package entrypoint

import (
	"cryptic-net/bootstrap"
	"cryptic-net/nebula"
	"cryptic-net/tarutil"
	"errors"
	"fmt"
	"io/fs"
	"net"
	"os"
	"regexp"
	"sort"

	"gopkg.in/yaml.v3"
)

var hostNameRegexp = regexp.MustCompile(`^[a-z][a-z0-9\-]*$`)

func validateHostName(name string) error {

	if !hostNameRegexp.MatchString(name) {
		return errors.New("a host's name must start with a letter and only contain letters, numbers, and dashes")
	}

	return nil
}

var subCmdHostsAdd = subCmd{
	name:      "add",
	descr:     "Adds a host to the network",
	checkLock: true,
	do: func(subCmdCtx subCmdCtx) error {

		flags := subCmdCtx.flagSet(false)

		name := flags.StringP(
			"name", "n", "",
			"Name of the new host",
		)

		ip := flags.StringP(
			"ip", "i", "",
			"IP of the new host",
		)

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

		if *name == "" || *ip == "" {
			return errors.New("--name and --ip are required")
		}

		if err := validateHostName(*name); err != nil {
			return fmt.Errorf("invalid hostname %q: %w", *name, err)
		}

		if net.ParseIP(*ip) == nil {
			return fmt.Errorf("invalid ip %q", *ip)
		}

		// TODO validate that the IP is in the correct CIDR

		env := subCmdCtx.env

		client, err := env.Bootstrap.GlobalBucketS3APIClient()
		if err != nil {
			return fmt.Errorf("creating client for global bucket: %w", err)
		}

		host := bootstrap.Host{
			Name: *name,
			Nebula: bootstrap.NebulaHost{
				IP: *ip,
			},
		}

		return bootstrap.PutGarageBoostrapHost(env.Context, client, host)
	},
}

var subCmdHostsList = subCmd{
	name:      "list",
	descr:     "Lists all hosts in the network, and their IPs",
	checkLock: true,
	do: func(subCmdCtx subCmdCtx) error {

		env := subCmdCtx.env

		client, err := env.Bootstrap.GlobalBucketS3APIClient()
		if err != nil {
			return fmt.Errorf("creating client for global bucket: %w", err)
		}

		hostsMap, err := bootstrap.GetGarageBootstrapHosts(env.Context, client)
		if err != nil {
			return fmt.Errorf("retrieving hosts from garage: %w", err)
		}

		hosts := make([]bootstrap.Host, 0, len(hostsMap))
		for _, host := range hostsMap {
			hosts = append(hosts, host)
		}

		sort.Slice(hosts, func(i, j int) bool { return hosts[i].Name < hosts[j].Name })

		return yaml.NewEncoder(os.Stdout).Encode(hosts)
	},
}

var subCmdHostsDelete = subCmd{
	name:      "delete",
	descr:     "Deletes a host from the network",
	checkLock: true,
	do: func(subCmdCtx subCmdCtx) error {

		flags := subCmdCtx.flagSet(false)

		name := flags.StringP(
			"name", "n", "",
			"Name of the host to delete",
		)

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

		if *name == "" {
			return errors.New("--name is required")
		}

		env := subCmdCtx.env

		client, err := env.Bootstrap.GlobalBucketS3APIClient()
		if err != nil {
			return fmt.Errorf("creating client for global bucket: %w", err)
		}

		return bootstrap.RemoveGarageBootstrapHost(env.Context, client, *name)
	},
}

func readAdminFS(path string) (fs.FS, error) {

	if path == "-" {

		outFS, err := tarutil.FSFromReader(os.Stdin)
		if err != nil {
			return nil, fmt.Errorf("reading admin.tgz from stdin: %w", err)
		}

		return outFS, nil
	}

	f, err := os.Open(path)
	if err != nil {
		return nil, fmt.Errorf("opening file: %w", err)
	}
	defer f.Close()

	return tarutil.FSFromReader(f)
}

var subCmdHostsMakeBootstrap = subCmd{
	name:      "make-bootstrap",
	descr:     "Creates a new bootstrap.tgz file for a particular host and writes it to stdout",
	checkLock: true,
	do: func(subCmdCtx subCmdCtx) error {

		flags := subCmdCtx.flagSet(false)

		name := flags.StringP(
			"name", "n", "",
			"Name of the host to generate bootstrap.tgz for",
		)

		adminPath := flags.StringP(
			"admin-path", "a", "",
			`Path to admin.tgz file. If the given path is "-" then stdin is used.`,
		)

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

		if *name == "" || *adminPath == "" {
			return errors.New("--name and --admin-path are required")
		}

		env := subCmdCtx.env

		adminFS, err := readAdminFS(*adminPath)
		if err != nil {
			return fmt.Errorf("reading admin.tgz with --admin-path of %q: %w", *adminPath, err)
		}

		client, err := env.Bootstrap.GlobalBucketS3APIClient()
		if err != nil {
			return fmt.Errorf("creating client for global bucket: %w", err)
		}

		// NOTE this isn't _technically_ required, but if the `hosts add`
		// command for this host has been run recently then it might not have
		// made it into the bootstrap file yet, and so won't be in
		// `env.Bootstrap`.
		hosts, err := bootstrap.GetGarageBootstrapHosts(env.Context, client)
		if err != nil {
			return fmt.Errorf("retrieving host info from garage: %w", err)
		}

		host, ok := hosts[*name]
		if !ok {
			return fmt.Errorf("couldn't find host into for %q in garage, has `cryptic-net hosts add` been run yet?", *name)
		}

		nebulaHostCert, err := nebula.NewHostCert(adminFS, host)
		if err != nil {
			return fmt.Errorf("creating new nebula host key/cert: %w", err)
		}

		newBootstrap := bootstrap.Bootstrap{
			Hosts:    hosts,
			HostName: *name,

			NebulaCertsCACert:   nebulaHostCert.CACert,
			NebulaCertsHostCert: nebulaHostCert.HostCert,
			NebulaCertsHostKey:  nebulaHostCert.HostKey,

			// TODO these should use adminFS
			GarageRPCSecret:                    env.Bootstrap.GarageRPCSecret,
			GarageGlobalBucketS3APICredentials: env.Bootstrap.GarageGlobalBucketS3APICredentials,
		}

		return newBootstrap.WriteTo(os.Stdout)
	},
}

var subCmdHosts = subCmd{
	name:  "hosts",
	descr: "Sub-commands having to do with configuration of hosts in the network",
	do: func(subCmdCtx subCmdCtx) error {
		return subCmdCtx.doSubCmd(
			subCmdHostsAdd,
			subCmdHostsList,
			subCmdHostsDelete,
			subCmdHostsMakeBootstrap,
		)
	},
}