package hostops

import (
	"context"

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

// A door that chooses its executor before it registers anything (region HA
// spec 2 §7, H27) carries the choice to the create through the context, so
// the create names exactly the box the door checked, and a refusal leaves
// nothing registered, nothing written to the claim and nothing for
// recovery to settle. selectExecutor still checks the choice against
// claim Plan 5's scope (namespace, region, pool, active, unfenced).

type chosenExecutorKey struct{}

type chosenExecutor struct {
	host string
	sel  hostclaim.ExecutorSelection
}

// WithChosenExecutor records sel as host's executor for the create that
// ctx carries.
func WithChosenExecutor(ctx context.Context, host string, sel hostclaim.ExecutorSelection) context.Context {
	return context.WithValue(ctx, chosenExecutorKey{}, chosenExecutor{host: host, sel: sel})
}

// ChosenExecutor is the executor ctx carries for host, if any: a door that
// already chose finds its choice here and does not choose again.
func ChosenExecutor(ctx context.Context, host string) (hostclaim.ExecutorSelection, bool) {
	c, ok := ctx.Value(chosenExecutorKey{}).(chosenExecutor)
	if !ok || c.host == "" || c.host != host || c.sel.Box == "" || c.sel.Enrollment == "" {
		return hostclaim.ExecutorSelection{}, false
	}
	return c.sel, true
}