package accounts

import (
	"encoding/hex"
	"fmt"
	"strconv"
	"strings"

	"github.com/logrusorgru/aurora"
	"github.com/manifoldco/promptui"
	"github.com/pkg/errors"
	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
	"github.com/prysmaticlabs/prysm/crypto/bls"
	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
	"github.com/prysmaticlabs/prysm/validator/accounts/petnames"
	"github.com/urfave/cli/v2"
)

// selectAccounts Ask user to select accounts via an interactive userprompt.
func selectAccounts(selectionPrompt string, pubKeys [][fieldparams.BLSPubkeyLength]byte) (filteredPubKeys []bls.PublicKey, err error) {
	pubKeyStrings := make([]string, len(pubKeys))
	for i, pk := range pubKeys {
		name := petnames.DeterministicName(pk[:], "-")
		pubKeyStrings[i] = fmt.Sprintf(
			"%d | %s | %#x", i, au.BrightGreen(name), au.BrightMagenta(bytesutil.Trunc(pk[:])),
		)
	}
	templates := &promptui.SelectTemplates{
		Label:    "{{ . }}",
		Active:   "\U0001F336 {{ .Name | cyan }}",
		Inactive: "  {{ .Name | cyan }}",
		Selected: "\U0001F336 {{ .Name | red | cyan }}",
		Details: `
--------- Account ----------
{{ "Name:" | faint }}	{{ .Name }}`,
	}
	var result string
	exit := "Done selecting"
	results := make([]int, 0)
	au := aurora.NewAurora(true)
	for result != exit {
		p := promptui.Select{
			Label:        selectionPrompt,
			HideSelected: true,
			Items:        append([]string{exit, allAccountsText}, pubKeyStrings...),
			Templates:    templates,
		}

		_, result, err = p.Run()
		if err != nil {
			return nil, err
		}
		if result == exit {
			fmt.Printf("%s\n", au.BrightRed("Done with selections").Bold())
			break
		}
		if result == allAccountsText {
			fmt.Printf("%s\n", au.BrightRed("[Selected all accounts]").Bold())
			for i := 0; i < len(pubKeys); i++ {
				results = append(results, i)
			}
			break
		}
		idx := strings.Index(result, " |")
		accountIndexStr := result[:idx]
		accountIndex, err := strconv.Atoi(accountIndexStr)
		if err != nil {
			return nil, err
		}
		results = append(results, accountIndex)
		fmt.Printf("%s %s\n", au.BrightRed("[Selected account]").Bold(), result)
	}

	// Deduplicate the results.
	seen := make(map[int]bool)
	for i := 0; i < len(results); i++ {
		if _, ok := seen[results[i]]; !ok {
			seen[results[i]] = true
		}
	}

	// Filter the public keys based on user input.
	filteredPubKeys = make([]bls.PublicKey, 0)
	for selectedIndex := range seen {
		pk, err := bls.PublicKeyFromBytes(pubKeys[selectedIndex][:])
		if err != nil {
			return nil, err
		}
		filteredPubKeys = append(filteredPubKeys, pk)
	}
	return filteredPubKeys, nil
}

// FilterPublicKeysFromUserInput collects the set of public keys from the
// command line or an interactive session.
func FilterPublicKeysFromUserInput(
	cliCtx *cli.Context,
	publicKeysFlag *cli.StringFlag,
	validatingPublicKeys [][fieldparams.BLSPubkeyLength]byte,
	selectionPrompt string,
) ([]bls.PublicKey, error) {
	if cliCtx.IsSet(publicKeysFlag.Name) {
		pubKeyStrings := strings.Split(cliCtx.String(publicKeysFlag.Name), ",")
		if len(pubKeyStrings) == 0 {
			return nil, fmt.Errorf(
				"could not parse %s. It must be a string of comma-separated hex strings",
				publicKeysFlag.Name,
			)
		}
		return filterPublicKeys(pubKeyStrings)
	}
	return selectAccounts(selectionPrompt, validatingPublicKeys)
}

func filterPublicKeys(pubKeyStrings []string) ([]bls.PublicKey, error) {
	var filteredPubKeys []bls.PublicKey
	for _, str := range pubKeyStrings {
		pkString := str
		if strings.Contains(pkString, "0x") {
			pkString = pkString[2:]
		}
		pubKeyBytes, err := hex.DecodeString(pkString)
		if err != nil {
			return nil, errors.Wrapf(err, "could not decode string %s as hex", pkString)
		}
		blsPublicKey, err := bls.PublicKeyFromBytes(pubKeyBytes)
		if err != nil {
			return nil, errors.Wrapf(err, "%#x is not a valid BLS public key", pubKeyBytes)
		}
		filteredPubKeys = append(filteredPubKeys, blsPublicKey)
	}
	return filteredPubKeys, nil
}