/*
Copyright 2017 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 (
	"k8s.io/apimachinery/pkg/util/wait"

	"github.com/Azure/azure-sdk-for-go/arm/compute"
	"github.com/Azure/azure-sdk-for-go/arm/network"
	"github.com/Azure/go-autorest/autorest"
	"github.com/golang/glog"
	"k8s.io/apimachinery/pkg/types"
)

// requestBackoff if backoff is disabled in cloud provider it
// returns a new Backoff object steps = 1
// This is to make sure that the requested command executes
// at least once
func (az *Cloud) requestBackoff() (resourceRequestBackoff wait.Backoff) {
	if az.CloudProviderBackoff {
		return az.resourceRequestBackoff
	}
	resourceRequestBackoff = wait.Backoff{
		Steps: 1,
	}

	return resourceRequestBackoff
}

// GetVirtualMachineWithRetry invokes az.getVirtualMachine with exponential backoff retry
func (az *Cloud) GetVirtualMachineWithRetry(name types.NodeName) (compute.VirtualMachine, error) {
	var machine compute.VirtualMachine
	var retryErr error
	err := wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		machine, retryErr = az.getVirtualMachine(name)
		if retryErr != nil {
			glog.Errorf("backoff: failure, will retry,err=%v", retryErr)
			return false, nil
		}
		glog.V(2).Info("backoff: success")
		return true, nil
	})
	if err == wait.ErrWaitTimeout {
		err = retryErr
	}

	return machine, err
}

// VirtualMachineClientListWithRetry invokes az.VirtualMachinesClient.List with exponential backoff retry
func (az *Cloud) VirtualMachineClientListWithRetry() ([]compute.VirtualMachine, error) {
	allNodes := []compute.VirtualMachine{}
	var result compute.VirtualMachineListResult
	err := wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		var retryErr error
		result, retryErr = az.VirtualMachinesClient.List(az.ResourceGroup)
		if retryErr != nil {
			glog.Errorf("VirtualMachinesClient.List(%v) - backoff: failure, will retry,err=%v",
				az.ResourceGroup,
				retryErr)
			return false, retryErr
		}
		glog.V(2).Infof("VirtualMachinesClient.List(%v) - backoff: success", az.ResourceGroup)
		return true, nil
	})
	if err != nil {
		return nil, err
	}

	appendResults := (result.Value != nil && len(*result.Value) > 0)
	for appendResults {
		allNodes = append(allNodes, *result.Value...)
		appendResults = false
		// follow the next link to get all the vms for resource group
		if result.NextLink != nil {
			err := wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
				var retryErr error
				result, retryErr = az.VirtualMachinesClient.ListNextResults(az.ResourceGroup, result)
				if retryErr != nil {
					glog.Errorf("VirtualMachinesClient.ListNextResults(%v) - backoff: failure, will retry,err=%v",
						az.ResourceGroup, retryErr)
					return false, retryErr
				}
				glog.V(2).Infof("VirtualMachinesClient.ListNextResults(%v): success", az.ResourceGroup)
				return true, nil
			})
			if err != nil {
				return allNodes, err
			}
			appendResults = (result.Value != nil && len(*result.Value) > 0)
		}
	}

	return allNodes, err
}

// GetIPForMachineWithRetry invokes az.getIPForMachine with exponential backoff retry
func (az *Cloud) GetIPForMachineWithRetry(name types.NodeName) (string, error) {
	var ip string
	err := wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		var retryErr error
		ip, retryErr = az.getIPForMachine(name)
		if retryErr != nil {
			glog.Errorf("backoff: failure, will retry,err=%v", retryErr)
			return false, nil
		}
		glog.V(2).Info("backoff: success")
		return true, nil
	})
	return ip, err
}

// CreateOrUpdateSGWithRetry invokes az.SecurityGroupsClient.CreateOrUpdate with exponential backoff retry
func (az *Cloud) CreateOrUpdateSGWithRetry(sg network.SecurityGroup) error {
	return wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		respChan, errChan := az.SecurityGroupsClient.CreateOrUpdate(az.ResourceGroup, *sg.Name, sg, nil)
		resp := <-respChan
		err := <-errChan
		glog.V(10).Infof("SecurityGroupsClient.CreateOrUpdate(%s): end", *sg.Name)
		return processRetryResponse(resp.Response, err)
	})
}

// CreateOrUpdateLBWithRetry invokes az.LoadBalancerClient.CreateOrUpdate with exponential backoff retry
func (az *Cloud) CreateOrUpdateLBWithRetry(lb network.LoadBalancer) error {
	return wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		respChan, errChan := az.LoadBalancerClient.CreateOrUpdate(az.ResourceGroup, *lb.Name, lb, nil)
		resp := <-respChan
		err := <-errChan
		glog.V(10).Infof("LoadBalancerClient.CreateOrUpdate(%s): end", *lb.Name)
		return processRetryResponse(resp.Response, err)
	})
}

// ListLBWithRetry invokes az.LoadBalancerClient.List with exponential backoff retry
func (az *Cloud) ListLBWithRetry() ([]network.LoadBalancer, error) {
	allLBs := []network.LoadBalancer{}
	var result network.LoadBalancerListResult

	err := wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		var retryErr error
		result, retryErr = az.LoadBalancerClient.List(az.ResourceGroup)
		if retryErr != nil {
			glog.Errorf("LoadBalancerClient.List(%v) - backoff: failure, will retry,err=%v",
				az.ResourceGroup,
				retryErr)
			return false, retryErr
		}
		glog.V(2).Infof("LoadBalancerClient.List(%v) - backoff: success", az.ResourceGroup)
		return true, nil
	})
	if err != nil {
		return nil, err
	}

	appendResults := (result.Value != nil && len(*result.Value) > 0)
	for appendResults {
		allLBs = append(allLBs, *result.Value...)
		appendResults = false

		// follow the next link to get all the vms for resource group
		if result.NextLink != nil {
			err := wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
				var retryErr error
				result, retryErr = az.LoadBalancerClient.ListNextResults(az.ResourceGroup, result)
				if retryErr != nil {
					glog.Errorf("LoadBalancerClient.ListNextResults(%v) - backoff: failure, will retry,err=%v",
						az.ResourceGroup,
						retryErr)
					return false, retryErr
				}
				glog.V(2).Infof("LoadBalancerClient.ListNextResults(%v) - backoff: success", az.ResourceGroup)
				return true, nil
			})
			if err != nil {
				return allLBs, err
			}
			appendResults = (result.Value != nil && len(*result.Value) > 0)
		}
	}

	return allLBs, nil
}

// ListPIPWithRetry list the PIP resources in the given resource group
func (az *Cloud) ListPIPWithRetry(pipResourceGroup string) ([]network.PublicIPAddress, error) {
	allPIPs := []network.PublicIPAddress{}
	var result network.PublicIPAddressListResult
	err := wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		var retryErr error
		result, retryErr = az.PublicIPAddressesClient.List(pipResourceGroup)
		if retryErr != nil {
			glog.Errorf("PublicIPAddressesClient.List(%v) - backoff: failure, will retry,err=%v",
				pipResourceGroup,
				retryErr)
			return false, retryErr
		}
		glog.V(2).Infof("PublicIPAddressesClient.List(%v) - backoff: success", pipResourceGroup)
		return true, nil
	})
	if err != nil {
		return nil, err
	}

	appendResults := (result.Value != nil && len(*result.Value) > 0)
	for appendResults {
		allPIPs = append(allPIPs, *result.Value...)
		appendResults = false

		// follow the next link to get all the pip resources for resource group
		if result.NextLink != nil {
			err := wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
				var retryErr error
				result, retryErr = az.PublicIPAddressesClient.ListNextResults(az.ResourceGroup, result)
				if retryErr != nil {
					glog.Errorf("PublicIPAddressesClient.ListNextResults(%v) - backoff: failure, will retry,err=%v",
						pipResourceGroup,
						retryErr)
					return false, retryErr
				}
				glog.V(2).Infof("PublicIPAddressesClient.ListNextResults(%v) - backoff: success", pipResourceGroup)
				return true, nil
			})
			if err != nil {
				return allPIPs, err
			}
			appendResults = (result.Value != nil && len(*result.Value) > 0)
		}
	}

	return allPIPs, nil
}

// CreateOrUpdatePIPWithRetry invokes az.PublicIPAddressesClient.CreateOrUpdate with exponential backoff retry
func (az *Cloud) CreateOrUpdatePIPWithRetry(pipResourceGroup string, pip network.PublicIPAddress) error {
	return wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		respChan, errChan := az.PublicIPAddressesClient.CreateOrUpdate(pipResourceGroup, *pip.Name, pip, nil)
		resp := <-respChan
		err := <-errChan
		glog.V(10).Infof("PublicIPAddressesClient.CreateOrUpdate(%s, %s): end", pipResourceGroup, *pip.Name)
		return processRetryResponse(resp.Response, err)
	})
}

// CreateOrUpdateInterfaceWithRetry invokes az.PublicIPAddressesClient.CreateOrUpdate with exponential backoff retry
func (az *Cloud) CreateOrUpdateInterfaceWithRetry(nic network.Interface) error {
	return wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		respChan, errChan := az.InterfacesClient.CreateOrUpdate(az.ResourceGroup, *nic.Name, nic, nil)
		resp := <-respChan
		err := <-errChan
		glog.V(10).Infof("InterfacesClient.CreateOrUpdate(%s): end", *nic.Name)
		return processRetryResponse(resp.Response, err)
	})
}

// DeletePublicIPWithRetry invokes az.PublicIPAddressesClient.Delete with exponential backoff retry
func (az *Cloud) DeletePublicIPWithRetry(pipResourceGroup string, pipName string) error {
	return wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		respChan, errChan := az.PublicIPAddressesClient.Delete(pipResourceGroup, pipName, nil)
		resp := <-respChan
		err := <-errChan
		return processRetryResponse(resp, err)
	})
}

// DeleteLBWithRetry invokes az.LoadBalancerClient.Delete with exponential backoff retry
func (az *Cloud) DeleteLBWithRetry(lbName string) error {
	return wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		respChan, errChan := az.LoadBalancerClient.Delete(az.ResourceGroup, lbName, nil)
		resp := <-respChan
		err := <-errChan
		return processRetryResponse(resp, err)
	})
}

// CreateOrUpdateRouteTableWithRetry invokes az.RouteTablesClient.CreateOrUpdate with exponential backoff retry
func (az *Cloud) CreateOrUpdateRouteTableWithRetry(routeTable network.RouteTable) error {
	return wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		respChan, errChan := az.RouteTablesClient.CreateOrUpdate(az.ResourceGroup, az.RouteTableName, routeTable, nil)
		resp := <-respChan
		err := <-errChan
		return processRetryResponse(resp.Response, err)
	})
}

// CreateOrUpdateRouteWithRetry invokes az.RoutesClient.CreateOrUpdate with exponential backoff retry
func (az *Cloud) CreateOrUpdateRouteWithRetry(route network.Route) error {
	return wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		respChan, errChan := az.RoutesClient.CreateOrUpdate(az.ResourceGroup, az.RouteTableName, *route.Name, route, nil)
		resp := <-respChan
		err := <-errChan
		glog.V(10).Infof("RoutesClient.CreateOrUpdate(%s): end", *route.Name)
		return processRetryResponse(resp.Response, err)
	})
}

// DeleteRouteWithRetry invokes az.RoutesClient.Delete with exponential backoff retry
func (az *Cloud) DeleteRouteWithRetry(routeName string) error {
	return wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		respChan, errChan := az.RoutesClient.Delete(az.ResourceGroup, az.RouteTableName, routeName, nil)
		resp := <-respChan
		err := <-errChan
		glog.V(10).Infof("RoutesClient.Delete(%s): end", az.RouteTableName)
		return processRetryResponse(resp, err)
	})
}

// CreateOrUpdateVMWithRetry invokes az.VirtualMachinesClient.CreateOrUpdate with exponential backoff retry
func (az *Cloud) CreateOrUpdateVMWithRetry(vmName string, newVM compute.VirtualMachine) error {
	return wait.ExponentialBackoff(az.requestBackoff(), func() (bool, error) {
		respChan, errChan := az.VirtualMachinesClient.CreateOrUpdate(az.ResourceGroup, vmName, newVM, nil)
		resp := <-respChan
		err := <-errChan
		glog.V(10).Infof("VirtualMachinesClient.CreateOrUpdate(%s): end", vmName)
		return processRetryResponse(resp.Response, err)
	})
}

// A wait.ConditionFunc function to deal with common HTTP backoff response conditions
func processRetryResponse(resp autorest.Response, err error) (bool, error) {
	if isSuccessHTTPResponse(resp) {
		glog.V(2).Infof("backoff: success, HTTP response=%d", resp.StatusCode)
		return true, nil
	}
	if shouldRetryAPIRequest(resp, err) {
		glog.Errorf("backoff: failure, will retry, HTTP response=%d, err=%v", resp.StatusCode, err)
		// suppress the error object so that backoff process continues
		return false, nil
	}
	// Fall-through: stop periodic backoff
	return true, nil
}

// shouldRetryAPIRequest determines if the response from an HTTP request suggests periodic retry behavior
func shouldRetryAPIRequest(resp autorest.Response, err error) bool {
	if err != nil {
		return true
	}
	// HTTP 4xx or 5xx suggests we should retry
	if 399 < resp.StatusCode && resp.StatusCode < 600 {
		return true
	}
	return false
}

// isSuccessHTTPResponse determines if the response from an HTTP request suggests success
func isSuccessHTTPResponse(resp autorest.Response) bool {
	// HTTP 2xx suggests a successful response
	if 199 < resp.StatusCode && resp.StatusCode < 300 {
		return true
	}
	return false
}