/*
Copyright 2024 p5x.

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 csi

import (
	"context"

	"github.com/container-storage-interface/spec/lib/go/csi"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

var (
	volumeCaps = []csi.VolumeCapability_AccessMode{
		{
			Mode: csi.VolumeCapability_AccessMode_SINGLE_NODE_WRITER,
		},
		{
			Mode: csi.VolumeCapability_AccessMode_MULTI_NODE_MULTI_WRITER,
		},
		{
			Mode: csi.VolumeCapability_AccessMode_MULTI_NODE_READER_ONLY,
		},
	}
)

type nodeService struct {
	nodeID string
	csi.UnimplementedNodeServer
}

var _ csi.NodeServer = &nodeService{}

func newNodeService(nodeID string) nodeService {
	return nodeService{
		nodeID: nodeID,
	}
}

// NodeStageVolume is called by the CO when a workload that wants to use the specified volume is placed (scheduled) on a node.
func (n *nodeService) NodeStageVolume(ctx context.Context, request *csi.NodeStageVolumeRequest) (*csi.NodeStageVolumeResponse, error) {
	return nil, status.Error(codes.Unimplemented, "")
}

// NodeUnstageVolume is called by the CO when a workload that was using the specified volume is being moved to a different node.
func (n *nodeService) NodeUnstageVolume(ctx context.Context, request *csi.NodeUnstageVolumeRequest) (*csi.NodeUnstageVolumeResponse, error) {
	return nil, status.Error(codes.Unimplemented, "")
}

// NodePublishVolume mounts the volume on the node.
func (n *nodeService) NodePublishVolume(ctx context.Context, request *csi.NodePublishVolumeRequest) (*csi.NodePublishVolumeResponse, error) {
	volumeID := request.GetVolumeId()
	if len(volumeID) == 0 {
		return nil, status.Error(codes.InvalidArgument, "Volume id not provided")
	}

	target := request.GetTargetPath()
	if len(target) == 0 {
		return nil, status.Error(codes.InvalidArgument, "Target path not provided")
	}

	volCap := request.GetVolumeCapability()
	if volCap == nil {
		return nil, status.Error(codes.InvalidArgument, "Volume capability not provided")
	}

	if !isValidVolumeCapabilities([]*csi.VolumeCapability{volCap}) {
		return nil, status.Error(codes.InvalidArgument, "Volume capability not supported")
	}

	readOnly := false
	if request.GetReadonly() || request.VolumeCapability.AccessMode.GetMode() == csi.VolumeCapability_AccessMode_MULTI_NODE_READER_ONLY {
		readOnly = true
	}

	options := make(map[string]string)
	if m := volCap.GetMount(); m != nil {
		for _, f := range m.MountFlags {
			// get mountOptions from PV.spec.mountOptions
			options[f] = ""
		}
	}

	if readOnly {
		// Todo add readonly in your mount options
	}

	// TODO modify your volume mount logic here

	return &csi.NodePublishVolumeResponse{}, nil
}

// NodeUnpublishVolume unmount the volume from the target path
func (n *nodeService) NodeUnpublishVolume(ctx context.Context, request *csi.NodeUnpublishVolumeRequest) (*csi.NodeUnpublishVolumeResponse, error) {
	target := request.GetTargetPath()
	if len(target) == 0 {
		return nil, status.Error(codes.InvalidArgument, "Target path not provided")
	}

	// TODO modify your volume umount logic here

	return &csi.NodeUnpublishVolumeResponse{}, nil
}

// NodeGetVolumeStats get the volume stats
func (n *nodeService) NodeGetVolumeStats(ctx context.Context, request *csi.NodeGetVolumeStatsRequest) (*csi.NodeGetVolumeStatsResponse, error) {
	return nil, status.Error(codes.Unimplemented, "")
}

// NodeExpandVolume expand the volume
func (n *nodeService) NodeExpandVolume(ctx context.Context, request *csi.NodeExpandVolumeRequest) (*csi.NodeExpandVolumeResponse, error) {
	return nil, status.Error(codes.Unimplemented, "")
}

// NodeGetCapabilities get the node capabilities
func (n *nodeService) NodeGetCapabilities(ctx context.Context, request *csi.NodeGetCapabilitiesRequest) (*csi.NodeGetCapabilitiesResponse, error) {
	return &csi.NodeGetCapabilitiesResponse{}, nil
}

// NodeGetInfo get the node info
func (n *nodeService) NodeGetInfo(ctx context.Context, request *csi.NodeGetInfoRequest) (*csi.NodeGetInfoResponse, error) {
	return &csi.NodeGetInfoResponse{NodeId: n.nodeID}, nil
}

func isValidVolumeCapabilities(volCaps []*csi.VolumeCapability) bool {
	hasSupport := func(cap *csi.VolumeCapability) bool {
		if csi.VolumeCapability_AccessMode_SINGLE_NODE_WRITER == cap.AccessMode.GetMode() {
			return true
		}

		if csi.VolumeCapability_AccessMode_MULTI_NODE_MULTI_WRITER == cap.AccessMode.GetMode() {
			return true
		}

		if csi.VolumeCapability_AccessMode_MULTI_NODE_READER_ONLY == cap.AccessMode.GetMode() {
			return true
		}

		//		for _, c := range volumeCaps {
		//			if c.GetMode() == cap.AccessMode.GetMode() {
		//				return true
		//			}
		//		}
		return false
	}

	foundAll := true
	for _, c := range volCaps {
		if !hasSupport(c) {
			foundAll = false
		}
	}
	return foundAll
}