/*
   Copyright The containerd Authors.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package namespaces

import (
	"context"
	"strings"

	eventstypes "github.com/containerd/containerd/api/events"
	api "github.com/containerd/containerd/api/services/namespaces/v1"
	"github.com/containerd/errdefs/pkg/errgrpc"
	"github.com/containerd/plugin"
	"github.com/containerd/plugin/registry"
	bolt "go.etcd.io/bbolt"
	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"

	"github.com/containerd/containerd/v2/core/events"
	"github.com/containerd/containerd/v2/core/metadata"
	"github.com/containerd/containerd/v2/pkg/namespaces"
	ptypes "github.com/containerd/containerd/v2/pkg/protobuf/types"
	"github.com/containerd/containerd/v2/plugins"
	"github.com/containerd/containerd/v2/plugins/services"
)

var empty = &ptypes.Empty{}

func init() {
	registry.Register(&plugin.Registration{
		Type: plugins.ServicePlugin,
		ID:   services.NamespacesService,
		Requires: []plugin.Type{
			plugins.EventPlugin,
			plugins.MetadataPlugin,
		},
		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
			m, err := ic.GetSingle(plugins.MetadataPlugin)
			if err != nil {
				return nil, err
			}
			ep, err := ic.GetSingle(plugins.EventPlugin)
			if err != nil {
				return nil, err
			}
			return &local{
				db:        m.(*metadata.DB),
				publisher: ep.(events.Publisher),
			}, nil
		},
	})
}

// Provide local namespaces service instead of local namespace store,
// because namespace store interface doesn't provide enough functionality
// for namespaces service.
type local struct {
	db        *metadata.DB
	publisher events.Publisher
}

var _ api.NamespacesClient = &local{}

func (l *local) Get(ctx context.Context, req *api.GetNamespaceRequest, _ ...grpc.CallOption) (*api.GetNamespaceResponse, error) {
	var resp api.GetNamespaceResponse

	return &resp, l.withStoreView(ctx, func(ctx context.Context, store namespaces.Store) error {
		labels, err := store.Labels(ctx, req.Name)
		if err != nil {
			return errgrpc.ToGRPC(err)
		}

		resp.Namespace = &api.Namespace{
			Name:   req.Name,
			Labels: labels,
		}

		return nil
	})
}

func (l *local) List(ctx context.Context, req *api.ListNamespacesRequest, _ ...grpc.CallOption) (*api.ListNamespacesResponse, error) {
	var resp api.ListNamespacesResponse

	return &resp, l.withStoreView(ctx, func(ctx context.Context, store namespaces.Store) error {
		namespaces, err := store.List(ctx)
		if err != nil {
			return err
		}

		for _, namespace := range namespaces {
			labels, err := store.Labels(ctx, namespace)
			if err != nil {
				// In general, this should be unlikely, since we are holding a
				// transaction to service this request.
				return errgrpc.ToGRPC(err)
			}

			resp.Namespaces = append(resp.Namespaces, &api.Namespace{
				Name:   namespace,
				Labels: labels,
			})
		}

		return nil
	})
}

func (l *local) Create(ctx context.Context, req *api.CreateNamespaceRequest, _ ...grpc.CallOption) (*api.CreateNamespaceResponse, error) {
	var resp api.CreateNamespaceResponse

	if err := l.withStoreUpdate(ctx, func(ctx context.Context, store namespaces.Store) error {
		if err := store.Create(ctx, req.Namespace.Name, req.Namespace.Labels); err != nil {
			return errgrpc.ToGRPC(err)
		}

		for k, v := range req.Namespace.Labels {
			if err := store.SetLabel(ctx, req.Namespace.Name, k, v); err != nil {
				return err
			}
		}

		resp.Namespace = req.Namespace
		return nil
	}); err != nil {
		return &resp, err
	}

	ctx = namespaces.WithNamespace(ctx, req.Namespace.Name)
	if err := l.publisher.Publish(ctx, "/namespaces/create", &eventstypes.NamespaceCreate{
		Name:   req.Namespace.Name,
		Labels: req.Namespace.Labels,
	}); err != nil {
		return &resp, err
	}

	return &resp, nil

}

func (l *local) Update(ctx context.Context, req *api.UpdateNamespaceRequest, _ ...grpc.CallOption) (*api.UpdateNamespaceResponse, error) {
	var resp api.UpdateNamespaceResponse
	if err := l.withStoreUpdate(ctx, func(ctx context.Context, store namespaces.Store) error {
		if req.UpdateMask != nil && len(req.UpdateMask.Paths) > 0 {
			for _, path := range req.UpdateMask.Paths {
				switch {
				case strings.HasPrefix(path, "labels."):
					key := strings.TrimPrefix(path, "labels.")
					if err := store.SetLabel(ctx, req.Namespace.Name, key, req.Namespace.Labels[key]); err != nil {
						return err
					}
				default:
					return status.Errorf(codes.InvalidArgument, "cannot update %q field", path)
				}
			}
		} else {
			// clear out the existing labels and then set them to the incoming request.
			// get current set of labels
			labels, err := store.Labels(ctx, req.Namespace.Name)
			if err != nil {
				return errgrpc.ToGRPC(err)
			}

			for k := range labels {
				if err := store.SetLabel(ctx, req.Namespace.Name, k, ""); err != nil {
					return err
				}
			}

			for k, v := range req.Namespace.Labels {
				if err := store.SetLabel(ctx, req.Namespace.Name, k, v); err != nil {
					return err
				}

			}
		}

		return nil
	}); err != nil {
		return &resp, err
	}

	ctx = namespaces.WithNamespace(ctx, req.Namespace.Name)
	if err := l.publisher.Publish(ctx, "/namespaces/update", &eventstypes.NamespaceUpdate{
		Name:   req.Namespace.Name,
		Labels: req.Namespace.Labels,
	}); err != nil {
		return &resp, err
	}

	return &resp, nil
}

func (l *local) Delete(ctx context.Context, req *api.DeleteNamespaceRequest, _ ...grpc.CallOption) (*ptypes.Empty, error) {
	if err := l.withStoreUpdate(ctx, func(ctx context.Context, store namespaces.Store) error {
		return errgrpc.ToGRPC(store.Delete(ctx, req.Name))
	}); err != nil {
		return empty, err
	}
	// set the namespace in the context before publishing the event
	ctx = namespaces.WithNamespace(ctx, req.Name)
	if err := l.publisher.Publish(ctx, "/namespaces/delete", &eventstypes.NamespaceDelete{
		Name: req.Name,
	}); err != nil {
		return empty, err
	}

	return empty, nil
}

func (l *local) withStore(ctx context.Context, fn func(ctx context.Context, store namespaces.Store) error) func(tx *bolt.Tx) error {
	return func(tx *bolt.Tx) error { return fn(ctx, metadata.NewNamespaceStore(tx)) }
}

func (l *local) withStoreView(ctx context.Context, fn func(ctx context.Context, store namespaces.Store) error) error {
	return l.db.View(l.withStore(ctx, fn))
}

func (l *local) withStoreUpdate(ctx context.Context, fn func(ctx context.Context, store namespaces.Store) error) error {
	return l.db.Update(l.withStore(ctx, fn))
}