package control

import (
	"flag"
	"fmt"
	"os"
	"strings"

	"golang.org/x/crypto/openpgp"

	"v2ray.com/core/common"
)

const (
	pubkey = `-----BEGIN PGP PUBLIC KEY BLOCK-----
Comment: GPGTools - https://gpgtools.org

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=xv/V
-----END PGP PUBLIC KEY BLOCK-----
`
)

func firstIdentity(m map[string]*openpgp.Identity) string {
	for k := range m {
		return k
	}
	return ""
}

type VerifyCommand struct{}

func (c *VerifyCommand) Name() string {
	return "verify"
}

func (c *VerifyCommand) Description() Description {
	return Description{
		Short: "Verify if a binary is officially signed.",
		Usage: []string{
			"v2ctl verify [--sig=<sig-file>] file",
			"Verify the file officially signed by V2Ray.",
		},
	}
}

func (c *VerifyCommand) Execute(args []string) error {
	fs := flag.NewFlagSet(c.Name(), flag.ContinueOnError)

	sigFile := fs.String("sig", "", "Path to the signature file")

	if err := fs.Parse(args); err != nil {
		return err
	}

	target := fs.Arg(0)
	if len(target) == 0 {
		return newError("empty file path.")
	}

	if len(*sigFile) == 0 {
		*sigFile = target + ".sig"
	}

	targetReader, err := os.Open(os.ExpandEnv(target))
	if err != nil {
		return newError("failed to open file: ", target).Base(err)
	}

	sigReader, err := os.Open(os.ExpandEnv(*sigFile))
	if err != nil {
		return newError("failed to open file ", *sigFile).Base(err)
	}

	keyring, err := openpgp.ReadArmoredKeyRing(strings.NewReader(pubkey))
	if err != nil {
		return newError("failed to create keyring").Base(err)
	}

	entity, err := openpgp.CheckDetachedSignature(keyring, targetReader, sigReader)
	if err != nil {
		return newError("failed to verify signature").Base(err)
	}

	fmt.Println("Signed by:", firstIdentity(entity.Identities))
	return nil
}

func init() {
	common.Must(RegisterCommand(&VerifyCommand{}))
}