/**

 * SQL-DK

 * Copyright © 2014 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.formatting;

import info.globalcode.sql.dk.ColorfulPrintWriter;

import info.globalcode.sql.dk.ColorfulPrintWriter.TerminalColor;

import java.util.Stack;

import javax.xml.namespace.QName;

import static info.globalcode.sql.dk.Functions.isEmpty;

import static info.globalcode.sql.dk.Functions.toHex;

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

import static info.globalcode.sql.dk.formatting.CommonProperties.COLORFUL;

import static info.globalcode.sql.dk.formatting.CommonProperties.COLORFUL_DESCRIPTION;

import java.nio.charset.Charset;

import java.util.EmptyStackException;

import java.util.HashMap;

import java.util.LinkedHashMap;

import java.util.Map;

import java.util.Map.Entry;

import java.util.logging.Level;

import java.util.logging.Logger;

/**

 * <p>

 * Provides helper methods for printing pretty intended and optionally colorful (syntax highlighted)

 * XML output.

 * </p>

 *

 * <p>

 * Must be used with care – bad usage can lead to invalid XML (e.g. using undeclared namespaces).

 * </p>

 *

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

 */

@PropertyDeclaration(name = COLORFUL, type = Boolean.class, description = COLORFUL_DESCRIPTION)

@PropertyDeclaration(name = AbstractXmlFormatter.PROPERTY_INDENT, type = String.class, description = "tab or sequence of spaces used for indentation of nested elements")

@PropertyDeclaration(name = AbstractXmlFormatter.PROPERTY_INDENT_TEXT, type = Boolean.class, description = "whether to indent text nodes")

public abstract class AbstractXmlFormatter extends AbstractFormatter {

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

	public static final String PROPERTY_INDENT = "indent";

	/**

	 * Whether text with line breaks should be indented (default). Otherwise original whitespace

	 * will be preserved.

	 */

	public static final String PROPERTY_INDENT_TEXT = "indentText";

	private static final TerminalColor ELEMENT_COLOR = TerminalColor.Magenta;

	private static final TerminalColor ATTRIBUTE_NAME_COLOR = TerminalColor.Green;

	private static final TerminalColor ATTRIBUTE_VALUE_COLOR = TerminalColor.Yellow;

	private static final TerminalColor XML_DECLARATION_COLOR = TerminalColor.Red;

	private static final TerminalColor XML_DOCTYPE_COLOR = TerminalColor.Cyan;

	private Stack<QName> treePosition = new Stack<>();

	private final ColorfulPrintWriter out;

	private final String indent;

	private final boolean indentText;

	public AbstractXmlFormatter(FormatterContext formatterContext) {

		super(formatterContext);

		boolean colorful = formatterContext.getProperties().getBoolean(COLORFUL, false);

		out = new ColorfulPrintWriter(formatterContext.getOutputStream(), false, colorful);

		indent = formatterContext.getProperties().getString(PROPERTY_INDENT, "\t");

		indentText = formatterContext.getProperties().getBoolean(PROPERTY_INDENT_TEXT, true);

		if (!indent.matches("\\s*")) {

			log.log(Level.WARNING, "Setting indent to „{0}“ is weird & freaky; in hex: {1}", new Object[]{indent, toHex(indent.getBytes())});

		}

	}

	protected void printStartDocument() {

		out.print(XML_DECLARATION_COLOR, "<?xml version=\"1.0\" encoding=\"" + Charset.defaultCharset().name() + "\"?>");

	}

	protected void printDoctype(String doctype) {

		out.print(XML_DOCTYPE_COLOR, "\n<!DOCTYPE " + doctype + ">");

	}

	protected void printEndDocument() {

		out.println();

		out.flush();

		if (!treePosition.empty()) {

			throw new IllegalStateException("Some elements are not closed: " + treePosition);

		}

	}

	protected void printStartElement(QName element) {

		printStartElement(element, null);

	}

	protected Map<QName, String> singleAttribute(QName name, String value) {

		Map<QName, String> attributes = new HashMap<>(2);

		attributes.put(name, value);

		return attributes;

	}

	protected void printStartElement(QName element, Map<QName, String> attributes) {

		printStartElement(element, attributes, false);

	}

	/**

	 * @param empty whether element should be closed <codfe>… /&gt;</code> (has no content, do not

	 * call {@linkplain #printEndElement()})

	 */

	private void printStartElement(QName element, Map<QName, String> attributes, boolean empty) {

		printIndent();

		out.print(ELEMENT_COLOR, "<" + toString(element));

		if (attributes != null) {

			for (Entry<QName, String> attribute : attributes.entrySet()) {

				out.print(" ");

				out.print(ATTRIBUTE_NAME_COLOR, toString(attribute.getKey()));

				out.print("=");

				out.print(ATTRIBUTE_VALUE_COLOR, '"' + escapeXmlAttribute(attribute.getValue()) + '"');

			}

		}

		if (empty) {

			out.print(ELEMENT_COLOR, "/>");

		} else {

			out.print(ELEMENT_COLOR, ">");

			treePosition.add(element);

		}

		out.flush();

	}

	/**

	 * Prints text node wrapped in given element without indenting the text and adding line breaks

	 * (useful for short texts).

	 *

	 * @param attributes use {@linkplain  LinkedHashMap} to preserve attributes order

	 */

	protected void printTextElement(QName element, Map<QName, String> attributes, String text) {

		printStartElement(element, attributes);

		String[] lines = text.split("\\n");

		if (indentText && lines.length > 1) {

			for (String line : lines) {

				printText(line, true);

			}

			printEndElement(true);

		} else {

			/*

			 * line breaks at the end of the text will be eaten – if you need them, use indentText = false

			 */

			if (lines.length == 1 && text.endsWith("\n")) {

				text = text.substring(0, text.length() - 1);

			}

			printText(text, false);

			printEndElement(false);

		}

	}

	protected void printEmptyElement(QName element, Map<QName, String> attributes) {

		printStartElement(element, attributes, true);

	}

	protected void printEndElement() {

		printEndElement(true);

	}

	private void printEndElement(boolean indent) {

		try {

			QName name = treePosition.pop();

			if (indent) {

				printIndent();

			}

			out.print(ELEMENT_COLOR, "</" + toString(name) + ">");

			out.flush();

		} catch (EmptyStackException e) {

			throw new IllegalStateException("No more elements to end.", e);

		}

	}

	protected void printText(String s, boolean indent) {

		if (indent) {

			printIndent();

		}

		out.print(escapeXmlText(s));

		out.flush();

	}

	protected void printIndent() {

		out.println();

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

			out.print(indent);

		}

	}

	protected static QName qname(String name) {

		return new QName(name);

	}

	protected static QName qname(String prefix, String name) {

		return new QName(null, name, prefix);

	}

	private String toString(QName name) {

		if (isEmpty(name.getPrefix(), true)) {

			return escapeName(name.getLocalPart());

		} else {

			return escapeName(name.getPrefix()) + ":" + escapeName(name.getLocalPart());

		}

	}

	private String escapeName(String s) {

		// TODO: avoid ugly values in <name name="…"/>		

		return s;

	}

	private static String escapeXmlText(String s) {

		return s.replaceAll("&", "&amp;").replaceAll("<", "&lt;").replaceAll(">", "&gt;");

		// Not needed:

		// return s.replaceAll("&", "&amp;").replaceAll("<", "&lt;").replaceAll(">", "&gt;").replaceAll("\"", "&quot;").replaceAll("'", "&apos;");

	}

	/**

	 * Expects attribute values enclosed in "quotes" not 'apostrophes'.

	 */

	private static String escapeXmlAttribute(String s) {

		return s.replaceAll("&", "&amp;").replaceAll("<", "&lt;").replaceAll(">", "&gt;").replaceAll("\"", "&quot;");

	}

}