package hcsoci

import (
	"os"

	"github.com/Microsoft/hcsshim/internal/hns"
	"github.com/Microsoft/hcsshim/internal/uvm"
	"github.com/sirupsen/logrus"
)

// NetNS returns the network namespace for the container
func (r *Resources) NetNS() string {
	return r.netNS
}

// Resources is the structure returned as part of creating a container. It holds
// nothing useful to clients, hence everything is lowercased. A client would use
// it in a call to ReleaseResource to ensure everything is cleaned up when a
// container exits.
type Resources struct {
	// containerRootInUVM is the base path in a utility VM where elements relating
	// to a container are exposed. For example, the mounted filesystem; the runtime
	// spec (in the case of LCOW); overlay and scratch (in the case of LCOW).
	//
	// For WCOW, this will be under C:\c\N, and for LCOW this will
	// be under /run/gcs/c/N. N is an atomic counter for each container created
	// in that utility VM. For LCOW this is also the "OCI Bundle Path".
	containerRootInUVM string

	// layers is an array of the layer folder paths which have been mounted either on
	// the host in the case or a WCOW Argon, or in a utility VM for WCOW Xenon and LCOW.
	layers []string

	// vsmbMounts is an array of the host-paths mounted into a utility VM to support
	// (bind-)mounts into a WCOW v2 Xenon.
	vsmbMounts []string

	// plan9Mounts is an array of all the host paths which have been added to
	// an LCOW utility VM
	plan9Mounts []string

	// netNS is the network namespace
	netNS string

	// networkEndpoints is the list of network endpoints used by the container
	networkEndpoints []string

	// createNetNS indicates if the network namespace has been created
	createdNetNS bool

	// addedNetNSToVM indicates if the network namespace has been added to the containers utility VM
	addedNetNSToVM bool

	// scsiMounts is an array of the host-paths mounted into a utility VM to
	// support scsi device passthrough.
	scsiMounts []string
}

// TODO: Method on the resources?
func ReleaseResources(r *Resources, vm *uvm.UtilityVM, all bool) error {
	if vm != nil && r.addedNetNSToVM {
		err := vm.RemoveNetNS(r.netNS)
		if err != nil {
			logrus.Warn(err)
		}
		r.addedNetNSToVM = false
	}

	if r.createdNetNS {
		for len(r.networkEndpoints) != 0 {
			endpoint := r.networkEndpoints[len(r.networkEndpoints)-1]
			err := hns.RemoveNamespaceEndpoint(r.netNS, endpoint)
			if err != nil {
				if !os.IsNotExist(err) {
					return err
				}
				logrus.Warnf("removing endpoint %s from namespace %s: does not exist", endpoint, r.NetNS())
			}
			r.networkEndpoints = r.networkEndpoints[:len(r.networkEndpoints)-1]
		}
		r.networkEndpoints = nil
		err := hns.RemoveNamespace(r.netNS)
		if err != nil && !os.IsNotExist(err) {
			return err
		}
		r.createdNetNS = false
	}

	if len(r.layers) != 0 {
		op := UnmountOperationSCSI
		if vm == nil || all {
			op = UnmountOperationAll
		}
		err := UnmountContainerLayers(r.layers, r.containerRootInUVM, vm, op)
		if err != nil {
			return err
		}
		r.layers = nil
	}

	if all {
		for len(r.vsmbMounts) != 0 {
			mount := r.vsmbMounts[len(r.vsmbMounts)-1]
			if err := vm.RemoveVSMB(mount); err != nil {
				return err
			}
			r.vsmbMounts = r.vsmbMounts[:len(r.vsmbMounts)-1]
		}

		for len(r.plan9Mounts) != 0 {
			mount := r.plan9Mounts[len(r.plan9Mounts)-1]
			if err := vm.RemovePlan9(mount); err != nil {
				return err
			}
			r.plan9Mounts = r.plan9Mounts[:len(r.plan9Mounts)-1]
		}

		for _, path := range r.scsiMounts {
			if err := vm.RemoveSCSI(path); err != nil {
				return err
			}
			r.scsiMounts = nil
		}
	}

	return nil
}