// +build !providerless

/*
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 azure

import (
	"context"
	"fmt"
	"net/http"
	"path"
	"regexp"
	"strings"
	"sync"
	"time"

	"github.com/Azure/azure-sdk-for-go/services/compute/mgmt/2019-12-01/compute"

	"k8s.io/apimachinery/pkg/types"
	kwait "k8s.io/apimachinery/pkg/util/wait"
	cloudprovider "k8s.io/cloud-provider"
	volerr "k8s.io/cloud-provider/volume/errors"
	"k8s.io/klog/v2"
	azcache "k8s.io/legacy-cloud-providers/azure/cache"
	"k8s.io/legacy-cloud-providers/azure/retry"
)

const (
	// for limits check https://docs.microsoft.com/en-us/azure/azure-subscription-service-limits#storage-limits
	maxStorageAccounts                     = 100 // max # is 200 (250 with special request). this allows 100 for everything else including stand alone disks
	maxDisksPerStorageAccounts             = 60
	storageAccountUtilizationBeforeGrowing = 0.5
	// Disk Caching is not supported for disks 4 TiB and larger
	// https://docs.microsoft.com/en-us/azure/virtual-machines/premium-storage-performance#disk-caching
	diskCachingLimit = 4096 // GiB

	maxLUN               = 64 // max number of LUNs per VM
	errLeaseFailed       = "AcquireDiskLeaseFailed"
	errLeaseIDMissing    = "LeaseIdMissing"
	errContainerNotFound = "ContainerNotFound"
	errStatusCode400     = "statuscode=400"
	errInvalidParameter  = `code="invalidparameter"`
	errTargetInstanceIds = `target="instanceids"`
	sourceSnapshot       = "snapshot"
	sourceVolume         = "volume"

	// WriteAcceleratorEnabled support for Azure Write Accelerator on Azure Disks
	// https://docs.microsoft.com/azure/virtual-machines/windows/how-to-enable-write-accelerator
	WriteAcceleratorEnabled = "writeacceleratorenabled"

	// see https://docs.microsoft.com/en-us/rest/api/compute/disks/createorupdate#create-a-managed-disk-by-copying-a-snapshot.
	diskSnapshotPath = "/subscriptions/%s/resourceGroups/%s/providers/Microsoft.Compute/snapshots/%s"

	// see https://docs.microsoft.com/en-us/rest/api/compute/disks/createorupdate#create-a-managed-disk-from-an-existing-managed-disk-in-the-same-or-different-subscription.
	managedDiskPath = "/subscriptions/%s/resourceGroups/%s/providers/Microsoft.Compute/disks/%s"
)

var defaultBackOff = kwait.Backoff{
	Steps:    20,
	Duration: 2 * time.Second,
	Factor:   1.5,
	Jitter:   0.0,
}

var (
	managedDiskPathRE  = regexp.MustCompile(`.*/subscriptions/(?:.*)/resourceGroups/(?:.*)/providers/Microsoft.Compute/disks/(.+)`)
	diskSnapshotPathRE = regexp.MustCompile(`.*/subscriptions/(?:.*)/resourceGroups/(?:.*)/providers/Microsoft.Compute/snapshots/(.+)`)
)

type controllerCommon struct {
	subscriptionID        string
	location              string
	storageEndpointSuffix string
	resourceGroup         string
	// store disk URI when disk is in attaching or detaching process
	diskAttachDetachMap sync.Map
	// vm disk map used to lock per vm update calls
	vmLockMap *lockMap
	cloud     *Cloud
}

// getNodeVMSet gets the VMSet interface based on config.VMType and the real virtual machine type.
func (c *controllerCommon) getNodeVMSet(nodeName types.NodeName, crt azcache.AzureCacheReadType) (VMSet, error) {
	// 1. vmType is standard, return cloud.VMSet directly.
	if c.cloud.VMType == vmTypeStandard {
		return c.cloud.VMSet, nil
	}

	// 2. vmType is Virtual Machine Scale Set (vmss), convert vmSet to scaleSet.
	ss, ok := c.cloud.VMSet.(*scaleSet)
	if !ok {
		return nil, fmt.Errorf("error of converting vmSet (%q) to scaleSet with vmType %q", c.cloud.VMSet, c.cloud.VMType)
	}

	// 3. If the node is managed by availability set, then return ss.availabilitySet.
	managedByAS, err := ss.isNodeManagedByAvailabilitySet(mapNodeNameToVMName(nodeName), crt)
	if err != nil {
		return nil, err
	}
	if managedByAS {
		// vm is managed by availability set.
		return ss.availabilitySet, nil
	}

	// 4. Node is managed by vmss
	return ss, nil
}

// AttachDisk attaches a vhd to vm. The vhd must exist, can be identified by diskName, diskURI.
// return (lun, error)
func (c *controllerCommon) AttachDisk(isManagedDisk bool, diskName, diskURI string, nodeName types.NodeName, cachingMode compute.CachingTypes) (int32, error) {
	diskEncryptionSetID := ""
	writeAcceleratorEnabled := false

	vmset, err := c.getNodeVMSet(nodeName, azcache.CacheReadTypeUnsafe)
	if err != nil {
		return -1, err
	}

	if isManagedDisk {
		diskName := path.Base(diskURI)
		resourceGroup, err := getResourceGroupFromDiskURI(diskURI)
		if err != nil {
			return -1, err
		}

		ctx, cancel := getContextWithCancel()
		defer cancel()

		disk, rerr := c.cloud.DisksClient.Get(ctx, resourceGroup, diskName)
		if rerr != nil {
			return -1, rerr.Error()
		}

		if disk.ManagedBy != nil && (disk.MaxShares == nil || *disk.MaxShares <= 1) {
			attachErr := fmt.Sprintf(
				"disk(%s) already attached to node(%s), could not be attached to node(%s)",
				diskURI, *disk.ManagedBy, nodeName)
			attachedNode, err := vmset.GetNodeNameByProviderID(*disk.ManagedBy)
			if err != nil {
				return -1, err
			}
			klog.V(2).Infof("found dangling volume %s attached to node %s", diskURI, attachedNode)
			danglingErr := volerr.NewDanglingError(attachErr, attachedNode, "")
			return -1, danglingErr
		}

		if disk.DiskProperties != nil {
			if disk.DiskProperties.DiskSizeGB != nil && *disk.DiskProperties.DiskSizeGB >= diskCachingLimit && cachingMode != compute.CachingTypesNone {
				// Disk Caching is not supported for disks 4 TiB and larger
				// https://docs.microsoft.com/en-us/azure/virtual-machines/premium-storage-performance#disk-caching
				cachingMode = compute.CachingTypesNone
				klog.Warningf("size of disk(%s) is %dGB which is bigger than limit(%dGB), set cacheMode as None",
					diskURI, *disk.DiskProperties.DiskSizeGB, diskCachingLimit)
			}

			if disk.DiskProperties.Encryption != nil &&
				disk.DiskProperties.Encryption.DiskEncryptionSetID != nil {
				diskEncryptionSetID = *disk.DiskProperties.Encryption.DiskEncryptionSetID
			}
		}

		if v, ok := disk.Tags[WriteAcceleratorEnabled]; ok {
			if v != nil && strings.EqualFold(*v, "true") {
				writeAcceleratorEnabled = true
			}
		}
	}

	instanceid, err := c.cloud.InstanceID(context.TODO(), nodeName)
	if err != nil {
		klog.Warningf("failed to get azure instance id (%v) for node %s", err, nodeName)
		return -1, fmt.Errorf("failed to get azure instance id for node %q (%v)", nodeName, err)
	}

	c.vmLockMap.LockEntry(strings.ToLower(string(nodeName)))
	defer c.vmLockMap.UnlockEntry(strings.ToLower(string(nodeName)))

	lun, err := c.GetNextDiskLun(nodeName)
	if err != nil {
		klog.Warningf("no LUN available for instance %q (%v)", nodeName, err)
		return -1, fmt.Errorf("all LUNs are used, cannot attach volume (%s, %s) to instance %q (%v)", diskName, diskURI, instanceid, err)
	}

	klog.V(2).Infof("Trying to attach volume %q lun %d to node %q.", diskURI, lun, nodeName)
	c.diskAttachDetachMap.Store(strings.ToLower(diskURI), "attaching")
	defer c.diskAttachDetachMap.Delete(strings.ToLower(diskURI))
	return lun, vmset.AttachDisk(isManagedDisk, diskName, diskURI, nodeName, lun, cachingMode, diskEncryptionSetID, writeAcceleratorEnabled)
}

// DetachDisk detaches a disk from host. The vhd can be identified by diskName or diskURI.
func (c *controllerCommon) DetachDisk(diskName, diskURI string, nodeName types.NodeName) error {
	_, err := c.cloud.InstanceID(context.TODO(), nodeName)
	if err != nil {
		if err == cloudprovider.InstanceNotFound {
			// if host doesn't exist, no need to detach
			klog.Warningf("azureDisk - failed to get azure instance id(%q), DetachDisk(%s) will assume disk is already detached",
				nodeName, diskURI)
			return nil
		}
		klog.Warningf("failed to get azure instance id (%v)", err)
		return fmt.Errorf("failed to get azure instance id for node %q (%v)", nodeName, err)
	}

	vmset, err := c.getNodeVMSet(nodeName, azcache.CacheReadTypeUnsafe)
	if err != nil {
		return err
	}

	klog.V(2).Infof("detach %v from node %q", diskURI, nodeName)

	// make the lock here as small as possible
	c.vmLockMap.LockEntry(strings.ToLower(string(nodeName)))
	c.diskAttachDetachMap.Store(strings.ToLower(diskURI), "detaching")
	err = vmset.DetachDisk(diskName, diskURI, nodeName)
	c.diskAttachDetachMap.Delete(strings.ToLower(diskURI))
	c.vmLockMap.UnlockEntry(strings.ToLower(string(nodeName)))

	if err != nil {
		if isInstanceNotFoundError(err) {
			// if host doesn't exist, no need to detach
			klog.Warningf("azureDisk - got InstanceNotFoundError(%v), DetachDisk(%s) will assume disk is already detached",
				err, diskURI)
			return nil
		}
		if retry.IsErrorRetriable(err) && c.cloud.CloudProviderBackoff {
			klog.Warningf("azureDisk - update backing off: detach disk(%s, %s), err: %v", diskName, diskURI, err)
			retryErr := kwait.ExponentialBackoff(c.cloud.RequestBackoff(), func() (bool, error) {
				c.vmLockMap.LockEntry(strings.ToLower(string(nodeName)))
				c.diskAttachDetachMap.Store(strings.ToLower(diskURI), "detaching")
				err := vmset.DetachDisk(diskName, diskURI, nodeName)
				c.diskAttachDetachMap.Delete(strings.ToLower(diskURI))
				c.vmLockMap.UnlockEntry(strings.ToLower(string(nodeName)))

				retriable := false
				if err != nil && retry.IsErrorRetriable(err) {
					retriable = true
				}
				return !retriable, err
			})
			if retryErr != nil {
				err = retryErr
				klog.V(2).Infof("azureDisk - update abort backoff: detach disk(%s, %s), err: %v", diskName, diskURI, err)
			}
		}
	}
	if err != nil {
		klog.Errorf("azureDisk - detach disk(%s, %s) failed, err: %v", diskName, diskURI, err)
		return err
	}

	klog.V(2).Infof("azureDisk - detach disk(%s, %s) succeeded", diskName, diskURI)
	return nil
}

// getNodeDataDisks invokes vmSet interfaces to get data disks for the node.
func (c *controllerCommon) getNodeDataDisks(nodeName types.NodeName, crt azcache.AzureCacheReadType) ([]compute.DataDisk, error) {
	vmset, err := c.getNodeVMSet(nodeName, crt)
	if err != nil {
		return nil, err
	}

	return vmset.GetDataDisks(nodeName, crt)
}

// GetDiskLun finds the lun on the host that the vhd is attached to, given a vhd's diskName and diskURI.
func (c *controllerCommon) GetDiskLun(diskName, diskURI string, nodeName types.NodeName) (int32, error) {
	// getNodeDataDisks need to fetch the cached data/fresh data if cache expired here
	// to ensure we get LUN based on latest entry.
	disks, err := c.getNodeDataDisks(nodeName, azcache.CacheReadTypeDefault)
	if err != nil {
		klog.Errorf("error of getting data disks for node %q: %v", nodeName, err)
		return -1, err
	}

	for _, disk := range disks {
		if disk.Lun != nil && (disk.Name != nil && diskName != "" && strings.EqualFold(*disk.Name, diskName)) ||
			(disk.Vhd != nil && disk.Vhd.URI != nil && diskURI != "" && strings.EqualFold(*disk.Vhd.URI, diskURI)) ||
			(disk.ManagedDisk != nil && strings.EqualFold(*disk.ManagedDisk.ID, diskURI)) {
			if disk.ToBeDetached != nil && *disk.ToBeDetached {
				klog.Warningf("azureDisk - find disk(ToBeDetached): lun %d name %q uri %q", *disk.Lun, diskName, diskURI)
			} else {
				// found the disk
				klog.V(2).Infof("azureDisk - find disk: lun %d name %q uri %q", *disk.Lun, diskName, diskURI)
				return *disk.Lun, nil
			}
		}
	}
	return -1, fmt.Errorf("cannot find Lun for disk %s", diskName)
}

// GetNextDiskLun searches all vhd attachment on the host and find unused lun. Return -1 if all luns are used.
func (c *controllerCommon) GetNextDiskLun(nodeName types.NodeName) (int32, error) {
	disks, err := c.getNodeDataDisks(nodeName, azcache.CacheReadTypeDefault)
	if err != nil {
		klog.Errorf("error of getting data disks for node %q: %v", nodeName, err)
		return -1, err
	}

	used := make([]bool, maxLUN)
	for _, disk := range disks {
		if disk.Lun != nil {
			used[*disk.Lun] = true
		}
	}
	for k, v := range used {
		if !v {
			return int32(k), nil
		}
	}
	return -1, fmt.Errorf("all luns are used")
}

// DisksAreAttached checks if a list of volumes are attached to the node with the specified NodeName.
func (c *controllerCommon) DisksAreAttached(diskNames []string, nodeName types.NodeName) (map[string]bool, error) {
	attached := make(map[string]bool)
	for _, diskName := range diskNames {
		attached[diskName] = false
	}

	// doing stalled read for getNodeDataDisks to ensure we don't call ARM
	// for every reconcile call. The cache is invalidated after Attach/Detach
	// disk. So the new entry will be fetched and cached the first time reconcile
	// loop runs after the Attach/Disk OP which will reflect the latest model.
	disks, err := c.getNodeDataDisks(nodeName, azcache.CacheReadTypeUnsafe)
	if err != nil {
		if err == cloudprovider.InstanceNotFound {
			// if host doesn't exist, no need to detach
			klog.Warningf("azureDisk - Cannot find node %q, DisksAreAttached will assume disks %v are not attached to it.",
				nodeName, diskNames)
			return attached, nil
		}

		return attached, err
	}

	for _, disk := range disks {
		for _, diskName := range diskNames {
			if disk.Name != nil && diskName != "" && strings.EqualFold(*disk.Name, diskName) {
				attached[diskName] = true
			}
		}
	}

	return attached, nil
}

func filterDetachingDisks(unfilteredDisks []compute.DataDisk) []compute.DataDisk {
	filteredDisks := []compute.DataDisk{}
	for _, disk := range unfilteredDisks {
		if disk.ToBeDetached != nil && *disk.ToBeDetached {
			if disk.Name != nil {
				klog.V(2).Infof("Filtering disk: %s with ToBeDetached flag set.", *disk.Name)
			}
		} else {
			filteredDisks = append(filteredDisks, disk)
		}
	}
	return filteredDisks
}

func (c *controllerCommon) filterNonExistingDisks(ctx context.Context, unfilteredDisks []compute.DataDisk) []compute.DataDisk {
	filteredDisks := []compute.DataDisk{}
	for _, disk := range unfilteredDisks {
		filter := false
		if disk.ManagedDisk != nil && disk.ManagedDisk.ID != nil {
			diskURI := *disk.ManagedDisk.ID
			exist, err := c.cloud.checkDiskExists(ctx, diskURI)
			if err != nil {
				klog.Errorf("checkDiskExists(%s) failed with error: %v", diskURI, err)
			} else {
				// only filter disk when checkDiskExists returns <false, nil>
				filter = !exist
				if filter {
					klog.Errorf("disk(%s) does not exist, removed from data disk list", diskURI)
				}
			}
		}

		if !filter {
			filteredDisks = append(filteredDisks, disk)
		}
	}
	return filteredDisks
}

func (c *controllerCommon) checkDiskExists(ctx context.Context, diskURI string) (bool, error) {
	diskName := path.Base(diskURI)
	resourceGroup, err := getResourceGroupFromDiskURI(diskURI)
	if err != nil {
		return false, err
	}

	if _, rerr := c.cloud.DisksClient.Get(ctx, resourceGroup, diskName); rerr != nil {
		if rerr.HTTPStatusCode == http.StatusNotFound {
			return false, nil
		}
		return false, rerr.Error()
	}

	return true, nil
}

func getValidCreationData(subscriptionID, resourceGroup, sourceResourceID, sourceType string) (compute.CreationData, error) {
	if sourceResourceID == "" {
		return compute.CreationData{
			CreateOption: compute.Empty,
		}, nil
	}

	switch sourceType {
	case sourceSnapshot:
		if match := diskSnapshotPathRE.FindString(sourceResourceID); match == "" {
			sourceResourceID = fmt.Sprintf(diskSnapshotPath, subscriptionID, resourceGroup, sourceResourceID)
		}

	case sourceVolume:
		if match := managedDiskPathRE.FindString(sourceResourceID); match == "" {
			sourceResourceID = fmt.Sprintf(managedDiskPath, subscriptionID, resourceGroup, sourceResourceID)
		}
	default:
		return compute.CreationData{
			CreateOption: compute.Empty,
		}, nil
	}

	splits := strings.Split(sourceResourceID, "/")
	if len(splits) > 9 {
		if sourceType == sourceSnapshot {
			return compute.CreationData{}, fmt.Errorf("sourceResourceID(%s) is invalid, correct format: %s", sourceResourceID, diskSnapshotPathRE)
		}
		return compute.CreationData{}, fmt.Errorf("sourceResourceID(%s) is invalid, correct format: %s", sourceResourceID, managedDiskPathRE)
	}
	return compute.CreationData{
		CreateOption:     compute.Copy,
		SourceResourceID: &sourceResourceID,
	}, nil
}

func isInstanceNotFoundError(err error) bool {
	errMsg := strings.ToLower(err.Error())
	return strings.Contains(errMsg, errStatusCode400) && strings.Contains(errMsg, errInvalidParameter) && strings.Contains(errMsg, errTargetInstanceIds)
}