package org.greenstone.gsdl3.gs3build.classifier;

import java.io.*;

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

import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

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

import org.w3c.dom.Element;

import org.greenstone.gsdl3.gs3build.doctypes.DocumentID;
import org.greenstone.gsdl3.gs3build.doctypes.DocumentInterface;
import org.greenstone.gsdl3.gs3build.util.XMLTools;
import org.greenstone.gsdl3.gs3build.database.*;
import org.greenstone.gsdl3.gs3build.util.MultiMap;
import org.greenstone.gsdl3.util.GSXML;

public class AZListClassifier extends AbstractClassifier
{
  GS3SQLConnection database;
  MultiMap         alphaMap;
  List             fields;
  String           name;

  class AZDocumentItem
  { public DocumentID documentId;
    public String     title;

    public AZDocumentItem(DocumentID documentId, String title)
    { this.documentId = documentId;
      this.title = title;
    }

    public String getTitle()
    { return this.title;
    }

    public DocumentID getID()
    { return this.documentId;
    }

    public String toString()
    { return this.title;
    }
  }

  private void sortList(String key)
  { List list = this.alphaMap.getAll(key);
    if (list.size() > 1) {
      int first, last;

      first = 0;
      last = list.size() - 1;
      while (first != last)
      { int at = (first + last) / 2;

        if (list.get(at).toString().compareTo(list.get(list.size() - 1).toString()) > 0) {
	  last = at;
        }
	else {
	  first = at + 1;
	}
      }

      Object newObject = list.get(list.size()-1);
      last = list.size() - 1;
      while (last > first) {
	list.set(last, list.get(last-1));
	last --;
      }
      list.set(first, newObject);
    }
  }

  public AZListClassifier(String name, List fields)
  { this.fields   = fields;
    this.alphaMap = new MultiMap();
    this.name     = name;
    //  System.out.println("AZList :"+fields.size());
  }

  public AZListClassifier()
  { this.fields = new ArrayList();
  }

  public void configure(List parameters)
  {
    Iterator iterator = parameters.iterator();
    while (iterator.hasNext()) {
      String param = iterator.next().toString();
      if (param.equals("-metadata")) {
	if (iterator.hasNext()) {
	  String field = iterator.next().toString();
	  if (field != null && field.length() > 0) {
	    this.fields.add(field);
	  }
	}
      }
    }
  }

  public void setDatabase(GS3SQLConnection connection)
  { this.database = connection;
  }

  public boolean classifyDocument(DocumentID documentID, DocumentInterface document)
  { // get the metadata item from the document
    Iterator thisField = this.fields.iterator();

    // for every field listed as being a scannable field...
    while (thisField.hasNext())
    { String fieldName = thisField.next().toString();
			
      // ...get the values for that field...
      List values = document.getDocumentMetadataItem(fieldName);

      if (values == null)
      {	continue;
      }

      // ...and send them to the classifier
      Iterator thisValue = values.iterator();
      while (thisValue.hasNext()) 
      { String value = thisValue.next().toString();

	String classText = null;

	int c = 0;
	while (c < value.length() && classText == null)
	{ if (Character.isDigit(value.charAt(c))) 
	  { classText = "0-9";
	  }
	  else if (Character.isLetter(value.charAt(c))) 
	  { classText = value.substring(c, c+1).toLowerCase();
	  }
  	  c ++;
	}

	if (classText != null) {
	    //	  System.out.println(classText + " " + documentID);
	  this.alphaMap.put(classText, new AZDocumentItem(documentID, value));
	  this.sortList(classText);
	}
      }
    }

    return true;    
  }

  public void startClassifierPass(int pass)
  {
  }

  public int getClassifierPasses()
  { return 1;
  }

  public void endClassifierPass(int pass)
  {
  }

  public void completeClassification()
  { this.writeSQL(this.database);
  }

  public int writeSQLClassifyNode(GS3SQLConnection connection, String parentId, int orderRef,
				  String label, String name, String description, int noOfLeafDocs)
  { GS3SQLAction action;
    GS3SQLSelect select;
    GS3SQLInsert insert;
  
    int classifyRef;

    // check for existing node
    select = new GS3SQLSelect("classifiers");
    select.addField("ClassifyRef");
    GS3SQLWhereItem whereItem = new GS3SQLWhereItem("ClassifyID", "=", label);
    GS3SQLWhere where = new GS3SQLWhere(whereItem);
    select.setWhere(where);


    try {
      Statement statement = connection.createStatement();
      ResultSet results = statement.executeQuery(select.toString());
      if (results.first()) {
	GS3SQLUpdate update = new GS3SQLUpdate("classifiers");
	update.setWhere(where);
	action = update;
 
	classifyRef = results.getInt("ClassifyRef");
      }
      else {
	insert = new GS3SQLInsert("classifiers");

	insert.addValue("ParentID", parentId);

	action = insert;
	classifyRef = -1;
      }
      action.addValue("ClassifyID", label);
      action.addValue("Name", name);
      action.addValue("Description", description);
      action.addValue("ClassifyOrder", Integer.toString(orderRef), GS3SQLField.INTEGER_TYPE);
      action.addValue("NumLeafDocs", Integer.toString(noOfLeafDocs), GS3SQLField.INTEGER_TYPE);

      // do the update/insert
      statement.execute(action.toString());


      // get the ClassifyRef if we don't already have it (have done a
      // insert action above)...
      if (classifyRef == -1) {
	results = statement.executeQuery(select.toString());
	if (!results.first()) {
	  return -1;
	}
	
	classifyRef = results.getInt("ClassifyRef");
      }
      
      statement.close();
    }  catch (SQLException sqlEx) {
	System.err.println("AZListClassifier.writeSQLClassifyNode(): "+sqlEx);
	return -1;
    }
  

    return classifyRef;
  }

  public boolean writeSQL(GS3SQLConnection connection)
  { GS3SQLAction action;
    GS3SQLSelect select;
    GS3SQLInsert insert;
 
    Iterator keys;
 
    String prefix = this.name;
    if (prefix==null || prefix.equals("")) {
	prefix = "CLAZ"+this.fields.get(0).toString();
	// TODO: write this name back to collectionConfig.xml
	this.name = prefix;
    }

    int leafCount = 0;
    keys = this.alphaMap.keySet().iterator();
    while (keys.hasNext()) {
      Object key = keys.next();

      List childDocs = (List) this.alphaMap.getAll(key);
      if (childDocs != null) {
	leafCount += childDocs.size();
      }
    }

    int parentClassify = this.writeSQLClassifyNode(connection, "", 0, prefix, "", "Classifier", leafCount);

    if (parentClassify < 0) 
    { return false;
    }

    try {
	Statement statement = connection.createStatement();
    
    List children;
    
    // TODO: cope with change rather than create from scratch...
    int nodeOrder = 1;
    keys = this.alphaMap.keySet().iterator();
    while (keys.hasNext()) {
      Object key = keys.next();

      List childDocs = (List) this.alphaMap.getAll(key);

      if (childDocs != null) {
	String className = prefix + "." + key.toString();

	int classifyRef = this.writeSQLClassifyNode(connection, prefix, nodeOrder, className, key.toString(), key.toString(), childDocs.size());

	// note the child documents...
        Iterator iterator = childDocs.iterator();
	int childOrder = 1;
	//St
	while (iterator.hasNext()) {
	  AZDocumentItem documentItem = (AZDocumentItem) iterator.next();
	  DocumentID docId = documentItem.getID();

	  insert = new GS3SQLInsert("classdocuments");
	  insert.addValue("ClassifyRef", Integer.toString(classifyRef), GS3SQLField.INTEGER_TYPE);
	  insert.addValue("DocID", docId.toString());
	  insert.addValue("DocOrder", Integer.toString(childOrder), GS3SQLField.INTEGER_TYPE);	  

	  statement.execute(insert.toString());

	  childOrder ++;
	}

	nodeOrder ++;
      }
    }

   
    /*
    else {
      // TODO: clear 'dead' child classifications

      // delete child documents
      GS3SQLDelete delete = new GS3SQLDelete("classdocuments");
      delete.setWhere(where);

      statement.execute(delete.toString());
    }

    // post the child nodes...
    Iterator iterator = this.childNodes.iterator();
    while (iterator.hasNext()) {
      AbstractHierarchyNode childNode = (AbstractHierarchyNode) iterator.next();

      if (!childNode.writeSQL(connection)) {
	return false;
      }
    }
    */
    statement.close();
    } catch (SQLException e) {
	System.err.println("AZListClassifier.writeSQL(): "+e);
	return false;
    }

    return true;
  }
    public boolean addClassifierDescription(Element classifier_list) {
	// TODO check that there are some docs in the classification
	Element classifier = classifier_list.getOwnerDocument().createElement(GSXML.CLASSIFIER_ELEM);
	classifier.setAttribute(GSXML.NAME_ATT, this.name);
	classifier_list.appendChild(classifier);
	return true;
    }

}