package org.greenstone.gsdl3.gs3build.indexers;

import java.util.List;
import java.util.ArrayList;
import java.util.Iterator;

import java.io.File;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;

import org.w3c.dom.*;

import org.greenstone.mg.*;

import org.greenstone.gsdl3.gs3build.doctypes.DocumentID;
import org.greenstone.gsdl3.gs3build.doctypes.DocumentInterface;
import org.greenstone.gsdl3.gs3build.doctypes.HTMLDocument;
import org.greenstone.gsdl3.gs3build.doctypes.METSDocument;
import org.greenstone.gsdl3.gs3build.metadata.*;
import org.greenstone.gsdl3.gs3build.xpointer.XPointer;
import org.greenstone.gsdl3.util.GSXML;
import org.greenstone.gsdl3.util.Misc;
import org.greenstone.gsdl3.util.Processing;

public class MGIndexer extends AbstractIndexer
{ 
    int          pass;
    int          documentSeqNo;
    int          sectionSeqNo;
    boolean      firstDocument;
    String       outputDirectory;
    //   InputStream  indexerFeedback;
    //   InputStream  indexerErrors;
    //OutputStream indexerTextfeed;
    StringBuffer indexBuffer;
    //Process      mg_passes;
    File         textDirectory;
    File         indexDirectory;
    String       indexStem;
    String       textStem;
    List         indexes;
    String       overallName; 
    
    String       currentIndexName;
    String       currentIndexLevel;
    String       currentIndexField;

    MGPassesWrapper mgPasses;
    
    static final char END_OF_DOCUMENT = (char) 2;
    static final char END_OF_SECTION  = (char) 3; // actually this is end of para for mg
    static final char END_OF_STREAM   = (char) 4;

    public static final String MG_INDEX_TYPE = "mg";
    public static final String INDEX_FILE_STEM = "index";
    
    class MGIndex
    { 
	String name=null;
	String level=null;
	String field=null;
	boolean error = false;// assume built until we get an error

	public MGIndex(String name, String level, String field)
	{ 
	    this.name  = name;
	    this.level = level;
	    this.field = field;
	}
	
	public MGIndex(String indexLabel)
	{ 
	    int colonAt = indexLabel.indexOf(':');
	    
	    if (colonAt >= 0) {
		this.field = indexLabel.substring(colonAt+1);
		this.level = indexLabel.substring(0, colonAt);
		createIndexName();
	    }
	}

	public String getLevel()
	{ 
	    return this.level;
	}

	public String getField()
	{ 
	    return this.field;
	}

	public String getName()
	{ 
	    if (this.name==null || this.name.equals("")) {
		createIndexName();
	    }
	    return this.name;
	}

	public boolean hasError() {
	    return this.error;
	}
	public void setError(boolean b) {
	    this.error = b;
	}

	private void createIndexName() {
	    StringBuffer new_name = new StringBuffer();
	    new_name.append(Character.toLowerCase((char) this.level.charAt(0)));

	    int c, w;
	    w = 0;
	    c = 0;
	    while (c < this.field.length() && w < 2) {
		char ch = this.field.charAt(c);

		ch = Character.toLowerCase(ch);
		if (Character.isLetter(ch)) {
		    if (ch != 'a' && ch != 'e' && ch != 'i' &&
			ch != 'o' && ch != 'u') {
			new_name.append(ch);
			w++;
		    }
		}
		c ++;
	    }
	    this.name = new_name.toString();
	}
    } // MGIndex

    public MGIndexer(String name)
    { 
	this.indexes = new ArrayList();
	this.overallName = name; 
    }

    public String getIndexType()
    { 
	return MG_INDEX_TYPE;
    } 

    public String getName()
    { 
	return this.overallName; 
    }

    //    private String getIndexDirectory(String level, String field)
    //    { StringBuffer directory = new StringBuffer();
    //      directory.append(Character.toLowerCase((char) level.charAt(0)));

    //      int c, w;
    //      w = 0;
    //      c = 0;
    //      while (c < field.length() && w < 2) {
    //        char ch = field.charAt(c);

    //        ch = Character.toLowerCase(ch);
    //        if (Character.isLetter(ch)) {
    //  	if (ch != 'a' && ch != 'e' && ch != 'i' &&
    //  	    ch != 'o' && ch != 'u') {
    //  	  directory.append(ch);
    //  	  w++;
    //  	}
    //        }
    //        c ++;
    //      }
    //      return directory.toString();
    //    }

    /**
     *  The output directory should be (collection)/building/text/ for
     *  normal Greenstone builds.
     *
     *  @param <code>String</code> the label to configure
     *  @param <code>String</code> the value...
     */ 
    public boolean configure(String label, String value)
    { 
	if (label.equals(IndexerManager.outputDir)) {
	    this.outputDirectory = value;
	    this.pass = 0;
    
	    // attempt to ensure that the text subdirectory exists
	    this.textDirectory = new File(outputDirectory, "text");
	    if (!textDirectory.exists()) {
		if (!textDirectory.mkdir()) {
		    return false;
		}
	    }
	    else if (!textDirectory.isDirectory()) {
		return false;
	    }
	    this.textStem = this.textDirectory.getPath() + File.separator + INDEX_FILE_STEM;

	    // Sign to the user which mg directory is being used...
	    System.out.println("Output MG directory is " + this.textStem);
	}
	else if (label.equals(IndexerInterface.GS2_INDEX_LABEL)) {
	    this.indexes.add(new MGIndex(value));
	}

	return true;
    }

    public boolean addIndex(String name, String level, String field)
    {
	MGIndex index = new MGIndex(name, level, field);
	this.indexes.add(index);
	return true;
    }

    private Node recurseDOM(DocumentInterface metsDoc, Node node, 
			    AbstractStructure structure, StringBuffer textBuffer,
			    StringBuffer extraBuffer, String namespace) 
	//String name, String namespace, String field)
    {
	// send out the ctrl-c...if this is
	if (structure.getStructureType().equals(METSDivision.DIVISION_TYPE)) {
	    // try doing this for all index types
	    if ((this.currentIndexName != null)) { // && this.level != null && this.level.equals(IndexerInterface.SECTION_LEVEL)) { //name.startsWith("s")) {
		METSDivision division = (METSDivision) structure;

		// get the division metadata block
		METSDescriptive descriptive;
		String metadataId = division.getDefaultMetadataReference();
		if (metadataId == null) {
		    descriptive = metsDoc.getDocumentMetadata().createDescriptive(division.getLabel());
		    division.addMetadataReference(descriptive.getID());
		}
		else {
		    // Get the descriptive item...
		    descriptive = metsDoc.getDocumentMetadata().getDescriptiveById(metadataId);
		}
	    
		descriptive.addMetadata("gsdl3", "mgseqno", this.overallName + "." + Integer.toString(this.sectionSeqNo));
	    
		metsDoc.setChanged(true);
		//metsDoc.setModified(true);
		//	System.out.println("Assigning " + this.sectionSeqNo + " to " + metsDoc.getID() + " " + division.getLabel());
	    } // section level
	
	    // append an 'end of section' marker
	    //textBuffer.append(END_OF_SECTION);
	    this.sectionSeqNo ++;
	
	    // for document-level indexes, always append an 'end of document' tag at the
	    // end of the document for each section.  Otherwise, each section is followed
	    // by an end of document character.  This ensures that all indexes use the
	    // same document numbering...
	    if (this.currentIndexLevel == null ||
		this.currentIndexLevel.equals(IndexerInterface.DOCUMENT_LEVEL)) {
		extraBuffer.append(END_OF_DOCUMENT);
	    }
	    else {
		textBuffer.append(END_OF_DOCUMENT);
		this.documentSeqNo ++;
	    }
	
	    // produce the body here for metadata output of divisions - in the case of
	    // text output, that will happen below...
	    if (!this.currentIndexField.equals("text")) {
		METSDescriptive descriptive;
	
		METSDivision division = (METSDivision) structure;

		String metadataId = division.getDefaultMetadataReference();
	    
		descriptive = metsDoc.getDocumentMetadata().getDescriptiveById(metadataId);
		if (descriptive != null) {
		    List values = descriptive.getMetadata(namespace, this.currentIndexField);
	  
		    if (values != null) {	
			Iterator valueIter = values.iterator();
			while (valueIter.hasNext()) {
			    String value = valueIter.next().toString();
	      
			    textBuffer.append(value);
			    if (valueIter.hasNext()) {
				//textBuffer.append(END_OF_SECTION);
			    }
			}
		    }
		}
	    }
	}

	// go through our children as required...
	Iterator children = structure.getChildIterator();
	Node startNode;
	while (children.hasNext()) {
	    AbstractStructure child = (AbstractStructure) children.next();
      
	    // get xpointer for child 
	    // get start position node
	    if (metsDoc.getDocumentType() == "METS"){
		startNode = ((METSDocument) metsDoc).getSectionStartNode((METSDivision) child);	  
	    } else {
		startNode = ((HTMLDocument) metsDoc).getSectionStartNode((METSDivision) child);
	    }
	    //Node startNode = ((HTMLDocument) metsDoc).getSectionStartNode((METSDivision) child);
      
	    // while this node isn't the child's start node, produce the HTML node text, if
	    // in text field mode...
	    if (this.currentIndexField.equals("text")) {
		while (node != startNode) {
		    XPointer.printNode(node, textBuffer, false);

		    // print buffer to node
		    node = XPointer.getNextNode(node, (this.currentIndexField.equals("text") ? textBuffer : null));
		}
	    }
      
	    // recurse to child
	    node = this.recurseDOM(metsDoc, node, child, textBuffer, extraBuffer, namespace); // name, namespace, field);
	} // while next child

	// close a document - the actual closing \B will be done by the main
	// loop, so only a required \C is printed here...
	if (structure.getStructureType().equals(METSStructure.STRUCTURE_TYPE)) {
	    while (node != null) {
		if (this.currentIndexField.equals("text")) {
		    XPointer.printNode(node, textBuffer, false);
		}
		node = XPointer.getNextNode(node, (this.currentIndexField.equals("text") ? textBuffer : null));
	    }
      
	    //textBuffer.append(END_OF_SECTION);
	    this.sectionSeqNo ++;
      
	}
	return node;
    }

    private String prepareDOM(DocumentInterface metsDoc, Document document, METSStructure structure, String namespace)
    {
	//  String name, String namespace, String field)
	StringBuffer extraBuffer = new StringBuffer();
	Node node = document.getDocumentElement();
	StringBuffer textBuffer = new StringBuffer();
	
	this.recurseDOM(metsDoc, node, structure, textBuffer, extraBuffer, namespace); //name, namespace, field);
	textBuffer.append(extraBuffer.toString());
	return textBuffer.toString();
    }

    /**
     *  Index a single document; the document interface can be used to extract individual
     *  metadata items etc. as required or desired and index those instead or as well as
     *  the body text of the document.
     */
    public boolean indexDocument(DocumentID docID, DocumentInterface document)
    {
	if (this.pass == 0) {
	    document.removeAllMetadata("gsdl3", "mgseqno");
	}
	
	if (!this.firstDocument) {
	    this.indexBuffer.append(END_OF_DOCUMENT);
	    mgPasses.processDocument(indexBuffer.toString());
	    this.indexBuffer.delete(0, this.indexBuffer.length());
	    
	}

	String docText = null;
	
	int startSeqNo = this.sectionSeqNo;
	this.sectionSeqNo ++;
	
	Document domDocument = document.getDOMDocument();
	if (domDocument != null) {
	    System.err.println("dom doc is not null");
	    METSStructure sections = document.getDocumentStructure().getStructure("Section");
	    if (sections != null) {
		System.err.println("sections are not null");
		docText = this.prepareDOM(document, domDocument, sections, "gsdl3"); //this.name, "gsdl3", this.field);
		//	System.out.println(docText);
	    }
	}
	if (docText == null) {
	    System.err.println("dom doc or sections was null - asking for doc text");
	    if (this.currentIndexField.equals("text")) {
		//docText = Character.toString(END_OF_DOCUMENT) + document.getDocumentText(); 
		docText = document.getDocumentText();
	    }
	    else {
		StringBuffer textBuffer = new StringBuffer();
		//textBuffer.append(END_OF_DOCUMENT);
		List values = document.getDocumentMetadataItem("gsdl3", this.currentIndexField);
		if (values != null) {
		    Iterator valueIter = values.iterator();
		    while (valueIter.hasNext()) {
			String value = valueIter.next().toString();
			
			textBuffer.append(value);
			if (valueIter.hasNext()) {
			    //textBuffer.append(END_OF_SECTION);
			    //	      sectionSeqNo ++;
			}
		    }
		}
		else {
		    textBuffer.append("No data");
		}
		docText = textBuffer.toString();
	    }
	    sectionSeqNo ++;
	}
	
	
	this.indexBuffer.append(docText);
	// remember that we're not on the first document, 
	this.firstDocument = false;
	// assign the sequence number on the first pass only, and increment the sequence number.
	if (this.pass == 0) {
	    document.addDocumentMetadata("gsdl3", "mgseqno", this.overallName+"."+Integer.toString(startSeqNo));
	}
	this.documentSeqNo += 1;

	return true;
    }

    /**
     *  Initialise the pass: open required files, check status
     */
    public boolean startPass(int passNumber) {
    	
	
	this.pass = passNumber;
	this.firstDocument = true;
	this.documentSeqNo = 1;
	this.sectionSeqNo  = 1;
	
	this.mgPasses = new MGPassesWrapper();
	this.indexBuffer = new StringBuffer();
	int indexNo = (this.pass - 2) / 2;
	MGIndex index = null;
	if (this.pass >= 2) {
	    index = (MGIndex) this.indexes.get(indexNo);
	    if (index.hasError()) {
		// an error has already occurred for this index, don't continue
		System.out.println("pass "+this.pass+": aborted due to errors in the previous pass");
		return false;
	    }
	    // attempt to ensure that the text subdirectory exists
	    this.indexDirectory = new File(outputDirectory, index.getName());
	    if (!indexDirectory.exists()) {
		if (!indexDirectory.mkdir()) {
		    return false;
		}
	    }
	    else if (!indexDirectory.isDirectory()) {
		return false;
	    }
	    
	    this.currentIndexLevel = index.getLevel();
	    this.currentIndexField = index.getField();
	    this.currentIndexName = index.getName();
	    
	    if (this.currentIndexLevel == null || this.currentIndexField == null ) {
		System.out.println("invalid index - level or field was null");
		return false;
	    }
	    this.indexStem = this.indexDirectory.getPath() + File.separatorChar + INDEX_FILE_STEM;  // TODO: modify for index
	    if (this.pass % 2 == 1) {
		this.currentIndexName = null; // why???
	    }
	}
	else {
	    
	    this.currentIndexField = "text";
	    this.currentIndexLevel = "section";
	    this.currentIndexName = null;
	}
	
	// get the parameters for this execution of mg_passes
	mgPasses.setFileName((this.pass < 2 ? this.textDirectory.toString() : this.indexDirectory.toString())+File.separator+ "index");
	if (!Misc.isWindows()) {
	    mgPasses.setBasePath("/");
	}
	int mgPass = this.pass < 2 ? this.pass : ((this.pass % 2) + 2);
	
	mgPasses.setBufferSize(100000);
 	
	switch (mgPass) {
	case 0:
	    // -b 100000 -T1
	    mgPasses.addPass(MGPassesWrapper.TEXT_PASS_1);
	    
	    
	    break;
	    
	case 1:
	    // -b 100000 -T2
	    mgPasses.addPass(MGPassesWrapper.TEXT_PASS_2);
	    break;
	    
	case 2:
	    // -b 100000 -2 -m 32 -s 0 -G -t 10 -N1
	    mgPasses.addPass(MGPassesWrapper.INDEX_PASS_1);
	    mgPasses.setInvfLevel(MGPassesWrapper.INVF_LEVEL_2);
	    mgPasses.setStemOptions(MGPassesWrapper.STEMMER_ENGLISH, MGPassesWrapper.NO_STEM_OR_CASE);
	    mgPasses.setInversionMemLimit(32);
	    mgPasses.ignoreSGMLTags(true);
	    break;
	    
	case 3:
	    // -b 100000 -2 -c 3 -G -t 10 -N2
	    mgPasses.addPass(MGPassesWrapper.INDEX_PASS_2);
	    mgPasses.setInvfLevel(MGPassesWrapper.INVF_LEVEL_2);
	    mgPasses.ignoreSGMLTags(true);
	    break;
	}
	
	mgPasses.init();
	System.out.println("Pass " + this.pass);
	return true;
    }
  
    /**
     *  Complete a pass - reset file counters, close files, etc.
     */
    public boolean endPass(int passNumber) {
	Process p;
	
	int indexNo = (passNumber - 2) / 2;
	MGIndex index = null;
	if (passNumber >= 2) {
	    index = (MGIndex) this.indexes.get(indexNo);
	}
	try {
	    this.indexBuffer.append(END_OF_DOCUMENT);
	    mgPasses.processDocument(indexBuffer.toString());
	    this.indexBuffer.delete(0, this.indexBuffer.length());
	    Thread.sleep(1000); // what for??
	}
	catch (InterruptedException ex) {
	    System.out.println(ex);
	}
	mgPasses.finish();
	try {
	    Thread.sleep(1000);
	} catch (Exception e) {}
	
	int exit_value = 0;
	System.out.println("Pass " + this.pass + " completed with " + exit_value);
	if (exit_value !=0) {
	    //assume something has gone wrong, don't continue
	    if (index != null) {
		index.setError(true);
		return false;
	    }
	}
	int mgPass = this.pass < 2 ? this.pass : ((this.pass % 2) + 2);
	String osextra = "";
	if (!Misc.isWindows()) {
	    osextra = " -d / ";
	}

	switch (mgPass) {
	    
	case 0:
	    System.out.println("Compressing dictionary");
	    exit_value = Processing.runProcess("mg_compression_dict -f " + this.textDirectory.toString()+File.separator+"index" + osextra + " -S -H -2 -k 5120");
	    if (exit_value == 0) {
		System.out.println("Compressed dictionary successfully written");
	    } else {
		System.err.println("Error from mg_compression_dict: " + exit_value);
		index.setError(true);
		
		return false;
	    }
	    break;
	    
	case 2:
	    System.out.println("Creating perfect hash");
	    exit_value = Processing.runProcess("mg_perf_hash_build -f " + this.indexDirectory.toString()+File.separator+ "index"+osextra);
	    if (exit_value ==0) {
		System.out.println("Perfect hashes completed");
	    } else {
		System.err.println("Unable to build the perfect hash");
		index.setError(true);
		return false;
	    }
	    break;
	    
	case 3:
	    System.out.println("Writing weights file");
	    exit_value = Processing.runProcess("mg_weights_build -f " + this.indexStem + " -t " + this.textStem + osextra);
	    if (exit_value ==0) {
		System.out.println("Weights file successfully written");
	    } else {
		System.err.println("Unable to create weights file");
		index.setError(true);
		return false;
	    }
	    
	    System.out.println("Creating inverted dictionary");
	    exit_value = Processing.runProcess("mg_invf_dict -f " + this.indexDirectory.toString()+File.separator+"index" + osextra);
	    if (exit_value ==0) {
		System.out.println("Inverted dictionary file successfully written");
	    } else {
		System.out.println("Unable to create inverted dictionary file");
		index.setError(true);
		return false;
	    }
	    
	    System.out.println("Creating Stem indexes");
	    exit_value = Processing.runProcess("mg_stem_idx -b 4096 -s1 -f " + this.indexDirectory.toString()+File.separator+"index"+osextra);
	    if (exit_value == 0) {
		System.out.println("Stemmed index 1 successfully written");
	    } else {
		System.out.println("Unable to create stemmed index 1");
		index.setError(true);
		return false;
	    }
	    
	    exit_value = Processing.runProcess("mg_stem_idx -b 4096 -s2 -f " + this.indexDirectory.toString()+File.separator+"index"+osextra);
	    if (exit_value == 0) {
		System.out.println("Stemmed index 2 successfully written");
	    } else {
		System.out.println("Unable to create stemmed index 2");
		index.setError(true);
		return false;
	    }
	    exit_value = Processing.runProcess("mg_stem_idx -b 4096 -s3 -f " + this.indexDirectory.toString()+File.separator+"index"+osextra);
	    if (exit_value == 0) {
		System.out.println("Stemmed index 3 successfully written");
	    } else {
		System.out.println("Unable to create stemmed index 3");
		index.setError(true);
		return false;
	    }
	    
	    break;
	} // switch

	mgPasses = null;
	return true;
    }
    
    /**
     *  Do any tidying up
     */
    public void tidyup()
    {
    }
    
    /**
     *  Return the number of passes required for this index.
     */
    public int getNumberOfPasses()
    { 
	return 2 + this.indexes.size() * 2;
    }

    public boolean addServiceDescriptions(org.w3c.dom.Element service_rack_list)
    {
	Document doc = service_rack_list.getOwnerDocument();

	// generate the list of indexes
	Element index_list = doc.createElement(GSXML.INDEX_ELEM+GSXML.LIST_MODIFIER);
	boolean found_index = false;
	String def_index = ""; // the default index will just be the first one created for now.
	for (int i=0; i<this.indexes.size(); i++) {
	    MGIndex index = (MGIndex)this.indexes.get(i);
	    if (!index.hasError()) {
		Element e = doc.createElement(GSXML.INDEX_ELEM);
		e.setAttribute(GSXML.NAME_ATT, index.getName());
		index_list.appendChild(e);
		if (found_index == false) {
		    // this is the first index
		    found_index = true;
		    def_index = index.getName();
		}
	    }
	}
	
	if (!found_index) {
	    // no indexes were able to be created, so we can't use them or the text
	    return false;
	}
	Element default_index = doc.createElement("defaultIndex");
	default_index.setAttribute(GSXML.NAME_ATT, def_index);
	Element base_index_name = doc.createElement("baseIndexPrefix");
	base_index_name.setAttribute(GSXML.NAME_ATT, overallName);
	Element index_stem = doc.createElement("indexStem");
	index_stem.setAttribute(GSXML.NAME_ATT, "index");
	
	Element search_service_elem = doc.createElement(GSXML.SERVICE_CLASS_ELEM);
	Element retrieve_service_elem = doc.createElement(GSXML.SERVICE_CLASS_ELEM);
	service_rack_list.appendChild(search_service_elem);
	service_rack_list.appendChild(retrieve_service_elem);

	search_service_elem.setAttribute(GSXML.NAME_ATT, "GS3MGSearch");  
	search_service_elem.appendChild(index_list);
	search_service_elem.appendChild(default_index);
	search_service_elem.appendChild(base_index_name);
	search_service_elem.appendChild(index_stem);
	
	retrieve_service_elem.setAttribute(GSXML.NAME_ATT, "GS3MGRetrieve");
	retrieve_service_elem.appendChild(default_index.cloneNode(true));
	retrieve_service_elem.appendChild(base_index_name.cloneNode(true));
	retrieve_service_elem.appendChild(index_stem.cloneNode(true));

	return true;
    }
    
}