# SPDX-License-Identifier: LGPL-2.1-or-later

# Copyright (c) 2019 Red Hat, Inc.
# Copyright (c) 2019 Tomáš Mráz <tmraz@fedoraproject.org>

from .configgenerator import ConfigGenerator


class LibsshGenerator(ConfigGenerator):
	CONFIG_NAME = 'libssh'
	SCOPES = {'ssh', 'libssh'}

	cipher_map = {
		'AES-256-GCM':'aes256-gcm@openssh.com',
		'AES-256-CTR':'aes256-ctr',
		'AES-192-GCM':'',  # not supported
		'AES-192-CTR':'aes192-ctr',
		'AES-128-GCM':'aes128-gcm@openssh.com',
		'AES-128-CTR':'aes128-ctr',
		'CHACHA20-POLY1305':'chacha20-poly1305@openssh.com',
		'CAMELLIA-256-GCM':'',
		'AES-256-CCM':'',
		'AES-192-CCM':'',
		'AES-128-CCM':'',
		'CAMELLIA-128-GCM':'',
		'AES-256-CBC':'aes256-cbc',
		'AES-192-CBC':'aes192-cbc',
		'AES-128-CBC':'aes128-cbc',
		'CAMELLIA-256-CBC':'',
		'CAMELLIA-128-CBC':'',
		'RC4-128':'',
		'DES-CBC':'',
		'CAMELLIA-128-CTS':'',
		'3DES-CBC':'3des-cbc'
	}

	mac_map_etm = {
		'HMAC-MD5':'',
		'UMAC-64':'',
		'UMAC-128':'',
		'HMAC-SHA1':'hmac-sha1-etm@openssh.com',
		'HMAC-SHA2-256':'hmac-sha2-256-etm@openssh.com',
		'HMAC-SHA2-512':'hmac-sha2-512-etm@openssh.com'
	}

	mac_map = {
		'HMAC-MD5':'',
		'UMAC-64':'',
		'UMAC-128':'',
		'HMAC-SHA1':'hmac-sha1',
		'HMAC-SHA2-256':'hmac-sha2-256',
		'HMAC-SHA2-512':'hmac-sha2-512'
	}

	kx_map = {
		'ECDHE-SECP521R1-SHA2-512':'ecdh-sha2-nistp521',
		'ECDHE-SECP384R1-SHA2-384':'ecdh-sha2-nistp384',
		'ECDHE-SECP256R1-SHA2-256':'ecdh-sha2-nistp256',
		'ECDHE-X25519-SHA2-256':'curve25519-sha256,curve25519-sha256@libssh.org',
		'DHE-FFDHE-1024-SHA1':'diffie-hellman-group1-sha1',
		'DHE-FFDHE-2048-SHA1':'diffie-hellman-group14-sha1',
		'DHE-FFDHE-2048-SHA2-256':'diffie-hellman-group14-sha256',
		'DHE-FFDHE-4096-SHA2-512':'diffie-hellman-group16-sha512',
		'DHE-FFDHE-8192-SHA2-512':'diffie-hellman-group18-sha512',
	}

	gx_map = {
		'DHE-SHA1':'diffie-hellman-group-exchange-sha1',
		'DHE-SHA2-256':'diffie-hellman-group-exchange-sha256',
	}

	sign_map = {
		'RSA-SHA1':'ssh-rsa',
		'DSA-SHA1':'ssh-dss',
		'RSA-SHA2-256':'rsa-sha2-256',
		'RSA-SHA2-512':'rsa-sha2-512',
		'ECDSA-SHA2-256':'ecdsa-sha2-nistp256',
		'ECDSA-SHA2-384':'ecdsa-sha2-nistp384',
		'ECDSA-SHA2-512':'ecdsa-sha2-nistp521',
		'EDDSA-ED25519':'ssh-ed25519',
	}

	sign_map_certs = {
		'RSA-SHA1':'ssh-rsa-cert-v01@openssh.com',
		'DSA-SHA1':'ssh-dss-cert-v01@openssh.com',
		'RSA-SHA2-256':'rsa-sha2-256-cert-v01@openssh.com',
		'RSA-SHA2-512':'rsa-sha2-512-cert-v01@openssh.com',
		'ECDSA-SHA2-256':'ecdsa-sha2-nistp256-cert-v01@openssh.com',
		'ECDSA-SHA2-384':'ecdsa-sha2-nistp384-cert-v01@openssh.com',
		'ECDSA-SHA2-512':'ecdsa-sha2-nistp521-cert-v01@openssh.com',
		'EDDSA-ED25519':'ssh-ed25519-cert-v01@openssh.com',
	}

	@classmethod
	def generate_config(cls, policy):
		p = policy.enabled
		cfg = ''
		sep = ','

		s = ''
		for i in p['cipher']:
			try:
				s = cls.append(s, cls.cipher_map[i], sep)
			except KeyError:
				pass

		if s:
			cfg += 'Ciphers ' + s + '\n'

		s = ''
		if policy.integers['ssh_etm']:
			for i in p['mac']:
				try:
					s = cls.append(s, cls.mac_map_etm[i], sep)
				except KeyError:
					pass
		for i in p['mac']:
			try:
				s = cls.append(s, cls.mac_map[i], sep)
			except KeyError:
				pass

		if s:
			cfg += 'MACs ' + s + '\n'

		s = ''
		for kx in p['key_exchange']:
			for h in p['hash']:
				if policy.integers['arbitrary_dh_groups'] == 1:
					try:
						val = cls.gx_map[kx + '-' + h]
						s = cls.append(s, val, sep)
					except KeyError:
						pass
				for g in p['group']:
					try:
						val = cls.kx_map[kx + '-' + g + '-' + h]
						s = cls.append(s, val, sep)
					except KeyError:
						pass

		if s:
			cfg += 'KexAlgorithms ' + s + '\n'

		s = ''
		for i in p['sign']:
			try:
				s = cls.append(s, cls.sign_map[i], sep)
			except KeyError:
				pass
			if policy.integers['ssh_certs']:
				try:
					s = cls.append(s, cls.sign_map_certs[i], sep)
				except KeyError:
					pass

		if s:
			cfg += 'HostKeyAlgorithms ' + s + '\n'
			cfg += 'PubkeyAcceptedKeyTypes ' + s + '\n'

		return cfg

	@classmethod
	def test_config(cls, config):  # pylint: disable=unused-argument
		return True
