package jwt

import (
	"github.com/urfave/cli"
)

// Command returns the cli.Command for jwt and related subcommands.
func Command() cli.Command {
	return cli.Command{
		Name:      "jwt",
		Usage:     "sign and verify data using JSON Web Tokens (JWT)",
		UsageText: "step crypto jwt <subcommand> [arguments] [global-flags] [subcommand-flags]",
		Description: `A JSON Web Token or JWT (pronounced "jot") is a compact data structure used
to represent some JSON encoded "claims" that are passed as the payload of a
JWS or JWE structure, enabling the claims to be digitally signed and/or
encrypted. The "claims" (or "claim set") are represented as an ordinary JSON
object. JWTs are represented using a compact format that's URL safe and can be
used in space-constrained environments. JWTs can be passed in HTTP
Authorization headers and as URI query parameters.

A "claim" is a piece of information asserted about a subject, represented as a
key/value pair. Logically a verified JWT can be interpreted as "<issuer> says to
<audience> that <subject>'s <claim-name> is <claim-value>" for each claim.

A JWT signed using JWS has three parts:

  1. A base64 encoded JSON object representing the JOSE (JSON Object
     Signing and Encryption) header that describes the cryptographic
     operations applied to the JWT Claims Set
  2. A base64 encoded JSON object representing the JWT Claims Set
  3. A base64 encoded digital signature of message authentication code

## EXAMPLES

Create a signed JWT using a JWK (with line breaks for display purposes only):
'''
$ step crypto jwt sign --key p256.priv.json --iss "joe@example.com" \
      --aud "https://example.com" --sub auth --exp $(date -v+1M +"%s")
eyJhbGciOiJFUzI1NiIsImtpZCI6IlpqR1g5N0xtY2ZsUG9sV3Zzb0FXekM1V1BXa05GRkgzUWRLTFVXOTc4aGsiLCJ0eXAiOiJKV1QifQ
.
eyJhdWQiOiJodHRwczovL2V4YW1wbGUuY29tIiwiZXhwIjoxNTM1MjM2MTUyLCJpYXQiOjE1MzI1NTc3NTQsImlzcyI6ImpvZUBleGFtcGxlLmNvbSIsIm5iZiI6MTUzMjU1Nzc1NCwic3ViIjoiYXV0aCJ9
.
Z4veKtRmZLoqHNlTrcYo2W1ikLkDcSNfrT52zAGS9cF90Zi3aTXt_75pkikREvMrkC4mhGDdqxCf9ZHq4VnSvg
'''

Create a signed JWT using a JWK and a custom payload:
'''
$ echo '{"srv":"https://srv.example.com"}' | step crypto jwt sign \
      --key p256.priv.json --iss "joe@example.com" \
      --aud "https://example.com" --sub auth --exp $(date -v+1M +"%s")
eyJhbGciOiJFUzI1NiIsImtpZCI6IlpqR1g5N0xtY2ZsUG9sV3Zzb0FXekM1V1BXa05GRkgzUWRLTFVXOTc4aGsiLCJ0eXAiOiJKV1QifQ
.
eyJhdWQiOiJodHRwczovL2V4YW1wbGUuY29tIiwiZXhwIjoxNTM1MjQyNDcyLCJpYXQiOjE1MzI1NjQwNzMsImlzcyI6ImpvZUBleGFtcGxlLmNvbSIsIm5iZiI6MTUzMjU2NDA3Mywic3J2IjoiaHR0cHM6Ly9zcnYuZXhhbXBsZS5jb20iLCJzdWIiOiJhdXRoIn0
.
DlSkxICjk2h1LarwJgXPbXQe7DwpLMOCvWp3I4GMcBP_5_QYPhVNBPQEeTKAUuQjYwlxZ5zVQnyp8ujvyf1Lqw
'''

Verify the the previous token:
'''
$ echo $TOKEN | step crypto jwt verify --key p256.pub.json --iss "joe@example.com" --aud "https://example.com"
{
  "header": {
    "alg": "ES256",
    "kid": "ZjGX97LmcflPolWvsoAWzC5WPWkNFFH3QdKLUW978hk",
    "typ": "JWT"
  },
  "payload": {
    "aud": "https://example.com",
    "exp": 1535242472,
    "iat": 1532564073,
    "iss": "joe@example.com",
    "nbf": 1532564073,
    "srv": "https://srv.example.com",
    "sub": "auth"
  },
  "signature": "DlSkxICjk2h1LarwJgXPbXQe7DwpLMOCvWp3I4GMcBP_5_QYPhVNBPQEeTKAUuQjYwlxZ5zVQnyp8ujvyf1Lqw"
}
'''

Read the information in the previous token without verifying it:
'''
$ echo $TOKEN | step crypto jwt inspect --insecure
{
  "header": {
    "alg": "ES256",
    "kid": "ZjGX97LmcflPolWvsoAWzC5WPWkNFFH3QdKLUW978hk",
    "typ": "JWT"
  },
  "payload": {
    "aud": "https://example.com",
    "exp": 1535242472,
    "iat": 1532564073,
    "iss": "joe@example.com",
    "nbf": 1532564073,
    "srv": "https://srv.example.com",
    "sub": "auth"
  },
  "signature": "DlSkxICjk2h1LarwJgXPbXQe7DwpLMOCvWp3I4GMcBP_5_QYPhVNBPQEeTKAUuQjYwlxZ5zVQnyp8ujvyf1Lqw"
}
'''`,
		Subcommands: cli.Commands{
			signCommand(),
			verifyCommand(),
			inspectCommand(),
		},
	}
}
