// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package main

import (
	"fmt"
	"strings"

	"v.io/v23/context"
	"v.io/v23/security"
	"v.io/v23/services/device"
)

const (
	clusterAgentServiceName     = "cluster-agent"
	clusterAgentServicePort     = 8193
	clusterAgentApplicationName = "cluster-agentd"
)

// createClusterAgent creates a ReplicationController and a Service to run the
// cluster agent.
func createClusterAgent(ctx *context.T, config *vkubeConfig) error {
	if err := createNamespaceIfNotExist(config.ClusterAgent.Namespace); err != nil {
		return err
	}
	version := "latest"
	if p := strings.Split(config.ClusterAgent.Image, ":"); len(p) == 2 {
		version = p[1]
	}
	ca := object{
		"apiVersion": "v1",
		"kind":       "ReplicationController",
		"metadata": object{
			"name": clusterAgentApplicationName + "-" + version,
			"labels": object{
				"application": clusterAgentApplicationName,
			},
			"namespace": config.ClusterAgent.Namespace,
		},
		"spec": object{
			"replicas": 1,
			"template": object{
				"metadata": object{
					"labels": object{
						"application": clusterAgentApplicationName,
						"deployment":  version,
					},
				},
				"spec": object{
					"containers": []object{
						object{
							"name":  "cluster-agentd",
							"image": config.ClusterAgent.Image,
							"ports": []object{
								object{
									"containerPort": clusterAgentServicePort,
								},
							},
							"resources": object{
								"limits": object{
									"cpu":    config.ClusterAgent.CPU,
									"memory": config.ClusterAgent.Memory,
								},
							},
							"volumeMounts": []object{
								object{
									"name":      "data",
									"mountPath": "/data",
								},
								object{
									"name":      "logs",
									"mountPath": "/logs",
								},
							},
							"env": []object{
								object{
									"name":  "ROOT_BLESSINGS",
									"value": rootBlessings(ctx),
								},
								object{
									"name":  "CLAIMER",
									"value": clusterAgentClaimer(config),
								},
								object{
									"name":  "ADMIN",
									"value": config.ClusterAgent.Admin,
								},
								object{
									"name":  "DATADIR",
									"value": "/data",
								},
								object{
									"name":  "LOGDIR",
									"value": "/logs",
								},
							},
						},
					},
					"volumes": []interface{}{
						object{
							"name":     "logs",
							"emptyDir": object{},
						},
					},
				},
			},
		},
	}
	if config.ClusterAgent.PersistentDisk == "" {
		ca.append("spec.template.spec.volumes", object{
			"name":     "data",
			"emptyDir": object{},
		})
	} else {
		ca.append("spec.template.spec.volumes", object{
			"name": "data",
			"gcePersistentDisk": object{
				"pdName": config.ClusterAgent.PersistentDisk,
				"fsType": "ext4",
			},
		})
	}

	if out, err := kubectlCreate(ca); err != nil {
		return fmt.Errorf("failed to create replication controller: %v\n%s\n", err, string(out))
	}

	svc := object{
		"apiVersion": "v1",
		"kind":       "Service",
		"metadata": object{
			"name":      clusterAgentServiceName,
			"namespace": config.ClusterAgent.Namespace,
		},
		"spec": object{
			"ports": []object{
				object{
					"port":       clusterAgentServicePort,
					"targetPort": clusterAgentServicePort,
				},
			},
			"selector": object{
				"application": clusterAgentApplicationName,
			},
			"type": "LoadBalancer",
		},
	}
	if config.ClusterAgent.ExternalIP != "" {
		svc.set("spec.loadBalancerIP", config.ClusterAgent.ExternalIP)
	}
	if out, err := kubectlCreate(svc); err != nil {
		return fmt.Errorf("failed to create service: %v\n%s\n", err, string(out))
	}
	return nil
}

// stopClusterAgent stops the cluster agent ReplicationController and deletes
// its Service.
func stopClusterAgent(config *vkubeConfig) error {
	if out, err := kubectl("--namespace="+config.ClusterAgent.Namespace, "stop", "rc", "-l", "application="+clusterAgentApplicationName); err != nil {
		return fmt.Errorf("failed to stop %s: %v: %s", clusterAgentApplicationName, err, out)
	}
	if out, err := kubectl("--namespace="+config.ClusterAgent.Namespace, "delete", "service", clusterAgentServiceName); err != nil {
		return fmt.Errorf("failed to delete %s: %v: %s", clusterAgentServiceName, err, out)
	}
	return nil
}

// clusterAgentClaimer returns the blessing name of the claimer of the cluster
// agent.
func clusterAgentClaimer(config *vkubeConfig) string {
	p := strings.Split(config.ClusterAgent.Blessing, security.ChainSeparator)
	return strings.Join(p[:len(p)-1], security.ChainSeparator)
}

// findClusterAgent returns the external address of the cluster agent.
func findClusterAgent(config *vkubeConfig, includeBlessings bool) (string, error) {
	out, err := kubectl("--namespace="+config.ClusterAgent.Namespace, "get", "service", clusterAgentServiceName, "-o", "json")
	if err != nil {
		return "", fmt.Errorf("failed to get info of %s: %v: %s", clusterAgentServiceName, err, out)
	}
	var svc object
	if err := svc.importJSON(out); err != nil {
		return "", fmt.Errorf("failed to parse kubectl output: %v", err)
	}
	ports := svc.getObjectArray("spec.ports")
	if len(ports) == 0 {
		return "", fmt.Errorf("service %q has no ports", clusterAgentServiceName)
	}
	port := ports[0].getInt("port")
	if port < 0 {
		return "", fmt.Errorf("service %q has no valid port: %v", clusterAgentServiceName, port)
	}
	ingress := svc.getObjectArray("status.loadBalancer.ingress")
	if len(ingress) == 0 {
		return "", fmt.Errorf("service %q has no loadbalancer ingress", clusterAgentServiceName)
	}
	ip := ingress[0].getString("ip")
	if ip == "" {
		return "", fmt.Errorf("service %q loadbalancer has no valid ip", clusterAgentServiceName)
	}
	if includeBlessings {
		return fmt.Sprintf("/(%s)@%s:%d", config.ClusterAgent.Blessing, ip, port), nil
	}
	return fmt.Sprintf("/%s:%d", ip, port), nil
}

// claimClusterAgent claims the cluster agent with the given blessing extension.
func claimClusterAgent(ctx *context.T, config *vkubeConfig, extension string) error {
	addr, err := findClusterAgent(config, false)
	if err != nil {
		return err
	}
	if err := device.ClaimableClient(addr).Claim(ctx, "", &granter{extension: extension}); err != nil {
		return err
	}
	return nil
}