/*
 * Copyright (C) 2015 LibreCCM Foundation.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301  USA
 */
package org.libreccm.testutils;

import org.dbunit.DatabaseUnitException;
import org.dbunit.database.DatabaseConnection;
import org.dbunit.database.IDatabaseConnection;
import org.dbunit.dataset.DataSetException;
import org.dbunit.dataset.IDataSet;
import org.dbunit.dataset.xml.FlatXmlDataSet;
import org.dbunit.operation.DatabaseOperation;
import org.junit.Test;

import java.io.IOException;
import java.net.URISyntaxException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

import org.h2.tools.RunScript;
import org.jboss.arquillian.persistence.dbunit.dataset.json.JsonDataSet;
import org.junit.runners.Parameterized;

import static org.libreccm.testutils.DatasetType.*;

import org.dbunit.database.DatabaseConfig;
import org.dbunit.dataset.xml.FlatXmlDataSetBuilder;
import org.jboss.arquillian.persistence.dbunit.dataset.yaml.YamlDataSet;

import java.io.InputStream;
import java.io.StringReader;
import java.nio.charset.StandardCharsets;
import java.sql.ResultSet;

/**
 *
 * For testing the CCM modules the Arquillian Persistence extension including
 * the DBUnit integration is used. Unfortunately there are some issues with
 * exception reporting if there errors in the datasets used for testing.
 * Therefore we provide this utility class which can be used to implement test
 * for the datasets outside of Arquillian.
 *
 * For testing an in-memory H2 database is used. The datasets are loaded into
 * the database using DBUnit classes. Before loading the dataset this class
 * creates the database schema. The SQL script for generating the schema is
 * loaded via {@code getClass().getResource(/sql/ddl/auto/h2.sql).toURI()}.
 * Therefore the utility expects to find the SQL for generating the database
 * schema in the classpath at th path {@code /sql/ddl/auto/h2.sql}. The default
 * {@code pom.xml} for modules take care of that.
 *
 * After each dataset the database is scrapped. To use this utility create a
 * JUnit test class using the {@link Parameterized} test runner from JUnit. An
 * example is the
 * <a href="../../../../../ccm-core/xref-test/org/libreccm/core/DatasetsTest.html"><code>DatasetsTest</code></a>
 * in the {@code org.libreccm.core} package of the ccm-core module.
 *
 * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
 */
public class DatasetsVerifier {

private final String datasetPath;

public DatasetsVerifier(final String datasetsPath) {
    this.datasetPath = datasetsPath;
}

/**
 * Overwrite this method if you are using another schema than the default one.
 *
 * @return An string array contains the names of the database schemata used by
 *         the datasets the test.
 */
public String[] getSchemas() {
    return new String[]{};
}

public DatasetType getDatasetType() {
    return JSON;
}

@Test
@edu.umd.cs.findbugs.annotations.SuppressWarnings(
    value = "DMI_EMPTY_DB_PASSWORD",
    justification = "H2 in mem database does not need a password")
public void verifyDataset() throws SQLException,
                                   URISyntaxException,
                                   IOException,
                                   DatabaseUnitException {
    //Create database connection to an in memory h2 database. Placed in
    //try-with-resources block to ensure that the connection is closed.
    final StringBuffer buffer = new StringBuffer("jdbc:h2:mem:testdatabase");
    //Create schema if necssary
//        if (getSchemas().length > 0) {
//            buffer.append(";INIT=");
//            for (final String schema : getSchemas()) {
//                if (buffer.length() > 0) {
//                    buffer.append("\\;");
//                }
//                buffer.append(String.format("CREATE SCHEMA IF NOT EXISTS %s",
//                                            schema));
//            }
//        }
    final String connectionStr = buffer.toString();
    try (final Connection connection = DriverManager
        .getConnection(connectionStr, "sa", "")) {
        final StringBuffer schemaCreateBuffer = new StringBuffer();
        for (final String schema : getSchemas()) {
            schemaCreateBuffer.append(String
                .format("CREATE SCHEMA IF NOT EXISTS %s;%n", schema));
        }

        try (final StringReader schemaCreateReader = new StringReader(
            schemaCreateBuffer.toString())) {
            RunScript.execute(connection, schemaCreateReader);
        }

        //Create DB tables etc 
        for (final String ddlFile : getDdlFiles()) {
            processDdlFile(connection, ddlFile);
        }

//            final Path schemaPath = Paths.get(getClass().getResource(
//                "/sql/ddl/auto/h2.sql").toURI());
//            RunScript.execute(connection, Files.newBufferedReader(
//                              schemaPath, StandardCharsets.UTF_8));
        connection.commit();

        System.out.println("DB Info:");
        System.out.println("Catalogs:");
        try (ResultSet resultSet = connection.getMetaData().getCatalogs()) {
            while(resultSet.next()) {
                System.out.println(resultSet.getString("table_cat"));
            }
        }
        System.out.println("Schemas");
        try(ResultSet resultSet = connection.getMetaData().getSchemas()) {
            while(resultSet.next()) {
                System.out.println(resultSet.getString("TABLE_SCHEM"));
            }
        }
        System.out.println("Tables");
        try (ResultSet resultSet = connection.getMetaData().getTables("TESTDATABASE", "CCM_CORE", null, null)) {
            while(resultSet.next()) {
                System.out.println(resultSet.getString("table_name"));
            }
        }
        System.out.println("settings columns:");
        try (ResultSet resultSet = connection.getMetaData().getColumns(
            "TESTDATABASE", "CCM_CORE", "SETTINGS", null
        )) {
            while (resultSet.next()) {
                System.out.printf("table_name = %s%n", resultSet.getString(
                                  "table_name"));
                System.out.printf("col_name   = %s%n", resultSet.getString(
                                  "column_name"));
            }
        }

        //Get dataset to test
        final IDataSet dataSet;
        try (final InputStream inputStream = getClass().getResourceAsStream(
            datasetPath)) {
            switch (getDatasetType()) {
                case FLAT_XML:
                    final FlatXmlDataSetBuilder builder
                        = new FlatXmlDataSetBuilder();
                    dataSet = builder.build(inputStream);
                    break;
                case JSON:
                    dataSet = new JsonDataSet(inputStream);
                    break;
                case YAML:
                    dataSet = new YamlDataSet(inputStream);
                    break;
                default:
                    throw new IllegalArgumentException(String.format(
                        "Unsupported DatasetType \"%s\"",
                        getDatasetType()));
            }
        }

        //Create DBUnit DB connection
        final IDatabaseConnection dbUnitConn
            = new DatabaseConnection(connection);
        dbUnitConn.getConfig().setProperty(
            "http://www.dbunit.org/features/qualifiedTableNames", true);
        //Check if dumping works the DB works before loading the dataset.
        System.out.println("Dump before loading dataset...");
        verifyDumping(dbUnitConn);
        
        //Put dataset into DB
        DatabaseOperation.CLEAN_INSERT.execute(dbUnitConn, dataSet);

        //Check if dumping works after loading the dataset
        System.out.println("Dump after loading dataset...");
        verifyDumping(dbUnitConn);
    }
}

protected String[] getDdlFiles() {
    return new String[]{"/sql/ddl/auto/libreccmh2.sql"};
}

private void processDdlFile(final Connection connection,
                            final String ddlFile) throws URISyntaxException,
                                                         SQLException,
                                                         IOException {
    final Path schemaPath = Paths.get(getClass().getResource(ddlFile)
        .toURI());
    RunScript.execute(connection,
                      Files.newBufferedReader(schemaPath,
                                              StandardCharsets.UTF_8));
}

private void verifyDumping(final IDatabaseConnection connection)
    throws SQLException, IOException, DataSetException {
    final IDataSet data = connection.createDataSet();
    FlatXmlDataSet.write(data, System.out);
}

}