package main

import (
	"context"
	"fmt"
	"io"
	"log"

	"github.com/spf13/cobra"

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

var approveCmd = &cobra.Command{
	Short: "Approves a candidate node, if specified; lists nodes pending approval otherwise.",
	Use:   "approve [node-id]",
	Args:  cobra.MaximumNArgs(1), // One positional argument: node ID
	Run:   doApprove,
}

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

// getNewNodes returns all nodes pending approval within the cluster.
func getNewNodes(ctx context.Context, mgmt api.ManagementClient) ([]*api.Node, error) {
	resN, err := mgmt.GetNodes(ctx, &api.GetNodesRequest{
		Filter: "node.state == NODE_STATE_NEW",
	})
	if err != nil {
		return nil, err
	}

	var nodes []*api.Node
	for {
		node, err := resN.Recv()
		if err == io.EOF {
			break
		}
		if err != nil {
			return nil, err
		}
		nodes = append(nodes, node)
	}
	return nodes, nil
}

// nodeById returns the node matching id, if it exists within nodes.
func nodeById(nodes []*api.Node, id string) *api.Node {
	for _, n := range nodes {
		if identity.NodeID(n.Pubkey) == id {
			return n
		}
	}
	return nil
}

func doApprove(cmd *cobra.Command, args []string) {
	// Collect credentials, validate command parameters, and try dialing the
	// cluster.
	ocert, opkey, err := getCredentials()
	if err == noCredentialsError {
		log.Fatalf("You have to take ownership of the cluster first: %v", err)
	}
	if len(flags.clusterEndpoints) == 0 {
		log.Fatal("Please provide at least one cluster endpoint using the --endpoint parameter.")
	}
	ctx := clicontext.WithInterrupt(context.Background())
	cc, err := dialCluster(ctx, opkey, ocert, flags.proxyAddr, flags.clusterEndpoints)
	if err != nil {
		log.Fatalf("While dialing the cluster: %v", err)
	}
	mgmt := api.NewManagementClient(cc)

	// Get a list of all nodes pending approval by calling Management.GetNodes.
	// We need this list regardless of whether we're actually approving nodes, or
	// just listing them.
	nodes, err := getNewNodes(ctx, mgmt)
	if err != nil {
		log.Fatalf("While fetching a list of nodes pending approval: %v", err)
	}

	if len(args) == 0 {
		// If no id was given, just list the nodes pending approval.
		if len(nodes) != 0 {
			for _, n := range nodes {
				fmt.Print(identity.NodeID(n.Pubkey))
			}
		} else {
			log.Print("There are no nodes pending approval at this time.")
		}
	} else {
		// Otherwise, try to approve the node matching the id.
		tgtNodeId := args[0]

		n := nodeById(nodes, tgtNodeId)
		if n == nil {
			log.Fatalf("Couldn't find a new node matching id %s", tgtNodeId)
		}
		_, err := mgmt.ApproveNode(ctx, &api.ApproveNodeRequest{
			Pubkey: n.Pubkey,
		})
		if err != nil {
			log.Fatalf("While approving node %s: %v", tgtNodeId, err)
		}
		log.Printf("Approved node %s.", tgtNodeId)
	}
}