package kubesource

import (
	"bytes"
	"io"
	"os"
	"reflect"
	"sort"
	"strings"
	"testing"

	"gopkg.in/yaml.v3"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
)

func yamlDocs(t *testing.T, path string) []map[string]any {
	t.Helper()
	b, err := os.ReadFile(path)
	if err != nil {
		t.Fatal(err)
	}
	var out []map[string]any
	dec := yaml.NewDecoder(bytes.NewReader(b))
	for {
		var m map[string]any
		if err := dec.Decode(&m); err == io.EOF {
			break
		} else if err != nil {
			t.Fatalf("%s: %v", path, err)
		}
		if m != nil {
			out = append(out, m)
		}
	}
	return out
}

func jsonFields(typ reflect.Type) []string {
	var out []string
	for i := 0; i < typ.NumField(); i++ {
		tag := strings.Split(typ.Field(i).Tag.Get("json"), ",")[0]
		if tag != "" && tag != "-" {
			out = append(out, tag)
		}
	}
	sort.Strings(out)
	return out
}

// TestCRDSchemasMatchTheGoSpecs keeps deploy/k8s/crds/crds.yaml and the spec
// structs from drifting: a field the schema lacks is pruned by the apiserver
// before the runtime ever sees it, and a schema field the struct lacks is
// accepted and silently ignored.
func TestCRDSchemasMatchTheGoSpecs(t *testing.T) {
	want := map[string]reflect.Type{
		"DNSZone":     reflect.TypeOf(DNSZoneSpec{}),
		"ClientGroup": reflect.TypeOf(ClientGroupSpec{}),
		"BlockList":   reflect.TypeOf(BlockListSpec{}),
	}
	seen := 0
	for _, doc := range yamlDocs(t, "../../deploy/k8s/crds/crds.yaml") {
		names := doc["spec"].(map[string]any)["names"].(map[string]any)
		kind := names["kind"].(string)
		typ, ok := want[kind]
		if !ok {
			t.Errorf("unexpected CRD kind %s", kind)
			continue
		}
		seen++
		versions := doc["spec"].(map[string]any)["versions"].([]any)
		schema := versions[0].(map[string]any)["schema"].(map[string]any)["openAPIV3Schema"].(map[string]any)
		props := schema["properties"].(map[string]any)["spec"].(map[string]any)["properties"].(map[string]any)
		var got []string
		for k := range props {
			got = append(got, k)
		}
		sort.Strings(got)
		if !reflect.DeepEqual(got, jsonFields(typ)) {
			t.Errorf("%s: schema fields %v, Go fields %v", kind, got, jsonFields(typ))
		}
		if plural := names["plural"].(string); plural != map[string]string{
			"DNSZone": ZoneGVR.Resource, "ClientGroup": GroupGVR.Resource, "BlockList": ListGVR.Resource,
		}[kind] {
			t.Errorf("%s: plural %q does not match the GVR the runtime watches", kind, plural)
		}
	}
	if seen != len(want) {
		t.Errorf("saw %d CRDs, want %d", seen, len(want))
	}
}

// TestExampleObjectsConvert makes sure the shipped examples are accepted by
// the runtime, so the first thing an operator copies is not a rejection.
func TestExampleObjectsConvert(t *testing.T) {
	n := 0
	for _, doc := range yamlDocs(t, "../../deploy/k8s/crds/examples.yaml") {
		u := &unstructured.Unstructured{Object: doc}
		var err error
		switch u.GetKind() {
		case "DNSZone":
			_, err = convertZone(u)
		case "ClientGroup":
			_, err = convertGroup(u)
		case "BlockList":
			_, err = convertList(u)
		default:
			t.Fatalf("unknown kind %s", u.GetKind())
		}
		if err != nil {
			t.Errorf("%s %s: %v", u.GetKind(), u.GetName(), err)
		}
		n++
	}
	if n != 3 {
		t.Fatalf("converted %d examples, want 3", n)
	}
}