package host

import (
	"context"
	"github.com/carlosframework/platform/internal/hostbox"
	"github.com/carlosframework/platform/internal/hostclaim"
	execlease "github.com/carlosframework/platform/internal/hostexec"
	"github.com/carlosframework/platform/internal/instancectl"
	"time"
)

func (h *ClaimLaunchRoot) execPermit(ctx context.Context, q hostbox.RoleLaunchRequest) (instancectl.ClaimExecPermit, error) {
	r := q.Reservation
	o, err := h.Guard.Claims.Read(ctx, r.Target.Host)
	if err != nil {
		return instancectl.ClaimExecPermit{}, err
	}
	if o.Absent || o.Claim == nil {
		return instancectl.ClaimExecPermit{}, hostbox.ErrChanged
	}
	_, boot, err := h.Clock.Now()
	if err != nil {
		return instancectl.ClaimExecPermit{}, err
	}
	// Serving also gets a finite start window. An operation's lease may only
	// shorten it; a later renewal cannot extend this reservation's permit.
	until := boot + int64(30*time.Second)
	state, err := h.readExecution(ctx, o.Claim)
	if err != nil {
		return instancectl.ClaimExecPermit{}, err
	}
	if o.Claim.Op.Kind != hostclaim.KindServing {
		if state.SafeUntil < until {
			until = state.SafeUntil
		}
	}
	if boot >= until {
		return instancectl.ClaimExecPermit{}, execlease.ErrLost
	}
	return instancectl.ClaimExecPermit{Reservation: r.ID, Inputs: r.Inputs, BootID: r.Target.BootID, SafeUntil: until, Containment: 1}, nil
}