package hsm

import (
	"context"
	"errors"
	"fmt"
	"log"
	"os"
	"strings"
	"syscall"

	"github.com/ThalesIgnite/crypto11"
	"golang.org/x/term"
)

func prepareCrypto11Context(ctx context.Context, label string) (*crypto11.Context, error) {
	storage, ok := GetSignerConfig(ctx).KeyStorage[label]
	if !ok {
		return nil, fmt.Errorf("could not find storage definition with label %s", label)
	}

	var (
		err        error
		p11Context *crypto11.Context
	)

	p11Config := &crypto11.Config{
		Path:       storage.Module,
		TokenLabel: storage.Label,
	}

	log.Printf("using PKCS#11 module %s", p11Config.Path)
	log.Printf("looking for token with label %s", p11Config.TokenLabel)

	p11Config.Pin, err = getPin(p11Config)
	if err != nil {
		return nil, err
	}

	p11Context, err = crypto11.Configure(p11Config)
	if err != nil {
		return nil, fmt.Errorf("could not configure PKCS#11 library: %v", err)
	}

	return p11Context, nil
}

func getPin(p11Config *crypto11.Config) (string, error) {
	tokenPinEnv := strings.ReplaceAll(p11Config.TokenLabel, "-", "_")
	tokenPinEnv = strings.ReplaceAll(tokenPinEnv, " ", "_")
	tokenPinEnv = strings.ToUpper(tokenPinEnv)
	tokenPinEnv = fmt.Sprintf("TOKEN_PIN_%s", tokenPinEnv)

	pin, found := os.LookupEnv(tokenPinEnv)
	if !found {
		log.Printf("environment variable %s has not been set", tokenPinEnv)

		if !term.IsTerminal(syscall.Stdin) {
			return "", errors.New("stdin is not a terminal")
		}

		fmt.Printf("Enter PIN for token %s: ", p11Config.TokenLabel)

		bytePin, err := term.ReadPassword(syscall.Stdin)
		if err != nil {
			return "", errors.New("could not read PIN")
		}

		fmt.Println()

		pin = string(bytePin)
	}

	return strings.TrimSpace(pin), nil
}