package org.ictclas4j.bean;



import java.io.DataInputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.util.ArrayList;



import org.apache.log4j.Logger;

import org.ictclas4j.utility.GFCommon;

import org.ictclas4j.utility.Utility;





public class ContextStat {

	private int tableLen;



	private int[] symbolTable;



	private ArrayList<TagContext> tcList;



	static Logger logger = Logger.getLogger(ContextStat.class);



	public ContextStat() { 

		tcList = new ArrayList<TagContext>();

	}



	public boolean load(String fileName) {

		return load(fileName, false);

	}



	public boolean load(String fileName, boolean isReset) {

		File file = new File(fileName);

		if (!file.canRead())

			return false;// fail while opening the file



		try {



			byte[] b = null;

			DataInputStream in = new DataInputStream(new FileInputStream(file));

			// ????

			tableLen = GFCommon.bytes2int(Utility.readBytes(in, 4), false);

			logger.debug("tableLen:" + tableLen);



			// ??????

			symbolTable = new int[tableLen];

			for (int i = 0; i < tableLen; i++) {

				b = Utility.readBytes(in, 4);

				symbolTable[i] = GFCommon.bytes2int(b, false);

				logger.debug("symbolTable[" + i + "]:" + symbolTable[i]);

			}



			long fileLen = file.length();

			long curLen = 4 + tableLen * 4;

			while (curLen < fileLen) {

				logger.debug("tagContext:");

				TagContext tc = new TagContext();



				// ?????

				b = Utility.readBytes(in, 4);

				int key = GFCommon.bytes2int(b);

				curLen += 4;

				logger.debug("\tkey:" + key);



				// ?????

				b = Utility.readBytes(in, 4);

				curLen += 4;

				int totalFreq = GFCommon.bytes2int(b, false);

				logger.debug("\ttotalFreq:" + totalFreq);



				// ????

				int[] tagFreq = new int[tableLen];

				for (int i = 0; i < tableLen; i++) {

					b = Utility.readBytes(in, 4);

					curLen += 4;

					tagFreq[i] = GFCommon.bytes2int(b, false);

					logger.debug("\ttagFreq[" + i + "]:" + tagFreq[i]);

				}



				// ???????

				int[][] contextArray = new int[tableLen][tableLen];

				for (int i = 0; i < tableLen; i++) {

					String pr = "";

					logger.debug("\tcontextArray[" + i + "]");

					for (int j = 0; j < tableLen; j++) {

						b = Utility.readBytes(in, 4);

						curLen += 4;

						contextArray[i][j] = GFCommon.bytes2int(b, false);

						pr += " " + contextArray[i][j];

					}

					logger.debug("\t\t" + pr);

				}



				tc.setTotalFreq(totalFreq);

				tc.setKey(key);

				tc.setTagFreq(tagFreq);

				tc.setContextArray(contextArray);

				tcList.add(tc);

			}

			in.close();

		} catch (FileNotFoundException e) {

			logger.debug(e);

		} catch (IOException e) {

			logger.debug(e);

		}

		return true;

	}



	public int getFreq(int key, int symbol) {

		TagContext tc = getItem(key);

		if (tc == null)

			return 0;



		int index = Utility.binarySearch(symbol, symbolTable);

		if (index == -1)// error finding the symbol

			return 0;



		// Add the frequency

		int frequency = 0;

		if (tc.getTagFreq() != null)

			frequency = tc.getTagFreq()[index];

		return frequency;



	}



	public double getPossibility(int key, int prev, int cur) {

		double result = 0;



		int curIndex = Utility.binarySearch(cur, symbolTable);

		int prevIndex = Utility.binarySearch(prev, symbolTable);



		TagContext tc = getItem(key);



		// return a lower value, not 0 to prevent data sparse

		if (tc == null || curIndex == -1 || prevIndex == -1

				|| tc.getContextArray()[prevIndex][curIndex] == 0

				|| tc.getTagFreq()[prevIndex] == 0)

			return 0.000001;

		

		int prevCurConFreq = tc.getContextArray()[prevIndex][curIndex];

		int prevFreq = tc.getTagFreq()[prevIndex];



		// 0.9 and 0.1 is a value based experience

		result = 0.9 * (double) prevCurConFreq;

		result /= (double) prevFreq;

		result += 0.1 * (double) prevFreq / (double) tc.getTotalFreq();



		return result;

	}



	public TagContext getItem(int key) {

		TagContext result = null; 

		

		if(tcList==null||tcList.size()==0)

			return null;

		if (key == 0  )

			result = tcList.get(0);

		else   {

			int i=0;

			for ( ; i < tcList.size() && tcList.get(i).getKey()<key; i++);

			if(i<tcList.size() && tcList.get(i).getKey()==key)

				result=tcList.get(i);

			else if(i-1<tcList.size())

				result=tcList.get(i-1);

		}

		

		return result;

	}



}