package main

import (
	"errors"
	"fmt"
	"isle/daemon"
	"isle/jsonutil"
	"isle/nebula"
	"net/netip"
	"os"
)

var subCmdNebulaCreateCert = subCmd{
	name:  "create-cert",
	descr: "Creates a signed nebula certificate file for an existing host and writes it to stdout",
	do: func(subCmdCtx subCmdCtx) error {
		var (
			flags    = subCmdCtx.flagSet(false)
			hostName nebula.HostName
			ip       netip.Addr
		)

		hostNameF := flags.VarPF(
			textUnmarshalerFlag{&hostName},
			"hostname", "h",
			"Name of the host to generate a certificate for",
		)

		pubKeyPath := flags.StringP(
			"public-key-path", "p", "",
			`Path to PEM file containing public key which will be embedded in the cert.`,
		)

		flags.Var(
			textUnmarshalerFlag{&ip},
			"ip",
			"IP address to create a cert for. If this is not given then the IP associated with the host via its `hosts create` call will be used",
		)

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

		if !hostNameF.Changed || *pubKeyPath == "" {
			return errors.New("--hostname and --pub-key-path are required")
		}

		hostPubPEM, err := os.ReadFile(*pubKeyPath)
		if err != nil {
			return fmt.Errorf("reading public key from %q: %w", *pubKeyPath, err)
		}

		var hostPub nebula.EncryptingPublicKey
		if err := hostPub.UnmarshalNebulaPEM(hostPubPEM); err != nil {
			return fmt.Errorf("unmarshaling public key as PEM: %w", err)
		}

		var res daemon.CreateNebulaCertificateResult
		err = subCmdCtx.daemonRCPClient.Call(
			subCmdCtx.ctx,
			&res,
			"CreateNebulaCertificate",
			daemon.CreateNebulaCertificateRequest{
				HostName:                hostName,
				HostEncryptingPublicKey: hostPub,
				Opts: daemon.CreateNebulaCertificateOpts{
					IP: ip,
				},
			},
		)
		if err != nil {
			return fmt.Errorf("calling CreateNebulaCertificate: %w", err)
		}

		nebulaHostCertPEM, err := res.HostNebulaCertifcate.Unwrap().MarshalToPEM()
		if err != nil {
			return fmt.Errorf("marshaling cert to PEM: %w", err)
		}

		if _, err := os.Stdout.Write([]byte(nebulaHostCertPEM)); err != nil {
			return fmt.Errorf("writing to stdout: %w", err)
		}

		return nil
	},
}

var subCmdNebulaShow = subCmd{
	name:  "show",
	descr: "Writes nebula network information to stdout in JSON 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)
		}

		hosts, err := subCmdCtx.getHosts()
		if err != nil {
			return fmt.Errorf("getting hosts: %w", err)
		}

		var caPublicCreds nebula.CAPublicCredentials
		err = subCmdCtx.daemonRCPClient.Call(
			subCmdCtx.ctx, &caPublicCreds, "GetNebulaCAPublicCredentials", nil,
		)
		if err != nil {
			return fmt.Errorf("calling GetNebulaCAPublicCredentials: %w", err)
		}

		caCert := caPublicCreds.Cert
		caCertDetails := caCert.Unwrap().Details

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

		subnet := caCertDetails.Subnets[0]

		type outLighthouse struct {
			PublicAddr string
			IP         string
		}

		out := struct {
			CACert      nebula.Certificate
			SubnetCIDR  string
			Lighthouses []outLighthouse
		}{
			CACert:     caCert,
			SubnetCIDR: subnet.String(),
		}

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

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

		if err := jsonutil.WriteIndented(os.Stdout, out); err != nil {
			return fmt.Errorf("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(
			subCmdNebulaCreateCert,
			subCmdNebulaShow,
		)
	},
}