// Package aghtls contains utilities for work with TLS.
package aghtls

import (
	"crypto/tls"

	"github.com/AdguardTeam/golibs/log"
	"golang.org/x/exp/slices"
)

// SaferCipherSuites returns a set of default cipher suites with vulnerable and
// weak cipher suites removed.
func SaferCipherSuites() (safe []uint16) {
	for _, s := range tls.CipherSuites() {
		switch s.ID {
		case
			tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA,
			tls.TLS_RSA_WITH_AES_128_CBC_SHA,
			tls.TLS_RSA_WITH_AES_256_CBC_SHA,
			tls.TLS_RSA_WITH_AES_128_CBC_SHA256,
			tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
			tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
			tls.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
			tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
			tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
			tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,
			tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256:
			// Less safe 3DES and CBC suites, go on.
		default:
			safe = append(safe, s.ID)
		}
	}

	return safe
}

// ParseCipherIDs returns a set of cipher suites with the cipher names provided
func ParseCipherIDs(ciphers []string) (userCiphers []uint16) {
	for _, s := range tls.CipherSuites() {
		if slices.Contains(ciphers, s.Name) {
			userCiphers = append(userCiphers, s.ID)
			log.Debug("user specified cipher : %s, ID : %d", s.Name, s.ID)
		} else {
			log.Error("unknown cipher : %s ", s)
		}
	}

	return userCiphers
}