/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 cloudstack

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"

	"github.com/xanzy/go-cloudstack/v2/cloudstack"
	"gopkg.in/gcfg.v1"
	"k8s.io/apimachinery/pkg/types"
	cloudprovider "k8s.io/cloud-provider"
	"k8s.io/klog"
)

// ProviderName is the name of this cloud provider.
const ProviderName = "external-cloudstack"

// CSConfig wraps the config for the CloudStack cloud provider.
type CSConfig struct {
	Global struct {
		APIURL      string `gcfg:"api-url"`
		APIKey      string `gcfg:"api-key"`
		SecretKey   string `gcfg:"secret-key"`
		SSLNoVerify bool   `gcfg:"ssl-no-verify"`
		ProjectID   string `gcfg:"project-id"`
		Zone        string `gcfg:"zone"`
	}
}

// CSCloud is an implementation of Interface for CloudStack.
type CSCloud struct {
	client    *cloudstack.CloudStackClient
	projectID string // If non-"", all resources will be created within this project
	zone      string
}

func init() {
	cloudprovider.RegisterCloudProvider(ProviderName, func(config io.Reader) (cloudprovider.Interface, error) {
		cfg, err := readConfig(config)
		if err != nil {
			return nil, err
		}

		return newCSCloud(cfg)
	})
}

func readConfig(config io.Reader) (*CSConfig, error) {
	cfg := &CSConfig{}

	if config == nil {
		return cfg, nil
	}

	if err := gcfg.ReadInto(cfg, config); err != nil {
		return nil, fmt.Errorf("could not parse cloud provider config: %v", err)
	}

	return cfg, nil
}

// newCSCloud creates a new instance of CSCloud.
func newCSCloud(cfg *CSConfig) (*CSCloud, error) {
	cs := &CSCloud{
		projectID: cfg.Global.ProjectID,
		zone:      cfg.Global.Zone,
	}

	if cfg.Global.APIURL != "" && cfg.Global.APIKey != "" && cfg.Global.SecretKey != "" {
		cs.client = cloudstack.NewAsyncClient(cfg.Global.APIURL, cfg.Global.APIKey, cfg.Global.SecretKey, !cfg.Global.SSLNoVerify)
	}

	if cs.client == nil {
		return nil, errors.New("no cloud provider config given")
	}

	return cs, nil
}

// Initialize passes a Kubernetes clientBuilder interface to the cloud provider
func (cs *CSCloud) Initialize(clientBuilder cloudprovider.ControllerClientBuilder, stop <-chan struct{}) {
}

// LoadBalancer returns an implementation of LoadBalancer for CloudStack.
func (cs *CSCloud) LoadBalancer() (cloudprovider.LoadBalancer, bool) {
	if cs.client == nil {
		return nil, false
	}

	return cs, true
}

// Instances returns an implementation of Instances for CloudStack.
func (cs *CSCloud) Instances() (cloudprovider.Instances, bool) {
	if cs.client == nil {
		return nil, false
	}

	return cs, true
}

// Zones returns an implementation of Zones for CloudStack.
func (cs *CSCloud) Zones() (cloudprovider.Zones, bool) {
	if cs.client == nil {
		return nil, false
	}

	return cs, true
}

// Clusters returns an implementation of Clusters for CloudStack.
func (cs *CSCloud) Clusters() (cloudprovider.Clusters, bool) {
	if cs.client == nil {
		return nil, false
	}

	klog.Warning("This cloud provider doesn't support clusters")
	return nil, false
}

// Routes returns an implementation of Routes for CloudStack.
func (cs *CSCloud) Routes() (cloudprovider.Routes, bool) {
	if cs.client == nil {
		return nil, false
	}

	klog.Warning("This cloud provider doesn't support routes")
	return nil, false
}

// ProviderName returns the cloud provider ID.
func (cs *CSCloud) ProviderName() string {
	return ProviderName
}

// HasClusterID returns true if the cluster has a clusterID
func (cs *CSCloud) HasClusterID() bool {
	return true
}

// GetZone returns the Zone containing the region that the program is running in.
func (cs *CSCloud) GetZone(ctx context.Context) (cloudprovider.Zone, error) {
	zone := cloudprovider.Zone{}

	if cs.zone == "" {
		hostname, err := os.Hostname()
		if err != nil {
			return zone, fmt.Errorf("failed to get hostname for retrieving the zone: %v", err)
		}

		instance, count, err := cs.client.VirtualMachine.GetVirtualMachineByName(hostname)
		if err != nil {
			if count == 0 {
				return zone, fmt.Errorf("could not find instance for retrieving the zone: %v", err)
			}
			return zone, fmt.Errorf("error getting instance for retrieving the zone: %v", err)
		}

		cs.zone = instance.Zonename
	}

	klog.V(2).Infof("Current zone is %v", cs.zone)
	zone.FailureDomain = cs.zone
	zone.Region = cs.zone

	return zone, nil
}

// GetZoneByProviderID returns the Zone, found by using the provider ID.
func (cs *CSCloud) GetZoneByProviderID(ctx context.Context, providerID string) (cloudprovider.Zone, error) {
	zone := cloudprovider.Zone{}

	instance, count, err := cs.client.VirtualMachine.GetVirtualMachineByID(
		providerID,
		cloudstack.WithProject(cs.projectID),
	)
	if err != nil {
		if count == 0 {
			return zone, fmt.Errorf("could not find node by ID: %v", providerID)
		}
		return zone, fmt.Errorf("error retrieving zone: %v", err)
	}

	klog.V(2).Infof("Current zone is %v", cs.zone)
	zone.FailureDomain = instance.Zonename
	zone.Region = instance.Zonename

	return zone, nil
}

// GetZoneByNodeName returns the Zone, found by using the node name.
func (cs *CSCloud) GetZoneByNodeName(ctx context.Context, nodeName types.NodeName) (cloudprovider.Zone, error) {
	zone := cloudprovider.Zone{}

	instance, count, err := cs.client.VirtualMachine.GetVirtualMachineByName(
		string(nodeName),
		cloudstack.WithProject(cs.projectID),
	)
	if err != nil {
		if count == 0 {
			return zone, fmt.Errorf("could not find node: %v", nodeName)
		}
		return zone, fmt.Errorf("error retrieving zone: %v", err)
	}

	klog.V(2).Infof("Current zone is %v", cs.zone)
	zone.FailureDomain = instance.Zonename
	zone.Region = instance.Zonename

	return zone, nil
}