/*
 * 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.nifi.mongodb;

import com.mongodb.MongoClient;
import com.mongodb.MongoClientOptions;
import com.mongodb.MongoClientURI;
import com.mongodb.WriteConcern;
import com.mongodb.client.MongoDatabase;
import java.util.ArrayList;
import java.util.List;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import javax.net.ssl.SSLContext;
import org.apache.nifi.annotation.documentation.CapabilityDescription;
import org.apache.nifi.annotation.documentation.Tags;
import org.apache.nifi.annotation.lifecycle.OnDisabled;
import org.apache.nifi.annotation.lifecycle.OnEnabled;
import org.apache.nifi.annotation.lifecycle.OnStopped;
import org.apache.nifi.components.PropertyDescriptor;
import org.apache.nifi.controller.AbstractControllerService;
import org.apache.nifi.controller.ConfigurationContext;
import org.apache.nifi.ssl.SSLContextService;

@Tags({"mongo", "mongodb", "service"})
@CapabilityDescription(
        "Provides a controller service that configures a connection to MongoDB and provides access to that connection to " +
                "other Mongo-related components."
)
public class MongoDBControllerService extends AbstractControllerService implements MongoDBClientService {
    private String uri;

    @OnEnabled
    public void onEnabled(final ConfigurationContext context) {
        this.uri = getURI(context);
        this.createClient(context);
    }

    static List<PropertyDescriptor> descriptors = new ArrayList<>();

    static {
        descriptors.add(URI);
        descriptors.add(DB_USER);
        descriptors.add(DB_PASSWORD);
        descriptors.add(SSL_CONTEXT_SERVICE);
        descriptors.add(CLIENT_AUTH);
    }

    protected MongoClient mongoClient;

    // TODO: Remove duplicate code by refactoring shared method to accept PropertyContext
    protected final void createClient(ConfigurationContext context) {
        if (mongoClient != null) {
            closeClient();
        }

        getLogger().info("Creating MongoClient");

        // Set up the client for secure (SSL/TLS communications) if configured to do so
        final SSLContextService sslService = context.getProperty(SSL_CONTEXT_SERVICE).asControllerService(SSLContextService.class);
        final SSLContext sslContext;

        if (sslService == null) {
            sslContext = null;
        } else {
            sslContext = sslService.createContext();
        }

        try {
            if(sslContext == null) {
                mongoClient = new MongoClient(new MongoClientURI(getURI(context)));
            } else {
                mongoClient = new MongoClient(new MongoClientURI(getURI(context), getClientOptions(sslContext)));
            }
        } catch (Exception e) {
            getLogger().error("Failed to schedule {} due to {}", new Object[] { this.getClass().getName(), e }, e);
            throw e;
        }
    }

    protected MongoClientOptions.Builder getClientOptions(final SSLContext sslContext) {
        MongoClientOptions.Builder builder = MongoClientOptions.builder();
        builder.sslEnabled(true);
        builder.sslContext(sslContext);
        return builder;
    }

    @OnStopped
    public final void closeClient() {
        if (mongoClient != null) {
            mongoClient.close();
            mongoClient = null;
        }
    }

    protected String getURI(final ConfigurationContext context) {
        final String uri = context.getProperty(URI).evaluateAttributeExpressions().getValue();
        final String user = context.getProperty(DB_USER).evaluateAttributeExpressions().getValue();
        final String passw = context.getProperty(DB_PASSWORD).evaluateAttributeExpressions().getValue();
        if (!uri.contains("@") && user != null && passw != null) {
            try {
                return uri.replaceFirst("://", "://" + URLEncoder.encode(user, StandardCharsets.UTF_8.toString()) + ":" + URLEncoder.encode(passw, StandardCharsets.UTF_8.toString()) + "@");
            } catch (final UnsupportedEncodingException e) {
                getLogger().warn("Failed to URL encode username and/or password. Using original URI.");
                return uri;
            }
        } else {
            return uri;
        }
    }

    @Override
    public WriteConcern getWriteConcern(final ConfigurationContext context) {
        final String writeConcernProperty = context.getProperty(WRITE_CONCERN).getValue();
        WriteConcern writeConcern = null;
        switch (writeConcernProperty) {
            case WRITE_CONCERN_ACKNOWLEDGED:
                writeConcern = WriteConcern.ACKNOWLEDGED;
                break;
            case WRITE_CONCERN_UNACKNOWLEDGED:
                writeConcern = WriteConcern.UNACKNOWLEDGED;
                break;
            case WRITE_CONCERN_FSYNCED:
                writeConcern = WriteConcern.JOURNALED;
                getLogger().warn("Using deprecated write concern FSYNCED");
                break;
            case WRITE_CONCERN_JOURNALED:
                writeConcern = WriteConcern.JOURNALED;
                break;
            case WRITE_CONCERN_REPLICA_ACKNOWLEDGED:
                writeConcern = WriteConcern.W2;
                getLogger().warn("Using deprecated write concern REPLICA_ACKNOWLEDGED");
                break;
            case WRITE_CONCERN_MAJORITY:
                writeConcern = WriteConcern.MAJORITY;
                break;
            case WRITE_CONCERN_W1:
                writeConcern = WriteConcern.W1;
                break;
            case WRITE_CONCERN_W2:
                writeConcern = WriteConcern.W2;
                break;
            case WRITE_CONCERN_W3:
                writeConcern = WriteConcern.W3;
                break;
            default:
                writeConcern = WriteConcern.ACKNOWLEDGED;
        }
        return writeConcern;
    }

    @Override
    protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
        return descriptors;
    }

    @OnDisabled
    public void onDisable() {
        this.mongoClient.close();
    }


    @Override
    public MongoDatabase getDatabase(String name) {
        return mongoClient.getDatabase(name);
    }

    @Override
    public String getURI() {
        return uri;
    }
}