package main

import (
	"context"
	"fmt"
	"log"

	"github.com/kedacore/http-add-on/pkg/k8s"
	appsv1 "k8s.io/api/apps/v1"
)

type forwardWaitFunc func(context.Context, string) error

func newDeployReplicasForwardWaitFunc(
	deployCache k8s.DeploymentCache,
) forwardWaitFunc {
	return func(ctx context.Context, deployName string) error {
		deployment, err := deployCache.Get(deployName)
		if err != nil {
			// if we didn't get the initial deployment state, bail out
			return fmt.Errorf("error getting state for deployment %s (%s)", deployName, err)
		}
		// if there is 1 or more replica, we're done waiting
		if deployment.Status.ReadyReplicas > 0 {
			return nil
		}
		watcher := deployCache.Watch(deployName)
		if err != nil {
			return fmt.Errorf("error getting the stream of deployment changes")
		}
		defer watcher.Stop()
		eventCh := watcher.ResultChan()
		for {
			select {
			case event := <-eventCh:
				deployment, ok := event.Object.(*appsv1.Deployment)
				if !ok {
					log.Println("Didn't get a deployment back in event")
				}
				if deployment.Status.ReadyReplicas > 0 {
					return nil
				}
			case <-ctx.Done():
				// otherwise, if the context is marked done before
				// we're done waiting, fail.
				return fmt.Errorf(
					"context marked done while waiting for deployment %s to reach > 0 replicas (%w)",
					deployName,
					ctx.Err(),
				)
			}
		}
	}
}