package org.javasimon.jdbc4;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
import java.util.StringTokenizer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * JDBC configuration contains Simon JDBC connection URL, real JDBC connection URL and Simon properties.
 * <p/>
 * It parses given url and than provides getters for driver's properties if provided or default values.
 * Prior to Simon 3.4, this class was known as org.javasimon.jdbc4.Driver.Url and only used in {@link Driver}.
 * It was externalized and is now used in both {@code org.javasimon.jdbc4.Driver}
 * and {@link org.javasimon.jdbcx4.SimonDataSource} and other Simon DataSources.
 *
 * @author Radovan Sninsky
 * @author gquintana
 * @since 3.4
 */
public class SimonConnectionConfiguration {
        /**
         * Default hierarchy prefix for Simon JDBC driver. All Simons created by Simon JDBC
         * driver without explicitly specified prefix are started with default prefix.
         */
        public static final String DEFAULT_PREFIX = "org.javasimon.jdbc";

        /**
         * Prefix used in JDBC connection URLs.
         */
        public static final String URL_PREFIX = "jdbc:simon";

        /**
         * Regex used to parse JDBC connection URL.
         */
        private static final Pattern URL_PATTERN = Pattern.compile("jdbc:(simon:)?([\\w]*):.*");

        /**
         * Name for the property holding the real driver class value.
         */
        public static final String REAL_DRIVER = "simon_real_drv";
        /**
         * Name for the driver property holding the hierarchy prefix given to JDBC Simons.
         */
        public static final String PREFIX = "simon_prefix";

        private static final Properties PROPERTIES = initProperties();

        /**
         * JDBC connection URL with Simon prefix.
         */
        private final String simonUrl;

        /**
         * JDBC connection URL without Simon prefix.
         */
        private final String realUrl;

        /**
         * Driver Id.
         */
        private final String driverId;

        /**
         * Real Driver class name.
         */
        private final String realDriver;

        /**
         * Simon hierarchy prefix.
         */
        private final String prefix;

        /**
         * Loads {@code driver.properties} file.
         */
        private static Properties initProperties() {
                InputStream stream = null;
                try {
                        // TODO: limited to known drivers, better find driver later based on JDBC connection URL without "simon" word
                        Properties properties = new Properties();
                        stream = Thread.currentThread().getContextClassLoader().getResourceAsStream("org/javasimon/jdbc4/drivers.properties");
                        if (stream != null) {
                                properties.load(stream);
                        }
                        return properties;
                } catch (IOException e) {
                        throw new IllegalStateException(e);
                } finally {
                        if (stream != null) {
                                try {
                                        stream.close();
                                } catch (IOException e) {
                                        // Doesn't matter
                                }
                        }
                }
        }

        /**
         * Class constructor, parses given connection URL and recognizes driver's properties.
         *
         * @param url given JDBC connection URL
         */
        public SimonConnectionConfiguration(String url) {
                Matcher m = URL_PATTERN.matcher(url);
                if (!m.matches()) {
                        throw new IllegalArgumentException(url + " is not a valid JDBC connection URL");
                }
                driverId = m.group(2);
                if (m.group(1) == null) {
                        // java:oracle:
                        simonUrl = url.replaceFirst("jdbc", URL_PREFIX);
                        realUrl = url;
                        realDriver = getProperty(driverId, "driver");
                        prefix = DEFAULT_PREFIX;
                } else {
                        //java:simon:oracle
                        simonUrl = url;
                        StringTokenizer st = new StringTokenizer(url, ";");
                        String lRealDriver = getProperty(driverId, "driver");
                        String lPrefix = DEFAULT_PREFIX;
                        StringBuilder realUrlBuilder = new StringBuilder();
                        while (st.hasMoreTokens()) {
                                String tokenPairStr = st.nextToken().trim();

                                if (tokenPairStr.startsWith(URL_PREFIX)) {
                                        realUrlBuilder.append(tokenPairStr.replaceFirst(URL_PREFIX, "jdbc"));
                                } else {
                                        String[] tokenPair = tokenPairStr.split("=", 2);
                                        String token = tokenPair[0];
                                        String tokenValue = tokenPair.length == 2 ? tokenPair[1].trim() : null;
                                        if (token.equalsIgnoreCase(REAL_DRIVER)) {
                                                lRealDriver = tokenValue;
                                        } else if (token.equalsIgnoreCase(PREFIX)) {
                                                lPrefix = tokenValue;
                                        } else {
                                                realUrlBuilder.append(';').append(tokenPairStr);
                                        }
                                }
                        }
                        realUrl = realUrlBuilder.toString();
                        realDriver = lRealDriver;
                        prefix = lPrefix;
                }
        }

        /**
         * Gets value of the specified property.
         *
         * @param driverId Driver Id
         * @param propertyName Property name
         * @return property value or {@code null}
         */
        private static String getProperty(String driverId, String propertyName) {
                String propertyValue = PROPERTIES.getProperty(DEFAULT_PREFIX + "." + driverId + "." + propertyName);
                if (propertyValue != null) {
                        propertyValue = propertyValue.trim();
                        if (propertyValue.isEmpty()) {
                                propertyValue = null;
                        }
                }
                return propertyValue;
        }

        /**
         * Returns orignal JDBC connection URL without any Simon stuff.
         *
         * @return original JDBC connection URL
         */
        public String getRealUrl() {
                return realUrl;
        }

        /**
         * Returns driver identifier (eg. oracle, postgres, mysql, h2, etc.).
         *
         * @return driver identifier
         */
        public String getDriverId() {
                return driverId;
        }

        /**
         * Returns fully qualified class name of the real driver.
         *
         * @return driver class FQN
         */
        public String getRealDriver() {
                return realDriver;
        }

        /**
         * Returns prefix for hierarchy of JDBC connection related Simons.
         *
         * @return prefix for JDBC Simons
         */
        public String getPrefix() {
                return prefix;
        }

        /**
         * Simon JDBC connection URL prefixed with {@code jdbc:simon:}.
         *
         * @return Simon JDBC connection URL
         */
        public String getSimonUrl() {
                return simonUrl;
        }

        /**
         * Tests whether URL is a Simon JDBC connection URL.
         */
        public static boolean isSimonUrl(String url) {
                return url != null && url.toLowerCase().startsWith(SimonConnectionConfiguration.URL_PREFIX);
        }

        /**
         * Gets the name of the class implementing {@link javax.sql.ConnectionPoolDataSource}.
         */
        public String getRealConnectionPoolDataSourceName() {
                return getProperty(driverId, "cpdatasource");
        }

        /**
         * Gets the name of the class implementing {@link javax.sql.DataSource}.
         */
        public String getRealDataSourceName() {
                return getProperty(driverId, "datasource");
        }

        /**
         * Gets the name of the class implementing {@link javax.sql.XADataSource}.
         */
        public String getRealXADataSourceName() {
                return getProperty(driverId, "xadatasource");
        }
}