package nl.bluering;
import java.util.*;

/**
* This library does all basic string  funtions
*/

public class StringLib
implements Interpreter
{
 public final static int CONCAT=1,SUB=2,STWITH=3,ENDSWITH=4,REVERSE=5;
 public final static int TOUPPER=6,TOLOWER=7,LENGTH=8,REPLACE=9;
 public final static int TRIM=10,CHARAT=11,INDEXOF=12,EQUALS=13,LASTINDEX=14,HREF=15;

 RootLib root;

 StringLib(RootLib r)
 {root=r;
  mountall(); 
 }
 public void setrootlib(RootLib r)
 {root=r;
 }
 void m(String name,int arity,int index,String help)
 {root.mount(new functionpointer(name,arity,this,index,help));}

 public void mountall()
 {
  m("concat",2,CONCAT,"glues two strings together");
  m("substring",3,SUB,"grabs anything between the given positions");
  m("startswith",2,STWITH,"returns true if a1 starts with a2");
  m("endswith",2,ENDSWITH,"returns true if a1 ends with a2");
  m("reverse",1,REVERSE,"reverses the string");
  m("toupper",1,TOUPPER,"convert to upper case");
  m("tolower",1,TOLOWER,"convert to lower case");
  m("length",1,LENGTH,"get the length of the string");
  m("replace",3,REPLACE,"replace all occurences of char a2 in a1 for a3");
  m("trim",1,TRIM,"remove spaces etc. on both ends");
  m("charat",2,CHARAT,"return ascii value of the character");
  m("indexof",2,INDEXOF,"get place number of a2 in a1");
  m("stringequals",2,EQUALS,"returns true if the strings are equal");
  m("lastindexof",2,LASTINDEX,"get place number of a2 in a1, searching backwards");  
  m("makehref",2,HREF,"make <a href> tag");  
 }

 public Variable run(Variable result,Expression e,int index) throws Exception
 {
  double d1,d2;
  switch(index)
  {case CONCAT:
   result.set(root.run(result,e.get(0)).getstring()+
             root.run(result,e.get(1)).getstring());
   break;
   case SUB:
    result.set(root.run(result,e.get(0)).getstring().substring(
	 root.run(result,e.get(1)).getint(),
	 root.run(result,e.get(2)).getint()
	));    
   break;
   case STWITH:
    result.set(root.run(result,e.get(0)).getstring().startsWith(
      root.run(result,e.get(1)).getstring()));    
   break;
   case ENDSWITH:
    result.set(root.run(result,e.get(0)).getstring().endsWith(
      root.run(result,e.get(1)).getstring()));    
   break;
   case REVERSE:
    result.set(new StringBuffer(root.run(result,e.get(0)).getstring()).reverse().toString());    
   break;
   case TOUPPER:
    result.set(root.run(result,e.get(0)).getstring().toUpperCase());    
   break;
   case TOLOWER:
    result.set(root.run(result,e.get(0)).getstring().toLowerCase());    
   break;
   case LENGTH:
    result.set(root.run(result,e.get(0)).getstring().length());    
   break;
   case REPLACE:
    result.set(root.run(result,e.get(0)).getstring().replace(
	(char)root.run(result,e.get(1)).getint(),
	(char)root.run(result,e.get(2)).getint()
	));    
   break;
   case TRIM:
    result.set(root.run(result,e.get(0)).getstring().trim());    
   break;
   case CHARAT:
    result.set(root.run(result,e.get(0)).getstring().charAt(
	 root.run(result,e.get(1)).getint()
	));    
   break;
   case INDEXOF:
    result.set(root.run(result,e.get(0)).getstring().indexOf(
	 (char)root.run(result,e.get(1)).getint()
	));    
   break;
   case EQUALS:
    result.set(root.run(result,e.get(0)).getstring().equals(
	 root.run(result,e.get(0)).getstring()
	));    
   break;   
   case LASTINDEX:
    result.set(root.run(result,e.get(0)).getstring().lastIndexOf(
    (char)root.run(result,e.get(1)).getint()
   ));    
   break;
   case HREF:
   String target=root.run(result,e.get(0)).getstring();
   String text=root.run(result,e.get(1)).getstring();   
   result.set("<a href=\""+target+"\">"+text+"</a>");
   break;
  }
  return result;
 }
}