package host

import (
	"context"
	"os"

	"github.com/carlosframework/platform/internal/release"
	"github.com/carlosframework/platform/internal/rootstate"
)

type generationPinSource struct {
	legacy    func() (bool, error)
	open      func() (rootstate.Store, error)
	verify    func(context.Context, []release.GenerationReservation) error
	reconcile func(context.Context, []release.GenerationReservation) (release.GenerationEvidence, error)
	retire    func(context.Context, *release.RootGenerations) error
}

func productionRootGenerationPins() release.PinSource {
	s := generationPinSource{legacy: legacyRootRestart, retire: productionRetireGenerations, open: func() (rootstate.Store, error) {
		return rootstate.Open(release.RootGenerationsDir, false, false)
	}}
	s.reconcile = (generationReconciler{read: productionGenerationInventory, kernel: productionRetiredGenerationKernelCensus}).reconcile
	return s
}

func (s generationPinSource) StagedPins(ctx context.Context, optDir string) (release.StagedPaths, error) {
	if s.legacy != nil {
		legacy, err := s.legacy()
		if err != nil {
			return nil, err
		}
		if legacy {
			return release.StagedPaths{}, nil
		}
	}
	if s.open == nil {
		return nil, os.ErrPermission
	}
	store, err := s.open()
	if err != nil {
		return nil, err
	}
	if store == nil {
		return nil, os.ErrPermission
	}
	defer store.Close()
	ledger := &release.RootGenerations{Store: store}
	if s.retire != nil {
		if err := s.retire(ctx, ledger); err != nil {
			return nil, err
		}
	}
	return (release.RootGenerationPins{Ledger: ledger, Verify: s.verify, Reconcile: s.reconcile}).StagedPins(ctx, optDir)
}