package nodebox.node;

import org.xml.sax.Attributes;

import org.xml.sax.SAXException;

import org.xml.sax.helpers.DefaultHandler;

import java.util.HashMap;

import java.util.Locale;

import java.util.Map;

/**

* Parses the ndbx file format.

* <p/>

* Because you can define both prototypes and "instances" that use these prototypes in the same file,

* you have to make sure that you define the prototypes before you instantiate them. NDBX can't handle

* files with arbitrary ordering. NodeLibrary.store() has support for sequential ordering of prototypes.

* This does not concern prototypes that are defined in other files or are builtin, since they will be

* loaded already.

*/

public class NDBXHandler extends DefaultHandler {

enum ParseState {

INVALID, IN_CODE, IN_DESCRIPTION, IN_VALUE, IN_MENU, IN_EXPRESSION

}

enum CodeType {

INVALID, PYTHON, JAVA

}

public static final String NDBX_FORMAT_VERSION = "formatVersion";

public static final String VAR_NAME = "name";

public static final String VAR_VALUE = "value";

public static final String CODE_TYPE = "type";

public static final String NODE_NAME = "name";

public static final String NODE_PROTOTYPE = "prototype";

public static final String NODE_TYPE = "type";

public static final String NODE_X = "x";

public static final String NODE_Y = "y";

public static final String NODE_RENDERED = "rendered";

public static final String NODE_EXPORTED = "exported";

public static final String MENU_KEY = "key";

public static final String PARAMETER_NAME = "name";

public static final String PARAMETER_TYPE = "type";

public static final String PARAMETER_WIDGET = "widget";

public static final String PARAMETER_LABEL = "label";

public static final String PARAMETER_HELP_TEXT = "help";

public static final String PARAMETER_DISPLAY_LEVEL = "display";

public static final String PARAMETER_ENABLE_EXPRESSION = "enableExpression";

public static final String PARAMETER_BOUNDING_METHOD = "bounding";

public static final String PARAMETER_MINIMUM_VALUE = "min";

public static final String PARAMETER_MAXIMUM_VALUE = "max";

public static final String VALUE_TYPE = "type";

public static final String PORT_NAME = "name";

public static final String PORT_CARDINALITY = "cardinality";

public static final String CONNECTION_OUTPUT = "output";

public static final String CONNECTION_INPUT = "input";

public static final String CONNECTION_PORT = "port";

private NodeLibraryManager manager;

private NodeLibrary library;

private Node rootNode;

private Node currentNode;

private Parameter currentParameter;

private String currentMenuKey;

private CodeType currentCodeType = CodeType.INVALID;

private Map<Parameter, String> expressionMap = new HashMap<Parameter, String>();

private ParseState state = ParseState.INVALID;

private StringBuffer characterData;

public NDBXHandler(NodeLibrary library, NodeLibraryManager manager) {

this.manager = manager;

this.library = library;

this.rootNode = library.getRootNode();

currentNode = null;

}

public NodeLibrary geNodeLibrary() {

return library;

}

@Override

public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

if (qName.equals("ndbx")) {

startNdbxTag(attributes);

} else if (qName.equals("var")) {

startVarTag(attributes);

} else if (qName.equals("code")) {

startCodeTag(attributes);

} else if (qName.equals("node")) {

startNodeTag(attributes);

} else if (qName.equals("description")) {

startDescriptionTag(attributes);

} else if (qName.equals("param")) {

startParameterTag(attributes);

} else if (qName.equals("value")) {

startValueTag(attributes);

} else if (qName.equals("expression")) {

startExpressionTag(attributes);

} else if (qName.equals("menu")) {

startMenuTag(attributes);

} else if (qName.equals("port")) {

startPortTag(attributes);

} else if (qName.equals("conn")) {

startConnectionTag(attributes);

} else {

throw new SAXException("Unknown tag " + qName);

}

}

@Override

public void endElement(String uri, String localName, String qName) throws SAXException {

if (qName.equals("ndbx")) {

// Top level element -- parsing finished.

} else if (qName.equals("var")) {

// Do nothing after var tag

} else if (qName.equals("code")) {

setLibraryCode(characterData.toString());

resetState();

currentCodeType = CodeType.INVALID;

} else if (qName.equals("node")) {

// Traverse up to the parent.

// This can result in currentNode being null if we traversed all the way up

currentNode = currentNode.getParent();

} else if (qName.equals("description")) {

setDescription(characterData.toString());

resetState();

} else if (qName.equals("param")) {

currentParameter = null;

} else if (qName.equals("value")) {

setValue(characterData.toString());

resetState();

currentCodeType = CodeType.INVALID;

} else if (qName.equals("expression")) {

setTemporaryExpression(characterData.toString());

resetState();

} else if (qName.equals("menu")) {

setMenuItem(characterData.toString());

resetState();

currentMenuKey = null;

} else if (qName.equals("port")) {

// Do nothing after port tag

} else if (qName.equals("conn")) {

// Do nothing after conn tag

} else {

// This should never happen, since the SAX parser has already formally validated the document.

// Unknown tags should be caught in startElement.

throw new AssertionError("Unknown end tag " + qName);

}

}

/**

* Called after valid character data was processed.

* <p/>

* This makes sure no extraneous data is added.

*/

private void resetState() {

state = ParseState.INVALID;

characterData = null;

currentMenuKey = null;

}

@Override

public void endDocument() throws SAXException {

// Since parameter expressions can refer to arbitrary other parameters in the network,

// we need to have the fully created document first before setting expressions.

// Expressions are evaluated once they are set so they can create dependencies on other

// parameters.

for (Map.Entry<Parameter, String> entry : expressionMap.entrySet()) {

entry.getKey().setExpression(entry.getValue());

}

}

private void startNdbxTag(Attributes attributes) throws SAXException {

// Make sure we use the correct format and file type.

String formatVersion = attributes.getValue(NDBX_FORMAT_VERSION);

if (formatVersion == null)

throw new SAXException("NodeBox file does not have required attribute formatVersion.");

if (!formatVersion.equals("0.9"))

throw new SAXException("Unknown formatVersion " + formatVersion);

}

private void startVarTag(Attributes attributes) throws SAXException {

// Variables that get stored in the NodeBox library.

String name = attributes.getValue(VAR_NAME);

String value = attributes.getValue(VAR_VALUE);

if (name == null) throw new SAXException("Name attribute is required in var tags.");

if (value == null) throw new SAXException("Value attribute is required in var tags.");

library.setVariable(name, value);

}

private void startCodeTag(Attributes attributes) throws SAXException {

String type = attributes.getValue(CODE_TYPE);

if (type == null) throw new SAXException("Type attribute is required in code tags.");

try {

currentCodeType = CodeType.valueOf(type.toUpperCase(Locale.US));

} catch (IllegalArgumentException e) {

throw new SAXException("Invalid type attribute in code tag: should be python or java, not " + type + ".");

}

state = ParseState.IN_CODE;

characterData = new StringBuffer();

}

private void setLibraryCode(String code) throws SAXException {

library.setCode(parseCode(code));

}

private void startNodeTag(Attributes attributes) throws SAXException {

String name = attributes.getValue(NODE_NAME);

String prototypeId = attributes.getValue(NODE_PROTOTYPE);

String typeAsString = attributes.getValue(NODE_TYPE);

if (name == null) throw new SAXException("Name attribute is required in node tags.");

if (prototypeId == null) throw new SAXException("Prototype attribute is required in node tags.");

Class dataClass = null;

if (typeAsString != null) {

try {

dataClass = Class.forName(typeAsString);

} catch (ClassNotFoundException e) {

throw new SAXException("Given type " + typeAsString + " not found.");

}

}

// Switch between relative and long identifiers.

// Long identifiers (e.g. "polygraph.rect") contain both a library and name and should be looked up using the manager.

// Only exported nodes will qualify.

// Short identifiers (e.g. "beta") contain only a name and are in the same library as this node.

// They should be looked up using the library. These can be non-exported nodes as well.

Node prototype;

if (prototypeId.contains(".")) {

// Long identifier

prototype = manager.getNode(prototypeId);

} else {

// Short identifier

prototype = library.getRootNode().getChild(prototypeId);

}

if (prototype == null) throw new SAXException("Unknown prototype " + prototypeId + " for node " + name);

// Create the child at the root of the node library or the current parent

Node newNode;

if (currentNode == null) {

newNode = library.getRootNode().create(prototype, name, dataClass);

} else {

newNode = currentNode.create(prototype, name, dataClass);

}

// Parse additional node flags.

String x = attributes.getValue(NODE_X);

String y = attributes.getValue(NODE_Y);

if (x != null)

newNode.setX(Double.parseDouble(x));

if (y != null)

newNode.setY(Double.parseDouble(y));

if ("true".equals(attributes.getValue(NODE_RENDERED)))

newNode.setRendered();

if ("true".equals(attributes.getValue(NODE_EXPORTED)))

newNode.setExported(true);

// Go down into the current node; this will now become the current network.

currentNode = newNode;

}

private void startDescriptionTag(Attributes attributes) throws SAXException {

if (currentNode == null) throw new SAXException("Description tag encountered without a current node.");

state = ParseState.IN_DESCRIPTION;

characterData = new StringBuffer();

}

private void setDescription(String description) throws SAXException {

if (currentNode == null) throw new SAXException("Description tag ended without a current node.");

currentNode.setDescription(description);

}

private void startParameterTag(Attributes attributes) throws SAXException {

String name = attributes.getValue(PARAMETER_NAME);

String typeAsString = attributes.getValue(PARAMETER_TYPE);

if (currentNode == null) throw new SAXException("Parameter tag encountered without a current node.");

if (name == null)

throw new SAXException("Name is required for parameter on node '" + currentNode.getName() + "'.");

if (typeAsString == null) {

// No type attribute was given, so the parameter should already exist.

currentParameter = currentNode.getParameter(name);

if (currentParameter == null)

throw new SAXException("Parameter '" + name + "' for node '" + currentNode.getName() + "' does not exist.");

} else {

Parameter.Type type = Parameter.Type.valueOf(typeAsString.toUpperCase(Locale.US));

if (currentNode.hasParameter(name)) {

currentParameter = currentNode.getParameter(name);

currentParameter.setType(type);

} else {

// Type was given, so this is a new parameter.

currentParameter = currentNode.addParameter(name, type);

}

}

// Parse parameter attributes.

String widget = attributes.getValue(PARAMETER_WIDGET);

String label = attributes.getValue(PARAMETER_LABEL);

String helpText = attributes.getValue(PARAMETER_HELP_TEXT);

String displayLevel = attributes.getValue(PARAMETER_DISPLAY_LEVEL);

String enableExpression = attributes.getValue(PARAMETER_ENABLE_EXPRESSION);

String boundingMethod = attributes.getValue(PARAMETER_BOUNDING_METHOD);

String minimumValue = attributes.getValue(PARAMETER_MINIMUM_VALUE);

String maximumValue = attributes.getValue(PARAMETER_MAXIMUM_VALUE);

if (widget != null)

currentParameter.setWidget(Parameter.Widget.valueOf(widget.toUpperCase(Locale.US)));

if (label != null)

currentParameter.setLabel(label);

if (helpText != null)

currentParameter.setHelpText(helpText);

if (displayLevel != null)

currentParameter.setDisplayLevel(Parameter.DisplayLevel.valueOf(displayLevel.toUpperCase(Locale.US)));

if (enableExpression != null)

currentParameter.setEnableExpression(enableExpression);

if (boundingMethod != null)

currentParameter.setBoundingMethod(Parameter.BoundingMethod.valueOf(boundingMethod.toUpperCase(Locale.US)));

if (minimumValue != null)

currentParameter.setMinimumValue(Float.parseFloat(minimumValue));

if (maximumValue != null)

currentParameter.setMaximumValue(Float.parseFloat(maximumValue));

}

/**

* Parse the value tag. This tag is inside of the param tag.

*

* @param attributes tag attributes

* @throws SAXException if the current parameter is null or a code parameter has no or invalid value type.

*/

private void startValueTag(Attributes attributes) throws SAXException {

if (currentParameter == null) throw new SAXException("Value tag encountered without current parameter.");

// If the prototype parameter has an expression clear it, or the node will fail to load.

if (currentParameter.hasExpression())

currentParameter.clearExpression();

state = ParseState.IN_VALUE;

characterData = new StringBuffer();

// The value tag should be empty except when the parameter type is code.

// Then the value tag has a type attribute that specifies the code type.

if (currentParameter.getType() != Parameter.Type.CODE) return;

String type = attributes.getValue(VALUE_TYPE);

if (type == null) throw new SAXException("Type attribute is required in code type parameters.");

try {

currentCodeType = CodeType.valueOf(type.toUpperCase(Locale.US));

} catch (IllegalArgumentException e) {

throw new SAXException("Invalid type attribute in code tag: should be python or java, not " + type + ".");

}

}

/**

* Sets the value on the current parameter.

*

* @param valueAsString the value of the parameter, to be parsed.

* @throws org.xml.sax.SAXException when there is no current node, if parameter was not found or if the value could not be parsed.

*/

private void setValue(String valueAsString) throws SAXException {

if (currentParameter == null) throw new SAXException("There is no current parameter.");

Object value;

if (currentParameter.getType() == Parameter.Type.CODE) {

value = parseCode(valueAsString);

} else {

try {

value = currentParameter.parseValue(valueAsString);

} catch (IllegalArgumentException e) {

throw new SAXException(currentParameter.getAbsolutePath() + ": could not parse value '" + valueAsString + "'", e);

}

}

try {

currentParameter.setValue(value);

} catch (IllegalArgumentException e) {

throw new SAXException(currentParameter.getAbsolutePath() + ": value '" + valueAsString + "' invalid for parameter", e);

}

}

/**

* Parse the expression tag. This tag is inside of the param tag.

*

* @param attributes tag attributes

* @throws SAXException if the current parameter is null or a code parameter has no or invalid value type.

*/

private void startExpressionTag(Attributes attributes) throws SAXException {

if (currentParameter == null) throw new SAXException("Expression tag encountered without current parameter.");

state = ParseState.IN_EXPRESSION;

characterData = new StringBuffer();

}

/**

* Parse the expression tag. This tag is inside of the param tag.

*

* @param attributes tag attributes

* @throws SAXException if the current parameter is null or a code parameter has no or invalid value type.

*/

private void startMenuTag(Attributes attributes) throws SAXException {

if (currentParameter == null) throw new SAXException("Menu tag encountered without current parameter.");

state = ParseState.IN_MENU;

String key = attributes.getValue(MENU_KEY);

if (key == null)

throw new SAXException("Attribute key for menu tag cannot be null.");

currentMenuKey = key;

characterData = new StringBuffer();

}

/**

* Sets the menu item on the current parameter.

* <p/>

* The menu key was already set as an attribute on the menu start tag.

*

* @param label the character data for the menu label.

*/

private void setMenuItem(String label) {

if (currentMenuKey == null) throw new AssertionError("Menu tag ends, but menu key is null.");

currentParameter.addMenuItem(currentMenuKey, label);

}

/**

* Parses the given source code and returns a new NodeCode object of the correct type.

* <p/>

* This method assumes that the currentCodeType is set.

*

* @param source the source code

* @return a NodeCode object

* @throws org.xml.sax.SAXException when there is no current node, if parameter was not found or if the value could not be parsed.

*/

private NodeCode parseCode(String source) throws SAXException {

if (currentCodeType == CodeType.PYTHON) {

return new PythonCode(source);

} else if (currentCodeType == CodeType.JAVA) {

throw new SAXException("Support for Java code is not implemented yet.");

} else {

throw new SAXException("Invalid code type.");

}

}

/**

* Sets the expression on the current parameter.

* <p/>

* Expressions are not set directly, because all dependencies can not always be met directly.

* So expressions are stored in a temporary map. When the whole document is parsed, all expressions will be set,

* which will also set the correct dependencies.

*

* @param expression the expression string

* @throws org.xml.sax.SAXException when there is no current node or if parameter was not found.

*/

private void setTemporaryExpression(String expression) throws SAXException {

if (currentParameter == null) throw new SAXException("There is no current parameter.");

expressionMap.put(currentParameter, expression);

}

private void startPortTag(Attributes attributes) throws SAXException {

String name = attributes.getValue(PORT_NAME);

String cardinalityAsString = attributes.getValue(PORT_CARDINALITY);

if (name == null)

throw new SAXException("Name is required for port on node '" + currentNode.getName() + "'.");

Port.Cardinality cardinality = Port.Cardinality.SINGLE;

if (cardinalityAsString != null) {

try {

cardinality = Port.Cardinality.valueOf(cardinalityAsString.toUpperCase(Locale.US));

} catch (IllegalArgumentException e) {

throw new SAXException("Invalid cardinality attribute in port tag: should be single or multiple, not " + cardinalityAsString + ".");

}

}

currentNode.addPort(name, cardinality);

}

private void startConnectionTag(Attributes attributes) throws SAXException {

// output node identifier, without package

String outputAsString = attributes.getValue(CONNECTION_OUTPUT);

// input node identifier, without package

String inputAsString = attributes.getValue(CONNECTION_INPUT);

// input port identifier

String portAsString = attributes.getValue(CONNECTION_PORT);

String currentNodeString = currentNode == null ? "<null>" : currentNode.getName();

if (outputAsString == null)

throw new SAXException("Output is required for connection in node '" + currentNodeString + "'.");

if (inputAsString == null)

throw new SAXException("Input is required for connection in node '" + currentNodeString + "'.");

if (portAsString == null)

throw new SAXException("Port is required for connection in node '" + currentNodeString + "'.");

Node output, input;

if (currentNode == null) {

output = rootNode.getChild(outputAsString);

input = rootNode.getChild(inputAsString);

} else {

output = currentNode.getChild(outputAsString);

input = currentNode.getChild(inputAsString);

}

if (output == null)

throw new SAXException("Output node '" + outputAsString + "' does not exist.");

if (input == null)

throw new SAXException("Input node '" + inputAsString + "' does not exist.");

Port port = input.getPort(portAsString);

if (port == null)

throw new SAXException("Port '" + portAsString + "' on node '" + inputAsString + "' does not exist.");

port.connect(output);

}

@Override

public void characters(char[] ch, int start, int length) throws SAXException {

switch (state) {

case IN_CODE:

if (currentCodeType == null)

throw new SAXException("Code encountered, but no current code type.");

break;

case IN_DESCRIPTION:

if (currentNode == null)

throw new SAXException("Description encountered, but no current node.");

break;

case IN_VALUE:

if (currentParameter == null)

throw new SAXException("Value encountered, but no current parameter.");

break;

case IN_EXPRESSION:

if (currentParameter == null)

throw new SAXException("Expression encountered, but no current parameter.");

break;

case IN_MENU:

if (currentParameter == null)

throw new SAXException("Menu encountered, but no current parameter.");

break;

default:

// Bail out when we don't recognize this state.

return;

}

// We have a valid character state, so we can safely append to characterData.

characterData.append(ch, start, length);

}

}