/*
 * 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.guacamole.vault.ksm.secret;

import com.google.inject.Inject;
import com.google.inject.Singleton;
import com.keepersecurity.secretsManager.core.KeeperRecord;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.Future;

import org.apache.guacamole.GuacamoleException;
import org.apache.guacamole.protocol.GuacamoleConfiguration;
import org.apache.guacamole.token.TokenFilter;
import org.apache.guacamole.vault.secret.VaultSecretService;

/**
 * Service which retrieves secrets from Keeper Secrets Manager.
 */
@Singleton
public class KsmSecretService implements VaultSecretService {

    /**
     * Client for retrieving records and secrets from Keeper Secrets Manager.
     */
    @Inject
    private KsmClient ksm;

    /**
     * Service for retrieving data from records.
     */
    @Inject
    private KsmRecordService recordService;

    @Override
    public String canonicalize(String nameComponent) {
        try {

            // As Keeper notation is essentially a URL, encode all components
            // using standard URL escaping
            return URLEncoder.encode(nameComponent, "UTF-8");

        }
        catch (UnsupportedEncodingException e) {
            throw new UnsupportedOperationException("Unexpected lack of UTF-8 support.", e);
        }
    }

    @Override
    public Future<String> getValue(String name) throws GuacamoleException {
        return ksm.getSecret(name);
    }

    /**
     * Adds contextual parameter tokens for the secrets in the given record to
     * the given map of existing tokens. The values of each token are
     * determined from secrets within the record. Depending on the record, this
     * will be a subset of the username, password, private key, and passphrase.
     *
     * @param tokens
     *     The map of parameter tokens that any new tokens should be added to.
     *
     * @param prefix
     *     The prefix that should be prepended to each added token.
     *
     * @param record
     *     The record to retrieve secrets from when generating tokens. This may
     *     be null.
     */
    private void addRecordTokens(Map<String, Future<String>> tokens, String prefix,
            KeeperRecord record) {

        if (record == null)
            return;

        // Username of server-related record
        String username = recordService.getUsername(record);
        if (username != null)
            tokens.put(prefix + "USERNAME", CompletableFuture.completedFuture(username));

        // Password of server-related record
        String password = recordService.getPassword(record);
        if (password != null)
            tokens.put(prefix + "PASSWORD", CompletableFuture.completedFuture(password));

        // Key passphrase of server-related record
        String passphrase = recordService.getPassphrase(record);
        if (passphrase != null)
            tokens.put(prefix + "PASSPHRASE", CompletableFuture.completedFuture(passphrase));

        // Private key of server-related record
        Future<String> privateKey = recordService.getPrivateKey(record);
        tokens.put(prefix + "KEY", privateKey);

    }
    
    @Override
    public Map<String, Future<String>> getTokens(GuacamoleConfiguration config,
            TokenFilter filter) throws GuacamoleException {

        Map<String, Future<String>> tokens = new HashMap<>();
        Map<String, String> parameters = config.getParameters();

        // Retrieve and define server-specific tokens, if any
        String hostname = parameters.get("hostname");
        if (hostname != null && !hostname.isEmpty())
            addRecordTokens(tokens, "KEEPER_SERVER_",
                    ksm.getRecordByHost(filter.filter(hostname)));

        // Retrieve and define user-specific tokens, if any
        String username = parameters.get("username");
        if (username != null && !username.isEmpty())
            addRecordTokens(tokens, "KEEPER_USER_",
                    ksm.getRecordByLogin(filter.filter(username)));

        // Tokens specific to RDP
        if ("rdp".equals(config.getProtocol())) {
        
            // Retrieve and define gateway server-specific tokens, if any
            String gatewayHostname = parameters.get("gateway-hostname");
            if (gatewayHostname != null && !gatewayHostname.isEmpty())
                addRecordTokens(tokens, "KEEPER_GATEWAY_",
                        ksm.getRecordByHost(filter.filter(gatewayHostname)));

            // Retrieve and define gateway user-specific tokens, if any
            String gatewayUsername = parameters.get("gateway-username");
            if (gatewayUsername != null && !gatewayUsername.isEmpty())
                addRecordTokens(tokens, "KEEPER_GATEWAY_USER_",
                        ksm.getRecordByLogin(filter.filter(gatewayUsername)));

        }

        return tokens;

    }

}