package main

import (
	"crypto/rand"
	"encoding/hex"
	"errors"
	"fmt"
	"isle/admin"
	"isle/bootstrap"
	"isle/daemon"
	"isle/garage"
	"isle/nebula"
	"net"
	"os"
	"strings"

	"dev.mediocregopher.com/mediocre-go-lib.git/mlog"
)

func randStr(l int) string {
	b := make([]byte, l)
	if _, err := rand.Read(b); err != nil {
		panic(err)
	}
	return hex.EncodeToString(b)
}

func readAdmin(path string) (admin.Admin, error) {

	if path == "-" {

		adm, err := admin.FromReader(os.Stdin)
		if err != nil {
			return admin.Admin{}, fmt.Errorf("parsing admin.json from stdin: %w", err)
		}

		return adm, nil
	}

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

	return admin.FromReader(f)
}

var subCmdAdminCreateNetwork = subCmd{
	name:  "create-network",
	descr: "Creates a new isle network, outputting the resulting admin.json to stdout",
	do: func(subCmdCtx subCmdCtx) error {

		flags := subCmdCtx.flagSet(false)

		daemonConfigPath := flags.StringP(
			"config-path", "c", "",
			"Optional path to a daemon.yml file to load configuration from.",
		)

		dumpConfig := flags.Bool(
			"dump-config", false,
			"Write the default configuration file to stdout and exit.",
		)

		name := flags.StringP(
			"name", "n", "",
			"Human-readable name to identify the network as.",
		)

		domain := flags.StringP(
			"domain", "d", "",
			"Domain name that should be used as the root domain in the network.",
		)

		ipNetStr := flags.StringP(
			"ip-net", "i", "",
			`IP+prefix (e.g. "10.10.0.1/16") which denotes the IP of this host, which will be the first host in the network, and the range of IPs which other hosts in the network can be assigned`,
		)

		hostName := flags.StringP(
			"hostname", "h", "",
			"Name of this host, which will be the first host in the network",
		)

		logLevelStr := flags.StringP(
			"log-level", "l", "info",
			`Maximum log level which should be output. Values can be "debug", "info", "warn", "error", "fatal". Does not apply to sub-processes`,
		)

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

		ctx := subCmdCtx.ctx

		if *dumpConfig {
			return daemon.CopyDefaultConfig(os.Stdout, envAppDirPath)
		}

		if *name == "" || *domain == "" || *ipNetStr == "" || *hostName == "" {
			return errors.New("--name, --domain, --ip-net, and --hostname are required")
		}

		logLevel := mlog.LevelFromString(*logLevelStr)
		if logLevel == nil {
			return fmt.Errorf("couldn't parse log level %q", *logLevelStr)
		}

		logger := subCmdCtx.logger.WithMaxLevel(logLevel.Int())

		*domain = strings.TrimRight(strings.TrimLeft(*domain, "."), ".")

		ip, subnet, err := net.ParseCIDR(*ipNetStr)
		if err != nil {
			return fmt.Errorf("parsing %q as a CIDR: %w", *ipNetStr, err)
		}

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

		runtimeDirCleanup, err := setupAndLockRuntimeDir(ctx, logger)
		if err != nil {
			return fmt.Errorf("setting up runtime directory: %w", err)
		}
		defer runtimeDirCleanup()

		daemonConfig, err := daemon.LoadConfig(envAppDirPath, *daemonConfigPath)
		if err != nil {
			return fmt.Errorf("loading daemon config: %w", err)
		}

		if len(daemonConfig.Storage.Allocations) < 3 {
			return fmt.Errorf("daemon config with at least 3 allocations was not provided")
		}

		nebulaCACreds, err := nebula.NewCACredentials(*domain, subnet)
		if err != nil {
			return fmt.Errorf("creating nebula CA cert: %w", err)
		}

		adminCreationParams := admin.CreationParams{
			ID:     randStr(32),
			Name:   *name,
			Domain: *domain,
		}

		garageBootstrap := bootstrap.Garage{
			RPCSecret:  randStr(32),
			AdminToken: randStr(32),
		}

		hostBootstrap, err := bootstrap.New(
			nebulaCACreds,
			adminCreationParams,
			garageBootstrap,
			*hostName,
			ip,
		)
		if err != nil {
			return fmt.Errorf("initializing bootstrap data: %w", err)
		}

		if hostBootstrap, err = coalesceDaemonConfigAndBootstrap(hostBootstrap, daemonConfig); err != nil {
			return fmt.Errorf("merging daemon config into bootstrap data: %w", err)
		}

		children, err := daemon.NewChildren(
			ctx,
			logger.WithNamespace("daemon"),
			daemonConfig,
			hostBootstrap,
			envBinDirPath,
			&daemon.Opts{
				// NOTE both stdout and stderr are sent to stderr, so that the
				// user can pipe the resulting admin.json to stdout.
				Stdout: os.Stderr,
			},
		)
		if err != nil {
			return fmt.Errorf("initializing children: %w", err)
		}
		defer func() {
			logger.Info(ctx, "Shutting down child processes")
			if err := children.Shutdown(); err != nil {
				logger.Error(ctx, "Failed to shut down children cleanly, there may be zombie children leftover", err)
			}
		}()

		logger.Info(ctx, "Applying garage layout")
		if err := daemon.GarageApplyLayout(
			ctx, logger, hostBootstrap, daemonConfig,
		); err != nil {
			return fmt.Errorf("applying garage layout: %w", err)
		}

		logger.Info(ctx, "initializing garage shared global bucket")
		garageGlobalBucketCreds, err := garageInitializeGlobalBucket(
			ctx, logger, hostBootstrap, daemonConfig,
		)

		if cErr := (garage.AdminClientError{}); errors.As(err, &cErr) && cErr.StatusCode == 409 {
			return fmt.Errorf("shared global bucket has already been created, are the storage allocations from a previously initialized isle being used?")

		} else if err != nil {
			return fmt.Errorf("initializing garage shared global bucket: %w", err)
		}

		hostBootstrap.Garage.GlobalBucketS3APICredentials = garageGlobalBucketCreds

		// rewrite the bootstrap now that the global bucket creds have been
		// added to it.
		if err := writeBootstrapToStateDir(hostBootstrap); err != nil {
			return fmt.Errorf("writing bootstrap file: %w", err)
		}

		logger.Info(ctx, "Network initialized successfully, writing admin.json to stdout")

		adm := admin.Admin{
			CreationParams: adminCreationParams,
		}
		adm.Nebula.CACredentials = nebulaCACreds
		adm.Garage.RPCSecret = hostBootstrap.Garage.RPCSecret
		adm.Garage.GlobalBucketS3APICredentials = hostBootstrap.Garage.GlobalBucketS3APICredentials

		if err := adm.WriteTo(os.Stdout); err != nil {
			return fmt.Errorf("writing admin.json to stdout")
		}

		return nil
	},
}

var subCmdAdminCreateBootstrap = subCmd{
	name:      "create-bootstrap",
	descr:     "Creates a new bootstrap.json file for a particular host and writes it to stdout",
	checkLock: false,
	do: func(subCmdCtx subCmdCtx) error {

		flags := subCmdCtx.flagSet(false)

		hostName := flags.StringP(
			"hostname", "h", "",
			"Name of the host to generate bootstrap.json for",
		)

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

		adminPath := flags.StringP(
			"admin-path", "a", "",
			`Path to admin.json 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 *hostName == "" || *ipStr == "" || *adminPath == "" {
			return errors.New("--hostname, --ip, and --admin-path are required")
		}

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

		ip := net.ParseIP(*ipStr)

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

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

		garageBootstrap := bootstrap.Garage{
			RPCSecret:                    adm.Garage.RPCSecret,
			AdminToken:                   randStr(32),
			GlobalBucketS3APICredentials: adm.Garage.GlobalBucketS3APICredentials,
		}

		newHostBootstrap, err := bootstrap.New(
			adm.Nebula.CACredentials,
			adm.CreationParams,
			garageBootstrap,
			*hostName,
			ip,
		)
		if err != nil {
			return fmt.Errorf("initializing bootstrap data: %w", err)
		}

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

		newHostBootstrap.Hosts = hostBootstrap.Hosts

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

var subCmdAdminCreateNebulaCert = subCmd{
	name:      "create-nebula-cert",
	descr:     "Creates a signed nebula certificate file and writes it to stdout",
	checkLock: false,
	do: func(subCmdCtx subCmdCtx) error {

		flags := subCmdCtx.flagSet(false)

		hostName := flags.StringP(
			"hostname", "h", "",
			"Name of the host to generate bootstrap.json for",
		)

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

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

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

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

		if *hostName == "" || *ipStr == "" || *adminPath == "" || *pubKeyPath == "" {
			return errors.New("--hostname, --ip, --admin-path, and --pub-key-path are required")
		}

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

		ip := net.ParseIP(*ipStr)

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

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

		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)
		}

		nebulaHostCert, err := nebula.NewHostCert(
			adm.Nebula.CACredentials, hostPub, *hostName, ip,
		)
		if err != nil {
			return fmt.Errorf("creating cert: %w", err)
		}

		nebulaHostCertPEM, err := nebulaHostCert.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 subCmdAdmin = subCmd{
	name:  "admin",
	descr: "Sub-commands which only admins can run",
	do: func(subCmdCtx subCmdCtx) error {
		return subCmdCtx.doSubCmd(
			subCmdAdminCreateNetwork,
			subCmdAdminCreateBootstrap,
			subCmdAdminCreateNebulaCert,
		)
	},
}