/*
 * Copyright 2004-2022 H2 Group. Multiple-Licensed under the MPL 2.0,
 * and the EPL 1.0 (https://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package org.h2.test.synth;

import java.io.File;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.sql.BatchUpdateException;
import java.sql.Blob;
import java.sql.CallableStatement;
import java.sql.Clob;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ParameterMetaData;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.sql.Savepoint;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Comparator;
import java.util.GregorianCalendar;
import java.util.HashMap;
import java.util.Map;

import org.h2.api.ErrorCode;
import org.h2.store.FileLister;
import org.h2.store.fs.FileUtils;
import org.h2.test.TestBase;
import org.h2.test.TestDb;
import org.h2.test.scripts.TestScript;
import org.h2.test.synth.sql.RandomGen;
import org.h2.tools.Backup;
import org.h2.tools.DeleteDbFiles;
import org.h2.tools.Restore;
import org.h2.util.MathUtils;

/**
 * A test that calls random methods with random parameters from JDBC objects.
 * This is sometimes called 'Fuzz Testing'.
 */
public class TestCrashAPI extends TestDb implements Runnable {

    private static final boolean RECOVER_ALL = false;

    private static final Class<?>[] INTERFACES = { Connection.class,
            PreparedStatement.class, Statement.class, ResultSet.class,
            ResultSetMetaData.class, Savepoint.class, ParameterMetaData.class,
            Clob.class, Blob.class, Array.class, CallableStatement.class };

    private static final String DIR = "synth";

    private final ArrayList<Object> objects = new ArrayList<>();
    private final HashMap<Class <?>, ArrayList<Method>> classMethods =
            new HashMap<>();
    private RandomGen random = new RandomGen();
    private ArrayList<String> statements;
    private int openCount;
    private long callCount;
    private volatile long maxWait = 60;
    private volatile boolean stopped;
    private volatile boolean running;
    private Thread mainThread;

    /**
     * Run just this test.
     *
     * @param a ignored
     */
    public static void main(String... a) throws Exception {
        System.setProperty("h2.delayWrongPasswordMin", "0");
        System.setProperty("h2.delayWrongPasswordMax", "0");
        TestBase.createCaller().init().testFromMain();
    }

    @Override
    public void run() {
        while (--maxWait > 0) {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                maxWait++;
                // ignore
            }
            if (maxWait > 0 && maxWait <= 10) {
                println("stopping...");
                stopped = true;
            }
        }
        if (maxWait == 0 && running) {
            objects.clear();
            if (running) {
                println("stopping (trying to interrupt)...");
                for (StackTraceElement e : mainThread.getStackTrace()) {
                    System.out.println(e.toString());
                }
                mainThread.interrupt();
            }
        }
    }

    private static void recoverAll() {
        org.h2.Driver.load();
        File[] files = new File("temp/backup").listFiles();
        Arrays.sort(files, Comparator.comparing(File::getName));
        for (File f : files) {
            if (!f.getName().startsWith("db-")) {
                continue;
            }
            DeleteDbFiles.execute("data", null, true);
            try {
                Restore.execute(f.getAbsolutePath(), "data", null);
            } catch (Exception e) {
                System.out.println(f.getName() + " restore error " + e);
                // ignore
            }
            ArrayList<String> dbFiles = FileLister.getDatabaseFiles("data", null, false);
            for (String name: dbFiles) {
                if (!name.endsWith(".h2.db")) {
                    continue;
                }
                name = name.substring(0, name.length() - 6);
                try {
                    DriverManager.getConnection("jdbc:h2:data/" + name, "sa", "").close();
                    System.out.println(f.getName() + " OK");
                } catch (SQLException e) {
                    System.out.println(f.getName() + " " + e);
                }
            }
        }
    }

    @Override
    public boolean isEnabled() {
        if (config.networked) {
            return false;
        }
        return true;
    }

    @Override
    public void test() throws Exception {
        if (RECOVER_ALL) {
            recoverAll();
            return;
        }

        if (config.networked) {
            return;
        }

        TestScript script = new TestScript();
        statements = script.getAllStatements(config);
        initMethods();

        int len = getSize(2, 6);
        Thread t = new Thread(this);
        try {
            mainThread = Thread.currentThread();
            t.start();
            running = true;
            for (int i = 0; i < len && !stopped; i++) {
                int seed = MathUtils.randomInt(Integer.MAX_VALUE);
                testCase(seed);
                deleteDb();
            }
        } finally {
            running = false;
            deleteDb();
            maxWait = -1;
            t.join();
        }
    }

    private void deleteDb() {
        try {
            deleteDb(getBaseDir() + "/" + DIR, null);
        } catch (Exception e) {
            // ignore
        }
    }

    private Connection getConnection(int seed, boolean delete) throws SQLException {
        openCount++;
        if (delete) {
            deleteDb();
        }
        // can not use FILE_LOCK=NO, otherwise something could be written into
        // the database in the finalize method

        String add = ";MAX_QUERY_TIMEOUT=10000";

//         int testing;
//        if(openCount >= 32) {
//            int test;
//            Runtime.getRuntime().halt(0);
//            System.exit(1);
//        }
        // System.out.println("now open " + openCount);
        // add += ";TRACE_LEVEL_FILE=3";
        // config.logMode = 2;
        // }

        String dbName = "crashApi" + seed;
        String url = getURL(DIR + "/" + dbName, true) + add;

//        int test;
//        url += ";DB_CLOSE_ON_EXIT=FALSE";
//      int test;
//      url += ";TRACE_LEVEL_FILE=3";

        Connection conn = null;
        String fileName = "temp/backup/db-" + uniqueId++ + ".zip";
        Backup.execute(fileName, getBaseDir() + "/" + DIR, dbName, true);
        // close databases earlier
        System.gc();
        try {
            conn = DriverManager.getConnection(url, "sa", getPassword(""));
            // delete the backup if opening was successful
            FileUtils.delete(fileName);
        } catch (SQLException e) {
            if (e.getErrorCode() == ErrorCode.WRONG_USER_OR_PASSWORD) {
                // delete if the password changed
                FileUtils.delete(fileName);
            }
            throw e;
        }
        int len = random.getInt(50);
        int first = random.getInt(statements.size() - len);
        int end = first + len;
        Statement stat = conn.createStatement();
        stat.execute("SET LOCK_TIMEOUT 10");
        stat.execute("SET WRITE_DELAY 0");
        if (random.nextBoolean()) {
            if (random.nextBoolean()) {
                double g = random.nextGaussian();
                int size = (int) Math.abs(10000 * g * g);
                stat.execute("SET CACHE_SIZE " + size);
            } else {
                stat.execute("SET CACHE_SIZE 0");
            }
        }
        stat.execute("SCRIPT NOPASSWORDS NOSETTINGS");
        for (int i = first; i < end && i < statements.size() && !stopped; i++) {
            try {
                stat.execute("SELECT * FROM TEST WHERE ID=1");
            } catch (Throwable t) {
                printIfBad(seed, -i, -1, t);
            }
            try {
                stat.execute("SELECT * FROM TEST WHERE ID=1 OR ID=1");
            } catch (Throwable t) {
                printIfBad(seed, -i, -1, t);
            }

            String sql = statements.get(i);
            try {
//                if(openCount == 32) {
//                    int test;
//                    System.out.println("stop!");
//                }
                stat.execute(sql);
            } catch (Throwable t) {
                printIfBad(seed, -i, -1, t);
            }
        }
        if (random.nextBoolean()) {
            try {
                conn.commit();
            } catch (Throwable t) {
                printIfBad(seed, 0, -1, t);
            }
        }
        return conn;
    }

    private void testCase(int seed) throws SQLException {
        printTime("seed: " + seed);
        callCount = 0;
        openCount = 0;
        random = new RandomGen();
        random.setSeed(seed);
        Connection c1 = getConnection(seed, true);
        Connection conn = null;
        for (int i = 0; i < 2000 && !stopped; i++) {
            // if(i % 10 == 0) {
            // for(int j=0; j<objects.size(); j++) {
            // System.out.print(objects.get(j));
            // System.out.print(" ");
            // }
            // System.out.println();
            // Thread.sleep(1);
            // }

            if (objects.size() == 0) {
                try {
                    conn = getConnection(seed, false);
                } catch (SQLException e) {
                    if ("08004".equals(e.getSQLState())) {
                        // Wrong user/password [08004]
                        try {
                            c1.createStatement().execute("SET PASSWORD ''");
                        } catch (Throwable t) {
                            // power off or so
                            break;
                        }
                        try {
                            conn = getConnection(seed, false);
                        } catch (Throwable t) {
                            printIfBad(seed, -i, -1, t);
                        }
                    } else if ("90098".equals(e.getSQLState())) {
                        // The database has been closed
                        break;
                    } else {
                        printIfBad(seed, -i, -1, e);
                    }
                }
                objects.add(conn);
            }
            int objectId = random.getInt(objects.size());
            if (random.getBoolean(1)) {
                objects.remove(objectId);
                continue;
            }
            if (random.getInt(2000) == 0 && conn != null) {
                setPowerOffCount(conn, random.getInt(50));
            }
            Object o = objects.get(objectId);
            if (o == null) {
                objects.remove(objectId);
                continue;
            }
            Class<?> in = getJdbcInterface(o);
            ArrayList<Method> methods = classMethods.get(in);
            Method m = methods.get(random.getInt(methods.size()));
            Object o2 = callRandom(seed, i, objectId, o, m);
            if (o2 != null) {
                objects.add(o2);
            }
        }
        try {
            if (conn != null) {
                conn.close();
            }
            c1.close();
        } catch (Throwable t) {
            printIfBad(seed, -101010, -1, t);
            try {
                deleteDb();
            } catch (Throwable t2) {
                printIfBad(seed, -101010, -1, t2);
            }
        }
        objects.clear();
    }

    private void printError(int seed, int id, Throwable t) {
        StringWriter writer = new StringWriter();
        t.printStackTrace(new PrintWriter(writer));
        String s = writer.toString();
        TestBase.logError("new TestCrashAPI().init(test).testCase(" +
                seed + "); // Bug " + s.hashCode() + " id=" + id +
                " callCount=" + callCount + " openCount=" + openCount +
                " " + t.getMessage(), t);
        throw new RuntimeException(t);
    }

    private Object callRandom(int seed, int id, int objectId, Object o, Method m) {
        // TODO m.isDefault() can be used on Java 8
        boolean isDefault =
                (m.getModifiers() & (Modifier.ABSTRACT | Modifier.PUBLIC | Modifier.STATIC)) == Modifier.PUBLIC
                && m.getDeclaringClass().isInterface();
        boolean allowNPE = isDefault || o instanceof Blob && "setBytes".equals(m.getName());
        Class<?>[] paramClasses = m.getParameterTypes();
        Object[] params = new Object[paramClasses.length];
        for (int i = 0; i < params.length; i++) {
            params[i] = getRandomParam(paramClasses[i]);
        }
        Object result = null;
        try {
            callCount++;
            result = m.invoke(o, params);
        } catch (IllegalArgumentException | IllegalAccessException e) {
            TestBase.logError("error", e);
        } catch (InvocationTargetException e) {
            Throwable t = e.getTargetException();
            printIfBad(seed, id, objectId, t, allowNPE);
        }
        if (result == null) {
            return null;
        }
        Class<?> in = getJdbcInterface(result);
        if (in == null) {
            return null;
        }
        return result;
    }

    private void printIfBad(int seed, int id, int objectId, Throwable t) {
        printIfBad(seed, id, objectId, t, false);
    }

    private void printIfBad(int seed, int id, int objectId, Throwable t, boolean allowNPE) {
        if (t instanceof BatchUpdateException) {
            // do nothing
        } else if (t.getClass().getName().contains("SQLClientInfoException")) {
            // do nothing
        } else if (t instanceof UnsupportedOperationException) {
            // do nothing - new Java8/9 stuff
        } else if (t instanceof SQLFeatureNotSupportedException) {
            // do nothing
        } else if (t instanceof SQLException) {
            SQLException s = (SQLException) t;
            int errorCode = s.getErrorCode();
            if (errorCode == 0) {
                printError(seed, id, s);
            } else if (errorCode == ErrorCode.OBJECT_CLOSED) {
                if (objectId >= 0 && objects.size() > 0) {
                    // TODO at least call a few more times after close - maybe
                    // there is still an error
                    objects.remove(objectId);
                }
            } else if (errorCode == ErrorCode.GENERAL_ERROR_1) {
                // General error [HY000]
                printError(seed, id, s);
            }
        } else if (allowNPE && t instanceof NullPointerException) {
            // do nothing, this methods may throw this exception
        } else {
            printError(seed, id, t);
        }
    }

    private Object getRandomParam(Class<?> type) {
        if (type == int.class) {
            return random.getRandomInt();
        } else if (type == byte.class) {
            return (byte) random.getRandomInt();
        } else if (type == short.class) {
            return (short) random.getRandomInt();
        } else if (type == long.class) {
            return random.getRandomLong();
        } else if (type == float.class) {
            return (float) random.getRandomDouble();
        } else if (type == boolean.class) {
            return random.nextBoolean();
        } else if (type == double.class) {
            return random.getRandomDouble();
        } else if (type == String.class) {
            if (random.getInt(10) == 0) {
                return null;
            }
            int randomId = random.getInt(statements.size());
            String sql = statements.get(randomId);
            if (random.getInt(10) == 0) {
                sql = random.modify(sql);
            }
            return sql;
        } else if (type == int[].class) {
            // TODO test with 'shared' arrays (make sure database creates a
            // copy)
            return random.getIntArray();
        } else if (type == java.io.Reader.class) {
            return null;
        } else if (type == java.sql.Array.class) {
            return null;
        } else if (type == byte[].class) {
            // TODO test with 'shared' arrays (make sure database creates a
            // copy)
            return random.getByteArray();
        } else if (type == Map.class) {
            return null;
        } else if (type == Object.class) {
            return null;
        } else if (type == java.sql.Date.class) {
            return random.randomDate();
        } else if (type == java.sql.Time.class) {
            return random.randomTime();
        } else if (type == java.sql.Timestamp.class) {
            return random.randomTimestamp();
        } else if (type == java.io.InputStream.class) {
            return null;
        } else if (type == String[].class) {
            return null;
        } else if (type == java.sql.Clob.class) {
            return null;
        } else if (type == java.sql.Blob.class) {
            return null;
        } else if (type == Savepoint.class) {
            // TODO should use generated savepoints
            return null;
        } else if (type == Calendar.class) {
            return new GregorianCalendar();
        } else if (type == java.net.URL.class) {
            return null;
        } else if (type == java.math.BigDecimal.class) {
            return new java.math.BigDecimal("" + random.getRandomDouble());
        } else if (type == java.sql.Ref.class) {
            return null;
        }
        return null;
    }

    private Class<?> getJdbcInterface(Object o) {
        for (Class <?> in : o.getClass().getInterfaces()) {
            if (classMethods.get(in) != null) {
                return in;
            }
        }
        return null;
    }

    private void initMethods() {
        for (Class<?> inter : INTERFACES) {
            ArrayList<Method> list = new ArrayList<>();
            for (Method m : inter.getMethods()) {
                list.add(m);
            }
            classMethods.put(inter, list);
        }
    }

}
