/**
 * 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, version 3 of the License.
 *
 * 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.formatting;

import info.globalcode.sql.dk.Parameter;
import info.globalcode.sql.dk.Xmlns;
import info.globalcode.sql.dk.configuration.DatabaseDefinition;
import static info.globalcode.sql.dk.Functions.notNull;
import info.globalcode.sql.dk.NamedParameter;
import info.globalcode.sql.dk.configuration.PropertyDeclaration;
import java.sql.Array;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.SQLXML;
import java.sql.Types;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.xml.namespace.QName;

/**
 * <p>
 * Prints machine-readable output – XML document containing resultsets and updates count. Good
 * choice for further processing – e.g. XSL transformation.</p>
 *
 * <p>
 * XML format is defined in the <a href="https://relational-pipes.globalcode.info/">Relational
 * pipes</a> specification.
 * </p>
 *
 * @author Ing. František Kučera (frantovo.cz)
 */
@PropertyDeclaration(name = XmlFormatter.PROPERTY_LABELED_COLUMNS, defaultValue = "false", type = Boolean.class, description = "whether to add 'label' attribute to each 'column' element")
public class XmlFormatter extends AbstractXmlFormatter {

	private static final String XML_ELEMENT_RELATION = "relation";
	private static final String XML_ELEMENT_NAME = "name";
	private static final String XML_ELEMENT_RECORD = "record";
	private static final String XML_ELEMENT_ATTRIBUTE = "attribute";
	private static final String XML_ATTRIBUTE_NAME = "name";
	private static final String XML_ATTRIBUTE_TYPE = "type";
	private static final String XML_ATTRIBUTE_STATEMENT = "statement";
	private static final String XML_NS_PREFIX_SQLDK = "sql-dk";

	private static final String RELPIPE_TYPE_BOOLEAN = "boolean";
	private static final String RELPIPE_TYPE_INTEGER = "integer";
	private static final String RELPIPE_TYPE_STRING = "string";
	private static final Map<Integer, String> RELPIPE_TYPES;

	static {
		Map<Integer, String> m = new HashMap<>();
		m.put(Types.BOOLEAN, RELPIPE_TYPE_BOOLEAN);
		m.put(Types.BIT, RELPIPE_TYPE_BOOLEAN); // TODO: relpipe "boolean" can not be null in the current version
		m.put(Types.INTEGER, RELPIPE_TYPE_INTEGER);
		// TODO: add more types when supported in Relational pipes
		m.put(Types.CHAR, RELPIPE_TYPE_STRING);
		m.put(Types.VARCHAR, RELPIPE_TYPE_STRING);
		RELPIPE_TYPES = Collections.unmodifiableMap(m);
	}

	public static final String NAME = "xml"; // bash-completion:formatter
	public static final String PROPERTY_LABELED_COLUMNS = "labeledColumns";
	private static final Logger log = Logger.getLogger(XmlFormatter.class.getName());
	private final boolean labeledColumns;

	private String currentDatabaseName;
	private int statementCounter;
	

	public XmlFormatter(FormatterContext formatterContext) {
		super(formatterContext);
		labeledColumns = formatterContext.getProperties().getBoolean(PROPERTY_LABELED_COLUMNS, false);
	}

	private QName qname(String localPart) {
		return new QName(Xmlns.RELPIPE, localPart);
	}

	private QName qnameDK(String localPart) {
		return new QName(Xmlns.SQLDK, localPart, XML_NS_PREFIX_SQLDK);
	}

	@Override
	public void writeStartBatch() {
		super.writeStartBatch();
		printStartDocument();
		Map<QName, String> attributes = new LinkedHashMap<>(2);
		attributes.put(qname("xmlns"), Xmlns.RELPIPE);
		attributes.put(new QName(null, XML_NS_PREFIX_SQLDK, "xmlns"), Xmlns.SQLDK);
		printStartElement(qname("relpipe"), attributes);
		statementCounter = 0;

	}

	@Override
	public void writeEndBatch() {
		super.writeEndBatch();
		printEndElement();
		printEndDocument();
	}

	@Override
	public void writeStartDatabase(DatabaseDefinition databaseDefinition) {
		super.writeStartDatabase(databaseDefinition);
		currentDatabaseName = databaseDefinition.getName();
		Map<QName, String> attributes = databaseDefinition.getName() == null ? null : singleAttribute(qname("name"), databaseDefinition.getName());
		printEmptyElement(qnameDK("database-start"), attributes);
	}

	@Override
	public void writeEndDatabase() {
		super.writeEndDatabase();
		Map<QName, String> attributes = currentDatabaseName == null ? null : singleAttribute(qname("name"), currentDatabaseName);
		printEmptyElement(qnameDK("database-end"), attributes);
	}

	private String getCurrentStatementName() {
		return "s" + statementCounter;
	}

	@Override
	public void writeStartStatement() {
		super.writeStartStatement();
		statementCounter++;
		printEmptyElement(qnameDK("statement-start"), singleAttribute(qname("id"), getCurrentStatementName()));
	}

	@Override
	public void writeEndStatement() {
		super.writeEndStatement();
		printEmptyElement(qnameDK("statement-end"), singleAttribute(qname("id"), getCurrentStatementName()));
	}

	@Override
	public void writeQuery(String sql) {
		super.writeQuery(sql);
		printTextElement(qnameDK("sql"), singleAttribute(qname(XML_ATTRIBUTE_STATEMENT), getCurrentStatementName()), sql);
	}

	@Override
	public void writeParameters(List<? extends Parameter> parameters) {
		super.writeParameters(parameters);

		if (parameters != null && parameters.size() > 0) {

			printStartElement(qnameDK("parameters"), singleAttribute(qname(XML_ATTRIBUTE_STATEMENT), getCurrentStatementName()));

			for (Parameter p : notNull(parameters)) {

				Map<QName, String> attributes = new LinkedHashMap<>(2);
				if (p instanceof NamedParameter) {
					attributes.put(qname(XML_ATTRIBUTE_NAME), ((NamedParameter) p).getName());
				}
				attributes.put(qname(XML_ATTRIBUTE_TYPE), p.getType().name());

				printTextElement(qnameDK("parameter"), attributes, String.valueOf(p.getValue()));
			}

			printEndElement();

		}

	}

	@Override
	public void writeStartResultSet(ColumnsHeader header) {
		super.writeStartResultSet(header);
		printStartElement(qname(XML_ELEMENT_RELATION), singleAttribute(qnameDK(XML_ATTRIBUTE_STATEMENT), getCurrentStatementName()));
		printTextElement(qname(XML_ELEMENT_NAME), null, getCurrentRelationName());

		printStartElement(qname("attributes-metadata"));
		for (ColumnDescriptor cd : header.getColumnDescriptors()) {
			Map<QName, String> attributes = new LinkedHashMap<>(6);

			attributes.put(qname(XML_ATTRIBUTE_NAME), cd.getLabel());
			attributes.put(qname(XML_ATTRIBUTE_TYPE), toRelpipeType(cd.getType()));

			attributes.put(qnameDK("tableName"), cd.getTableName());
			attributes.put(qnameDK("columnName"), cd.getName());
			attributes.put(qnameDK("jdbcTypeName"), cd.getTypeName());
			attributes.put(qnameDK("jdbcType"), String.valueOf(cd.getType()));

			printEmptyElement(qname("attribute-metadata"), attributes);
		}
		printEndElement();
	}

	/**
	 * @param jdbcType value from {@linkplain Types}
	 * @return
	 */
	private String toRelpipeType(int jdbcType) {
		return RELPIPE_TYPES.getOrDefault(jdbcType, RELPIPE_TYPE_STRING);
	}

	@Override
	public void writeEndResultSet() {
		super.writeEndResultSet();
		printEndElement();
	}

	@Override
	public void writeStartRow() {
		super.writeStartRow();
		printStartElement(qname(XML_ELEMENT_RECORD));
	}

	@Override
	public void writeColumnValue(Object value) {
		super.writeColumnValue(value);

		Map<QName, String> attributes = null;
		if (labeledColumns) {
			attributes = new LinkedHashMap<>(2);
			attributes.put(qname(XML_ATTRIBUTE_NAME), getCurrentColumnsHeader().getColumnDescriptors().get(getCurrentColumnsCount() - 1).getLabel());
			attributes.put(qname(XML_ATTRIBUTE_TYPE), toRelpipeType(getCurrentColumnsHeader().getColumnDescriptors().get(getCurrentColumnsCount() - 1).getType()));
		}

		if (value == null) {
			if (attributes == null) {
				attributes = new LinkedHashMap<>(2);
			}
			// TODO: synchronize syntax with Relational pipes (after adding support of null values)
			attributes.put(qnameDK("null"), "true");
			printEmptyElement(qname(XML_ELEMENT_ATTRIBUTE), attributes);
		} else if (value instanceof Array) {

			Array sqlArray = (Array) value;
			try {
				Object[] array = (Object[]) sqlArray.getArray();
				printStartElement(qname(XML_ELEMENT_ATTRIBUTE), attributes);
				printArray(array);
				printEndElement();
			} catch (SQLException e) {
				// FIXME: rewrite array formatting, remember array mode, don't try sqlArray.getArray() again and again if it has failed
				log.log(Level.SEVERE, "Unable to format array", e);
				try {
					ResultSet arrayResultSet = sqlArray.getResultSet();
					//int columnCount = arrayResultSet.getMetaData().getColumnCount();
					ArrayList<Object> arrayList = new ArrayList<>();
					while (arrayResultSet.next()) {
						arrayList.add(arrayResultSet.getObject(2));
						// for (int i = 1; i <= columnCount; i++) {
						// 	log.log(Level.INFO, "Array column {0} = {1}", new Object[]{i, arrayResultSet.getObject(i)});
						// }
					}

					printStartElement(qname(XML_ELEMENT_ATTRIBUTE), attributes);
					// FIXME: instanceof SQLXML, see below
					printArray(arrayList.toArray());
					printEndElement();

				} catch (SQLException e2) {
					// FIXME: fix logging, error recovery
					log.log(Level.SEVERE, "Second level fuck up !!!", e2);
				}

				writeColumnValue(String.valueOf(value));
			}

		} else if (value instanceof SQLXML) { // FIXME: move to separate method, to AbstractFormatter?
			SQLXML xml = (SQLXML) value;
			// TODO: parse DOM/SAX and transplant XML, don't escape (optional)
			try {
				printTextElement(qname(XML_ELEMENT_ATTRIBUTE), attributes, xml.getString());
			} catch (SQLException e) {
				log.log(Level.SEVERE, "Unable to format XML", e);
				writeColumnValue(String.valueOf(value));
			}
		} else {
			printTextElement(qname(XML_ELEMENT_ATTRIBUTE), attributes, toString(value));
		}
	}

	private void printArray(Object[] array) {
		// TODO: synchronize array syntax with Relational pipes
		printStartElement(qnameDK("array"));
		for (Object o : array) {
			if (o instanceof Object[]) {
				printStartElement(qnameDK("item"));
				printArray((Object[]) o);
				printEndElement();
			} else {
				printTextElement(qnameDK("item"), null, String.valueOf(o));
			}
		}
		printEndElement();
	}

	@Override
	public void writeEndRow() {
		super.writeEndRow();
		printEndElement();
	}

	@Override
	public void writeUpdatesResult(int updatedRowsCount) {
		super.writeUpdatesResult(updatedRowsCount);
		printTextElement(qnameDK("updatedRecords"), singleAttribute(qnameDK(XML_ATTRIBUTE_STATEMENT), getCurrentStatementName()), String.valueOf(updatedRowsCount));
	}

	protected String toString(Object value) {
		return String.valueOf(value);
	}
}