/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.syncope.core.spring.policy;

import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import javax.crypto.BadPaddingException;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import org.apache.commons.collections4.IterableUtils;
import org.apache.commons.collections4.Predicate;
import org.apache.commons.lang3.StringUtils;
import org.apache.syncope.common.lib.policy.HaveIBeenPwnedPasswordRuleConf;
import org.apache.syncope.common.lib.policy.PasswordRuleConf;
import org.apache.syncope.common.lib.types.CipherAlgorithm;
import org.apache.syncope.core.persistence.api.dao.PasswordRule;
import org.apache.syncope.core.persistence.api.dao.PasswordRuleConfClass;
import org.apache.syncope.core.persistence.api.entity.user.User;
import org.apache.syncope.core.spring.security.Encryptor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.web.client.HttpStatusCodeException;
import org.springframework.web.client.RestTemplate;

@PasswordRuleConfClass(HaveIBeenPwnedPasswordRuleConf.class)
public class HaveIBeenPwnedPasswordRule implements PasswordRule {

    protected static final Logger LOG = LoggerFactory.getLogger(HaveIBeenPwnedPasswordRule.class);

    private static final Encryptor ENCRYPTOR = Encryptor.getInstance();

    @Override
    public void enforce(final PasswordRuleConf conf, final User user) {
        String clearPassword = user.getClearPassword();
        String password = user.getPassword();

        if (password != null && clearPassword != null) {
            try {
                final String sha1 = ENCRYPTOR.encode(clearPassword, CipherAlgorithm.SHA1);

                HttpHeaders headers = new HttpHeaders();
                headers.set(HttpHeaders.USER_AGENT, "Apache Syncope");
                ResponseEntity<String> response = new RestTemplate().exchange(
                        URI.create("https://api.pwnedpasswords.com/range/" + sha1.substring(0, 5)),
                        HttpMethod.GET,
                        new HttpEntity<>(null, headers),
                        String.class);
                if (StringUtils.isNotBlank(response.getBody())) {
                    if (IterableUtils.matchesAny(
                            Arrays.asList(response.getBody().split("\\n")), new Predicate<String>() {

                        @Override
                        public boolean evaluate(final String line) {
                            return sha1.equals(sha1.substring(0, 5) + StringUtils.substringBefore(line, ":"));
                        }
                    })) {

                        throw new PasswordPolicyException("Password pwned");
                    }
                }
            } catch (UnsupportedEncodingException | InvalidKeyException | NoSuchAlgorithmException
                    | BadPaddingException | IllegalBlockSizeException | NoSuchPaddingException e) {

                LOG.error("Could not encode the password value as SHA1", e);
            } catch (HttpStatusCodeException e) {
                LOG.error("Error while contacting the PwnedPasswords service", e);
            }
        }
    }
}
