//go:build linux

package host

import (
	"context"
	"log"
	"reflect"

	"github.com/carlosframework/platform/internal/hostbox"
)

func (p *servingParkRoot) commitServingReboot(ctx context.Context, id string) error {
	return p.prepareOrCommitServingReboot(ctx, id, true)
}

// The namespace binding is durable first. An unbound record still carries its
// old boot and every filesystem effect refuses it, including reused mount IDs.
// A lost reply at either write is replayed against fresh independent evidence.
func (l *servingParkLedger) commitRebootLocked(ctx context.Context, saved servingParkRecord, active *servingParkRebootAuthority) error {
	fresh, err := l.observeRebootPreparation(ctx, saved, active)
	if err != nil {
		return err
	}
	body, err := l.state.Read(servingNamespacePreparationName(saved.Authorization.ID, fresh.Observation.Topology))
	if err != nil {
		return err
	}
	var prepared servingParkRebootPreparation
	if servingParkDecode(body, &prepared) != nil || !reflect.DeepEqual(prepared, fresh) {
		return hostbox.ErrChanged
	}
	t := fresh.Observation.Topology
	namespace := servingParkBootBinding{Version: 1, ID: "namespace", BeforeBoot: t.Previous.BootID, BootID: t.BootID, BeforeParent: t.Previous.Parent, Parent: t.CurrentParent}
	if err := ctx.Err(); err != nil {
		return err
	}
	if err := l.write("current-namespace.json", namespace); err != nil {
		return err
	}
	again, err := l.observeRebootPreparation(ctx, saved, active)
	if err != nil {
		return err
	}
	if !reflect.DeepEqual(fresh, again) {
		return hostbox.ErrChanged
	}
	record := servingParkBootBinding{Version: 1, ID: "retirement-" + saved.Authorization.ID, BeforeBoot: saved.Source.BootID, BootID: t.BootID, BeforeParent: saved.Source.Parent, Parent: t.CurrentParent}
	if err := ctx.Err(); err != nil {
		return err
	}
	prior, err := servingParkReadBinding(l.state, record.ID)
	if err != nil {
		return err
	}
	if saved.Source.Volume != "" && saved.Source.Volume == t.Volume && (prior == nil || prior.Volume != "") {
		record.Volume = t.Volume
	} else {
		log.Printf("Host %q: serving database retirement %q retained: %s.", saved.Authorization.Successor.Host, saved.Authorization.ID, hostbox.ErrChanged)
	}
	return l.write("current-"+record.ID+".json", record)
}

func (f *servingParkFS) readNamespace() (servingParkNamespace, error) {
	var n servingParkNamespace
	body, err := f.state.Read("namespace.json")
	if err != nil {
		return n, err
	}
	if servingParkDecode(body, &n) != nil {
		return n, hostbox.ErrChanged
	}
	b, err := servingParkReadBinding(f.state, "namespace")
	if err != nil || b == nil {
		return n, err
	}
	if n.BootID != b.BeforeBoot || n.Parent != b.BeforeParent {
		return n, hostbox.ErrChanged
	}
	n.BootID = b.BootID
	if err = b.directory(&n.Parent, false); err != nil {
		return n, err
	}
	err = b.directory(&n.Root, false)
	return n, err
}