/*
 * Copyright 2012-2017 Red Hat, Inc.
 *
 * This file is part of Thermostat.
 *
 * Thermostat is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2, or (at your
 * option) any later version.
 *
 * Thermostat is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Thermostat; see the file COPYING.  If not see
 * <http://www.gnu.org/licenses/>.
 *
 * Linking this code with other modules is making a combined work
 * based on this code.  Thus, the terms and conditions of the GNU
 * General Public License cover the whole combination.
 *
 * As a special exception, the copyright holders of this code give
 * you permission to link this code with independent modules to
 * produce an executable, regardless of the license terms of these
 * independent modules, and to copy and distribute the resulting
 * executable under terms of your choice, provided that you also
 * meet, for each linked independent module, the terms and conditions
 * of the license of that module.  An independent module is a module
 * which is not derived from or based on this code.  If you modify
 * this code, you may extend this exception to your version of the
 * library, but you are not obligated to do so.  If you do not wish
 * to do so, delete this exception statement from your version.
 */

package com.redhat.thermostat.gateway.tests.utils;

import java.io.IOException;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;

import org.bson.Document;

import com.mongodb.MongoClient;
import com.mongodb.ServerAddress;
import com.mongodb.client.MongoCollection;
import com.redhat.thermostat.gateway.common.util.OS;


import java.net.Socket;
import java.net.ServerSocket;
import java.net.SocketAddress;
import java.net.InetSocketAddress;

// Please see http://pmd.sourceforge.net/pmd-5.0.5/rules/java/basic.html#AvoidUsingHardCodedIP 
// and https://pmd.github.io/pmd-5.8.1/usage/suppressing.html for more information
@SuppressWarnings("PMD.AvoidUsingHardCodedIP")
public class MongodTestUtil {

    private static final int WAIT_FOR_MAX_ITERATIONS = 100;
    private static final long WAIT_FOR_SLEEP_DURATION = 250L;
    private static final int DEFAULT_PORT = 27519;

    private final String databaseName = "thermostat";
    private final String host = "127.0.0.1";
    private final int port;
    public final String listenAddress;

    private MongoClient mongoClient;
    private Path tempDbDir;
    private Path tempLogFile;
    public Process process;
    private boolean connectedToDatabase;

    public MongodTestUtil() {
        this(DEFAULT_PORT);
    }

    public MongodTestUtil(int port) {
        this.port = port;
        this.listenAddress = host + ":" + port;
    }

    public void startMongod() throws IOException, InterruptedException {
        tempDbDir = Files.createTempDirectory("tms-mongo");
        tempDbDir.toFile().deleteOnExit();
        Files.createDirectories(tempDbDir.resolve("data/db"));
        tempLogFile = tempDbDir.resolve("mongod.log");
        tempLogFile.toFile().deleteOnExit();

        String[] posixCommand = {"mongod", "--dbpath", tempDbDir.resolve("data/db").toAbsolutePath().toString(), "--port", String.valueOf(port), "--fork", "--logpath", tempLogFile.toAbsolutePath().toString()};
        String[] windowsCommand = {"cmd", "/c", "mongod", "--dbpath", tempDbDir.resolve("data/db").toAbsolutePath().toString(), "--port", String.valueOf(port), "--logpath", tempLogFile.toAbsolutePath().toString()};
        ProcessBuilder builder = new ProcessBuilder(OS.IS_UNIX ? posixCommand : windowsCommand);
        process = builder.start();
        waitForSocketToBind(host, port);
        mongoClient = new MongoClient(new ServerAddress(host, port));
    }

    public void stopMongod() throws IOException, InterruptedException {
        if (mongoClient != null) {
            try {
                mongoClient.getDatabase("admin").runCommand(new Document("shutdown", 1));
            } catch (Exception ignored) {
                /*
                following exception is always thrown:
                com.mongodb.MongoSocketReadException: Prematurely reached end of stream
                ( probably expected, connection gets closed? )
                */
            } finally {
                mongoClient.close();
                mongoClient = null;
            }
            waitForSocketToClose(port);
            finish();
        }
    }

    public void dropCollection(String collectionName) {
        mongoClient.getDatabase(databaseName).getCollection(collectionName).drop();
    }


    public MongoCollection<Document> getCollection(String collectionName) {
        return mongoClient.getDatabase(databaseName).getCollection(collectionName);
    }

    private void finish() throws IOException {

        // some environments (Windows) may still have the file marked as in use for a few seconds
        // this code retries a few times, then gives up.

        final int NUM_RETRIES = 5;
        final int WAIT_TIME_MILLIS = 1000;
        IOException savedException = null;
        for (int i = NUM_RETRIES; i > 0; i--) {
            try {
                Files.walkFileTree(tempDbDir, new SimpleFileVisitor<Path>() {
                    @Override
                    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
                        Files.delete(file);
                        return FileVisitResult.CONTINUE;
                    }

                    @Override
                    public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
                        Files.delete(dir);
                        return FileVisitResult.CONTINUE;
                    }

                });
                savedException = null;
                break;
            } catch (IOException fsException) {
                savedException = fsException;
                try {
                    Thread.sleep(WAIT_TIME_MILLIS);
                } catch (InterruptedException ignored) {
                    // we don't really care if we got interrupted as we'll try this a few times
                }
            }
        }
        if (savedException != null) {
            throw savedException;
        }
    }

    private void waitForSocketToBind(String host, int port) throws InterruptedException {
        for (int i = 0; i < WAIT_FOR_MAX_ITERATIONS; ++i) {
            /* Try to connect to socket, if it fails, port is not bound yet */
            try (Socket socket = new Socket()) {
                SocketAddress address = new InetSocketAddress(host, port);
                socket.connect(address);
                return;
            } catch (IOException e) {
                /* ignored */
            }
            Thread.sleep(WAIT_FOR_SLEEP_DURATION);
        }
        throw new RuntimeException("Timeout waiting for mongodb socket to bind reached!");
    }

    private void waitForSocketToClose(int port) throws InterruptedException {
        for (int i = 0; i < WAIT_FOR_MAX_ITERATIONS; ++i) {
            /* Try to bind socket, if it fails, port is still in use */
            try (ServerSocket socket = new ServerSocket()) {
                SocketAddress address = new InetSocketAddress(port);
                socket.bind(address, 0);
                return;
            } catch (IOException e) {
                /* ignored */
            }
            Thread.sleep(WAIT_FOR_SLEEP_DURATION);
        }
        throw new RuntimeException("Timeout waiting for mongodb socket to close reached!");
    }

}