/**

 * SQL-DK

 * Copyright © 2013 František Kučera (frantovo.cz)

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program. If not, see <http://www.gnu.org/licenses/>.

 */

package info.globalcode.sql.dk;

import info.globalcode.sql.dk.configuration.Configuration;

import info.globalcode.sql.dk.configuration.ConfigurationException;

import info.globalcode.sql.dk.configuration.ConfigurationProvider;

import info.globalcode.sql.dk.configuration.DatabaseDefinition;

import info.globalcode.sql.dk.configuration.FormatterDefinition;

import info.globalcode.sql.dk.configuration.Properties;

import info.globalcode.sql.dk.configuration.Property;

import info.globalcode.sql.dk.formatting.ColumnsHeader;

import info.globalcode.sql.dk.formatting.FakeSqlArray;

import info.globalcode.sql.dk.formatting.Formatter;

import info.globalcode.sql.dk.formatting.FormatterContext;

import info.globalcode.sql.dk.formatting.FormatterException;

import java.io.BufferedReader;

import java.io.ByteArrayOutputStream;

import java.io.InputStreamReader;

import java.io.PrintStream;

import java.sql.Array;

import java.sql.Driver;

import java.sql.DriverManager;

import java.sql.DriverPropertyInfo;

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.EnumSet;

import java.util.HashSet;

import java.util.List;

import java.util.ServiceLoader;

import java.util.Set;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.TimeUnit;

import java.util.logging.Level;

import java.util.logging.LogRecord;

import java.util.logging.Logger;

import javax.sql.rowset.RowSetMetaDataImpl;

/**

 * Displays info like help, version etc.

 *

 * @author Ing. František Kučera (frantovo.cz)

 */

public class InfoLister {

	private static final Logger log = Logger.getLogger(InfoLister.class.getName());

	/**

	 * Fake database name for output formatting

	 */

	public static final String CONFIG_DB_NAME = "sqldk_configuration";

	private final PrintStream out;

	private final ConfigurationProvider configurationProvider;

	private final CLIOptions options;

	private Formatter formatter;

	public InfoLister(PrintStream out, ConfigurationProvider configurationProvider, CLIOptions options) {

		this.out = out;

		this.configurationProvider = configurationProvider;

		this.options = options;

	}

	public void showInfo() throws ConfigurationException, FormatterException {

		EnumSet<InfoType> commands = options.getShowInfo();

		boolean formattinNeeded = false;

		for (InfoType infoType : commands) {

			switch (infoType) {

				case CONNECTION:

				case JDBC_DRIVERS:

				case JDBC_PROPERTIES:

				case DATABASES:

				case FORMATTERS:

				case TYPES:

					formattinNeeded = true;

					break;

			}

		}

		if (formattinNeeded) {

			try (Formatter f = getFormatter()) {

				formatter = f;

				formatter.writeStartBatch();

				DatabaseDefinition dd = new DatabaseDefinition();

				dd.setName(CONFIG_DB_NAME);

				formatter.writeStartDatabase(dd);

				showInfos(commands);

				formatter.writeEndDatabase();

				formatter.writeEndBatch();

				formatter.close();

			}

		} else {

			showInfos(commands);

		}

	}

	private void showInfos(EnumSet<InfoType> commands) throws ConfigurationException, FormatterException {

		for (InfoType infoType : commands) {

			infoType.showInfo(this);

		}

	}

	private void listFormatters() throws ConfigurationException, FormatterException {

		ColumnsHeader header = constructHeader(

				new HeaderField("name", SQLType.VARCHAR),

				new HeaderField("built_in", SQLType.BOOLEAN),

				new HeaderField("default", SQLType.BOOLEAN),

				new HeaderField("class_name", SQLType.VARCHAR),

				new HeaderField("valid", SQLType.BOOLEAN));

		List<Object[]> data = new ArrayList<>();

		String defaultFormatter = configurationProvider.getConfiguration().getDefaultFormatter();

		defaultFormatter = defaultFormatter == null ? Configuration.DEFAULT_FORMATTER : defaultFormatter;

		for (FormatterDefinition fd : configurationProvider.getConfiguration().getBuildInFormatters()) {

			data.add(new Object[]{fd.getName(), true, defaultFormatter.equals(fd.getName()), fd.getClassName(), isInstantiable(fd)});

		}

		for (FormatterDefinition fd : configurationProvider.getConfiguration().getFormatters()) {

			data.add(new Object[]{fd.getName(), false, defaultFormatter.equals(fd.getName()), fd.getClassName(), isInstantiable(fd)});

		}

		printTable(formatter, header, "-- configured and built-in output formatters", null, data);

	}

	private boolean isInstantiable(FormatterDefinition fd) {

		try {

			try (ByteArrayOutputStream testStream = new ByteArrayOutputStream()) {

				fd.getInstance(new FormatterContext(testStream, new Properties(0)));

				return true;

			}

		} catch (Exception e) {

			log.log(Level.SEVERE, "Unable to create an instance of formatter: " + fd.getName(), e);

			return false;

		}

	}

	public void listTypes() throws FormatterException, ConfigurationException {

		ColumnsHeader header = constructHeader(new HeaderField("name", SQLType.VARCHAR), new HeaderField("code", SQLType.INTEGER));

		List<Object[]> data = new ArrayList<>();

		for (SQLType sqlType : SQLType.values()) {

			data.add(new Object[]{sqlType.name(), sqlType.getCode()});

		}

		printTable(formatter, header, "-- data types", null, data);

		log.log(Level.INFO, "Type names in --types option are case insensitive");

	}

	public void listDatabases() throws ConfigurationException, FormatterException {

		ColumnsHeader header = constructHeader(

				new HeaderField("database_name", SQLType.VARCHAR),

				new HeaderField("user_name", SQLType.VARCHAR),

				new HeaderField("database_url", SQLType.VARCHAR));

		List<Object[]> data = new ArrayList<>();

		final List<DatabaseDefinition> configuredDatabases = configurationProvider.getConfiguration().getDatabases();

		if (configuredDatabases.isEmpty()) {

			log.log(Level.WARNING, "No databases are configured.");

		} else {

			for (DatabaseDefinition dd : configuredDatabases) {

				data.add(new Object[]{dd.getName(), dd.getUserName(), dd.getUrl()});

			}

		}

		printTable(formatter, header, "-- configured databases", null, data);

	}

	public void listJdbcDrivers() throws FormatterException, ConfigurationException {

		ColumnsHeader header = constructHeader(

				new HeaderField("class", SQLType.VARCHAR),

				new HeaderField("version", SQLType.VARCHAR),

				new HeaderField("major", SQLType.INTEGER),

				new HeaderField("minor", SQLType.INTEGER),

				new HeaderField("jdbc_compliant", SQLType.BOOLEAN));

		List<Object[]> data = new ArrayList<>();

		final ServiceLoader<Driver> drivers = ServiceLoader.load(Driver.class);

		for (Driver d : drivers) {

			data.add(new Object[]{

				d.getClass().getName(),

				d.getMajorVersion() + "." + d.getMinorVersion(),

				d.getMajorVersion(),

				d.getMinorVersion(),

				d.jdbcCompliant()

			});

		}

		printTable(formatter, header, "-- discovered JDBC drivers (available on the CLASSPATH)", null, data);

	}

	public void listJdbcProperties() throws FormatterException, ConfigurationException {

		for (String dbName : options.getDatabaseNamesToListProperties()) {

			ColumnsHeader header = constructHeader(

					new HeaderField("property_name", SQLType.VARCHAR),

					new HeaderField("required", SQLType.BOOLEAN),

					new HeaderField("choices", SQLType.ARRAY),

					new HeaderField("configured_value", SQLType.VARCHAR),

					new HeaderField("description", SQLType.VARCHAR));

			List<Object[]> data = new ArrayList<>();

			DatabaseDefinition dd = configurationProvider.getConfiguration().getDatabase(dbName);

			Driver driver = findDriver(dd);

			if (driver == null) {

				log.log(Level.WARNING, "No JDBC driver was found for DB: {0} with URL: {1}", new Object[]{dd.getName(), dd.getUrl()});

			} else {

				log.log(Level.INFO, "For DB: {0} was found JDBC driver: {1}", new Object[]{dd.getName(), driver.getClass().getName()});

				try {

					DriverPropertyInfo[] propertyInfos = driver.getPropertyInfo(dd.getUrl(), dd.getProperties().getJavaProperties());

					Set<String> standardProperties = new HashSet<>();

					for (DriverPropertyInfo pi : propertyInfos) {

						Array choices = new FakeSqlArray(pi.choices, SQLType.VARCHAR);

						data.add(new Object[]{

							pi.name,

							pi.required,

							choices.getArray() == null ? "" : choices,

							pi.value == null ? "" : pi.value,

							pi.description

						});

						standardProperties.add(pi.name);

					}

					for (Property p : dd.getProperties()) {

						if (!standardProperties.contains(p.getName())) {

							data.add(new Object[]{

								p.getName(),

								"",

								"",

								p.getValue(),

								""

							});

							log.log(Level.WARNING, "Your configuration contains property „{0}“ not declared by the JDBC driver.", p.getName());

						}

					}

				} catch (SQLException e) {

					log.log(Level.WARNING, "Error during getting property infos.", e);

				}

				List<Parameter> parameters = new ArrayList<>();

				parameters.add(new NamedParameter("database", dbName, SQLType.VARCHAR));

				parameters.add(new NamedParameter("driver_class", driver.getClass().getName(), SQLType.VARCHAR));

				parameters.add(new NamedParameter("driver_major_version", driver.getMajorVersion(), SQLType.INTEGER));

				parameters.add(new NamedParameter("driver_minor_version", driver.getMinorVersion(), SQLType.INTEGER));

				printTable(formatter, header, "-- configured and configurable JDBC driver properties", parameters, data);

			}

		}

	}

	private Driver findDriver(DatabaseDefinition dd) {

		final ServiceLoader<Driver> drivers = ServiceLoader.load(Driver.class);

		for (Driver d : drivers) {

			try {

				if (d.acceptsURL(dd.getUrl())) {

					return d;

				}

			} catch (SQLException e) {

				log.log(Level.WARNING, "Error during finding JDBC driver for: " + dd.getName(), e);

			}

		}

		return null;

	}

	/**

	 * Parallelism for connection testing – maximum concurrent database connections.

	 */

	private static final int TESTING_THREAD_COUNT = 64;

	/**

	 * Time limit for all connection testing threads – particular timeouts per connection will be

	 * much smaller.

	 */

	private static final long TESTING_AWAIT_LIMIT = 1;

	private static final TimeUnit TESTING_AWAIT_UNIT = TimeUnit.DAYS;

	public void testConnections() throws FormatterException, ConfigurationException {

		ColumnsHeader header = constructHeader(

				new HeaderField("database_name", SQLType.VARCHAR),

				new HeaderField("configured", SQLType.BOOLEAN),

				new HeaderField("connected", SQLType.BOOLEAN));

		log.log(Level.FINE, "Testing DB connections in {0} threads", TESTING_THREAD_COUNT);

		ExecutorService es = Executors.newFixedThreadPool(TESTING_THREAD_COUNT);

		final Formatter currentFormatter = formatter;

		printHeader(currentFormatter, header, "-- database configuration and connectivity test", null);

		for (final String dbName : options.getDatabaseNamesToTest()) {

			preloadDriver(dbName);

		}

		for (final String dbName : options.getDatabaseNamesToTest()) {

			es.submit(new Runnable() {

				// TODO: Java 8 – lambda

				@Override

				public void run() {

					final Object[] row = testConnection(dbName);

					synchronized (currentFormatter) {

						printRow(currentFormatter, row);

					}

				}

			});

		}

		es.shutdown();

		try {

			log.log(Level.FINEST, "Waiting for test results: {0} {1}", new Object[]{TESTING_AWAIT_LIMIT, TESTING_AWAIT_UNIT.name()});

			boolean finished = es.awaitTermination(TESTING_AWAIT_LIMIT, TESTING_AWAIT_UNIT);

			if (finished) {

				log.log(Level.FINEST, "All testing threads finished in time limit.");

			} else {

				throw new FormatterException("Exceeded total time limit for test threads – this should never happen");

			}

		} catch (InterruptedException e) {

			throw new FormatterException("Interrupted while waiting for test results", e);

		}

		printFooter(currentFormatter);

	}

	/**

	 * JDBC driver classes should be preloaded in single thread to avoid deadlocks while doing

	 * {@linkplain DriverManager#registerDriver(java.sql.Driver)} during parallel connections.

	 *

	 * @param dbName

	 */

	private void preloadDriver(String dbName) {

		try {

			DatabaseDefinition dd = configurationProvider.getConfiguration().getDatabase(dbName);

			Driver driver = findDriver(dd);

			if (driver == null) {

				log.log(Level.WARNING, "No Driver found for DB: {0}", dbName);

			} else {

				log.log(Level.FINEST, "Driver preloading for DB: {0} was successfull", dbName);

			}

		} catch (Exception e) {

			LogRecord r = new LogRecord(Level.WARNING, "Failed to preload the Driver for DB: {0}");

			r.setParameters(new Object[]{dbName});

			r.setThrown(e);

			log.log(r);

		}

	}

	public Object[] testConnection(String dbName) {

		log.log(Level.FINE, "Testing connection to database: {0}", dbName);

		boolean succesfullyConnected = false;

		boolean succesfullyConfigured = false;

		try {

			DatabaseDefinition dd = configurationProvider.getConfiguration().getDatabase(dbName);

			log.log(Level.FINE, "Database definition was loaded from configuration");

			succesfullyConfigured = true;

			try (DatabaseConnection dc = dd.connect(options.getDatabaseProperties())) {

				succesfullyConnected = dc.test();

			}

			log.log(Level.FINE, "Database connection test was successful");

		} catch (ConfigurationException | SQLException | RuntimeException e) {

			log.log(Level.SEVERE, "Error during testing connection " + dbName, e);

		}

		return new Object[]{dbName, succesfullyConfigured, succesfullyConnected};

	}

	public void printResource(String fileName) {

		try (BufferedReader reader = new BufferedReader(new InputStreamReader(getClass().getClassLoader().getResourceAsStream(fileName)))) {

			while (true) {

				String line = reader.readLine();

				if (line == null) {

					break;

				} else {

					println(line);

				}

			}

		} catch (Exception e) {

			log.log(Level.SEVERE, "Unable to print this info. Please see our website for it: " + Constants.WEBSITE, e);

		}

	}

	private void println(String line) {

		out.println(line);

	}

	private void printTable(Formatter formatter, ColumnsHeader header, String sql, List<Parameter> parameters, List<Object[]> data) throws ConfigurationException, FormatterException {

		printHeader(formatter, header, sql, parameters);

		for (Object[] row : data) {

			printRow(formatter, row);

		}

		printFooter(formatter);

	}

	private void printHeader(Formatter formatter, ColumnsHeader header, String sql, List<Parameter> parameters) {

		formatter.writeStartStatement();

		if (sql != null) {

			formatter.writeQuery(sql);

			if (parameters != null) {

				formatter.writeParameters(parameters);

			}

		}

		formatter.writeStartResultSet(header);

	}

	private void printRow(Formatter formatter, Object[] row) {

		formatter.writeStartRow();

		for (Object cell : row) {

			formatter.writeColumnValue(cell);

		}

		formatter.writeEndRow();

	}

	private void printFooter(Formatter formatter) {

		formatter.writeEndResultSet();

		formatter.writeEndStatement();

	}

	private Formatter getFormatter() throws ConfigurationException, FormatterException {

		String formatterName = options.getFormatterName();

		formatterName = formatterName == null ? Configuration.DEFAULT_FORMATTER_PREFETCHING : formatterName;

		FormatterDefinition fd = configurationProvider.getConfiguration().getFormatter(formatterName);

		FormatterContext context = new FormatterContext(out, options.getFormatterProperties());

		return fd.getInstance(context);

	}

	private ColumnsHeader constructHeader(HeaderField... fields) throws FormatterException {

		try {

			RowSetMetaDataImpl metaData = new RowSetMetaDataImpl();

			metaData.setColumnCount(fields.length);

			for (int i = 0; i < fields.length; i++) {

				HeaderField hf = fields[i];

				int sqlIndex = i + 1;

				metaData.setColumnName(sqlIndex, hf.name);

				metaData.setColumnLabel(sqlIndex, hf.name);

				metaData.setColumnType(sqlIndex, hf.type.getCode());

				metaData.setColumnTypeName(sqlIndex, hf.type.name());

			}

			return new ColumnsHeader(metaData);

		} catch (SQLException e) {

			throw new FormatterException("Error while constructing table headers", e);

		}

	}

	private static class HeaderField {

		String name;

		SQLType type;

		public HeaderField(String name, SQLType type) {

			this.name = name;

			this.type = type;

		}

	}

	public enum InfoType {

		HELP {

					@Override

					public void showInfo(InfoLister infoLister) {

						infoLister.printResource(Constants.HELP_FILE);

					}

				},

		VERSION {

					@Override

					public void showInfo(InfoLister infoLister) {

						infoLister.printResource(Constants.VERSION_FILE);

					}

				},

		LICENSE {

					@Override

					public void showInfo(InfoLister infoLister) {

						infoLister.printResource(Constants.LICENSE_FILE);

					}

				},

		FORMATTERS {

					@Override

					public void showInfo(InfoLister infoLister) throws FormatterException, ConfigurationException {

						infoLister.listFormatters();

					}

				},

		TYPES {

					@Override

					public void showInfo(InfoLister infoLister) throws FormatterException, ConfigurationException {

						infoLister.listTypes();

					}

				},

		JDBC_DRIVERS {

					@Override

					public void showInfo(InfoLister infoLister) throws ConfigurationException, FormatterException {

						infoLister.listJdbcDrivers();

					}

				},

		JDBC_PROPERTIES {

					@Override

					public void showInfo(InfoLister infoLister) throws ConfigurationException, FormatterException {

						infoLister.listJdbcProperties();

					}

				},

		DATABASES {

					@Override

					public void showInfo(InfoLister infoLister) throws FormatterException, ConfigurationException {

						infoLister.listDatabases();

					}

				},

		CONNECTION {

					@Override

					public void showInfo(InfoLister infoLister) throws FormatterException, ConfigurationException {

						infoLister.testConnections();

					}

				};

		public abstract void showInfo(InfoLister infoLister) throws ConfigurationException, FormatterException;

	}

}