt.Errorf("startup blocked: shutdown intent is active (%s)", currentIntent.Reason)
		}
		if writeErr := state.MustWriteIntent(o.cfg.State.IntentPath, state.IntentStartupInProgress, opts.Reason, "startup"); writeErr != nil {
			return fmt.Errorf("set startup intent: %w", writeErr)
		}
		defer func() {
			if err == nil {
				if writeErr := state.MustWriteIntent(o.cfg.State.IntentPath, state.IntentNormal, opts.Reason, "startup"); writeErr != nil {
					o.log.Printf("warning: write startup completion intent failed: %v", writeErr)
				}
			}
		}()
	}

	o.log.Printf("startup control-planes=%s", strings.Join(o.cfg.ControlPlanes, ","))

	o.reportFluxSource(ctx, opts.ForceFluxBranch)
	o.startControlPlanes(ctx, o.cfg.ControlPlanes)

	apiPoll := time.Duration(o.cfg.Startup.APIPollSeconds) * time.Second
	apiAttempts := o.cfg.Startup.APIWaitSeconds / o.cfg.Startup.APIPollSeconds
	if apiAttempts < 1 {
		apiAttempts = 1
	}
	if err := o.waitForAPI(ctx, apiAttempts, apiPoll); err != nil {
		return err
	}

	workers, err := o.effectiveWorkers(ctx)
	if err != nil {
		return err
	}
	o.log.Printf("startup workers=%s", strings.Join(workers, ","))
	o.startWorkers(ctx, workers)
	o.bestEffort("uncordon workers", func() error { return o.uncordonWorkers(ctx, workers) })

	if opts.ForceFluxBranch != "" {
		patch := fmt.Sprintf(`{"spec":{"ref":{"branch":"%s"}}}`, opts.ForceFluxBranch)
		if _, err := o.kubectl(ctx, 20*time.Second, "-n", "flux-system", "patch", "gitrepository", "flux-system", "--type=merge", "-p", patch); err != nil {
			return fmt.Errorf("force flux branch: %w", err)
		}
	}

	needsLocalBootstrap := false
	bootstrapReasons := []string{}
	if !opts.SkipLocalBootstrap {
		ready, readyErr := o.fluxSourceReady(ctx)
		if readyErr != nil {
			o.log.Printf("warning: unable to read flux source readiness: %v", readyErr)
			needsLocalBootstrap = true
			bootstrapReasons = append(bootstrapReasons, "flux source readiness check failed")
		}
		if !ready {
			needsLocalBootstrap = true
			bootstrapReasons = append(bootstrapReasons, "flux source not ready")
		}
	}

	missing, missingErr := o.missingCriticalStartupWorkloads(ctx)
	if missingErr != nil {
		o.log.Printf("warning: unable to inspect critical startup workloads: %v", missingErr)
	}
	if len(missing) > 0 {
		o.log.Printf("startup critical workloads not ready; applying targeted recovery first: %s", strings.Join(missing, ", "))
	}
	if err := o.ensureCriticalStartupWorkloads(ctx); err != nil {
		return err
	}

	if !opts.SkipLocalBootstrap && needsLocalBootstrap {
		if ready, err := o.waitForFluxSourceReady(ctx, 5*time.Minute); err != nil {
			o.log.Printf("warning: flux source readiness wait failed before local bootstrap: %v", err)
		} else if ready {
			o.log.Printf("flux source became ready after targeted recovery; skipping local bootstrap")
			needsLocalBootstrap = false
		}
	}

	if !opts.SkipLocalBootstrap && needsLocalBootstrap {
		o.log.Printf("startup bootstrap required after wait: %s", strings.Join(bootstrapReasons, "; "))
		if err := o.bootstrapLocal(ctx); err != nil {
			return err
		}
		if err := o.ensureCriticalStartupWorkloads(ctx); err != nil {
			return err
		}
		ready, err := o.fluxSourceReady(ctx)
		if err != nil {
			return fmt.Errorf("flux source readiness after bootstrap: %w", err)
		}
		if !ready {
			return fmt.Errorf("flux source still not ready after local bootstrap")
		}
	}

	o.bestEffort("restore scaled workloads", func() error { return o.restoreScaledApps(ctx) })

	if err := o.resumeFluxAndReconcile(ctx); err != nil {
		return err
	}
	o.log.Printf("startup flow complete")
	return nil
}

func (o *Orchestrator) Shutdown(ctx context.Context, opts ShutdownOptions) (err error) {
	unlock, err := state.AcquireLock(o.cfg.State.LockPath)
	if err != nil {
		return err
	}
	defer unlock()

	record := state.RunRecord{
		ID:        fmt.Sprintf("shutdown-%d", time.Now().UnixNano()),
		Action:    "shutdown",
		Reason:    opts.Reason,
		StartedAt: time.Now().UTC(),
	}
	defer o.finalizeRecord(&record, &err)
	if !o.runner.DryRun {
		if writeErr := state.MustWriteIntent(o.cfg.State.IntentPath, state.IntentShuttingDown, opts.Reason, "shutdown"); writeErr != nil {
			return fmt.Errorf("set shutdown intent: %w", writeErr)
		}
		defer func() {
			final := state.IntentShuttingDown
			if err == nil {
				final = state.IntentShutdownComplete
			}
			if writeErr := state.MustWriteIntent(o.cfg.State.IntentPath, final, opts.Reason, "shutdown"); writeErr != nil {
				o.log.Printf("warning: write shutdown completion intent failed: %v", writeErr)
			}
		}()
	}

	workers, err := o.effectiveWorkers(ctx)
	if err != nil {
		return err
	}
	o.log.Printf("shutdown control-planes=%s workers=%s", strings.Join(o.cfg.ControlPlanes, ","), strings.Join(workers, ","))

	o.reportFluxSource(ctx, "")

	skipEtcd := opts.SkipEtcdSnapshot || o.cfg.Shutdown.SkipEtcdSnapshot
	if !skipEtcd {
		o.bestEffort("etcd snapshot", func() error {
			return o.takeEtcdSnapshot(ctx, o.cfg.ControlPlanes[0])
		})
	}

	o.bestEffort("suspend flux", func() error { return o.patchFluxSuspendAll(ctx, true) })
	o.bestEffort("scale down apps", func() error { return o.scaleDownApps(ctx) })

	skipDrain := opts.SkipDrain || o.cfg.Shutdown.SkipDrain
	if !skipDrain {
		o.bestEffort("drain workers", func() error { return o.drainWorkers(ctx, workers) })
	}

	o.stopWorkers(ctx, workers)
	o.stopControlPlanes(ctx, o.cfg.ControlPlanes)
	if o.cfg.Shutdown.PoweroffEnabled {
		o.bestEffort("poweroff hosts", func() error { return o.poweroffHosts(ctx, workers) })
	}
	o.log.Printf("shutdown flow complete")
	return nil
}

func (o *Orchestrator) EstimatedShutdownSeconds() int {
	return o.store.ShutdownP95(o.cfg.Shutdown.DefaultBudgetSeconds)
}

func (o *Orchestrator) finalizeRecord(record *state.RunRecord, err *error) {
	record.EndedAt = time.Now().UTC()
	record.DurationSeconds = int(record.EndedAt.Sub(record.StartedAt).Seconds())
	record.Success = *err == nil
	if *err != nil {
		record.Error = (*err).Error()
	}
	if appendErr := o.store.Append(*record); appendErr != nil {
		o.log.Printf("warning: append run record failed: %v", appendErr)
	}
}

func (o *Orchestrator) effectiveWorkers(ctx context.Context) ([]string, error) {
	if len(o.cfg.Workers) > 0 {
		return append([]string{}, o.cfg.Workers...), nil
	}
	workers, err := o.discoverWorkers(ctx)
	if err == nil {
		return workers, nil
	}
	fallback := o.fallbackWorkersFromInventory()
	if len(fallback) == 0 {
		return nil, err
	}
	o.log.Printf("warning: worker discovery failed via kubernetes API (%v); falling back to inventory workers=%s", err, strings.Join(fallback, ","))
	return fallback, nil
}

func (o *Orchestrator) discoverWorkers(ctx context.Context) ([]string, error) {
	out, err := o.kubectl(ctx, 15*time.Second,
		"get", "nodes",
		"-o", "custom-columns=NAME:.metadata.name,CP:.metadata.labels.node-role\\.kubernetes\\.io/control-plane,MASTER:.metadata.labels.node-role\\.kubernetes\\.io/master",
		"--no-headers",
	)
	if err != nil {
		return nil, fmt.Errorf("discover workers: %w", err)
	}
	var workers []string
	for _, line := range lines(out) {
		fields := strings.Fields(line)
		if len(fields) < 3 {
			continue
		}
		if fields[1] == "<none>" && fields[2] == "<none>" {
			workers = append(workers, fields[0])
		}
	}
	if len(workers) == 0 {
		return nil, fmt.Errorf("no workers discovered")
	}
	return workers, nil
}

func (o *Orchestrator) fallbackWorkersFromInventory() []string {
	cp := make(map[string]struct{}, len(o.cfg.ControlPlanes))
	for _, node := range o.cfg.ControlPlanes {
		cp[strings.TrimSpace(node)] = struct{}{}
	}

	candidates := make(map[string]struct{})
	add := func(node string) {
		name := strings.TrimSpace(node)
		if name == "" {
			return
		}
		if _, isCP := cp[name]; isCP {
			return
		}
		candidates[name] = struct{}{}
	}

	for _, node := range o.cfg.SSHManagedNodes {
		add(node)
	}
	if len(candidates) == 0 {
		for node := range o.cfg.SSHNodeHosts {
			add(node)
		}
	}

	workers := make([]string, 0, len(candidates))
	for node := range candidates {
		workers = append(workers, node)
	}
	sort.Strings(workers)
	return workers
}

func (o *Orchestrator) patchFluxSuspendAll(ctx context.Context, suspend bool) error {
	patch := fmt.Sprintf(`{"spec":{"suspend":%t}}`, suspend)

	ksOut, err := o.kubectl(ctx, 20*time.Second,
		"-n", "flux-system", "get", "kustomizations.kustomize.toolkit.fluxcd.io",
		"-o", "jsonpath={range .items[*]}{.metadata.name}{'\\n'}{end}",
	)
	if err != nil {
		return err
	}
	for _, ks := range lines(ksOut) {
		_, patchErr := o.kubectl(ctx, 20*time.Second, "-n", "flux-system", "patch", "kustomization", ks, "--type=merge", "-p", patch)
		if patchErr != nil {
			o.log.Printf("warning: patch kustomization %s failed: %v", ks, patchErr)
		}
	}

	hrOut, err := o.kubectl(ctx, 25*time.Second,
		"get", "helmreleases.helm.toolkit.fluxcd.io", "-A",
		"-o", "jsonpath={range .items[*]}{.metadata.namespace}{'/'}{.metadata.name}{'\\n'}{end}",
	)
	if err != nil {
		return err
	}
	for _, hr := range lines(hrOut) {
		parts := strings.SplitN(hr, "/", 2)
		if len(parts) != 2 {
			continue
		}
		_, patchErr := o.kubectl(ctx, 20*time.Second, "-n", parts[0], "patch", "helmrelease", parts[1], "--type=merge", "-p", patch)
		if patchErr != nil {
			o.log.Printf("warning: patch helmrelease %s failed: %v", hr, patchErr)
		}
	}
	return nil
}

func (o *Orchestrator) scaleDownApps(ctx context.Context) error {
	targets, err := o.listScalableWorkloads(ctx)
	if err != nil {
		return err
	}
	if err := o.writeScaledWorkloadSnapshot(targets); err != nil {
		return err
	}
	if len(targets) == 0 {
		o.log.Printf("scale down apps: no workloads above 0 replicas")
		return nil
	}

	parallelism := o.cfg.Shutdown.ScaleParallelism
	if parallelism <= 0 {
		parallelism = 8
	}
	o.log.Printf("scale down apps targets=%d parallelism=%d", len(targets), parallelism)
	return o.scaleWorkloads(ctx, targets, 0, parallelism)
}

func (o *Orchestrator) restoreScaledApps(ctx context.Context) error {
	snapshot, err := o.readScaledWorkloadSnapshot()
	if err != nil {
		return err
	}
	if snapshot == nil || len(snapshot.Entries) == 0 {
		o.log.Printf("restore scaled workloads: no snapshot entries to restore")
		return nil
	}

	parallelism := o.cfg.Shutdown.ScaleParallelism
	if parallelism <= 0 {
		parallelism = 8
	}
	o.log.Printf("restore scaled workloads entries=%d parallelism=%d snapshot_at=%s", len(snapshot.Entries), parallelism, snapshot.GeneratedAt.Format(time.RFC3339))
	if err := o.scaleWorkloads(ctx, snapshot.Entries, -1, parallelism); err != nil {
		return err
	}
	if o.runner.DryRun {
		return nil
	}
	if err := os.Remove(o.scaledWorkloadSnapshotPath()); err != nil && !os.IsNotExist(err) {
		return fmt.Errorf("remove scaled workload snapshot: %w", err)
	}
	return nil
}

func (o *Orchestrator) listScalableWorkloads(ctx context.Context) ([]workloadScaleEntry, error) {
	exclude := map[string]struct{}{}
	for _, ns := range o.cfg.ExcludedNamespaces {
		exclude[strings.TrimSpace(ns)] = struct{}{}
	}

	collect := func(kind string) ([]workloadScaleEntry, error) {
		out, err := o.kubectl(
			ctx,
			25*time.Second,
			"get",
			kind,
			"-A",
			"-o",
			"jsonpath={range .items[*]}{.metadata.namespace}{'\\t'}{.metadata.name}{'\\t'}{.spec.replicas}{'\\n'}{end}",
		)
		if err != nil {
			return nil, err
		}
		var entries []workloadScaleEntry
		for _, line := range lines(out) {
			parts := strings.Split(line, "\t")
			if len(parts) < 3 {
				continue
			}
			ns := strings.TrimSpace(parts[0])
			if _, skip := exclude[ns]; skip {
				continue
			}
			replicas, convErr := strconv.Atoi(strings.TrimSpace(parts[2]))
			if convErr != nil || replicas <= 0 {
				continue
			}
			entries = append(entries, workloadScaleEntry{
				Namespace: ns,
				Kind:      kind,
				Name:      strings.TrimSpace(parts[1]),
				Replicas:  replicas,
			})
		}
		return entries, nil
	}

	deployments, err := collect("deployment")
	if err != nil {
		return nil, fmt.Errorf("collect deployments: %w", err)
	}
	statefulsets, err := collect("statefulset")
	if err != nil {
		return nil, fmt.Errorf("collect statefulsets: %w", err)
	}
	targets := append(deployments, statefulsets...)
	sort.Slice(targets, func(i, j int) bool {
		a, b := targets[i], targets[j]
		if a.Namespace != b.Namespace {
			return a.Namespace < b.Namespace
		}
		if a.Kind != b.Kind {
			return a.Kind < b.Kind
		}
		return a.Name < b.Name
	})
	return targets, nil
}

func (o *Orchestrator) scaleWorkloads(ctx context.Context, entries []workloadScaleEntry, forceReplicas int, parallelism int) error {
	if len(entries) == 0 {
		return nil
	}
	if parallelism <= 0 {
		parallelism = 1
	}
	if parallelism > len(entries) {
		parallelism = len(entries)
	}

	sem := make(chan struct{}, parallelism)
	var wg sync.WaitGroup
	errCh := make(chan error, len(entries))

	for _, entry := range entries {
		entry := entry
		wg.Add(1)
		go func() {
			defer wg.Done()
			sem <- struct{}{}
			defer func() { <-sem }()

			replicas := entry.Replicas
			if forceReplicas >= 0 {
				replicas = forceReplicas
			}
			if _, err := o.kubectl(
				ctx,
				20*time.Second,
				"-n",
				entry.Namespace,
				"scale",
				entry.Kind,
				entry.Name,
				fmt.Sprintf("--replicas=%d", replicas),
			); err != nil {
				if isNotFoundErr(err) {
					o.log.Printf("warning: skip missing workload while scaling %s/%s/%s", entry.Namespace, entry.Kind, entry.Name)
					return
				}
				errCh <- fmt.Errorf("scale %s/%s/%s -> %d: %w", entry.Namespace, entry.Kind, entry.Name, replicas, err)
			}
		}()
	}

	wg.Wait()
	close(errCh)

	errorCount := len(errCh)
	if errorCount == 0 {
		return nil
	}
	errs := make([]string, 0, len(errCh))
	for err := range errCh {
		errs = append(errs, err.Error())
		if len(errs) >= 5 {
			break
		}
	}
	return fmt.Errorf("scaling had %d errors (first: %s)", errorCount, strings.Join(errs, " | "))
}

func (o *Orchestrator) scaledWorkloadSnapshotPath() string {
	return filepath.Join(o.cfg.State.Dir, "scaled-workloads.json")
}

func (o *Orchestrator) writeScaledWorkloadSnapshot(entries []workloadScaleEntry) error {
	if o.runner.DryRun {
		return nil
	}
	if err := os.MkdirAll(o.cfg.State.Dir, 0o755); err != nil {
		return fmt.Errorf("ensure state dir: %w", err)
	}
	payload := workloadScaleSnapshot{
		GeneratedAt: time.Now().UTC(),
		Entries:     entries,
	}
	b, err := json.MarshalIndent(payload, "", "  ")
	if err != nil {
		return fmt.Errorf("marshal scaled workload snapshot: %w", err)
	}
	if err := os.WriteFile(o.scaledWorkloadSnapshotPath(), b, 0o644); err != nil {
		return fmt.Errorf("write scaled workload snapshot: %w", err)
	}
	return nil
}

func (o *Orchestrator) readScaledWorkloadSnapshot() (*workloadScaleSnapshot, error) {
	if o.runner.DryRun {
		return nil, nil
	}
	b, err := os.ReadFile(o.scaledWorkloadSnapshotPath())
	if err != nil {
		if os.IsNotExist(err) {
			return nil, nil
		}
		return nil, fmt.Errorf("read scaled workload snapshot: %w", err)
	}
	var snapshot workloadScaleSnapshot
	if err := json.Unmarshal(b, &snapshot); err != nil {
		return nil, fmt.Errorf("decode scaled workload snapshot: %w", err)
	}
	return &snapshot, nil
}

func (o *Orchestrator) drainWorkers(ctx context.Context, workers []string) error {
	total := len(workers)
	if total == 0 {
		return nil
	}
	parallelism := o.cfg.Shutdown.DrainParallelism
	if parallelism <= 0 {
		parallelism = 6
	}
	if parallelism > total {
		parallelism = total
	}

	o.log.Printf("drain workers total=%d parallelism=%d", total, parallelism)
	sem := make(chan struct{}, parallelism)
	var wg sync.WaitGroup
	errCh := make(chan error, total)

	for idx, node := range workers {
		idx := idx
		node := node
		wg.Add(1)
		go func() {
			defer wg.Done()
			sem <- struct{}{}
			defer func() { <-sem }()

			o.log.Printf("drain worker %d/%d: %s", idx+1, total, node)
			if _, err := o.kubectl(ctx, 20*time.Second, "cordon", node); err != nil {
				o.log.Printf("warning: cordon %s failed: %v", node, err)
			}
			if _, err := o.kubectl(ctx, 3*time.Minute, "drain", node, "--ignore-daemonsets", "--delete-emptydir-data", "--grace-period=30", "--timeout=180s"); err != nil {
				errCh <- fmt.Errorf("drain %s failed: %w", node, err)
				return
			}
		}()
	}

	wg.Wait()
	close(errCh)
	if len(errCh) == 0 {
		return nil
	}
	count := len(errCh)
	samples := []string{}
	for err := range errCh {
		samples = append(samples, err.Error())
		if len(samples) >= 4 {
			break
		}
	}
	return fmt.Errorf("drain workers had %d errors (first: %s)", count, strings.Join(samples, " | "))
}

func (o *Orchestrator) uncordonWorkers(ctx context.Context, workers []string) error {
	for _, node := range workers {
		if _, err := o.kubectl(ctx, 20*time.Second, "uncordon", node); err != nil {
			o.log.Printf("warning: uncordon %s failed: %v", node, err)
		}
	}
	return nil
}

func (o *Orchestrator) stopWorkers(ctx context.Context, workers []string) {
	o.runSSHAcrossNodes(ctx, workers, "stop k3s-agent", "sudo systemctl stop k3s-agent || true")
}

func (o *Orchestrator) startWorkers(ctx context.Context, workers []string) {
	o.runSSHAcrossNodes(ctx, workers, "start k3s-agent", "sudo systemctl start k3s-agent || true")
}

func (o *Orchestrator) stopControlPlanes(ctx context.Context, cps []string) {
	o.runSSHAcrossNodes(ctx, cps, "stop k3s", "sudo systemctl stop k3s || true")
}

func (o *Orchestrator) startControlPlanes(ctx context.Context, cps []string) {
	o.runSSHAcrossNodes(ctx, cps, "start k3s", "sudo systemctl start k3s || true")
}

func (o *Orchestrator) runSSHAcrossNodes(ctx context.Context, nodes []string, action, command string) {
	if len(nodes) == 0 {
		return
	}
	parallelism := o.cfg.Shutdown.SSHParallelism
	if parallelism <= 0 {
		parallelism = 8
	}
	if parallelism > len(nodes) {
		parallelism = len(nodes)
	}

	sem := make(chan struct{}, parallelism)
	var wg sync.WaitGroup
	for _, node := range nodes {
		node := node
		if !o.sshManaged(node) {
			o.log.Printf("skip %s on %s: node not in ssh_managed_nodes", action, node)
			continue
		}
		wg.Add(1)
		go func() {
			defer wg.Done()
			sem <- struct{}{}
			defer func() { <-sem }()
			o.bestEffort(action+" on "+node, func() error {
				_, err := o.ssh(ctx, node, command)
				return err
			})
		}()
	}
	wg.Wait()
}

func (o *Orchestrator) takeEtcdSnapshot(ctx context.Context, node string) error {
	if !o.sshManaged(node) {
		return fmt.Errorf("cannot run etcd snapshot on %s: node not in ssh_managed_nodes", node)
	}
	name := "pre-shutdown-" + time.Now().UTC().Format("20060102-150405")
	_, err := o.ssh(ctx, node, "sudo k3s etcd-snapshot save --name "+name)
	return err
}

func (o *Orchestrator) waitForAPI(ctx context.Context, attempts int, sleep time.Duration) error {
	if o.runner.DryRun {
		return nil
	}
	for i := 0; i < attempts; i++ {
		_, err := o.kubectl(ctx, 5*time.Second, "version", "--request-timeout=5s")
		if err == nil {
			return nil
		}
		time.Sleep(sleep)
	}
	return fmt.Errorf("kubernetes API did not become reachable within timeout")
}

func (o *Orchestrator) fluxSourceReady(ctx context.Context) (bool, error) {
	out, err := o.kubectl(ctx, 10*time.Second, "-n", "flux-system", "get", "gitrepository", "flux-system", "-o", "jsonpath={.status.conditions[?(@.type==\"Ready\")].status}")
	if err != nil {
		return false, err
	}
	return strings.Contains(out, "True"), nil
}

func (o *Orchestrator) reportFluxSource(ctx context.Context, forceBranch string) {
	urlOut, urlErr := o.kubectl(ctx, 10*time.Second, "-n", "flux-system", "get", "gitrepository", "flux-system", "-o", "jsonpath={.spec.url}")
	if urlErr == nil {
		o.log.Printf("flux-source-url=%s", strings.TrimSpace(urlOut))
	}
	branchOut, branchErr := o.kubectl(ctx, 10*time.Second, "-n", "flux-system", "get", "gitrepository", "flux-system", "-o", "jsonpath={.spec.ref.branch}")
	if branchErr == nil {
		branch := strings.TrimSpace(branchOut)
		o.log.Printf("flux-source-branch=%s", branch)
		if forceBranch == "" && branch != o.cfg.ExpectedFluxBranch {
			o.log.Printf("warning: flux source branch is '%s', expected '%s'", branch, o.cfg.ExpectedFluxBranch)
		}
	}
}

func (o *Orchestrator) bootstrapLocal(ctx context.Context) error {
	failures := 0
	for _, rel := range o.cfg.LocalBootstrapPaths {
		full := filepath.Join(o.cfg.IACRepoPath, rel)
		o.log.Printf("local bootstrap apply -k %s", full)
		if o.runner.DryRun {
			continue
		}
		if _, err := o.kubectl(ctx, 2*time.Minute, "apply", "-k", full); err != nil {
			o.log.Printf("warning: local bootstrap apply failed at %s: %v", full, err)
			o.log.Printf("local bootstrap fallback render/apply with LoadRestrictionsNone for %s", full)
			if fallbackErr := o.applyKustomizeFallback(ctx, full); fallbackErr != nil {
				failures++
				o.log.Printf("warning: local bootstrap fallback failed at %s: %v", full, fallbackErr)
				continue
			}
		}
	}
	if failures == len(o.cfg.LocalBootstrapPaths) {
		return fmt.Errorf("local bootstrap apply failed for every configured path (%d total)", failures)
	}
	return nil
}

func (o *Orchestrator) applyKustomizeFallback(ctx context.Context, full string) error {
	cmd := fmt.Sprintf("kubectl kustomize --load-restrictor=LoadRestrictionsNone %q | kubectl apply -f -", full)
	if _, err := o.runSensitive(ctx, 3*time.Minute, "sh", "-lc", cmd); err != nil {
		return err
	}
	return nil
}

func (o *Orchestrator) waitForFluxSourceReady(ctx context.Context, window time.Duration) (bool, error) {
	if o.runner.DryRun {
		return true, nil
	}
	deadline := time.Now().Add(window)
	for {
		ready, err := o.fluxSourceReady(ctx)
		if err != nil {
			return false, err
		}
		if ready {
			return true, nil
		}
		if time.Now().After(deadline) {
			return false, nil
		}
		select {
		case <-ctx.Done():
			return false, ctx.Err()
		case <-time.After(5 * time.Second):
		}
	}
}

func (o *Orchestrator) resumeFluxAndReconcile(ctx context.Context) error {
	if err := o.patchFluxSuspendAll(ctx, false); err != nil {
		return err
	}

	now := time.Now().UTC().Format(time.RFC3339)
	if _, err := o.kubectl(
		ctx,
		25*time.Second,
		"-n", "flux-system",
		"annotate",
		"kustomizations.kustomize.toolkit.fluxcd.io",
		"--all",
		"reconcile.fluxcd.io/requestedAt="+now,
		"--overwrite",
	); err != nil {
		o.log.Printf("warning: annotate kustomizations for reconcile failed: %v", err)
	}
	if _, err := o.kubectl(
		ctx,
		25*time.Second,
		"annotate",
		"--all-namespaces",
		"helmreleases.helm.toolkit.fluxcd.io",
		"--all",
		"reconcile.fluxcd.io/requestedAt="+now,
		"--overwrite",
	); err != nil {
		o.log.Printf("warning: annotate helmreleases for reconcile failed: %v", err)
	}

	if o.runner.CommandExists("flux") {
		sourceCmd := []string{"reconcile", "source", "git", "flux-system", "-n", "flux-system", "--timeout=60s"}
		if _, err := o.run(ctx, 75*time.Second, "flux", sourceCmd...); err != nil {
			o.log.Printf("warning: flux command failed (%s): %v", strings.Join(sourceCmd, " "), err)
		}
	}
	return nil
}

func (o *Orchestrator) kubectl(ctx context.Context, timeout time.Duration, args ...string) (string, error) {
	return o.run(ctx, timeout, "kubectl", args...)
}

func (o *Orchestrator) ssh(ctx context.Context, node string, command string) (string, error) {
	host := node
	if mapped, ok := o.cfg.SSHNodeHosts[node]; ok && strings.TrimSpace(mapped) != "" {
		host = strings.TrimSpace(mapped)
	}
	sshUser := o.cfg.SSHUser
	if override, ok := o.cfg.SSHNodeUsers[node]; ok && strings.TrimSpace(override) != "" {
		sshUser = strings.TrimSpace(override)
	}
	target := host
	if sshUser != "" {
		target = sshUser + "@" + host
	}
	sshConfigFile := o.resolveSSHConfigFile()
	sshIdentity := o.resolveSSHIdentityFile()
	baseArgs := []string{
		"-o", "BatchMode=yes",
		"-o", "ConnectTimeout=8",
		"-o", "StrictHostKeyChecking=accept-new",
	}
	if sshConfigFile != "" {
		baseArgs = append(baseArgs, "-F", sshConfigFile)
	}
	if sshIdentity != "" {
		baseArgs = append(baseArgs, "-i", sshIdentity)
	}
	if o.cfg.SSHPort > 0 {
		baseArgs = append(baseArgs, "-p", strconv.Itoa(o.cfg.SSHPort))
	}
	attempts := make([][]string, 0, 2)
	attemptNames := make([]string, 0, 2)
	if o.cfg.SSHJumpHost != "" {
		jump := o.cfg.SSHJumpHost
		if o.cfg.SSHJumpUser != "" {
			jump = o.cfg.SSHJumpUser + "@" + jump
		}
		if o.cfg.SSHPort > 0 && !strings.Contains(jump, ":") {
			jump = fmt.Sprintf("%s:%d", jump, o.cfg.SSHPort)
		}
		withJump := append([]string{}, baseArgs...)
		withJump = append(withJump, "-J", jump, target, command)
		attempts = append(attempts, withJump)
		attemptNames = append(attemptNames, "jump")
	}
	direct := append([]string{}, baseArgs...)
	direct = append(direct, target, command)
	attempts = append(attempts, direct)
	attemptNames = append(attemptNames, "direct")

	var lastOut string
	var lastErr error
	for i, args := range attempts {
		out, err := o.run(ctx, 45*time.Second, "ssh", args...)
		if err == nil {
			if i > 0 {
				o.log.Printf("warning: ssh %s path failed for %s, using %s path", attemptNames[i-1], node, attemptNames[i])
			}
			return out, nil
		}
		lastOut = out
		lastErr = err
		if i < len(attempts)-1 {
			o.log.Printf("warning: ssh %s path failed for %s: %v; trying %s path", attemptNames[i], node, err, attemptNames[i+1])
		}
	}
	return lastOut, lastErr
}

func (o *Orchestrator) run(ctx context.Context, timeout time.Duration, name string, args ...string) (string, error) {
	runCtx, cancel := context.WithTimeout(ctx, timeout)
	defer cancel()
	return o.runner.Run(runCtx, name, args...)
}

func (o *Orchestrator) runSensitive(ctx context.Context, timeout time.Duration, name string, args ...string) (string, error) {
	runCtx, cancel := context.WithTimeout(ctx, timeout)
	defer cancel()

	cmd := exec.CommandContext(runCtx, name, args...)
	cmd.Env = os.Environ()
	if o.runner.Kubeconfig != "" {
		cmd.Env = append(cmd.Env, "KUBECONFIG="+o.runner.Kubeconfig)
	}
	out, err := cmd.CombinedOutput()
	trimmed := strings.TrimSpace(string(out))
	if err != nil {
		if trimmed == "" {
			return "", fmt.Errorf("%s failed: %w", name, err)
		}
		return trimmed, fmt.Errorf("%s failed: %w", name, err)
	}
	return trimmed, nil
}

func lines(in string) []string {
	in = strings.TrimSpace(in)
	if in == "" {
		return nil
	}
	parts := strings.Split(in, "\n")
	out := make([]string, 0, len(parts))
	for _, p := range parts {
		v := strings.TrimSpace(p)
		if v != "" {
			out = append(out, v)
		}
	}
	return out
}

func (o *Orchestrator) sshManaged(node string) bool {
	if len(o.cfg.SSHManagedNodes) == 0 {
		return true
	}
	for _, allowed := range o.cfg.SSHManagedNodes {
		if strings.TrimSpace(allowed) == node {
			return true
		}
	}
	return false
}

func (o *Orchestrator) resolveSSHConfigFile() string {
	if strings.TrimSpace(o.cfg.SSHConfigFile) != "" {
		return strings.TrimSpace(o.cfg.SSHConfigFile)
	}
	candidates := []string{
		"/home/atlas/.ssh/config",
		"/home/tethys/.ssh/config",
	}
	for _, p := range candidates {
		if stat, err := os.Stat(p); err == nil && !stat.IsDir() {
			return p
		}
	}
	return ""
}

func (o *Orchestrator) resolveSSHIdentityFile() string {
	if strings.TrimSpace(o.cfg.SSHIdentityFile) != "" {
		return strings.TrimSpace(o.cfg.SSHIdentityFile)
	}
	candidates := []string{
		"/home/atlas/.ssh/id_ed25519",
		"/home/tethys/.ssh/id_ed25519",
	}
	for _, p := range candidates {
		if stat, err := os.Stat(p); err == nil && !stat.IsDir() {
			return p
		}
	}
	return ""
}

func (o *Orchestrator) bestEffort(name string, fn func() error) {
	if err := fn(); err != nil {
		o.log.Printf("warning: %s: %v", name, err)
	}
}

func (o *Orchestrator) missingCriticalStartupWorkloads(ctx context.Context) ([]string, error) {
	missing := []string{}
	for _, w := range criticalStartupWorkloads {
		ready, err := o.workloadReady(ctx, w)
		if err != nil {
			if isNotFoundErr(err) {
				missing = append(missing, fmt.Sprintf("%s/%s/%s(not found)", w.Namespace, w.Kind, w.Name))
				continue
			}
			return nil, fmt.Errorf("check %s/%s/%s: %w", w.Namespace, w.Kind, w.Name, err)
		}
		if !ready {
			missing = append(missing, fmt.Sprintf("%s/%s/%s", w.Namespace, w.Kind, w.Name))
		}
	}
	return missing, nil
}

func (o *Orchestrator) ensureCriticalStartupWorkloads(ctx context.Context) error {
	for _, w := range criticalStartupWorkloads {
		if err := o.ensureWorkloadReplicas(ctx, w, 1); err != nil {
			if isNotFoundErr(err) {
				o.log.Printf("warning: startup workload missing, skipping scale: %s/%s/%s", w.Namespace, w.Kind, w.Name)
				continue
			}
			return fmt.Errorf("scale %s/%s/%s: %w", w.Namespace, w.Kind, w.Name, err)
		}
		if err := o.waitWorkloadReady(ctx, w); err != nil {
			if isNotFoundErr(err) {
				o.log.Printf("warning: startup workload missing during readiness wait: %s/%s/%s", w.Namespace, w.Kind, w.Name)
				continue
			}
			return err
		}
	}
	return nil
}

func (o *Orchestrator) ensureWorkloadReplicas(ctx context.Context, w startupWorkload, replicas int) error {
	_, err := o.kubectl(
		ctx,
		45*time.Second,
		"-n",
		w.Namespace,
		"scale",
		w.Kind,
		w.Name,
		fmt.Sprintf("--replicas=%d", replicas),
	)
	return err
}

func (o *Orchestrator) waitWorkloadReady(ctx context.Context, w startupWorkload) error {
	if w.Namespace == "vault" && w.Kind == "statefulset" && w.Name == "vault" {
		return o.waitVaultReady(ctx, w)
	}

	timeout := "240s"
	if w.Kind == "statefulset" {
		timeout = "360s"
	}
	_, err := o.kubectl(
		ctx,
		7*time.Minute,
		"-n",
		w.Namespace,
		"rollout",
		"status",
		fmt.Sprintf("%s/%s", w.Kind, w.Name),
		"--timeout="+timeout,
	)
	if err != nil {
		return fmt.Errorf("wait ready %s/%s/%s: %w", w.Namespace, w.Kind, w.Name, err)
	}
	return nil
}

func (o *Orchestrator) waitVaultReady(ctx context.Context, w startupWorkload) error {
	if o.runner.DryRun {
		return nil
	}

	deadline := time.Now().Add(7 * time.Minute)
	var lastErr error
	for time.Now().Before(deadline) {
		ready, err := o.workloadReady(ctx, w)
		if err == nil && ready {
			return nil
		}
		if err != nil {
			lastErr = err
		}

		if err := o.ensureVaultUnsealed(ctx); err != nil {
			lastErr = err
			o.log.Printf("warning: vault readiness still blocked: %v", err)
		}

		ready, err = o.workloadReady(ctx, w)
		if err == nil && ready {
			return nil
		}
		if err != nil {
			lastErr = err
		}

		select {
		case <-ctx.Done():
			return ctx.Err()
		case <-time.After(5 * time.Second):
		}
	}

	if lastErr != nil {
		return fmt.Errorf("wait ready %s/%s/%s: %w", w.Namespace, w.Kind, w.Name, lastErr)
	}
	return fmt.Errorf("wait ready %s/%s/%s: timeout", w.Namespace, w.Kind, w.Name)
}

func (o *Orchestrator) ensureVaultUnsealed(ctx context.Context) error {
	if o.runner.DryRun {
		return nil
	}

	phase, err := o.kubectl(ctx, 15*time.Second, "-n", "vault", "get", "pod", "vault-0", "-o", "jsonpath={.status.phase}")
	if err != nil {
		return fmt.Errorf("vault pod phase check failed: %w", err)
	}
	if strings.TrimSpace(phase) != "Running" {
		return fmt.Errorf("vault-0 pod phase is %q", strings.TrimSpace(phase))
	}

	sealed, err := o.vaultSealed(ctx)
	if err != nil {
		return err
	}
	if !sealed {
		return nil
	}

	unsealKey, err := o.vaultUnsealKey(ctx)
	if err != nil {
		return err
	}

	for attempt := 1; attempt <= 5; attempt++ {
		o.log.Printf("vault is sealed; attempting auto-unseal (%d/5)", attempt)
		if _, err := o.runSensitive(
			ctx,
			30*time.Second,
			"kubectl",
			"-n", "vault",
			"exec", "vault-0", "--",
			"vault", "operator", "unseal", unsealKey,
		); err != nil {
			return fmt.Errorf("vault unseal attempt %d failed: %w", attempt, err)
		}

		sealed, err = o.vaultSealed(ctx)
		if err != nil {
			return err
		}
		if !sealed {
			o.log.Printf("vault auto-unseal succeeded")
			return nil
		}
		time.Sleep(2 * time.Second)
	}

	return fmt.Errorf("vault remained sealed after 5 auto-unseal attempts")
}

func (o *Orchestrator) vaultSealed(ctx context.Context) (bool, error) {
	out, err := o.kubectl(
		ctx,
		25*time.Second,
		"-n", "vault",
		"exec", "vault-0", "--",
		"sh", "-lc",
		"VAULT_ADDR=http://127.0.0.1:8200 vault status -format=json 2>/dev/null || true",
	)
	if err != nil {
		return false, fmt.Errorf("vault status check failed: %w", err)
	}
	sealed, err := parseVaultSealed(out)
	if err != nil {
		return false, fmt.Errorf("parse vault status: %w", err)
	}
	return sealed, nil
}

func parseVaultSealed(raw string) (bool, error) {
	trimmed := strings.TrimSpace(raw)
	if trimmed == "" {
		return false, fmt.Errorf("empty vault status output")
	}
	start := strings.Index(trimmed, "{")
	end := strings.LastIndex(trimmed, "}")
	if start < 0 || end < 0 || end < start {
		return false, fmt.Errorf("vault status payload missing JSON object")
	}
	payload := trimmed[start : end+1]

	type vaultStatus struct {
		Sealed bool `json:"sealed"`
	}
	var st vaultStatus
	if err := json.Unmarshal([]byte(payload), &st); err != nil {
		return false, err
	}
	return st.Sealed, nil
}

func (o *Orchestrator) vaultUnsealKey(ctx context.Context) (string, error) {
	out, err := o.kubectl(
		ctx,
		15*time.Second,
		"-n", "vault",
		"get", "secret", "vault-init",
		"-o", "jsonpath={.data.unseal_key_b64}",
	)
	if err != nil {
		return "", fmt.Errorf("read vault-init secret: %w", err)
	}
	decoded, err := base64.StdEncoding.DecodeString(strings.TrimSpace(out))
	if err != nil {
		return "", fmt.Errorf("decode vault-init unseal_key_b64: %w", err)
	}
	key := strings.TrimSpace(string(decoded))
	if key == "" {
		return "", fmt.Errorf("vault-init unseal key is empty")
	}
	return key, nil
}

func (o *Orchestrator) workloadReady(ctx context.Context, w startupWorkload) (bool, error) {
	out, err := o.kubectl(
		ctx,
		20*time.Second,
		"-n",
		w.Namespace,
		"get",
		w.Kind,
		w.Name,
		"-o",
		"jsonpath={.status.readyReplicas}",
	)
	if err != nil {
		return false, err
	}
	raw := strings.TrimSpace(out)
	if raw == "" || raw == "<no value>" {
		return false, nil
	}
	n, err := strconv.Atoi(raw)
	if err != nil {
		return false, fmt.Errorf("parse readyReplicas %q: %w", raw, err)
	}
	return n >= 1, nil
}

func isNotFoundErr(err error) bool {
	if err == nil {
		return false
	}
	msg := strings.ToLower(err.Error())
	return strings.Contains(msg, "not found") || strings.Contains(msg, "(notfound)")
}

func (o *Orchestrator) poweroffHosts(ctx context.Context, workers []string) error {
	delay := o.cfg.Shutdown.PoweroffDelaySeconds
	if delay <= 0 {
		delay = 25
	}

	localNames := map[string]struct{}{}
	if hn, err := os.Hostname(); err == nil && strings.TrimSpace(hn) != "" {
		localNames[strings.TrimSpace(hn)] = struct{}{}
	}
	if o.cfg.SSHUser != "" {
		localNames[o.cfg.SSHUser] = struct{}{}
	}

	hostSet := map[string]struct{}{}
	for _, n := range o.cfg.ControlPlanes {
		hostSet[n] = struct{}{}
	}
	for _, n := range workers {
		hostSet[n] = struct{}{}
	}
	for _, n := range o.cfg.Shutdown.ExtraPoweroffHosts {
		if strings.TrimSpace(n) != "" {
			hostSet[strings.TrimSpace(n)] = struct{}{}
		}
	}

	hosts := make([]string, 0, len(hostSet))
	for h := range hostSet {
		hosts = append(hosts, h)
	}
	sort.Strings(hosts)

	remoteCmd := fmt.Sprintf(`sudo nohup sh -c 'sleep %d; systemctl poweroff' >/dev/null 2>&1 &`, delay)
	for _, host := range hosts {
		host = strings.TrimSpace(host)
		if host == "" {
			continue
		}
		if _, isLocal := localNames[host]; isLocal {
			continue
		}
		o.bestEffort("schedule poweroff on "+host, func() error {
			_, err := o.ssh(ctx, host, remoteCmd)
			return err
		})
	}

	if o.cfg.Shutdown.PoweroffLocalHost {
		o.bestEffort("schedule local host poweroff", func() error {
			_, err := o.run(ctx, 5*time.Second, "sh", "-c", fmt.Sprintf("nohup sh -c 'sleep %d; systemctl poweroff' >/dev/null 2>&1 &", delay+10))
			return err
		})
	}
	return nil
}