package main

import (
	"context"
	"crypto/ed25519"
	"encoding/pem"
	"log"
	"net"
	"os"
	"path/filepath"

	"github.com/adrg/xdg"
	"github.com/spf13/cobra"
	"google.golang.org/grpc"

	clicontext "source.monogon.dev/metropolis/cli/pkg/context"
	"source.monogon.dev/metropolis/node"
	"source.monogon.dev/metropolis/node/core/rpc"
	apb "source.monogon.dev/metropolis/proto/api"
)

var takeownershipCommand = &cobra.Command{
	Use:   "takeownership <node-addr>",
	Short: "Takes ownership of a new Metropolis cluster",
	Long: `This takes ownership of a new Metropolis cluster by asking the new
cluster to issue an owner certificate to for the owner key generated by a
previous invocation of metroctl install on this machine.`,
	Example: "takeownership 192.0.2.1",
	Args:    cobra.ExactArgs(1), // One positional argument: the node address
	Run:     doTakeOwnership,
}

func doTakeOwnership(cmd *cobra.Command, args []string) {
	ctx := clicontext.WithInterrupt(context.Background())
	ownerPrivateKeyPEM, err := os.ReadFile(filepath.Join(xdg.ConfigHome, "metroctl/owner-key.pem"))
	if os.IsNotExist(err) {
		log.Fatalf("Owner key does not exist. takeownership needs to be executed on the same system that has previously installed the cluster using metroctl install.")
	} else if err != nil {
		log.Fatalf("Failed to load owner private key: %v", err)
	}
	block, _ := pem.Decode(ownerPrivateKeyPEM)
	if block == nil {
		log.Fatalf("owner-key.pem contains invalid PEM")
	}
	if block.Type != ownerKeyType {
		log.Fatalf("owner-key.pem contains a PEM block that's not a %v", ownerKeyType)
	}
	if len(block.Bytes) != ed25519.PrivateKeySize {
		log.Fatal("owner-key.pem contains non-Ed25519 key")
	}
	ownerPrivateKey := ed25519.PrivateKey(block.Bytes)

	ephCreds, err := rpc.NewEphemeralCredentials(ownerPrivateKey, nil)
	if err != nil {
		log.Fatalf("Failed to create ephemeral credentials: %v", err)
	}
	client, err := grpc.Dial(net.JoinHostPort(args[0], node.CuratorServicePort.PortString()), grpc.WithTransportCredentials(ephCreds))
	if err != nil {
		log.Fatalf("Failed to create client to given node address: %v", err)
	}
	defer client.Close()
	aaa := apb.NewAAAClient(client)
	ownerCert, err := rpc.RetrieveOwnerCertificate(ctx, aaa, ownerPrivateKey)
	if err != nil {
		log.Fatalf("Failed to retrive owner certificate from cluster: %v", err)
	}
	ownerCertPEM := pem.Block{
		Type:  "CERTIFICATE",
		Bytes: ownerCert.Certificate[0],
	}
	if err := os.WriteFile(filepath.Join(xdg.ConfigHome, "metroctl/owner.pem"), pem.EncodeToMemory(&ownerCertPEM), 0644); err != nil {
		log.Printf("Failed to store retrieved owner certificate: %v", err)
		log.Fatalln("Sorry, the cluster has been lost as taking ownership cannot be repeated. Fix the reason the file couldn't be written and reinstall the node.")
	}
	log.Print("Successfully retrieved owner credentials! You now own this cluster.")
}

func init() {
	rootCmd.AddCommand(takeownershipCommand)
}