package k8s

import (
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/rest"
)

func TestNewReturnsErrorWhenNoClusterConfigOrValidKubeconfigExists(t *testing.T) {
	restore := swapClientTestHooks()
	defer restore()

	inClusterConfigFn = func() (*rest.Config, error) {
		return nil, errors.New("cluster config exploded")
	}
	t.Setenv("KUBECONFIG", "/definitely/missing/kubeconfig")

	client, err := New()
	if err == nil || client != nil {
		t.Fatalf("expected New to fail without usable Kubernetes config, got client=%#v err=%v", client, err)
	}
	if !strings.Contains(err.Error(), "load kubeconfig") {
		t.Fatalf("expected kubeconfig load error, got %v", err)
	}
}

func TestNewReturnsInClusterErrorWhenNoKubeconfigIsProvided(t *testing.T) {
	restore := swapClientTestHooks()
	defer restore()

	inClusterConfigFn = func() (*rest.Config, error) {
		return nil, errors.New("cluster config exploded")
	}
	t.Setenv("KUBECONFIG", "")

	client, err := New()
	if err == nil || client != nil {
		t.Fatalf("expected in-cluster config error, got client=%#v err=%v", client, err)
	}
	if !strings.Contains(err.Error(), "load in-cluster config: cluster config exploded") {
		t.Fatalf("expected in-cluster config error, got %v", err)
	}
}

func TestNewLoadsKubeconfigAndBuildsClientset(t *testing.T) {
	restore := swapClientTestHooks()
	defer restore()

	inClusterConfigFn = func() (*rest.Config, error) {
		return nil, errors.New("not in cluster")
	}

	kubeconfigPath := filepath.Join(t.TempDir(), "config")
	if err := os.WriteFile(kubeconfigPath, []byte(`apiVersion: v1
kind: Config
clusters:
- cluster:
    server: https://127.0.0.1:6443
  name: local
contexts:
- context:
    cluster: local
    user: local
  name: local
current-context: local
users:
- name: local
  user:
    token: test-token
`), 0o600); err != nil {
		t.Fatalf("write kubeconfig: %v", err)
	}
	t.Setenv("KUBECONFIG", kubeconfigPath)

	client, err := New()
	if err != nil {
		t.Fatalf("expected kubeconfig-backed client construction, got %v", err)
	}
	if client == nil || client.Clientset == nil {
		t.Fatalf("expected populated client, got %#v", client)
	}
}

func TestNewWrapsClientsetConstructionFailures(t *testing.T) {
	restore := swapClientTestHooks()
	defer restore()

	inClusterConfigFn = func() (*rest.Config, error) {
		return &rest.Config{Host: "https://127.0.0.1:6443"}, nil
	}
	newForConfigFn = func(*rest.Config) (kubernetes.Interface, error) {
		return nil, errors.New("clientset exploded")
	}

	client, err := New()
	if err == nil || client != nil {
		t.Fatalf("expected clientset construction error, got client=%#v err=%v", client, err)
	}
	if !strings.Contains(err.Error(), "build clientset: clientset exploded") {
		t.Fatalf("expected wrapped clientset error, got %v", err)
	}
}

func swapClientTestHooks() func() {
	originalInCluster := inClusterConfigFn
	originalBuildConfig := buildConfigFromFlagsFn
	originalNewForConfig := newForConfigFn

	return func() {
		inClusterConfigFn = originalInCluster
		buildConfigFromFlagsFn = originalBuildConfig
		newForConfigFn = originalNewForConfig
	}
}