/*
Copyright 2022 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 protokube

import (
	"context"
	"fmt"
	"os"

	"github.com/hetznercloud/hcloud-go/v2/hcloud"
	"github.com/hetznercloud/hcloud-go/v2/hcloud/metadata"
	"k8s.io/klog/v2"
	version "k8s.io/kops"
	"k8s.io/kops/protokube/pkg/gossip"
	gossiphetzner "k8s.io/kops/protokube/pkg/gossip/hetzner"
	"k8s.io/kops/upup/pkg/fi/cloudup/hetzner"
)

// HetznerCloudProvider defines the Hetzner Cloud volume implementation.
type HetznerCloudProvider struct {
	hcloudClient *hcloud.Client
	server       *hcloud.Server
}

var _ CloudProvider = &HetznerCloudProvider{}

// NewHetznerCloudProvider returns a new Hetzner Cloud provider.
func NewHetznerCloudProvider() (*HetznerCloudProvider, error) {
	serverID, err := metadata.NewClient().InstanceID()
	if err != nil {
		return nil, fmt.Errorf("failed to retrieve server id: %s", err)
	}
	klog.V(4).Infof("Found ID of the running server: %d", serverID)

	hcloudToken := os.Getenv("HCLOUD_TOKEN")
	if hcloudToken == "" {
		return nil, fmt.Errorf("%s is required", "HCLOUD_TOKEN")
	}
	opts := []hcloud.ClientOption{
		hcloud.WithToken(hcloudToken),
		hcloud.WithApplication("kops", version.Version),
	}
	hcloudClient := hcloud.NewClient(opts...)

	// TODO(hakman): Get server info from server metadata
	server, _, err := hcloudClient.Server.GetByID(context.TODO(), serverID)
	if err != nil || server == nil {
		return nil, fmt.Errorf("failed to get info for the running server: %s", err)
	}

	klog.V(4).Infof("Found name of the running server: %q", server.Name)
	if server.Datacenter != nil && server.Datacenter.Location != nil {
		klog.V(4).Infof("Found location of the running server: %q", server.Datacenter.Location.Name)
	} else {
		return nil, fmt.Errorf("failed to find location of the running server")
	}
	if len(server.PrivateNet) > 0 {
		klog.V(4).Infof("Found first private net IP of the running server: %q", server.PrivateNet[0].IP.String())
	} else {
		return nil, fmt.Errorf("failed to find private net of the running server")
	}

	h := &HetznerCloudProvider{
		hcloudClient: hcloudClient,
		server:       server,
	}

	return h, nil
}

func (h *HetznerCloudProvider) GossipSeeds() (gossip.SeedProvider, error) {
	clusterName, ok := h.server.Labels[hetzner.TagKubernetesClusterName]
	if !ok {
		return nil, fmt.Errorf("failed to find cluster name label for running server: %v", h.server.Labels)
	}
	return gossiphetzner.NewSeedProvider(h.hcloudClient, clusterName)
}

func (h *HetznerCloudProvider) InstanceID() string {
	return fmt.Sprintf("%s-%d", h.server.Name, h.server.ID)
}
