package controllers

import (
	"context"
	"sync"
	"time"

	s3v1beta1 "github.com/crossplane/provider-aws/apis/s3/v1beta1"
	iamv1alpha1 "github.com/crossplane/provider-gcp/apis/iam/v1alpha1"
	storagev1alpha3 "github.com/crossplane/provider-gcp/apis/storage/v1alpha3"
	"github.com/go-logr/logr"
	"github.com/pingcap/errors"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/types"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/builder"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller"
	"sigs.k8s.io/controller-runtime/pkg/predicate"

	corev1 "k8s.io/api/core/v1"
	"k8s.io/client-go/tools/record"

	cloudv1 "github.com/tidbcloud/infra-api/api/v1"
	"github.com/tidbcloud/infra-api/controllers/common"
	"github.com/tidbcloud/infra-api/controllers/provider"
	gardenerprovider "github.com/tidbcloud/infra-api/controllers/provider/gardener"
	"github.com/tidbcloud/infra-api/controllers/utils"
	"github.com/tidbcloud/infra-api/pkg/gardener"
	metricsctrl "github.com/tidbcloud/infra-api/pkg/metrics/controller"
	"github.com/tidbcloud/infra-api/pkg/o11y"
	awsapi "github.com/tidbcloud/infra-api/pkg/providers/aws"
	"github.com/tidbcloud/infra-api/pkg/providers/gcp"
)

var indexOnce sync.Once

// NetworkReconciler reconciles a Network object
type NetworkReconciler struct {
	client.Client
	Log       logr.Logger
	Scheme    *runtime.Scheme
	Recorder  record.EventRecorder
	AWSClient awsapi.Client
	GCPAPI    gcp.GCPAPI

	Config      *cloudv1.InfraAPIConfig
	GardenerEnv gardener.GardenerAPI
	registry    map[string]provider.NetworkReconciler
}

//+kubebuilder:rbac:groups=cloud.pingcap.com,resources=networks,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=cloud.pingcap.com,resources=networks/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=cloud.pingcap.com,resources=networks/finalizers,verbs=update

// Reconcile is part of the main kubernetes reconciliation loop which aims to
// move the current state of the cluster closer to the desired state.
// TODO(user): Modify the Reconcile function to compare the state specified by
// the Network object against the actual cluster state, and then
// perform operations to make the cluster state reflect the state specified by
// the user.
//
// For more details, check Reconcile and its Result here:
// - https://pkg.go.dev/sigs.k8s.io/controller-runtime@v0.7.2/pkg/reconcile
func (r *NetworkReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	start := time.Now()
	defer func() {
		metricsctrl.ReconcileDuration.WithLabelValues("network").Observe(time.Since(start).Seconds())
	}()

	var network cloudv1.Network
	err := r.Get(ctx, req.NamespacedName, &network)
	if err != nil {
		return ctrl.Result{}, client.IgnoreNotFound(err)
	}

	var provider cloudv1.Provider
	err = r.Get(ctx, types.NamespacedName{Name: network.Spec.Provider}, &provider)
	if err != nil {
		// TODO validate it by webhook
		if apierrors.IsNotFound(err) {
			r.Recorder.Eventf(&network, corev1.EventTypeWarning, "UnknownProvider", "unknown provider %q", network.Spec.Provider)
		}
		return ctrl.Result{}, err
	}

	var providerType cloudv1.ProviderType
	err = r.Get(ctx, types.NamespacedName{Name: provider.Spec.Type}, &providerType)
	if err != nil {
		return ctrl.Result{}, err
	}

	reconciler, ok := r.registry[providerType.Name]
	if !ok {
		return ctrl.Result{}, errors.Errorf("unsupported provider type %q", providerType.Name)
	}

	return reconciler.Reconcile(ctx, &providerType, &provider, &network)
}

// SetupWithManager sets up the controller with the Manager.
func (r *NetworkReconciler) SetupWithManager(
	mgr ctrl.Manager,
	o11yNewAgentEnabled bool,
	manifestDirectoryPrefix string,
	o11yConfig *cloudv1.ObservabilityInfraConfig,
	o11yApi o11y.Api,
	maxConcurrentReconciles int,
	p ...predicate.Predicate,
) error {
	// TODO: register in main?
	g := gardenerprovider.NewNetworkReconciler(
		r.Client, r.GardenerEnv, r.Config, r.AWSClient, r.GCPAPI, r.Recorder,
		o11yNewAgentEnabled,
		manifestDirectoryPrefix,
		o11yConfig,
		o11yApi)
	if err := r.RegisterReconciler("aws", g); err != nil {
		return err
	}
	if err := r.RegisterReconciler("gcp", g); err != nil {
		return err
	}

	indexOnce.Do(func() {
		if err := mgr.GetFieldIndexer().IndexField(context.TODO(), &cloudv1.Network{}, "spec.region", func(obj client.Object) []string {
			n := obj.(*cloudv1.Network)
			return []string{n.Spec.Region}
		}); err != nil {
			return
		}
	})

	return ctrl.NewControllerManagedBy(mgr).
		For(&cloudv1.Network{}, builder.WithPredicates(p...)).
		WithEventFilter(utils.GetMigrationAnnotationSkipPredicator()).
		WithOptions(controller.Options{RateLimiter: common.DefaultRateLimiter(), MaxConcurrentReconciles: maxConcurrentReconciles}).
		Owns(&s3v1beta1.Bucket{}).
		Owns(&storagev1alpha3.Bucket{}).
		Owns(&iamv1alpha1.ServiceAccount{}).
		Complete(r)
}

// RegisterReconciler register a provider type specified network reconciler.
func (r *NetworkReconciler) RegisterReconciler(providerType string, reconciler provider.NetworkReconciler) error {
	if r.registry == nil {
		r.registry = map[string]provider.NetworkReconciler{}
	}

	_, ok := r.registry[providerType]
	if ok {
		return errors.Errorf("provider type %q already registered", providerType)
	}

	r.registry[providerType] = reconciler

	return nil
}