package eu.openaire.urls_controller.configuration;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

import javax.annotation.PostConstruct;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

@Repository
public class ImpalaConnector {

    private static final Logger logger = LoggerFactory.getLogger(ImpalaConnector.class);

    @Autowired
    private JdbcTemplate jdbcTemplate;

    private final boolean isTestEnvironment;
    private final String initialDatabaseName;
    private final String testDatabaseName;

    public static String databaseName;

    public static final Lock databaseLock = new ReentrantLock(true);  // This lock is locking the threads trying to execute queries in the database.


    public ImpalaConnector(@Value("${services.pdfaggregation.controller.isTestEnvironment}") boolean isTestEnvironment,
                            @Value("${services.pdfaggregation.controller.db.initialDatabaseName}") String initialDatabaseName,
                           @Value("${services.pdfaggregation.controller.db.testDatabaseName}") String testDatabaseName) {
        this.isTestEnvironment = isTestEnvironment;
        this.initialDatabaseName = initialDatabaseName;
        this.testDatabaseName = testDatabaseName;
    }


    @PostConstruct
    public void init() {
        logger.info("Max available memory to the Controller: " +  Runtime.getRuntime().maxMemory() + " bytes.");
        try {
            boolean supportsBatchUpdates = jdbcTemplate.getDataSource().getConnection().getMetaData().supportsBatchUpdates();
            logger.info("The database " + (supportsBatchUpdates ? "supports" : "does not support") + " \"BatchUpdates\"!");
        } catch (Exception e) {
            logger.error("Error testing if database supports batch updates!", e);
        }
        createDatabase();   // In case of an exception, the App will exit with the stacktrace.
    }


    private void createDatabase()
    {
        if ( isTestEnvironment ) {
            logger.info("Going to create (if not exist) the test-database \"" + testDatabaseName + "\" and its tables. Also will fill some tables with data from database \"" + initialDatabaseName + "\".");
            jdbcTemplate.execute("CREATE DATABASE IF NOT EXISTS " + testDatabaseName);

            jdbcTemplate.execute("CREATE TABLE IF NOT EXISTS " + testDatabaseName + ".publication stored as parquet as select * from " + initialDatabaseName + ".publication");
            jdbcTemplate.execute("COMPUTE STATS " + testDatabaseName + ".publication");

            jdbcTemplate.execute("CREATE TABLE IF NOT EXISTS " + testDatabaseName + ".publication_pids stored as parquet as select * from " + initialDatabaseName + ".publication_pids");
            jdbcTemplate.execute("COMPUTE STATS " + testDatabaseName + ".publication_pids");

            jdbcTemplate.execute("CREATE TABLE IF NOT EXISTS " + testDatabaseName + ".publication_urls stored as parquet as select * from " + initialDatabaseName + ".publication_urls");
            jdbcTemplate.execute("COMPUTE STATS " + testDatabaseName + ".publication_urls");

            jdbcTemplate.execute("CREATE TABLE IF NOT EXISTS " + testDatabaseName + ".datasource stored as parquet as select * from " + initialDatabaseName + ".datasource");
            jdbcTemplate.execute("COMPUTE STATS " + testDatabaseName + ".datasource");

            jdbcTemplate.execute("CREATE TABLE IF NOT EXISTS " + testDatabaseName + ".assignment (id string, original_url string, workerid string, `date` timestamp) stored as parquet");
            jdbcTemplate.execute("COMPUTE STATS " + testDatabaseName + ".assignment");

            databaseName = testDatabaseName;    // For the rest of the queries.
        } else {
            logger.info("Going to create or validate the tables that are populated by the Controller, for the \"initialDatabase\" = \"" + initialDatabaseName + "\"");
            databaseName = initialDatabaseName;
        }

        // For both cases, got check and create the tables which will be populated by the Controller.

        // Drop the "current_assignment" table. It is a temporary table which is created on-demand during execution.
        jdbcTemplate.execute("DROP TABLE IF EXISTS " + databaseName + ".current_assignment PURGE");

        jdbcTemplate.execute("CREATE TABLE IF NOT EXISTS " + databaseName + ".attempt (id string, original_url string, `date` timestamp, status string, error_class string, error_message string) stored as parquet");
        jdbcTemplate.execute("COMPUTE STATS " + databaseName + ".attempt");

        jdbcTemplate.execute("CREATE TABLE IF NOT EXISTS " + databaseName + ".payload (id string, original_url string, actual_url string, `date` timestamp, mimetype string, size string, `hash` string, `location` string, provenance string) stored as parquet");
        jdbcTemplate.execute("COMPUTE STATS " + databaseName + ".payload");

        logger.info("The " + (isTestEnvironment ? "test-" : "") + "database \"" + databaseName + "\" and its tables were created or validated.");
    }


    public static String handleQueryException(String queryName, String query, Exception e) {
        String errorMsg = "Problem when executing the query \"" + queryName + "\"!\n";
        logger.error(errorMsg  + "\n\n" + query + "\n\n", e);
        return errorMsg;
    }

}