package org.maltparser.core.feature.system;

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.maltparser.core.config.ConfigurationRegistry;
import org.maltparser.core.exception.MaltChainedException;
import org.maltparser.core.feature.FeatureException;
import org.maltparser.core.feature.function.Function;
import org.maltparser.core.helper.Util;
import org.maltparser.core.plugin.Plugin;
import org.maltparser.core.plugin.PluginLoader;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
/**
 *  
 *
 * @author Johan Hall
 * @since 1.0
**/
public class FeatureEngine extends HashMap<String, FunctionDescription> {
	public final static long serialVersionUID = 3256444702936019250L;
	
	public FeatureEngine() {
		super();
	}

	public Function newFunction(String functionName, ConfigurationRegistry registry) throws MaltChainedException {
		int i = 0;
		Function func = null;
		while (true) {
			FunctionDescription funcDesc = get(functionName + "~~" + i);
			if (funcDesc == null) {
				break;
			}
			func = funcDesc.newFunction(registry);
			if (func != null) {
				break;
			}
			i++;
		}
		return func;
	}
	
	public void load(String urlstring) throws MaltChainedException {
		load(Util.findURL(urlstring));
	}
	
	public void load(PluginLoader plugins) throws MaltChainedException {
		 for (Plugin plugin : plugins) {
			URL url = null;
			try {
				url = new URL("jar:"+plugin.getUrl() + "!/appdata/plugin.xml");
			} catch (MalformedURLException e) {
				throw new FeatureException("Malformed URL: 'jar:"+plugin.getUrl() + "!plugin.xml'", e);
			}
			try { 
				InputStream is = url.openStream();
				is.close();
			} catch (IOException e) {
				continue;
			}

			load(url);
		}
	}
	
	public void load(URL specModelURL) throws MaltChainedException {
        try {
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder db = dbf.newDocumentBuilder();
            Element root = null;

            root = db.parse(specModelURL.openStream()).getDocumentElement();

            if (root == null) {
            	throw new FeatureException("The feature system file '"+specModelURL.getFile()+"' cannot be found. ");
            }
            
            readFeatureSystem(root);
        } catch (IOException e) {
        	throw new FeatureException("The feature system file '"+specModelURL.getFile()+"' cannot be found. ", e);
        } catch (ParserConfigurationException e) {
        	throw new FeatureException("Problem parsing the file "+specModelURL.getFile()+". ", e);
        } catch (SAXException e) {
        	throw new FeatureException("Problem parsing the file "+specModelURL.getFile()+". ", e);
        }
	}
	
	public void readFeatureSystem(Element system) throws MaltChainedException {
		NodeList functions = system.getElementsByTagName("function");
		for (int i = 0; i < functions.getLength(); i++) {
			readFunction((Element)functions.item(i));
		}
	}
	
	public void readFunction(Element function) throws MaltChainedException {
		boolean hasSubFunctions = function.getAttribute("hasSubFunctions").equalsIgnoreCase("true");
		
		boolean hasFactory = false;
		if (function.getAttribute("hasFactory").length() > 0) {
			hasFactory = function.getAttribute("hasFactory").equalsIgnoreCase("true");
		}
		Class<?> clazz = null;
		try {
			if (PluginLoader.instance() != null) {
				clazz = PluginLoader.instance().getClass(function.getAttribute("class"));
			}
			if (clazz == null) {
				clazz = Class.forName(function.getAttribute("class"));
			}
		} catch (ClassNotFoundException e) { 
			throw new FeatureException("The feature system could not find the function class"+function.getAttribute("class")+".", e);
		}
		if (hasSubFunctions) {
			NodeList subfunctions = function.getElementsByTagName("subfunction");
			for (int i = 0; i < subfunctions.getLength(); i++) {
				readSubFunction((Element)subfunctions.item(i), clazz, hasFactory);
			}
		} else {
			int i = 0;
			String n = null;
			while (true) {
				n = function.getAttribute("name") + "~~" + i;
				if (!containsKey(n)) {
					break;
				}
				i++;
			}
			put(n, new FunctionDescription(function.getAttribute("name"), clazz, false, hasFactory));
		}
	}
	
	public void readSubFunction(Element subfunction, Class<?> clazz, boolean hasFactory) throws MaltChainedException {
		int i = 0;
		String n = null;
		while (true) {
			n = subfunction.getAttribute("name") + "~~" + i;
			if (!containsKey(n)) {
				break;
			}
			i++;
		}
		put(n, new FunctionDescription(subfunction.getAttribute("name"), clazz, true, hasFactory));
	}

	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		if (this.size() != ((FeatureEngine)obj).size()) {
			return false;
		}
		for (String name : keySet()) {
			if (!get(name).equals(((FeatureEngine)obj).get(name))) {
				return false;
			}
		}
		return true;
	}

	public String toString() {
		StringBuilder sb = new StringBuilder();
		for (String name : keySet()) {
			sb.append(name);
			sb.append('\t');
			sb.append(get(name));
			sb.append('\n');
		}
		return sb.toString();
	}
}