/**
 * 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.cxf.systest.http_undertow;

import java.nio.charset.Charset;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.Principal;
import java.util.Arrays;
import java.util.Collections;
import java.util.Map;
import java.util.Set;

import io.undertow.security.idm.Account;
import io.undertow.security.idm.Credential;
import io.undertow.security.idm.DigestCredential;
import io.undertow.security.idm.IdentityManager;
import io.undertow.security.idm.PasswordCredential;
import io.undertow.util.HexConverter;

class MapIdentityManager implements IdentityManager {

    private static final Charset UTF_8 = Charset.forName("UTF-8");

    private final Map<String, char[]> users;

    MapIdentityManager(final Map<String, char[]> users) {
        this.users = users;
    }

    @Override
    public Account verify(Account account) {
        // An existing account so for testing assume still valid.
        return account;
    }

    @Override
    public Account verify(String id, Credential credential) {
        Account account = getAccount(id);
        if (account != null && verifyCredential(account, credential)) {
            return account;
        }

        return null;
    }

    @Override
    public Account verify(Credential credential) {
        return null;
    }

    private boolean verifyCredential(Account account, Credential credential) {
        if (credential instanceof PasswordCredential) {
            char[] password = ((PasswordCredential) credential).getPassword();
            char[] expectedPassword = users.get(account.getPrincipal().getName());

            return Arrays.equals(password, expectedPassword);
        } else if (credential instanceof DigestCredential) {
            DigestCredential digCred = (DigestCredential) credential;
            MessageDigest digest = null;
            try {
                digest = digCred.getAlgorithm().getMessageDigest();

                digest.update(account.getPrincipal().getName().getBytes(UTF_8));
                digest.update((byte) ':');
                digest.update(digCred.getRealm().getBytes(UTF_8));
                digest.update((byte) ':');
                char[] expectedPassword = users.get(account.getPrincipal().getName());
                digest.update(new String(expectedPassword).getBytes(UTF_8));

                return digCred.verifyHA1(HexConverter.convertToHexBytes(digest.digest()));
            } catch (NoSuchAlgorithmException e) {
                throw new IllegalStateException("Unsupported Algorithm", e);
            } finally {
                digest.reset();
            }
        }
        return false;
    }

    private Account getAccount(final String id) {
        if (users.containsKey(id)) {
            return new Account() {

                private static final long serialVersionUID = 1L;
                private final Principal principal = new Principal() {

                    @Override
                    public String getName() {
                        return id;
                    }
                };

                @Override
                public Principal getPrincipal() {
                    return principal;
                }

                @Override
                public Set<String> getRoles() {
                    return Collections.emptySet();
                }

            };
        }
        return null;
    }

}
