package main

import (
	"fmt"
	"os"

	"github.com/slackhq/nebula/cert"
	"gopkg.in/yaml.v3"
)

var subCmdNebulaShow = subCmd{
	name:  "show",
	descr: "Writes nebula network information to stdout in yaml format",
	do: func(subCmdCtx subCmdCtx) error {

		flags := subCmdCtx.flagSet(false)
		if err := flags.Parse(subCmdCtx.args); err != nil {
			return fmt.Errorf("parsing flags: %w", err)
		}

		hostBootstrap, err := loadHostBootstrap()
		if err != nil {
			return fmt.Errorf("loading host bootstrap: %w", err)
		}

		caPublicCreds := hostBootstrap.Nebula.CAPublicCredentials
		caCert, _, err := cert.UnmarshalNebulaCertificateFromPEM([]byte(caPublicCreds.CertPEM))
		if err != nil {
			return fmt.Errorf("unmarshaling ca.crt: %w", err)
		}

		if len(caCert.Details.Subnets) != 1 {
			return fmt.Errorf(
				"malformed ca.crt, contains unexpected subnets %#v",
				caCert.Details.Subnets,
			)
		}

		subnet := caCert.Details.Subnets[0]

		type outLighthouse struct {
			PublicAddr string `yaml:"public_addr"`
			IP         string `yaml:"ip"`
		}

		out := struct {
			CACert      string          `yaml:"ca_cert_pem"`
			SubnetCIDR  string          `yaml:"subnet_cidr"`
			Lighthouses []outLighthouse `yaml:"lighthouses"`
		}{
			CACert:     caPublicCreds.CertPEM,
			SubnetCIDR: subnet.String(),
		}

		for _, h := range hostBootstrap.Hosts {
			if h.Nebula.PublicAddr == "" {
				continue
			}

			out.Lighthouses = append(out.Lighthouses, outLighthouse{
				PublicAddr: h.Nebula.PublicAddr,
				IP:         h.IP().String(),
			})
		}

		if err := yaml.NewEncoder(os.Stdout).Encode(out); err != nil {
			return fmt.Errorf("yaml encoding to stdout: %w", err)
		}

		return nil
	},
}

var subCmdNebula = subCmd{
	name:  "nebula",
	descr: "Sub-commands related to the nebula VPN",
	do: func(subCmdCtx subCmdCtx) error {
		return subCmdCtx.doSubCmd(
			subCmdNebulaShow,
		)
	},
}