/**

 * 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

 *

 * 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 static info.globalcode.sql.dk.Functions.findByName;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.List;

import java.util.logging.Level;

import java.util.logging.Logger;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import java.util.regex.PatternSyntaxException;

/**

 * Has named parameters.

 *

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

 */

public class SQLCommandNamed extends SQLCommand {

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

	private String namePrefix;

	private String nameSuffix;

	private List<NamedParameter> parameters;

	private List<NamedParameter> parametersUsed = new ArrayList<>();

	private StringBuilder updatedQuery;

	private Pattern pattern;

	private SQLCommandNumbered numbered;

	public SQLCommandNamed(String query, List<NamedParameter> parameters, String namePrefix, String nameSuffix) {

		super(query);

		this.updatedQuery = new StringBuilder(query.length());

		this.parameters = parameters;

		this.namePrefix = namePrefix;

		this.nameSuffix = nameSuffix;

	}

	@Override

	public PreparedStatement prepareStatement(Connection c) throws SQLException {

		return getSQLCommandNumbered().prepareStatement(c);

	}

	@Override

	public void parametrize(PreparedStatement ps) throws SQLException {

		getSQLCommandNumbered().parametrize(ps);

	}

	private void prepare() throws SQLException {

		try {

			buildPattern();

			placeParametersAndUpdateQuery();

			logPossiblyMissingParameters();

		} catch (PatternSyntaxException e) {

			throw new SQLException("Name prefix „" + namePrefix + "“ or suffix „" + nameSuffix + "“ contain a wrong regular expression. " + e.getLocalizedMessage(), e);

		}

	}

	/**

	 * @return SQL command with named parameters converted to SQL command with numbered parameters

	 */

	public SQLCommandNumbered getSQLCommandNumbered() throws SQLException {

		if (numbered == null) {

			prepare();

			numbered = new SQLCommandNumbered(updatedQuery.toString(), parametersUsed);

		}

		return numbered;

	}

	/**

	 * Builds a regexp pattern that matches all parameter names (with prefix/suffix) and which has

	 * one group: parameter name (without prefix/suffix)

	 */

	private void buildPattern() throws PatternSyntaxException {

		StringBuilder patternString = new StringBuilder();

		patternString.append(namePrefix);

		patternString.append("(?<paramName>");

		for (int i = 0; i < parameters.size(); i++) {

			patternString.append(Pattern.quote(parameters.get(i).getName()));

			if (i < parameters.size() - 1) {

				patternString.append("|");

			}

		}

		patternString.append(")");

		patternString.append(nameSuffix);

		pattern = Pattern.compile(patternString.toString());

	}

	private void placeParametersAndUpdateQuery() {

		final String originalQuery = getQuery();

		Matcher m = pattern.matcher(originalQuery);

		int lastPosition = 0;

		while (m.find(lastPosition)) {

			String name = m.group("paramName");

			updatedQuery.append(originalQuery.substring(lastPosition, m.start()));

			updatedQuery.append("?");

			parametersUsed.add(findByName(parameters, name));

			lastPosition = m.end();

		}

		updatedQuery.append(originalQuery.substring(lastPosition, originalQuery.length()));

		for (NamedParameter definedParameter : parameters) {

			if (findByName(parametersUsed, definedParameter.getName()) == null) {

				/**

				 * User can have predefined set of parameters and use them with different SQL

				 * queries that use only subset of these parameters → just warning, not exception.

				 */

				log.log(Level.WARNING, "Parameter „{0}“ is defined but not used in the query: „{1}“", new Object[]{definedParameter.getName(), originalQuery});

			}

		}

	}

	private void logPossiblyMissingParameters() {

		Pattern p = Pattern.compile(namePrefix + "(?<paramName>.+?)" + nameSuffix);

		Matcher m = p.matcher(updatedQuery);

		int lastPosition = 0;

		while (m.find(lastPosition)) {

			/**

			 * We have not parsed and understood the SQL query; the parameter-like looking string

			 * could be inside a literal part of the query → just warning, not exception.

			 */

			log.log(Level.WARNING, "Possibly missing parameter „{0}“ in the query: „{1}“", new Object[]{m.group("paramName"), getQuery()});

			lastPosition = m.end();

		}

	}

	@Override

	public List<NamedParameter> getParameters() {

		return parameters;

	}

}