/*
Copyright 2018 The Kubernetes 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 cephfs

import (
	"context"
	"os"

	"github.com/golang/glog"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"

	"github.com/container-storage-interface/spec/lib/go/csi/v0"
	"github.com/kubernetes-csi/drivers/pkg/csi-common"
)

type nodeServer struct {
	*csicommon.DefaultNodeServer
}

func getOrCreateUser(volOptions *volumeOptions, volId volumeID, req *csi.NodeStageVolumeRequest) (*credentials, error) {
	var (
		userCr = &credentials{}
		err    error
	)

	// Retrieve the credentials (possibly create a new user as well)

	if volOptions.ProvisionVolume {
		// The volume is provisioned dynamically, create a dedicated user

		// First, store admin credentials - those are needed for creating a user

		adminCr, err := getAdminCredentials(req.GetNodeStageSecrets())
		if err != nil {
			return nil, err
		}

		if err = storeCephCredentials(volId, adminCr); err != nil {
			return nil, err
		}

		nodeCache.insert(volId, &nodeCacheEntry{volOptions: volOptions, cephAdminID: adminCr.id})

		// Then create the user

		if ent, err := createCephUser(volOptions, adminCr, volId); err != nil {
			return nil, err
		} else {
			userCr.id = ent.Entity[len(cephEntityClientPrefix):]
			userCr.key = ent.Key
		}

		// Set the correct volume root path
		volOptions.RootPath = getVolumeRootPath_ceph(volId)
	} else {
		// The volume is pre-made, credentials are supplied by the user

		userCr, err = getUserCredentials(req.GetNodeStageSecrets())
		if err != nil {
			return nil, err
		}

		nodeCache.insert(volId, &nodeCacheEntry{volOptions: volOptions})
	}

	if err = storeCephCredentials(volId, userCr); err != nil {
		return nil, err
	}

	return userCr, nil
}

func (ns *nodeServer) NodeStageVolume(ctx context.Context, req *csi.NodeStageVolumeRequest) (*csi.NodeStageVolumeResponse, error) {
	if err := validateNodeStageVolumeRequest(req); err != nil {
		return nil, status.Error(codes.InvalidArgument, err.Error())
	}

	// Configuration

	stagingTargetPath := req.GetStagingTargetPath()
	volId := volumeID(req.GetVolumeId())

	volOptions, err := newVolumeOptions(req.GetVolumeAttributes())
	if err != nil {
		glog.Errorf("error reading volume options for volume %s: %v", volId, err)
		return nil, status.Error(codes.InvalidArgument, err.Error())
	}

	if err = createMountPoint(stagingTargetPath); err != nil {
		glog.Errorf("failed to create staging mount point at %s for volume %s: %v", stagingTargetPath, volId, err)
		return nil, status.Error(codes.Internal, err.Error())
	}

	cephConf := cephConfigData{Monitors: volOptions.Monitors, VolumeID: volId}
	if err = cephConf.writeToFile(); err != nil {
		glog.Errorf("failed to write ceph config file to %s for volume %s: %v", getCephConfPath(volId), volId, err)
		return nil, status.Error(codes.Internal, err.Error())
	}

	// Check if the volume is already mounted

	isMnt, err := isMountPoint(stagingTargetPath)

	if err != nil {
		glog.Errorf("stat failed: %v", err)
		return nil, status.Error(codes.Internal, err.Error())
	}

	if isMnt {
		glog.Infof("cephfs: volume %s is already mounted to %s, skipping", volId, stagingTargetPath)
		return &csi.NodeStageVolumeResponse{}, nil
	}

	// It's not, mount now

	cr, err := getOrCreateUser(volOptions, volId, req)
	if err != nil {
		glog.Error(err)
		return nil, status.Error(codes.Internal, err.Error())
	}

	m, err := newMounter(volOptions)
	if err != nil {
		glog.Errorf("failed to create mounter for volume %s: %v", volId, err)
	}

	glog.V(4).Infof("cephfs: mounting volume %s with %s", volId, m.name())
	if err = m.mount(stagingTargetPath, cr, volOptions, volId); err != nil {
		glog.Errorf("failed to mount volume %s: %v", volId, err)
		return nil, status.Error(codes.Internal, err.Error())
	}

	glog.Infof("cephfs: successfully mounted volume %s to %s", volId, stagingTargetPath)

	return &csi.NodeStageVolumeResponse{}, nil
}

func (ns *nodeServer) NodePublishVolume(ctx context.Context, req *csi.NodePublishVolumeRequest) (*csi.NodePublishVolumeResponse, error) {
	if err := validateNodePublishVolumeRequest(req); err != nil {
		return nil, status.Error(codes.InvalidArgument, err.Error())
	}

	// Configuration

	targetPath := req.GetTargetPath()
	volId := req.GetVolumeId()

	if err := createMountPoint(targetPath); err != nil {
		glog.Errorf("failed to create mount point at %s: %v", targetPath, err)
		return nil, status.Error(codes.Internal, err.Error())
	}

	// Check if the volume is already mounted

	isMnt, err := isMountPoint(targetPath)

	if err != nil {
		glog.Errorf("stat failed: %v", err)
		return nil, status.Error(codes.Internal, err.Error())
	}

	if isMnt {
		glog.Infof("cephfs: volume %s is already bind-mounted to %s", volId, targetPath)
		return &csi.NodePublishVolumeResponse{}, nil
	}

	// It's not, mount now

	if err = bindMount(req.GetStagingTargetPath(), req.GetTargetPath(), req.GetReadonly()); err != nil {
		glog.Errorf("failed to bind-mount volume %s: %v", volId, err)
		return nil, status.Error(codes.Internal, err.Error())
	}

	glog.Infof("cephfs: successfuly bind-mounted volume %s to %s", volId, targetPath)

	return &csi.NodePublishVolumeResponse{}, nil
}

func (ns *nodeServer) NodeUnpublishVolume(ctx context.Context, req *csi.NodeUnpublishVolumeRequest) (*csi.NodeUnpublishVolumeResponse, error) {
	if err := validateNodeUnpublishVolumeRequest(req); err != nil {
		return nil, status.Error(codes.InvalidArgument, err.Error())
	}

	targetPath := req.GetTargetPath()

	// Unmount the bind-mount
	if err := unmountVolume(targetPath); err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	os.Remove(targetPath)

	glog.Infof("cephfs: successfuly unbinded volume %s from %s", req.GetVolumeId(), targetPath)

	return &csi.NodeUnpublishVolumeResponse{}, nil
}

func (ns *nodeServer) NodeUnstageVolume(ctx context.Context, req *csi.NodeUnstageVolumeRequest) (*csi.NodeUnstageVolumeResponse, error) {
	if err := validateNodeUnstageVolumeRequest(req); err != nil {
		return nil, status.Error(codes.InvalidArgument, err.Error())
	}

	volId := volumeID(req.GetVolumeId())
	stagingTargetPath := req.GetStagingTargetPath()

	// Unmount the volume
	if err := unmountVolume(stagingTargetPath); err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	os.Remove(stagingTargetPath)

	ent, err := nodeCache.pop(volId)
	if err != nil {
		glog.Error(err)
		return nil, status.Error(codes.Internal, err.Error())
	}

	if ent.volOptions.ProvisionVolume {
		// We've created a dedicated Ceph user in NodeStageVolume,
		// it's about to be deleted here.

		if err = deleteCephUser(&credentials{id: ent.cephAdminID}, volId); err != nil {
			glog.Errorf("failed to delete ceph user %s for volume %s: %v", getCephUserName(volId), volId, err)

			// Reinsert cache entry for retry
			nodeCache.insert(volId, ent)

			return nil, status.Error(codes.Internal, err.Error())
		}
	}

	glog.Infof("cephfs: successfuly umounted volume %s from %s", req.GetVolumeId(), stagingTargetPath)

	return &csi.NodeUnstageVolumeResponse{}, nil
}

func (ns *nodeServer) NodeGetCapabilities(ctx context.Context, req *csi.NodeGetCapabilitiesRequest) (*csi.NodeGetCapabilitiesResponse, error) {
	return &csi.NodeGetCapabilitiesResponse{
		Capabilities: []*csi.NodeServiceCapability{
			{
				Type: &csi.NodeServiceCapability_Rpc{
					Rpc: &csi.NodeServiceCapability_RPC{
						Type: csi.NodeServiceCapability_RPC_STAGE_UNSTAGE_VOLUME,
					},
				},
			},
		},
	}, nil
}