package hostops

import (
	"context"
	"github.com/carlosframework/platform/internal/hostclaim"
	"github.com/carlosframework/platform/internal/park"
	"github.com/carlosframework/platform/internal/termfence"
)

// MoveFenceRegions preserves the verifier's roster/enrollment checks, then
// projects only its region binding into the move's engine vocabulary.
// Signed fence bytes and the cloud region are never edited.
type MoveFenceRegions struct {
	Authority  hostclaim.FenceAuthority
	HomeRegion string
}

func (a MoveFenceRegions) ValidateFence(ctx context.Context, f termfence.Record) (hostclaim.FenceBinding, error) {
	if a.Authority == nil {
		return hostclaim.FenceBinding{}, hostclaim.ErrFence
	}
	binding, err := a.Authority.ValidateFence(ctx, f)
	if err != nil {
		return hostclaim.FenceBinding{}, err
	}
	if binding.Region == "" || (a.HomeRegion != "" && (a.HomeRegion != binding.FleetHomeRegion || park.PlacementRegion(a.HomeRegion) != a.HomeRegion)) {
		return hostclaim.FenceBinding{}, hostclaim.ErrFence
	}
	binding.Region = park.PlacementRegion(park.HomePlacementCode(a.HomeRegion, binding.Region))
	if binding.Region == "" {
		return hostclaim.FenceBinding{}, hostclaim.ErrFence
	}
	return binding, nil
}