package org.daisy.pipeline.braille.liblouis.pef;
   
   import java.util.HashMap;
   import java.util.Map;
   import java.nio.charset.Charset;
   
   import org.daisy.dotify.api.table.BrailleConverter;
   
   import org.liblouis.DisplayTable;
  
  public class LiblouisDisplayTableBrailleConverter implements BrailleConverter {
  	
  	private final Map<Character,Character> b2t = new HashMap<Character,Character>();
  	private final Map<Character,Character> t2b = new HashMap<Character,Character>();
  	
  	private final DisplayTable table;
  
  	public LiblouisDisplayTableBrailleConverter(DisplayTable table) {
  		this.table = table;
  		try {
  			char[] brailleRange = new char[256];
  			int i = 0;
  			for (; i < 256; i++)
  				brailleRange[i] = (char)(0x2800+i);
  			char[] tableDef = table.encode(String.valueOf(brailleRange)).toCharArray();
  			for (i = 255; i >= 0; i--) {
  				t2b.put(tableDef[i], brailleRange[i]);
  				b2t.put(brailleRange[i], tableDef[i]); }}
  		catch (Throwable e) {
  			throw new RuntimeException(e); }
  	}
  	
  	/**
  	 * @return Unicode braille string
  	 */
  	public String toBraille(String text) {
  		StringBuffer buf = new StringBuffer();
  		Character b;
  		for (char t : text.toCharArray()) {
  			b = t2b.get(t);
  			if (b == null) {
  				// character might map to a virtual dot pattern
  				// DisplayTable.decode() will return the base pattern without virtual dots
  				b = table.decode(t);
  				// assume that blank means the table does not contain the character
  				if (b != '\u2800')
  					t2b.put(t, b);
  				else
  					throw new IllegalArgumentException("Character '" + t + "' (0x" + Integer.toHexString((int)(t)) + ") not found.");
  			}
  			buf.append(b); }
  		return buf.toString();
  	}
  	
  	/**
  	 * @param braille Unicode braille string
  	 */
  	public String toText(String braille) {
  		StringBuffer buf = new StringBuffer();
  		Character t;
  		for (char b : braille.toCharArray()) {
  			t = b2t.get(b);
  			if (t == null)
  				throw new IllegalArgumentException("Braille pattern '" + b + "' (0x" + Integer.toHexString((int)(b)) + ") not found.");
  			buf.append(t); }
  		return buf.toString();
  	}
  	
  	private static final Charset charset = Charset.forName("ISO-8859-1");
  	
  	public Charset getPreferredCharset() {
  		return charset;
  	}
  	
  	public boolean supportsEightDot() {
  		return true;
  	}
  
  	@Override
  	public String toString() {
  		return table.toString();
  	}
  }