/**
 * Copyright (c) 2005, www.fontbox.org
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. Neither the name of fontbox; nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * http://www.fontbox.org
 *
 */
package com.itextpdf.text.pdf.fonts.cmaps;

import com.itextpdf.text.ExceptionConverter;
import com.itextpdf.text.Utilities;
import com.itextpdf.text.pdf.PdfObject;
import com.itextpdf.text.pdf.PdfString;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import com.itextpdf.text.error_messages.MessageLocalization;

/**
 * This class represents a CMap file.
 *
 * @author Ben Litchfield (ben@benlitchfield.com)
 * @since	2.1.4
 */
public class CMapToUnicode extends AbstractCMap {

    private Map<Integer, String> singleByteMappings = new HashMap<Integer, String>();
    private Map<Integer, String> doubleByteMappings = new HashMap<Integer, String>();

    /**
     * Creates a new instance of CMap.
     */
    public CMapToUnicode() {
        //default constructor
    }

    /**
     * This will tell if this cmap has any one byte mappings.
     *
     * @return true If there are any one byte mappings, false otherwise.
     */
    public boolean hasOneByteMappings() {
        return !singleByteMappings.isEmpty();
    }

    /**
     * This will tell if this cmap has any two byte mappings.
     *
     * @return true If there are any two byte mappings, false otherwise.
     */
    public boolean hasTwoByteMappings() {
        return !doubleByteMappings.isEmpty();
    }

    /**
     * This will perform a lookup into the map.
     *
     * @param code The code used to lookup.
     * @param offset The offset into the byte array.
     * @param length The length of the data we are getting.
     *
     * @return The string that matches the lookup.
     */
    public String lookup(byte[] code, int offset, int length) {

        String result = null;
        Integer key = null;
        if (length == 1) {

            key = Integer.valueOf(code[offset] & 0xff);
            result = singleByteMappings.get(key);
        } else if (length == 2) {
            int intKey = code[offset] & 0xff;
            intKey <<= 8;
            intKey += code[offset + 1] & 0xff;
            key = Integer.valueOf(intKey);

            result = doubleByteMappings.get(key);
        }

        return result;
    }

    public Map<Integer, Integer> createReverseMapping() throws IOException {
        Map<Integer, Integer> result = new HashMap<Integer, Integer>();
        for (Map.Entry<Integer, String> entry : singleByteMappings.entrySet()) {
            result.put(convertToInt(entry.getValue()), entry.getKey());
        }
        for (Map.Entry<Integer, String> entry : doubleByteMappings.entrySet()) {
            result.put(convertToInt(entry.getValue()), entry.getKey());
        }
        return result;
    }

    public Map<Integer, Integer> createDirectMapping() throws IOException {
        Map<Integer, Integer> result = new HashMap<Integer, Integer>();
        for (Map.Entry<Integer, String> entry : singleByteMappings.entrySet()) {
            result.put(entry.getKey(), convertToInt(entry.getValue()));
        }
        for (Map.Entry<Integer, String> entry : doubleByteMappings.entrySet()) {
            result.put(entry.getKey(), convertToInt(entry.getValue()));
        }
        return result;
    }

    private int convertToInt(String s) throws IOException {
        byte[] b = s.getBytes("UTF-16BE");
        int value = 0;
        for (int i = 0; i < b.length - 1; i++) {
            value += b[i] & 0xff;
            value <<= 8;
        }
        value += b[b.length - 1] & 0xff;
        return value;
    }

    void addChar(int cid, String uni) {
        doubleByteMappings.put(Integer.valueOf(cid), uni);
    }
    
    @Override
    void addChar(PdfString mark, PdfObject code) {
        try {
            byte[] src = mark.getBytes();
            String dest = createStringFromBytes(code.getBytes());
            if (src.length == 1) {
                singleByteMappings.put(Integer.valueOf(src[0] & 0xff), dest);
            } else if (src.length == 2) {
                int intSrc = src[0] & 0xFF;
                intSrc <<= 8;
                intSrc |= src[1] & 0xFF;
                doubleByteMappings.put(Integer.valueOf(intSrc), dest);
            } else {
                throw new IOException(MessageLocalization.getComposedMessage("mapping.code.should.be.1.or.two.bytes.and.not.1", src.length));
            }
        }
        catch (Exception ex) {
            throw new ExceptionConverter(ex);
        }
    }
    
    private String createStringFromBytes(byte[] bytes) throws IOException {
        String retval = null;
        if (bytes.length == 1) {
            retval = new String(bytes);
        } else {
            retval = new String(bytes, "UTF-16BE");
        }
        return retval;
    }

    public static CMapToUnicode getIdentity() {
        CMapToUnicode uni = new CMapToUnicode();
        for (int i = 0; i < 65537; i++) {
            uni.addChar(i, Utilities.convertFromUtf32(i));
        }
        return uni;
    }
}
