package host

import (
	"context"
	"github.com/carlosframework/platform/internal/hostbox"
	"github.com/carlosframework/platform/internal/hostwrite"
	"github.com/carlosframework/platform/internal/registry"
	"github.com/carlosframework/platform/internal/schedule"
)

func ClaimTimerDelivery(set *ClaimProducerSet, newID func() string) schedule.DeliveryAdmission {
	return func(ctx context.Context, work hostwrite.Work, rt registry.Route, t registry.Timer) (context.Context, func(), error) {
		if set == nil || newID == nil {
			return nil, nil, hostwrite.ErrUnavailable
		}
		selected, err := hostbox.Selected(work)
		if err != nil {
			return nil, nil, err
		}
		if selected.Host != rt.Host || t.Host != rt.Host || selected.Captured.Incarnation != rt.ClaimIncarnation || selected.Captured.Stamp != rt.ClaimStamp || t.ClaimIncarnation != rt.ClaimIncarnation || t.ClaimStamp != rt.ClaimStamp {
			return nil, nil, hostbox.ErrChanged
		}
		set.mu.Lock()
		var chosen *ClaimProducers
		for _, p := range set.items {
			if p.target.Host == selected.Host && p.target.Incarnation == selected.Captured.Incarnation && p.target.Stamp == selected.Captured.Stamp && p.target.Session == selected.Session && p.target.Box == selected.Box {
				if chosen != nil {
					set.mu.Unlock()
					return nil, nil, hostbox.ErrChanged
				}
				chosen = p
			}
		}
		set.mu.Unlock()
		if chosen == nil {
			return nil, nil, hostwrite.ErrUnavailable
		}
		var child context.Context
		var finish func(error)
		err = work.With(ctx, hostwrite.Identity{}, func() error {
			var e error
			child, finish, e = chosen.Register(ctx, chosen.target, "timer-"+newID())
			return e
		})
		if err != nil {
			return nil, nil, err
		}
		return child, func() { finish(nil) }, nil
	}
}