package app

import (
	"fmt"
	"k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/klog"
	"net/http"
	"time"
)

// WaitForAPIServer waits for the API Server's /healthz endpoint to report "ok" before timeout.
func WaitForAPIServer(client clientset.Interface, timeout time.Duration) error {
	var lastErr error

	err := wait.PollImmediate(time.Second, timeout, func() (bool, error) {
		healthStatus := 0
		result := client.Discovery().RESTClient().Get().AbsPath("/healthz").Do().StatusCode(&healthStatus)
		if result.Error() != nil {
			lastErr = fmt.Errorf("failed to get apiserver /healthz status: %v", result.Error())
			return false, nil
		}
		if healthStatus != http.StatusOK {
			content, _ := result.Raw()
			lastErr = fmt.Errorf("APIServer isn't healthy: %v", string(content))
			klog.Warningf("APIServer isn't healthy yet: %v. Waiting a little while.", string(content))
			return false, nil
		}

		return true, nil
	})

	if err != nil {
		return fmt.Errorf("%v: %v", err, lastErr)
	}

	return nil
}