/*
 * Copyright Debezium Authors.
 *
 * Licensed under the Apache Software License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
 */
package io.debezium.connector.db2;

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.kafka.common.config.ConfigDef;
import org.apache.kafka.common.config.ConfigValue;
import org.apache.kafka.connect.connector.Task;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import io.debezium.DebeziumException;
import io.debezium.annotation.ThreadSafe;
import io.debezium.config.Configuration;
import io.debezium.connector.common.RelationalBaseSourceConnector;
import io.debezium.relational.RelationalDatabaseConnectorConfig;
import io.debezium.relational.TableId;

/**
 * The main connector class used to instantiate configuration and execution classes
 *
 * @author Jiri Pechanec, Luis Garcés-Erice
 *
 */

@ThreadSafe
public class Db2Connector extends RelationalBaseSourceConnector {

    private static final Logger LOGGER = LoggerFactory.getLogger(Db2Connector.class);

    private Map<String, String> properties;

    @Override
    public String version() {
        return Module.version();
    }

    @Override
    public void start(Map<String, String> props) {
        this.properties = Collections.unmodifiableMap(new HashMap<>(props));
    }

    @Override
    public Class<? extends Task> taskClass() {
        return Db2ConnectorTask.class;
    }

    @Override
    public List<Map<String, String>> taskConfigs(int maxTasks) {
        if (maxTasks > 1) {
            throw new IllegalArgumentException("Only a single connector task may be started");
        }

        return Collections.singletonList(properties);
    }

    @Override
    public void stop() {
    }

    @Override
    public ConfigDef config() {
        return Db2ConnectorConfig.configDef();
    }

    @Override
    protected void validateConnection(Map<String, ConfigValue> configValues, Configuration config) {
        ConfigValue hostnameValue = configValues.get(RelationalDatabaseConnectorConfig.HOSTNAME.name());
        // Try to connect to the database ...
        Db2ConnectorConfig connectorConfig = new Db2ConnectorConfig(config);
        try (Db2Connection connection = new Db2Connection(connectorConfig)) {
            try {
                connection.connect();
                connection.execute("SELECT 1 FROM sysibm.sysdummy1");
                LOGGER.info("Successfully tested connection for {} with user '{}'", connection.connectionString(), connection.username());
            }
            catch (SQLException e) {
                LOGGER.error("Failed testing connection for {} with user '{}'", connection.connectionString(), connection.username(), e);
                hostnameValue.addErrorMessage("Unable to connect: " + e.getMessage());
            }
        }
        catch (SQLException e) {
            LOGGER.error("Unexpected error shutting down the database connection", e);
        }
    }

    @Override
    protected Map<String, ConfigValue> validateAllFields(Configuration config) {
        return config.validate(Db2ConnectorConfig.ALL_FIELDS);
    }

    @SuppressWarnings("unchecked")
    @Override
    public List<TableId> getMatchingCollections(Configuration config) {
        Db2ConnectorConfig connectorConfig = new Db2ConnectorConfig(config);
        try (Db2Connection connection = new Db2Connection(connectorConfig)) {
            return new ArrayList<>(
                    connection.readTableNames(null, null, null, new String[]{ "TABLE" }));
        }
        catch (SQLException e) {
            throw new DebeziumException(e);
        }
    }
}
