package host

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"os"

	"github.com/carlosframework/platform/internal/hostclaim"
	"github.com/carlosframework/platform/internal/hostguard"
	"github.com/carlosframework/platform/internal/provision"
	"github.com/carlosframework/platform/internal/registry"
	"github.com/carlosframework/platform/internal/release"
	"github.com/carlosframework/platform/internal/rootparticipation"
	"github.com/carlosframework/platform/internal/rootstate"
)

type rootHistoryAccess func(context.Context, func(*release.RootHistory) error) error

func productionCreationHistory(ctx context.Context, effect func(*release.RootHistory) error) error {
	legacy, err := legacyRootRestart()
	if err != nil {
		return err
	}
	if legacy {
		return os.ErrPermission
	}
	return participationRelease.With(ctx, func(ctx context.Context) error {
		s, err := rootstate.Open(release.RootHistoryDir, true, false)
		if err != nil {
			return err
		}
		defer s.Close()
		return effect(&release.RootHistory{Store: s})
	})
}

// Inventory additions do not change the identity of the installation.
func rootHistoryInstallation(in hostguard.RootInstallation) string {
	in.Artifacts = hostguard.InstallationArtifacts{}
	in.Empty = false
	in.InventoryRevision = 0
	in.Registration = hostguard.InstallationRegistration{}
	raw, _ := json.Marshal(in)
	sum := sha256.Sum256(raw)
	return hex.EncodeToString(sum[:])
}

func rootHistoryCreation(store release.Store) func(context.Context, registry.Route) (string, error) {
	return func(ctx context.Context, rt registry.Route) (string, error) {
		census, err := rootparticipation.Open()
		if err != nil {
			return "", err
		}
		defer census.State.Close()
		state, err := rootstate.Open("/var/lib/carlos-claims/authority/fences", false, false)
		if err != nil {
			return "", err
		}
		defer state.Close()
		return (rootRestartRequestSource{state: state, store: store, census: census.Census}).creation(ctx, rt)
	}
}

func (s rootRestartRequestSource) creation(ctx context.Context, rt registry.Route) (string, error) {
	in, err := s.installation(ctx, rt.Host)
	if err != nil {
		return "", err
	}
	if in.Host != rt.Host || in.Account != rt.Account || in.App != rt.App || in.Record != provision.RecordKey(in.Account, in.App, in.Host) {
		return "", os.ErrPermission
	}
	rec, _, err := provision.GetRecordETag(ctx, s.store, in.Account, in.App, in.Host)
	if err != nil {
		return "", err
	}
	inc, err := hostclaim.Incarnation(rec.Account, rec.App, rec.Host, rec.CreatedAt)
	if err != nil || inc != in.Incarnation {
		return "", os.ErrPermission
	}
	return rootHistoryInstallation(in), nil
}