package de.superx.servlet;

import java.io.File;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import org.apache.log4j.Logger;
import org.apache.log4j.spi.LoggingEvent;
import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test;
import org.springframework.test.context.ContextConfiguration;

import de.superx.BaseDbTest;
import de.superx.TestApplicationConfigPg;
import de.superx.bin.ExecuteMask;
import de.superx.common.UngueltigeEingabeException;
import de.superx.sec.InputCheckRegistry;
import de.superx.util.UnittestAppender;

//@ContextConfiguration(classes = { TestApplicationConfigPg.class })
public class SQLInjectionTest extends BaseDbTest {

    Logger logger = Logger.getLogger(ExecuteMask.class);
    
    private static String outputFilename;

    @BeforeClass
    public static void setup() throws Exception {
        outputFilename = String.join(File.separator, "test", "output_160440.html");
        InputCheckRegistry.registerDefaultChecks();
        ExecuteMask.setMyWEBINFFilePath(SuperXManager.getWEB_INFPfad());
    }

    @SuppressWarnings("static-method")
    @Test
    public void testExpansionInjection() throws Exception {
        String[] params = buildParamsStudierendeDatenblatt("123)@@SEMICOLON@@insert into xdummy(c) values (2)@@SEMICOLON@@commit@@SEMICOLON@@--");
        Logger sxsql_ServerLogger = setUpLogger();
        UnittestAppender ta = setUpTestAppender(sxsql_ServerLogger);
        try (Connection conn = SxPools.get(MANDANTEN_ID).getConnection()) {
            String entries_before = getXDummyEntries(conn);

            boolean bla = setFieldAttribute(conn, 160462, "{InputCheck:disabled}");
            try {
                ExecuteMask.execute(params);
            } catch (Exception e) {
                // as most exceptions are not throws, but caught and written to log, we have to analize the log...
            }
            assertThatInjectionAttemptCausedSQLException(ta);
            assertThatSQLExceptionWasNotCausedByFaultyTestEnvironment(ta);
            String entries_after = getXDummyEntries(conn);
            Assert.assertEquals("Count of 'xdummy' entries should not have changed, when injection is prevented", entries_before, entries_after);
        }
    }

    @SuppressWarnings("static-method")
    @Test
    public void testDatabaseFunctionInjection() throws Exception {
        String[] params = buildParamsStudierendeDatenblatt("sp_get_keylist_str($$bla1$$,$$bla2$$)::INT");
        try (Connection conn = SxPools.get(MANDANTEN_ID).getConnection()) {
            boolean bla = setFieldAttribute(conn, 160462, "{InputCheck:matrikelnummern}");
        }
        executeMaskAndValidateExpectedOutcome(params);
    }

    @SuppressWarnings("static-method")
    @Test
    public void testMultilineCommentInjection() throws Exception {
        String[] params = buildParamsVerwundbarkeitstest("bla\nblub", "");
        try (Connection conn = SxPools.get(MANDANTEN_ID).getConnection()) {
            prepareVerwundbarbeitstest(conn);
        }
        executeMaskAndValidateExpectedOutcome(params);
    }

    @SuppressWarnings("static-method")
    @Test
    public void testZombieParameterInjection() throws Exception {
        String[] params = buildParamsVerwundbarkeitstest("", "ksjasf");
        try (Connection conn = SxPools.get(MANDANTEN_ID).getConnection()) {
            prepareVerwundbarbeitstest(conn);
        }
        executeMaskAndValidateExpectedOutcome(params);
    }

    private static void assertThatSQLExceptionWasNotCausedByFaultyTestEnvironment(UnittestAppender ta) {
        String message = null;
        boolean log_events_contain_errors_due_to_missing_db_functions = false;
        for (LoggingEvent event : ta.loggingEventList) {
            message = event.getMessage().toString();
            if (message != null && message.contains("Fehler beim Aufruf eine benutzerdefinierten Funktion")) {
                log_events_contain_errors_due_to_missing_db_functions = true;
                break;
            }
        }
        Assert.assertFalse("Found error message:\n" + message, log_events_contain_errors_due_to_missing_db_functions);
    }

    private static void assertThatInjectionAttemptCausedSQLException(UnittestAppender ta) {
        boolean log_events_contain_exception_with_injected_sql = false;
        for (LoggingEvent event : ta.loggingEventList) {
            String message = event.getMessage().toString();
            if (message != null && message.contains("insert into xdummy(")) {
                log_events_contain_exception_with_injected_sql = true;
                break;
            }
        }
        Assert.assertTrue("Application log should contain an SQLException due to injected SQL", log_events_contain_exception_with_injected_sql);
    }

    private static UnittestAppender setUpTestAppender(Logger sxsql_ServerLogger) {
        UnittestAppender ta = new UnittestAppender();
        sxsql_ServerLogger.addAppender(ta);
        return ta;
    }

    private static Logger setUpLogger() {
        Logger sxsql_ServerLogger = Logger.getLogger("superx_" + MANDANTEN_ID);
        sxsql_ServerLogger.setAdditivity(false);
        sxsql_ServerLogger.removeAllAppenders();
        sxsql_ServerLogger.setLevel(org.apache.log4j.Level.ALL);
        return sxsql_ServerLogger;
    }

    private static void executeMaskAndValidateExpectedOutcome(String[] params) {
        try {
            ExecuteMask.execute(params);
        } catch (Exception e) {
            Assert.assertTrue(
                    "Exception is expected to be caused by InputCheck and thus to be of type UngueltigeEingabeException",
                    e.getClass().equals(UngueltigeEingabeException.class)
            );
        }
    }

    private static boolean setFieldAttribute(Connection conn, int tid, String value) throws SQLException {
        Statement statement = conn.createStatement();
        return statement.execute("UPDATE felderinfo SET attribut = '" + value + "' WHERE tid = " + tid + ";");
    }

    private static void prepareVerwundbarbeitstest(Connection conn) throws SQLException {
        try (Statement statement = conn.createStatement()) {
            // extend the mask-SQL with
            // 1. the /* <SQL-snippet> -- <<HTTP-Parameter>>*/ pattern, which is quite common in superx
            // 2. a parameter placeholder, which has no configuration in table 'felderinfo' ('zombie_parameter')
            statement.execute("UPDATE maskeninfo mi SET select_stmt = replace(select_stmt, 'where  ', " +
                            "E'WHERE\\n/* 1 = 1 AND -- <<Inhalt2>>*/\\n/* <<zombie_parameter>> AND */') " +
                            "WHERE mi.name = 'Verwundbarkeitstest';");
            // replace the GROUP BY clauses with versions that also work in H2 (should be rolled out in the unl-file as well)
            statement.execute("UPDATE felderinfo SET relation = replace(relation, 'group by 1', 'group by buchungsab_fb') " +
                            "WHERE name = 'Buchungsab_fb' AND tid IN" +
                            "(SELECT felderinfo_id FROM masken_felder_bez mfb JOIN maskeninfo mi ON mfb.maskeninfo_id = mi.tid AND mi.name = 'Verwundbarkeitstest');");
            statement.execute("UPDATE felderinfo SET relation = replace(relation, 'group by 1', 'group by projnr_ins') " +
                            "WHERE name = 'Projnr_ins' AND tid IN" +
                            "(SELECT felderinfo_id FROM masken_felder_bez mfb JOIN maskeninfo mi ON mfb.maskeninfo_id = mi.tid AND mi.name = 'Verwundbarkeitstest');");
            statement.execute("UPDATE felderinfo SET zeilenanzahl = 1 " +
                            "WHERE name = 'Inhalt2' AND tid IN" +
                            "(SELECT felderinfo_id FROM masken_felder_bez mfb JOIN maskeninfo mi ON mfb.maskeninfo_id = mi.tid AND mi.name = 'Verwundbarkeitstest');");
        }
    }

    private static String getXDummyEntries(Connection conn) throws SQLException {
        String entries = "";
        try (Statement statement = conn.createStatement();
                        ResultSet resultSet = statement.executeQuery("select count(*) entries from xdummy")) {
            resultSet.next();
            entries = resultSet.getString("entries");
        }
        return entries;
    }

    private static String[] buildParamsStudierendeDatenblatt(String injection) {
        String contenttype = "";
        String stylesheet = "tabelle_html_datenblatt.xsl";
        String[] params = { "-tid:160440", "-out:" + outputFilename, "-user:admin",
                "-params:Köpfe oder Fälle ?=KoF_2&Stichtag=1"
                        + "&Matrikel-Nr.=" + injection
                        + "&stylesheet=" + stylesheet + "&tablestylesheet=" + stylesheet + "&contenttype="
                        + contenttype,
                "-logger:" + logConfigPath, "-mandantenID:" + MANDANTEN_ID };
        return params;
    }

    private static String[] buildParamsVerwundbarkeitstest(String multiline_injection_payload, String zombie_param_injection_payload) {
        String contenttype = "";
        String stylesheet = "tabelle_html_datenblatt.xsl";
        String[] params = { "-tid:71580", "-out:" + outputFilename, "-user:admin",
                "-params:Inhalt=test"
                + "&Inhalt2=" + multiline_injection_payload
                + "zombie_parameter=" + zombie_param_injection_payload
                + "&Jahr=2018&stylesheet=" + stylesheet
                + "&tablestylesheet=" + stylesheet
                + "&contenttype=" + contenttype,
                "-logger:" + logConfigPath, "-mandantenID:" + MANDANTEN_ID };
        return params;
    }
}