package driver

import (
	"context"
	"fmt"
	"os"

	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/pb/mount_pb"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
	"k8s.io/mount-utils"
)

type Volume struct {
	VolumeId   string
	StagedPath string

	mounter   Mounter
	unmounter Unmounter

	// unix socket used to manage volume
	localSocket string
}

func NewVolume(volumeID string, mounter Mounter) *Volume {
	return &Volume{
		VolumeId:    volumeID,
		mounter:     mounter,
		localSocket: GetLocalSocket(volumeID),
	}
}

func (vol *Volume) Stage(stagingTargetPath string) error {
	// check whether it can be mounted
	if isMnt, err := checkMount(stagingTargetPath); err != nil {
		return err
	} else if isMnt {
		// try to unmount before mounting again
		_ = mountutil.Unmount(stagingTargetPath)
	}

	if u, err := vol.mounter.Mount(stagingTargetPath); err == nil {
		if vol.StagedPath != "" {
			if vol.StagedPath == stagingTargetPath {
				glog.Warningf("staged path is already set to %s for volume %s", vol.StagedPath, vol.VolumeId)
			} else {
				glog.Warningf("staged path is already set to %s and differs from %s for volume %s", vol.StagedPath, stagingTargetPath, vol.VolumeId)
			}
		}

		vol.StagedPath = stagingTargetPath
		vol.unmounter = u

		return nil
	} else {
		return err
	}
}

func (vol *Volume) Publish(stagingTargetPath string, targetPath string, readOnly bool) error {
	// check whether it can be mounted
	if isMnt, err := checkMount(targetPath); err != nil {
		return err
	} else if isMnt {
		// maybe already mounted?
		return nil
	}

	// Use bind mount to create an alias of the real mount point.
	mountOptions := []string{"bind"}
	if readOnly {
		mountOptions = append(mountOptions, "ro")
	}

	if err := mountutil.Mount(stagingTargetPath, targetPath, "", mountOptions); err != nil {
		return err
	}

	return nil
}

func (vol *Volume) Quota(sizeByte int64) error {
	target := fmt.Sprintf("passthrough:///unix://%s", vol.localSocket)
	dialOption := grpc.WithTransportCredentials(insecure.NewCredentials())

	clientConn, err := grpc.Dial(target, dialOption)
	if err != nil {
		return err
	}
	defer clientConn.Close()

	// We can't create PV of zero size, so we're using quota of 1 byte to define no quota.
	if sizeByte == 1 {
		sizeByte = 0
	}

	client := mount_pb.NewSeaweedMountClient(clientConn)
	_, err = client.Configure(context.Background(), &mount_pb.ConfigureRequest{
		CollectionCapacity: sizeByte,
	})
	return err
}

func (vol *Volume) Unpublish(targetPath string) error {
	// Try unmounting target path and deleting it.
	if err := mount.CleanupMountPoint(targetPath, mountutil, true); err != nil {
		return err
	}

	return nil
}

func (vol *Volume) Unstage(stagingTargetPath string) error {
	glog.V(0).Infof("unmounting volume %s from %s", vol.VolumeId, stagingTargetPath)

	if stagingTargetPath != vol.StagedPath && vol.StagedPath != "" {
		glog.Warningf("staging path %s differs for volume %s at %s", stagingTargetPath, vol.VolumeId, vol.StagedPath)
	}

	if vol.unmounter == nil {
		// This can happen when the volume was rebuilt from an existing staging path
		// after a CSI driver restart. In this case, we need to force unmount.
		glog.Infof("volume %s has no unmounter (rebuilt from existing mount), using force unmount", vol.VolumeId)

		// Clean up using mount utilities. This will also handle unmounting.
		if err := mount.CleanupMountPoint(stagingTargetPath, mountutil, true); err != nil {
			glog.Warningf("error cleaning up mount point for volume %s: %v", vol.VolumeId, err)
		}

		return nil
	}

	if err := vol.unmounter.Unmount(); err != nil {
		glog.Errorf("error unmounting volume during unstage: %s, err: %v", stagingTargetPath, err)
		return err
	}

	if err := os.Remove(stagingTargetPath); err != nil && !os.IsNotExist(err) {
		glog.Errorf("error removing staging path for volume %s at %s, err: %v", vol.VolumeId, stagingTargetPath, err)
		return err
	}

	return nil
}