package de.ugoe.cs.cpdp;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.LinkedList;
import java.util.List;
import java.util.logging.Level;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import de.ugoe.cs.cpdp.dataprocessing.IProcessesingStrategy;
import de.ugoe.cs.cpdp.dataprocessing.ISetWiseProcessingStrategy;
import de.ugoe.cs.cpdp.dataselection.IPointWiseDataselectionStrategy;
import de.ugoe.cs.cpdp.dataselection.ISetWiseDataselectionStrategy;
import de.ugoe.cs.cpdp.eval.IEvaluationStrategy;
import de.ugoe.cs.cpdp.loader.IVersionLoader;
import de.ugoe.cs.cpdp.training.ISetWiseTrainingStrategy;
import de.ugoe.cs.cpdp.training.ITrainingStrategy;
import de.ugoe.cs.cpdp.versions.IVersionFilter;
import de.ugoe.cs.util.StringTools;
import de.ugoe.cs.util.console.Console;

/**
 * Class that contains all meta information about an experiment, i.e., its configuration. The configuration is loaded from an XML file.
 * <br><br>
 * In the current implementation, the experiment configuration can only be created using an XML file. Programmatic creation of experiment configurations is currently not possibly. 
 * @author Steffen Herbold
 */
public class ExperimentConfiguration  extends DefaultHandler {

	/**
	 * handle of the file that contains the configuration
	 */
	private final File configFile;
	
	/**
	 * name of the experiment (automatically set to the file name without the .xml ending)
	 */
	private String experimentName = "exp";
	
	/**
	 * loads instances
	 */
	private List<IVersionLoader> loaders;
	
	/**
	 * path were the results of the experiments are stored
	 */
	private String resultsPath = "results";
	
	/**
	 * data set filters applied to all data
	 */
	private List<IVersionFilter> versionFilters;
	
	/**
	 * data set filters that decide if a data set is used as test data
	 */
	private List<IVersionFilter> testVersionFilters;
	
	/**
	 * data set filters that decide if a data is used as candidate training data
	 */
	private List<IVersionFilter> trainingVersionFilters;
	
	/**
	 * setwise data processors that are applied before the setwise data selection
	 */
	private List<ISetWiseProcessingStrategy> setwisepreprocessors;
	
	/**
	 * setwise data selection strategies
	 */
	private List<ISetWiseDataselectionStrategy> setwiseselectors;
	
	/**
	 * setwise data processors that are applied after the setwise data selection
	 */
	private List<ISetWiseProcessingStrategy> setwisepostprocessors;
	
	/**
	 * setwise trainers, i.e., trainers that require the selected training data to be separate from each other
	 */
	private List<ISetWiseTrainingStrategy> setwiseTrainers;
	
	/**
	 * data processors that are applied before the pointwise data selection
	 */
	private List<IProcessesingStrategy> preprocessors;
	
	/**
	 * pointwise data selection strategies
	 */
	private List<IPointWiseDataselectionStrategy> pointwiseselectors;
	
	/**
	 * data processors that are applied before the pointwise data selection
	 */
	private List<IProcessesingStrategy> postprocessors;
	
	/**
	 * normal trainers, i.e., trainers that require the selected training data in a single data set
	 */
	private List<ITrainingStrategy> trainers;
	
	/**
	 * evaluators used for the the experiment results
	 */
	private List<IEvaluationStrategy> evaluators;
	
	/**
	 * Constructor. Creates a new configuration from a given file. 
	 * @param filename name of the file from the configuration is loaded.
	 * @throws ExperimentConfigurationException thrown if there is an error creating the configuration
	 */
	public ExperimentConfiguration(String filename) throws ExperimentConfigurationException {
		this(new File(filename));
	}
	
	/**
	 * Constructor. Creates a new configuration from a given file. 
	 * @param filename handle of the file from the configuration is loaded.
	 * @throws ExperimentConfigurationException thrown if there is an error creating the configuration
	 */
	public ExperimentConfiguration(File file) throws ExperimentConfigurationException {
		loaders = new LinkedList<>();
		versionFilters = new LinkedList<>();
		testVersionFilters = new LinkedList<>();
		trainingVersionFilters = new LinkedList<>();
		setwisepreprocessors = new LinkedList<>();
		setwiseselectors = new LinkedList<>();
		setwisepostprocessors = new LinkedList<>();
		setwiseTrainers = new LinkedList<>();
		preprocessors = new LinkedList<>();
		pointwiseselectors = new LinkedList<>();
		postprocessors = new LinkedList<>();		
		trainers = new LinkedList<>();
		evaluators = new LinkedList<>();
		
		if (file == null) {
            throw new IllegalArgumentException("file must not be null");
        }
		if (file.isDirectory()) {
			throw new IllegalArgumentException("file must not be a directory");
		}
		configFile = file;
		
		experimentName = file.getName().split("\\.")[0];

        final SAXParserFactory spf = SAXParserFactory.newInstance();
        spf.setValidating(true);

        SAXParser saxParser = null;
        InputSource inputSource = null;
        try {
			saxParser = spf.newSAXParser();
		} catch (ParserConfigurationException | SAXException e) {
			throw new ExperimentConfigurationException(e);
		}
		
        InputStreamReader reader = null;
		try {
			reader = new InputStreamReader(new FileInputStream(file), "UTF-8");
			inputSource = new InputSource(reader);
		} catch (UnsupportedEncodingException | FileNotFoundException e) {
			throw new ExperimentConfigurationException("Could not open configuration file.", e);
		}
		
        if (inputSource != null) {
            inputSource.setSystemId("file://" + file.getAbsolutePath());
			try {
				saxParser.parse(inputSource, this);
			} catch (SAXException | IOException e) {
				throw new ExperimentConfigurationException("Error parsing configuration.", e);
			}
		}
        if( reader!=null ) {
        	try {
				reader.close();
			} catch (IOException e) {
				throw new ExperimentConfigurationException("Error closing reader.", e);
			}
        }
	}
	
	/**
	 * returns the name of the experiment
	 * @return name of the experiment
	 */
	public String getExperimentName() {
		return experimentName;
	}
	
	/**
	 * returns the loaders for instances
	 * @return data loaders
	 */
	public List<IVersionLoader> getLoaders() {
		return loaders;
	}
	
	/**
	 * returns the results path
	 * @return results path
	 */
	public String getResultsPath() {
		return resultsPath;
	}
	
	/**
	 * returns the data set filters of the experiment
	 * @return data set filters of the experiment
	 */
	public List<IVersionFilter> getVersionFilters() {
		return versionFilters;
	}
	
	/**
	 * returns the test set filters of the experiment
	 * @return test set filters of the experiment
	 */
	public List<IVersionFilter> getTestVersionFilters() {
		return testVersionFilters;
	}
	
	/**
	 * returns the candidate training version filters of the experiment 
	 * @return candidate training version filters of the experiment
	 */
	public List<IVersionFilter> getTrainingVersionFilters() {
		return trainingVersionFilters;
	}
	
	/**
	 * returns the setwise processors applied before the setwise data selection
	 * @return setwise processors applied before the setwise data selection
	 */
	public List<ISetWiseProcessingStrategy> getSetWisePreprocessors() {
		return setwisepreprocessors;
	}
	
	/**
	 * returns the setwise data selection strategies
	 * @return setwise data selection strategies
	 */
	public List<ISetWiseDataselectionStrategy> getSetWiseSelectors() {
		return setwiseselectors;
	}
	
	/**
	 * returns the setwise processors applied after the setwise data selection
	 * @return setwise processors applied after the setwise data selection
	 */
	public List<ISetWiseProcessingStrategy> getSetWisePostprocessors() {
		return setwisepostprocessors;
	}
	
	/**
	 * returns the setwise training algorithms
	 * @return setwise training algorithms
	 */
	public List<ISetWiseTrainingStrategy> getSetWiseTrainers() {
		return setwiseTrainers;
	}
	
	/**
	 * returns the processors applied before the pointwise data selection
	 * @return processors applied before the pointwise data selection
	 */
	public List<IProcessesingStrategy> getPreProcessors() {
		return preprocessors;
	}
	
	/**
	 * returns the pointwise data selection strategies
	 * @return pointwise data selection strategies
	 */
	public List<IPointWiseDataselectionStrategy> getPointWiseSelectors() {
		return pointwiseselectors;
	}
	
	/**
	 * returns the processors applied after the pointwise data selection
	 * @return processors applied after the pointwise data selection
	 */
	public List<IProcessesingStrategy> getPostProcessors() {
		return postprocessors;
	}
	
	/**
	 * returns the normal training algorithm 
	 * @return normal training algorithms
	 */
	public List<ITrainingStrategy> getTrainers() {
		return trainers;
	}
	
	/**
	 * returns the evaluation strategies
	 * @return evaluation strategies
	 */
	public List<IEvaluationStrategy> getEvaluators() {
		return evaluators;
	}
	
	/* (non-Javadoc)
	 * @see org.xml.sax.helpers.DefaultHandler#startElement(java.lang.String, java.lang.String, java.lang.String, org.xml.sax.Attributes)
	 */
	@Override
	public void startElement(String uri, String localName, String qName,
			Attributes attributes) throws SAXException {
		try {
			if( qName.equals("config") ) {
				// ingore
			}
			else if( qName.equals("loader") ) {
				final IVersionLoader loader = (IVersionLoader) Class.forName("de.ugoe.cs.cpdp.loader." + attributes.getValue("name")).newInstance();
				loader.setLocation(attributes.getValue("datalocation"));
				loaders.add(loader);
				
				// TODO location as relative
			} 
			else if( qName.equals("resultspath") ) {
				resultsPath = attributes.getValue("path");
			}
			else if( qName.equals("versionfilter") ) {
				final IVersionFilter filter = (IVersionFilter) Class.forName("de.ugoe.cs.cpdp.versions." + attributes.getValue("name")).newInstance();
				filter.setParameter(attributes.getValue("param"));
				versionFilters.add(filter);
			}
			else if( qName.equals("testVersionfilter") ) {
				final IVersionFilter filter = (IVersionFilter) Class.forName("de.ugoe.cs.cpdp.versions." + attributes.getValue("name")).newInstance();
				filter.setParameter(attributes.getValue("param"));
				testVersionFilters.add(filter);
			}
			else if( qName.equals("trainVersionfilter") ) {
				final IVersionFilter filter = (IVersionFilter) Class.forName("de.ugoe.cs.cpdp.versions." + attributes.getValue("name")).newInstance();
				filter.setParameter(attributes.getValue("param"));
				trainingVersionFilters.add(filter);
			}
			else if( qName.equals("setwisepreprocessor") ) {
				final ISetWiseProcessingStrategy processor = (ISetWiseProcessingStrategy) Class.forName("de.ugoe.cs.cpdp.dataprocessing." + attributes.getValue("name")).newInstance(); 
				processor.setParameter(attributes.getValue("param"));
				setwisepreprocessors.add(processor);
			}
			else if( qName.equals("setwiseselector") ) {
				final ISetWiseDataselectionStrategy selection = (ISetWiseDataselectionStrategy) Class.forName("de.ugoe.cs.cpdp.dataselection." +  attributes.getValue("name")).newInstance();
				selection.setParameter(attributes.getValue("param"));
				setwiseselectors.add(selection);
			}
			else if( qName.equals("setwisepostprocessor") ) {
				final ISetWiseProcessingStrategy processor = (ISetWiseProcessingStrategy) Class.forName("de.ugoe.cs.cpdp.dataprocessing." + attributes.getValue("name")).newInstance(); 
				processor.setParameter(attributes.getValue("param"));
				setwisepostprocessors.add(processor);
			}
			else if( qName.equals("setwisetrainer") ) {
				final ISetWiseTrainingStrategy trainer = (ISetWiseTrainingStrategy) Class.forName("de.ugoe.cs.cpdp.training." +  attributes.getValue("name")).newInstance();
				trainer.setParameter(attributes.getValue("param"));
				setwiseTrainers.add(trainer);
			}
			else if( qName.equals("preprocessor") ) {
				final IProcessesingStrategy processor = (IProcessesingStrategy) Class.forName("de.ugoe.cs.cpdp.dataprocessing." +  attributes.getValue("name")).newInstance();
				processor.setParameter( attributes.getValue("param"));
				preprocessors.add(processor);
			}
			else if( qName.equals("pointwiseselector") ) {
				final IPointWiseDataselectionStrategy selection = (IPointWiseDataselectionStrategy) Class.forName("de.ugoe.cs.cpdp.dataselection." +  attributes.getValue("name")).newInstance();
				selection.setParameter( attributes.getValue("param"));
				pointwiseselectors.add(selection);
			}
			else if( qName.equals("postprocessor") ) {
				final IProcessesingStrategy processor = (IProcessesingStrategy) Class.forName("de.ugoe.cs.cpdp.dataprocessing." +  attributes.getValue("name")).newInstance();
				processor.setParameter( attributes.getValue("param"));
				postprocessors.add(processor);
			}
			else if( qName.equals("trainer") ) {
				final ITrainingStrategy trainer = (ITrainingStrategy) Class.forName("de.ugoe.cs.cpdp.training." +  attributes.getValue("name")).newInstance();
				trainer.setParameter(attributes.getValue("param"));
				trainers.add(trainer);
			}
			else if( qName.equals("eval") ) {
				final IEvaluationStrategy evaluator = (IEvaluationStrategy) Class.forName("de.ugoe.cs.cpdp.eval." + attributes.getValue("name")).newInstance();
				evaluators.add(evaluator);
			}
			else if( qName.equals("partialconfig") ) {
				String path = attributes.getValue("path");
				try {
					boolean relative = true;
					if( attributes.getValue("relative")!=null ) {
						relative = Boolean.parseBoolean(attributes.getValue("relative"));
					}
					
					if( relative ) {
						path = configFile.getParentFile().getPath() + "/" + path;
					}
					addConfigurations(new ExperimentConfiguration(path));
				} catch (ExperimentConfigurationException e) {
					throw new SAXException("Could not load partial configuration: " + path, e);
				}	
			} else {
				Console.traceln(Level.WARNING, "element in config-file " +  configFile.getName() + " ignored: " + qName);
			}
		}
        catch (NoClassDefFoundError | ClassNotFoundException | IllegalAccessException | InstantiationException | ClassCastException e) {
        	throw new SAXException("Could not initialize class correctly", (Exception) e);
        }
	}
	
	/**
	 * Adds the information of another experiment configuration to this configuration. This mechanism allows the usage of partial configuration files. The name of the other configuration is lost.
	 * <br><br>
	 * If the current data path is the empty string (&quot;&quot;), it is override by the datapath of the other configuration. Otherwise, the current data path is kept.
	 * @param other experiment whose information is added
	 */
	private void addConfigurations(ExperimentConfiguration other) {
		if( "results".equals(resultsPath) ) {
			resultsPath = other.resultsPath;
		}
		loaders.addAll(other.loaders);
		versionFilters.addAll(other.versionFilters);
		testVersionFilters.addAll(other.testVersionFilters);
		trainingVersionFilters.addAll(other.trainingVersionFilters);
		setwisepreprocessors.addAll(other.setwisepreprocessors);
		setwiseselectors.addAll(other.setwiseselectors);
		setwisepostprocessors.addAll(other.setwisepostprocessors);
		setwiseTrainers.addAll(other.setwiseTrainers);
		preprocessors.addAll(other.preprocessors);
		pointwiseselectors.addAll(other.pointwiseselectors);
		postprocessors.addAll(other.postprocessors);
		trainers.addAll(other.trainers);
		evaluators.addAll(other.evaluators);
	}
	
	/* (non-Javadoc)
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		final StringBuilder builder = new StringBuilder();
		builder.append("Experiment name: " + experimentName + StringTools.ENDLINE);
		builder.append("Loaders: " + loaders + StringTools.ENDLINE);
		builder.append("Results path: " + resultsPath + StringTools.ENDLINE);
		builder.append("Version filters: " + versionFilters.toString() + StringTools.ENDLINE);
		builder.append("Test version filters: " + testVersionFilters.toString() + StringTools.ENDLINE);
		builder.append("Training version filters: " + trainingVersionFilters.toString() + StringTools.ENDLINE);
		builder.append("Setwise preprocessors: " + setwisepreprocessors.toString() + StringTools.ENDLINE);
		builder.append("Setwise selectors: " + setwiseselectors.toString() + StringTools.ENDLINE);
		builder.append("Setwise postprocessors: " + setwisepostprocessors.toString() + StringTools.ENDLINE);
		builder.append("Setwise trainers: " + setwiseTrainers.toString() + StringTools.ENDLINE);
		builder.append("Pointwise preprocessors: " + preprocessors.toString() + StringTools.ENDLINE);
		builder.append("Pointwise selectors: " + pointwiseselectors.toString() + StringTools.ENDLINE);
		builder.append("Pointwise postprocessors: " + postprocessors.toString() + StringTools.ENDLINE);
		builder.append("Pointwise trainers: " + trainers.toString() + StringTools.ENDLINE);
		builder.append("Evaluators: " + evaluators.toString() + StringTools.ENDLINE);
		
		return builder.toString();
	}
}