package command

import (
	"bytes"
	"crypto/rand"
	"encoding/base64"
	"fmt"
	"io"
	"os"
	"strings"

	"github.com/hashicorp/go-secure-stdlib/base62"
	"github.com/hashicorp/go-secure-stdlib/password"
	uuid "github.com/hashicorp/go-uuid"
	"github.com/hashicorp/vault/api"
	"github.com/hashicorp/vault/helper/pgpkeys"
	"github.com/hashicorp/vault/helper/xor"
	"github.com/mitchellh/cli"
	"github.com/posener/complete"
)

var (
	_ cli.Command             = (*OperatorGenerateRootCommand)(nil)
	_ cli.CommandAutocomplete = (*OperatorGenerateRootCommand)(nil)
)

type generateRootKind int

const (
	generateRootRegular generateRootKind = iota
	generateRootDR
	generateRootRecovery
)

type OperatorGenerateRootCommand struct {
	*BaseCommand

	flagInit          bool
	flagCancel        bool
	flagStatus        bool
	flagDecode        string
	flagOTP           string
	flagPGPKey        string
	flagNonce         string
	flagGenerateOTP   bool
	flagDRToken       bool
	flagRecoveryToken bool

	testStdin io.Reader // for tests
}

func (c *OperatorGenerateRootCommand) Synopsis() string {
	return "Generates a new root token"
}

func (c *OperatorGenerateRootCommand) Help() string {
	helpText := `
Usage: vault operator generate-root [options] [KEY]

  Generates a new root token by combining a quorum of share holders. One of
  the following must be provided to start the root token generation:

    - A base64-encoded one-time-password (OTP) provided via the "-otp" flag.
      Use the "-generate-otp" flag to generate a usable value. The resulting
      token is XORed with this value when it is returned. Use the "-decode"
      flag to output the final value.

    - A file containing a PGP key or a keybase username in the "-pgp-key"
      flag. The resulting token is encrypted with this public key.

  An unseal key may be provided directly on the command line as an argument to
  the command. If key is specified as "-", the command will read from stdin. If
  a TTY is available, the command will prompt for text.

  Generate an OTP code for the final token:

      $ vault operator generate-root -generate-otp

  Start a root token generation:

      $ vault operator generate-root -init -otp="..."
      $ vault operator generate-root -init -pgp-key="..."

  Enter an unseal key to progress root token generation:

      $ vault operator generate-root -otp="..."

` + c.Flags().Help()
	return strings.TrimSpace(helpText)
}

func (c *OperatorGenerateRootCommand) Flags() *FlagSets {
	set := c.flagSet(FlagSetHTTP | FlagSetOutputFormat)

	f := set.NewFlagSet("Command Options")

	f.BoolVar(&BoolVar{
		Name:       "init",
		Target:     &c.flagInit,
		Default:    false,
		EnvVar:     "",
		Completion: complete.PredictNothing,
		Usage: "Start a root token generation. This can only be done if " +
			"there is not currently one in progress.",
	})

	f.BoolVar(&BoolVar{
		Name:       "cancel",
		Target:     &c.flagCancel,
		Default:    false,
		EnvVar:     "",
		Completion: complete.PredictNothing,
		Usage: "Reset the root token generation progress. This will discard any " +
			"submitted unseal keys or configuration.",
	})

	f.BoolVar(&BoolVar{
		Name:       "status",
		Target:     &c.flagStatus,
		Default:    false,
		EnvVar:     "",
		Completion: complete.PredictNothing,
		Usage: "Print the status of the current attempt without providing an " +
			"unseal key.",
	})

	f.StringVar(&StringVar{
		Name:       "decode",
		Target:     &c.flagDecode,
		Default:    "",
		EnvVar:     "",
		Completion: complete.PredictAnything,
		Usage: "The value to decode; setting this triggers a decode operation. " +
			" If the value is \"-\" then read the encoded token from stdin.",
	})

	f.BoolVar(&BoolVar{
		Name:       "generate-otp",
		Target:     &c.flagGenerateOTP,
		Default:    false,
		EnvVar:     "",
		Completion: complete.PredictNothing,
		Usage: "Generate and print a high-entropy one-time-password (OTP) " +
			"suitable for use with the \"-init\" flag.",
	})

	f.BoolVar(&BoolVar{
		Name:       "dr-token",
		Target:     &c.flagDRToken,
		Default:    false,
		EnvVar:     "",
		Completion: complete.PredictNothing,
		Usage: "Set this flag to do generate root operations on DR Operational " +
			"tokens.",
	})

	f.BoolVar(&BoolVar{
		Name:       "recovery-token",
		Target:     &c.flagRecoveryToken,
		Default:    false,
		EnvVar:     "",
		Completion: complete.PredictNothing,
		Usage: "Set this flag to do generate root operations on Recovery Operational " +
			"tokens.",
	})

	f.StringVar(&StringVar{
		Name:       "otp",
		Target:     &c.flagOTP,
		Default:    "",
		EnvVar:     "",
		Completion: complete.PredictAnything,
		Usage:      "OTP code to use with \"-decode\" or \"-init\".",
	})

	f.VarFlag(&VarFlag{
		Name:       "pgp-key",
		Value:      (*pgpkeys.PubKeyFileFlag)(&c.flagPGPKey),
		Default:    "",
		EnvVar:     "",
		Completion: complete.PredictAnything,
		Usage: "Path to a file on disk containing a binary or base64-encoded " +
			"public PGP key. This can also be specified as a Keybase username " +
			"using the format \"keybase:<username>\". When supplied, the generated " +
			"root token will be encrypted and base64-encoded with the given public " +
			"key.",
	})

	f.StringVar(&StringVar{
		Name:       "nonce",
		Target:     &c.flagNonce,
		Default:    "",
		EnvVar:     "",
		Completion: complete.PredictAnything,
		Usage: "Nonce value provided at initialization. The same nonce value " +
			"must be provided with each unseal key.",
	})

	return set
}

func (c *OperatorGenerateRootCommand) AutocompleteArgs() complete.Predictor {
	return nil
}

func (c *OperatorGenerateRootCommand) AutocompleteFlags() complete.Flags {
	return c.Flags().Completions()
}

func (c *OperatorGenerateRootCommand) Run(args []string) int {
	f := c.Flags()

	if err := f.Parse(args); err != nil {
		c.UI.Error(err.Error())
		return 1
	}

	args = f.Args()
	if len(args) > 1 {
		c.UI.Error(fmt.Sprintf("Too many arguments (expected 0-1, got %d)", len(args)))
		return 1
	}

	if c.flagDRToken && c.flagRecoveryToken {
		c.UI.Error("Both -recovery-token and -dr-token flags are set")
		return 1
	}

	client, err := c.Client()
	if err != nil {
		c.UI.Error(err.Error())
		return 2
	}

	kind := generateRootRegular
	switch {
	case c.flagDRToken:
		kind = generateRootDR
	case c.flagRecoveryToken:
		kind = generateRootRecovery
	}

	switch {
	case c.flagGenerateOTP:
		otp, code := c.generateOTP(client, kind)
		if code == 0 {
			switch Format(c.UI) {
			case "", "table":
				return PrintRaw(c.UI, otp)
			default:
				status := map[string]interface{}{
					"otp":        otp,
					"otp_length": len(otp),
				}
				return OutputData(c.UI, status)
			}
		}
		return code
	case c.flagDecode != "":
		return c.decode(client, c.flagDecode, c.flagOTP, kind)
	case c.flagCancel:
		return c.cancel(client, kind)
	case c.flagInit:
		return c.init(client, c.flagOTP, c.flagPGPKey, kind)
	case c.flagStatus:
		return c.status(client, kind)
	default:
		// If there are no other flags, prompt for an unseal key.
		key := ""
		if len(args) > 0 {
			key = strings.TrimSpace(args[0])
		}
		return c.provide(client, key, kind)
	}
}

// generateOTP generates a suitable OTP code for generating a root token.
func (c *OperatorGenerateRootCommand) generateOTP(client *api.Client, kind generateRootKind) (string, int) {
	f := client.Sys().GenerateRootStatus
	switch kind {
	case generateRootDR:
		f = client.Sys().GenerateDROperationTokenStatus
	case generateRootRecovery:
		f = client.Sys().GenerateRecoveryOperationTokenStatus
	}

	status, err := f()
	if err != nil {
		c.UI.Error(fmt.Sprintf("Error getting root generation status: %s", err))
		return "", 2
	}

	switch status.OTPLength {
	case 0:
		// This is the fallback case
		buf := make([]byte, 16)
		readLen, err := rand.Read(buf)
		if err != nil {
			c.UI.Error(fmt.Sprintf("Error reading random bytes: %s", err))
			return "", 2
		}

		if readLen != 16 {
			c.UI.Error(fmt.Sprintf("Read %d bytes when we should have read 16", readLen))
			return "", 2
		}

		return base64.StdEncoding.EncodeToString(buf), 0

	default:
		otp, err := base62.Random(status.OTPLength)
		if err != nil {
			c.UI.Error(fmt.Errorf("Error reading random bytes: %w", err).Error())
			return "", 2
		}

		return otp, 0
	}
}

// decode decodes the given value using the otp.
func (c *OperatorGenerateRootCommand) decode(client *api.Client, encoded, otp string, kind generateRootKind) int {
	if encoded == "" {
		c.UI.Error("Missing encoded value: use -decode=<string> to supply it")
		return 1
	}
	if otp == "" {
		c.UI.Error("Missing otp: use -otp to supply it")
		return 1
	}

	if encoded == "-" {
		// Pull our fake stdin if needed
		stdin := (io.Reader)(os.Stdin)
		if c.testStdin != nil {
			stdin = c.testStdin
		}

		var buf bytes.Buffer
		if _, err := io.Copy(&buf, stdin); err != nil {
			c.UI.Error(fmt.Sprintf("Failed to read from stdin: %s", err))
			return 1
		}

		encoded = buf.String()

		if encoded == "" {
			c.UI.Error("Missing encoded value. When using -decode=\"-\" value must be passed via stdin.")
			return 1
		}
	}

	f := client.Sys().GenerateRootStatus
	switch kind {
	case generateRootDR:
		f = client.Sys().GenerateDROperationTokenStatus
	case generateRootRecovery:
		f = client.Sys().GenerateRecoveryOperationTokenStatus
	}

	status, err := f()
	if err != nil {
		c.UI.Error(fmt.Sprintf("Error getting root generation status: %s", err))
		return 2
	}

	var token string
	switch status.OTPLength {
	case 0:
		// Backwards compat
		tokenBytes, err := xor.XORBase64(encoded, otp)
		if err != nil {
			c.UI.Error(fmt.Sprintf("Error xoring token: %s", err))
			return 1
		}

		uuidToken, err := uuid.FormatUUID(tokenBytes)
		if err != nil {
			c.UI.Error(fmt.Sprintf("Error formatting base64 token value: %s", err))
			return 1
		}
		token = strings.TrimSpace(uuidToken)

	default:
		tokenBytes, err := base64.RawStdEncoding.DecodeString(encoded)
		if err != nil {
			c.UI.Error(fmt.Errorf("Error decoding base64'd token: %w", err).Error())
			return 1
		}

		tokenBytes, err = xor.XORBytes(tokenBytes, []byte(otp))
		if err != nil {
			c.UI.Error(fmt.Errorf("Error xoring token: %w", err).Error())
			return 1
		}
		token = string(tokenBytes)
	}

	switch Format(c.UI) {
	case "", "table":
		return PrintRaw(c.UI, token)
	default:
		tokenJSON := map[string]interface{}{
			"token": token,
		}
		return OutputData(c.UI, tokenJSON)
	}
}

// init is used to start the generation process
func (c *OperatorGenerateRootCommand) init(client *api.Client, otp, pgpKey string, kind generateRootKind) int {
	// Validate incoming fields. Either OTP OR PGP keys must be supplied.
	if otp != "" && pgpKey != "" {
		c.UI.Error("Error initializing: cannot specify both -otp and -pgp-key")
		return 1
	}

	// Start the root generation
	f := client.Sys().GenerateRootInit
	switch kind {
	case generateRootDR:
		f = client.Sys().GenerateDROperationTokenInit
	case generateRootRecovery:
		f = client.Sys().GenerateRecoveryOperationTokenInit
	}
	status, err := f(otp, pgpKey)
	if err != nil {
		c.UI.Error(fmt.Sprintf("Error initializing root generation: %s", err))
		return 2
	}

	switch Format(c.UI) {
	case "table":
		return c.printStatus(status)
	default:
		return OutputData(c.UI, status)
	}
}

// provide prompts the user for the seal key and posts it to the update root
// endpoint. If this is the last unseal, this function outputs it.
func (c *OperatorGenerateRootCommand) provide(client *api.Client, key string, kind generateRootKind) int {
	f := client.Sys().GenerateRootStatus
	switch kind {
	case generateRootDR:
		f = client.Sys().GenerateDROperationTokenStatus
	case generateRootRecovery:
		f = client.Sys().GenerateRecoveryOperationTokenStatus
	}
	status, err := f()
	if err != nil {
		c.UI.Error(fmt.Sprintf("Error getting root generation status: %s", err))
		return 2
	}

	// Verify a root token generation is in progress. If there is not one in
	// progress, return an error instructing the user to start one.
	if !status.Started {
		c.UI.Error(wrapAtLength(
			"No root generation is in progress. Start a root generation by " +
				"running \"vault operator generate-root -init\"."))
		c.UI.Warn(wrapAtLength(fmt.Sprintf(
			"If starting root generation using the OTP method and generating "+
				"your own OTP, the length of the OTP string needs to be %d "+
				"characters in length.", status.OTPLength)))
		return 1
	}

	var nonce string

	switch key {
	case "-": // Read from stdin
		nonce = c.flagNonce

		// Pull our fake stdin if needed
		stdin := (io.Reader)(os.Stdin)
		if c.testStdin != nil {
			stdin = c.testStdin
		}

		var buf bytes.Buffer
		if _, err := io.Copy(&buf, stdin); err != nil {
			c.UI.Error(fmt.Sprintf("Failed to read from stdin: %s", err))
			return 1
		}

		key = buf.String()
	case "": // Prompt using the tty
		// Nonce value is not required if we are prompting via the terminal
		nonce = status.Nonce

		w := getWriterFromUI(c.UI)
		fmt.Fprintf(w, "Operation nonce: %s\n", nonce)
		fmt.Fprintf(w, "Unseal Key (will be hidden): ")
		key, err = password.Read(os.Stdin)
		fmt.Fprintf(w, "\n")
		if err != nil {
			if err == password.ErrInterrupted {
				c.UI.Error("user canceled")
				return 1
			}

			c.UI.Error(wrapAtLength(fmt.Sprintf("An error occurred attempting to "+
				"ask for the unseal key. The raw error message is shown below, but "+
				"usually this is because you attempted to pipe a value into the "+
				"command or you are executing outside of a terminal (tty). If you "+
				"want to pipe the value, pass \"-\" as the argument to read from "+
				"stdin. The raw error was: %s", err)))
			return 1
		}
	default: // Supplied directly as an arg
		nonce = c.flagNonce
	}

	// Trim any whitespace from they key, especially since we might have prompted
	// the user for it.
	key = strings.TrimSpace(key)

	// Verify we have a nonce value
	if nonce == "" {
		c.UI.Error("Missing nonce value: specify it via the -nonce flag")
		return 1
	}

	// Provide the key, this may potentially complete the update
	fUpd := client.Sys().GenerateRootUpdate
	switch kind {
	case generateRootDR:
		fUpd = client.Sys().GenerateDROperationTokenUpdate
	case generateRootRecovery:
		fUpd = client.Sys().GenerateRecoveryOperationTokenUpdate
	}
	status, err = fUpd(key, nonce)
	if err != nil {
		c.UI.Error(fmt.Sprintf("Error posting unseal key: %s", err))
		return 2
	}
	switch Format(c.UI) {
	case "table":
		return c.printStatus(status)
	default:
		return OutputData(c.UI, status)
	}
}

// cancel cancels the root token generation
func (c *OperatorGenerateRootCommand) cancel(client *api.Client, kind generateRootKind) int {
	f := client.Sys().GenerateRootCancel
	switch kind {
	case generateRootDR:
		f = client.Sys().GenerateDROperationTokenCancel
	case generateRootRecovery:
		f = client.Sys().GenerateRecoveryOperationTokenCancel
	}
	if err := f(); err != nil {
		c.UI.Error(fmt.Sprintf("Error canceling root token generation: %s", err))
		return 2
	}
	c.UI.Output("Success! Root token generation canceled (if it was started)")
	return 0
}

// status is used just to fetch and dump the status
func (c *OperatorGenerateRootCommand) status(client *api.Client, kind generateRootKind) int {
	f := client.Sys().GenerateRootStatus
	switch kind {
	case generateRootDR:
		f = client.Sys().GenerateDROperationTokenStatus
	case generateRootRecovery:
		f = client.Sys().GenerateRecoveryOperationTokenStatus
	}

	status, err := f()
	if err != nil {
		c.UI.Error(fmt.Sprintf("Error getting root generation status: %s", err))
		return 2
	}
	switch Format(c.UI) {
	case "table":
		return c.printStatus(status)
	default:
		return OutputData(c.UI, status)
	}
}

// printStatus dumps the status to output
func (c *OperatorGenerateRootCommand) printStatus(status *api.GenerateRootStatusResponse) int {
	out := []string{}
	out = append(out, fmt.Sprintf("Nonce | %s", status.Nonce))
	out = append(out, fmt.Sprintf("Started | %t", status.Started))
	out = append(out, fmt.Sprintf("Progress | %d/%d", status.Progress, status.Required))
	out = append(out, fmt.Sprintf("Complete | %t", status.Complete))
	if status.PGPFingerprint != "" {
		out = append(out, fmt.Sprintf("PGP Fingerprint | %s", status.PGPFingerprint))
	}
	switch {
	case status.EncodedToken != "":
		out = append(out, fmt.Sprintf("Encoded Token | %s", status.EncodedToken))
	case status.EncodedRootToken != "":
		out = append(out, fmt.Sprintf("Encoded Root Token | %s", status.EncodedRootToken))
	}
	if status.OTP != "" {
		c.UI.Warn(wrapAtLength("A One-Time-Password has been generated for you and is shown in the OTP field. You will need this value to decode the resulting root token, so keep it safe."))
		out = append(out, fmt.Sprintf("OTP | %s", status.OTP))
	}
	if status.OTPLength != 0 {
		out = append(out, fmt.Sprintf("OTP Length | %d", status.OTPLength))
	}

	output := columnOutput(out, nil)
	c.UI.Output(output)
	return 0
}