/* Copyright (C) 2007 Michael Goffioul
 **
 ** This program is free software; you can redistribute it and/or modify
 ** it under the terms of the GNU General Public License as published by
 ** the Free Software Foundation; either version 2 of the License, or
 ** (at your option) any later version.
 **
 ** This program is distributed in the hope that it will be useful,
 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 ** GNU General Public License for more details.
 **
 ** You should have received a copy of the GNU General Public License
 ** along with this program; If not, see <http://www.gnu.org/licenses/>.
 */

package org.octave;

import java.lang.reflect.*;

public class ClassHelper
{
   private static OctClassLoader loader;

   static
   {
      ClassLoader l = ClassHelper.class.getClassLoader ();
      loader = ( l instanceof OctClassLoader ? ( OctClassLoader ) l :
                 new OctClassLoader ( l ) );
   }


   /**
    * Add the given path to the classpath.
    * @param name String - path to addd to the classpath
    * @return boolean - true if the given path exists and was added to the classpath.
    * @throws Exception
    */
   public static boolean addClassPath ( String name )
      throws Exception
   {
      boolean found = false;
      java.io.File f = new java.io.File ( name );
      if ( f.exists () )
      {
         loader.addClassPath ( name );
         found = true;
      }
      return ( found );
   }


   // new -MH-
   /**
    *
    * @param name String - path to remove from classpath.
    * @return boolean - true if the given path existed in the classpath before it was removed.
    * @throws Exception
    */
   public static boolean removeClassPath ( String name )
      throws Exception
   {
      boolean found = false;
      java.io.File f = new java.io.File ( name );
      java.net.URL urlToRemove = f.toURI ().toURL ();
      // save urls in current class path
      java.net.URL[] urls = loader.getURLs ();

      // create a completely new class loader because java.net.URLClassLoader has no removeClassPath() method
      ClassLoader l = ClassHelper.class.getClassLoader ();
      loader = ( l instanceof OctClassLoader ? ( OctClassLoader ) l :
                 new OctClassLoader ( l ) );

      // add the previous urls back, except for the one
      for ( int i = 0; i < urls.length; i++ )
      {
         java.net.URL url = urls[i];
         if ( !url.equals ( urlToRemove ) )
         {
            loader.addURL ( url );
         }
         else
         {
            // path to remove
            found = true;
         }
      }

      return ( found );
   }


   public static String getClassPath ()
   {
      StringBuffer buf = new StringBuffer ();
      String pathSep = System.getProperty ( "path.separator" );
      java.net.URL[] urls = loader.getURLs ();

      for ( int i = 0; i < urls.length; i++ )
      {
         try
         {
            java.io.File f = new java.io.File ( urls[i].toURI () );
            if ( buf.length () > 0 )
            {
               buf.append ( pathSep );
            }
            buf.append ( f.toString () );
         }
         catch ( java.net.URISyntaxException ex )
         {}
      }
      return buf.toString ();
   }


   // new -MH-
   // return list of methods for given class name
   public static String getMethods ( String classname )
      throws ClassNotFoundException
   {
      return ( getMethods ( Class.forName ( classname ) ) );
   }


   // new -MH-
   // return list of methods for given class instance
   public static String getMethods ( Object obj )
      throws ClassNotFoundException
   {
      return ( getMethods ( obj.getClass () ) );
   }


   // new -MH-
   // return list of methods for given class
   public static String getMethods ( Class klass )
   {
      StringBuffer sb = new StringBuffer ();

      Method theMethod[] = klass.getMethods ();
      for ( int i = 0; i < theMethod.length; i++ )
      {
         if ( i > 0 )
         {
            sb.append ( ";" );
         }
         sb.append ( theMethod[i].getReturnType ().getCanonicalName () );
         sb.append ( " " );
         sb.append ( theMethod[i].getName () );
         sb.append ( "(" );

         Class theParameter[] = theMethod[i].getParameterTypes ();
         for ( int j = 0; j < theParameter.length; j++ )
         {
            if ( j > 0 )
            {
               sb.append ( ", " );
            }
            sb.append ( theParameter[j].getCanonicalName () );
         }
         sb.append ( ")" );

         Class theExceptions[] = theMethod[i].getExceptionTypes ();
         if ( theExceptions.length > 0 )
         {
            sb.append ( " throws " );
            for ( int j = 0; j < theExceptions.length; j++ )
            {
               if ( j > 0 )
               {
                  sb.append ( ", " );
               }
               sb.append ( theExceptions[j].getCanonicalName () );
            }
         }
      }

      return ( sb.toString () );
   }


   // new -MH-
   // return list of fields for given class
   public static String getFields ( Class klass )
   {
      StringBuffer sb = new StringBuffer ();

      Field theField[] = klass.getFields ();
      for ( int i = 0; i < theField.length; i++ )
      {
         if ( i > 0 )
         {
            sb.append ( ";" );
         }
         sb.append ( theField[i].toString () );
      }

      return ( sb.toString () );
   }


   // new -MH-
   // return list of fields for given class name
   public static String getFields ( String classname )
      throws ClassNotFoundException
   {
      return ( getFields ( Class.forName ( classname ) ) );
   }


   // new -MH-
   // return list of fields for given class instance
   public static String getFields ( Object obj )
      throws ClassNotFoundException
   {
      return ( getFields ( obj.getClass () ) );
   }


   public static Method findMethod ( Class cls, String name, Class[] argTypes )
   {
      try
      {
         return cls.getMethod ( name, argTypes );
      }
      catch ( Exception e )
      {
         Method[] mList = cls.getMethods ();
         Method m;
         for ( int i = 0; i < mList.length; i++ )
         {
            m = mList[i];
            if ( m.getName ().equals ( name ) &&
                 m.getParameterTypes ().length == argTypes.length &&
                 isCallableFrom ( m, argTypes ) )
            {
               return m;
            }
         }
         return null;
      }
   }


   public static Constructor findConstructor ( Class cls, Class[] argTypes )
   {
      try
      {
         return cls.getConstructor ( argTypes );
      }
      catch ( Exception e )
      {
         Constructor[] cList = cls.getConstructors ();
         //System.out.println("# constructors: " + cList.length);
         Constructor c;
         for ( int i = 0; i < cList.length; i++ )
         {
            //System.out.println("Considering constructor: " + cList[i]);
            c = cList[i];
            if ( c.getParameterTypes ().length == argTypes.length &&
                 isCallableFrom ( c, argTypes ) )
            {
               return c;
            }
         }
         return null;
      }
   }


   private static Object invokeMethod ( Method m, Object target, Object[] args )
      throws Exception
   {
      try
      {
         return m.invoke ( target, args );
      }
      catch ( IllegalAccessException ex )
      {
         String mName = m.getName ();
         Class[] pTypes = m.getParameterTypes ();
         Class currClass = target.getClass ();

         while ( currClass != null )
         {
            try
            {
               Method meth = currClass.getMethod ( mName, pTypes );
               if ( !meth.equals ( m ) )
               {
                  return meth.invoke ( target, args );
               }
            }
            catch ( NoSuchMethodException ex2 )
            {}
            catch ( IllegalAccessException ex2 )
            {}

            Class[] ifaceList = currClass.getInterfaces ();
            for ( int i = 0; i < ifaceList.length; i++ )
            {
               try
               {
                  Method meth = ifaceList[i].getMethod ( mName, pTypes );
                  return meth.invoke ( target, args );
               }
               catch ( NoSuchMethodException ex2 )
               {}
               catch ( IllegalAccessException ex2 )
               {}
            }

            currClass = currClass.getSuperclass ();
         }

         throw ex;
      }
   }


   public static Object invokeMethod ( Object target, String name,
                                       Object[] args, Class[] argTypes )
      throws Throwable
   {
      Method m = findMethod ( target.getClass (), name, argTypes );
      if ( m != null )
      {
         try
         {
            Object result = invokeMethod ( m, target,
                                           castArguments ( args, argTypes,
               m.getParameterTypes () ) );
            return result;
         }
         catch ( InvocationTargetException ex )
         {
            throw ex.getCause ();
         }
      }
      else
      {
         throw new NoSuchMethodException ( name );
      }
   }


   public static Object invokeStaticMethod ( String cls, String name,
                                             Object[] args, Class[] argTypes )
      throws Throwable
   {
      Method m = findMethod ( Class.forName ( cls, true, loader ), name,
                              argTypes );
      if ( m != null )
      {
         try
         {
            Object result = m.invoke ( null,
                                       castArguments ( args, argTypes,
               m.getParameterTypes () ) );
            return result;
         }
         catch ( InvocationTargetException ex )
         {
            throw ex.getCause ();
         }
      }
      else
      {
         throw new NoSuchMethodException ( name );
      }
   }


   public static Object invokeConstructor ( String cls, Object[] args,
                                            Class[] argTypes )
      throws Throwable
   {
      Constructor c = findConstructor ( Class.forName ( cls, true, loader ),
                                        argTypes );
      if ( c != null )
      {
         try
         {
            Object result = c.newInstance ( castArguments ( args, argTypes,
               c.getParameterTypes () ) );
            return result;
         }
         catch ( InvocationTargetException ex )
         {
            throw ex.getCause ();
         }
      }
      else
      {
         throw new NoSuchMethodException ( cls );
      }
   }


   public static Object getField ( Object target, String name )
      throws Throwable
   {
      try
      {
         Field f = target.getClass ().getField ( name );
         return f.get ( target );
      }
      catch ( NoSuchFieldException ex )
      {
         try
         {
            return invokeMethod ( target, name, new Object[0], new Class[0] );
         }
         catch ( NoSuchMethodException ex2 )
         {
            throw ex;
         }
      }
   }


   public static Object getStaticField ( String cls, String name )
      throws Throwable
   {
      try
      {
         Field f = Class.forName ( cls, true, loader ).getField ( name );
         return f.get ( null );
      }
      catch ( NoSuchFieldException ex )
      {
         try
         {
            return invokeStaticMethod ( cls, name, new Object[0], new Class[0] );
         }
         catch ( NoSuchMethodException ex2 )
         {
            throw ex;
         }
      }
   }


   public static void setField ( Object target, String name, Object value )
      throws Exception
   {
      Field f = target.getClass ().getField ( name );
      f.set ( target, castArgument ( value, value.getClass (), f.getType () ) );
   }


   public static void setStaticField ( String cls, String name, Object value )
      throws Exception
   {
      Field f = Class.forName ( cls, true, loader ).getField ( name );
      f.set ( null, castArgument ( value, value.getClass (), f.getType () ) );
   }


   private static boolean isCallableFrom ( Method m, Class[] argTypes )
   {
      Class[] expTypes = m.getParameterTypes ();
      for ( int i = 0; i < argTypes.length; i++ )
      {
         if ( !isCallableFrom ( expTypes[i], argTypes[i] ) )
         {
            return false;
         }
      }
      return true;
   }


   private static boolean isCallableFrom ( Constructor c, Class[] argTypes )
   {
      Class[] expTypes = c.getParameterTypes ();
      for ( int i = 0; i < argTypes.length; i++ )
      {
         if ( !isCallableFrom ( expTypes[i], argTypes[i] ) )
         {
            return false;
         }
      }
      return true;
   }


   private static boolean isCallableFrom ( Class expCls, Class argCls )
   {
      //System.out.println("isCallableFrom: "+expCls.getCanonicalName() + " <=? " + argCls.getCanonicalName());
      if ( argCls == null )
      {
         return!expCls.isPrimitive ();
      }
      else if ( expCls.isAssignableFrom ( argCls ) )
      {
         return true;
      }
      else if ( ( isNumberClass ( expCls ) || isBooleanClass ( expCls ) ) &&
                isNumberClass ( argCls ) )
      {
         return true;
      }
      else if ( isCharClass ( expCls ) && argCls.equals ( Character.class ) )
      {
         /*
          modified into a more strict check to avoid char to string matching
          to avoid matching method signatureslike
          java_method(char) with octave_call('a String')
          Date: 28-08-2010
          Author: Martin Hepperle
          */
         return true;
      }
      else if ( isStringClass ( expCls ) && argCls.equals ( String.class ) )
      {
         /*
          added for strict String to String matching
          java_method(String) with octave_call('a String')
          but not
          java_method(char) with octave_call('a String')
          Date: 28-08-2010
          Author: Martin Hepperle
          */
         return true;
      }
      else if ( expCls.isArray () && argCls.isArray () &&
                isCallableFrom ( expCls.getComponentType (),
                                 argCls.getComponentType () ) )
      {
         return true;
      }
      else if ( expCls.equals ( Object.class ) && argCls.isPrimitive () )
      {
         return true;
      }
      else
      {
         return false;
      }
   }


   private static boolean isNumberClass ( Class cls )
   {
      return (
         cls.equals ( Integer.TYPE ) ||
         cls.equals ( Integer.class ) ||
         cls.equals ( Short.TYPE ) ||
         cls.equals ( Short.class ) ||
         cls.equals ( Long.TYPE ) ||
         cls.equals ( Long.class ) ||
         cls.equals ( Float.TYPE ) ||
         cls.equals ( Float.class ) ||
         cls.equals ( Double.TYPE ) ||
         cls.equals ( Double.class )
         );
   }


   private static boolean isBooleanClass ( Class cls )
   {
      return (
         cls.equals ( Boolean.class ) ||
         cls.equals ( Boolean.TYPE )
         );
   }


   private static boolean isCharClass ( Class cls )
   {
      return (
         cls.equals ( Character.class ) ||
         cls.equals ( Character.TYPE )
         );
   }


   /**
    * Check whether the supplied class is a String class.
    *
    * Added for more strict char/string mathicng of method signatures
    * Date: 28-08-2010
    * Author: Martin Hepperle
    * @param cls Class - the class to check
    * @return boolean - true if clas is of class java.lang.String
    */
   private static boolean isStringClass ( Class cls )
   {
      return (
         cls.equals ( String.class )
         );
   }


   private static Object[] castArguments ( Object[] args, Class[] argTypes,
                                           Class[] expTypes )
   {
      for ( int i = 0; i < args.length; i++ )
      {
         args[i] = castArgument ( args[i], argTypes[i], expTypes[i] );
      }
      return args;
   }


   private static Object castArgument ( Object obj, Class type, Class expType )
   {
      // System.out.println("expType:"+expType.getCanonicalName() + " <= type:" + type.getCanonicalName());
      if ( type == null || expType.isAssignableFrom ( type ) )
      {
         return obj;
      }
      else if ( isNumberClass ( expType ) )
      {
         if ( expType.equals ( Integer.TYPE ) || expType.equals ( Integer.class ) )
         {
            return new Integer ( ( ( Number ) obj ).intValue () );
         }
         else if ( expType.equals ( Double.TYPE ) || expType.equals ( Double.class ) )
         {
            return new Double ( ( ( Number ) obj ).doubleValue () );
         }
         else if ( expType.equals ( Short.TYPE ) || expType.equals ( Short.class ) )
         {
            return new Short ( ( ( Number ) obj ).shortValue () );
         }
         else if ( expType.equals ( Long.TYPE ) || expType.equals ( Long.class ) )
         {
            return new Long ( ( ( Number ) obj ).longValue () );
         }
      }
      else if ( isBooleanClass ( expType ) )
      {
         return new Boolean ( ( ( Number ) obj ).intValue () != 0 );
      }
      else if ( isCharClass ( expType ) )
      {
         String s = obj.toString ();
         if ( s.length () != 1 )
         {
            throw new ClassCastException ( "cannot cast " + s + " to character" );
         }
         return new Character ( s.charAt ( 0 ) );
      }
      else if ( expType.isArray () && type.isArray () )
      {
         return castArray ( obj, type.getComponentType (),
                            expType.getComponentType () );
      }
      else if ( type.isPrimitive () )
      {
         return obj;
      }
      return null;
   }


   private static Object castArray ( Object obj, Class elemType,
                                     Class elemExpType )
   {
      int len = Array.getLength ( obj );
      Object result = Array.newInstance ( elemExpType, len );
      for ( int i = 0; i < len; i++ )
      {
         Array.set ( result, i,
                     castArgument ( Array.get ( obj, i ), elemType, elemExpType ) );
      }
      return result;
   }


   private static int getArrayClassNDims ( Class cls )
   {
      if ( cls != null && cls.isArray () )
      {
         return ( 1 + getArrayClassNDims ( cls.getComponentType () ) );
      }
      else
      {
         return 0;
      }
   }


   private static Class getArrayElemClass ( Class cls )
   {
      if ( cls.isArray () )
      {
         return getArrayElemClass ( cls.getComponentType () );
      }
      else
      {
         return cls;
      }
   }


   private static Object getArrayElements ( Object array, int[][] idx,
                                            int offset,
                                            int ndims, Class elemType )
   {
      if ( offset >= ndims )
      {
         Object elem = Array.get ( array, idx[offset][0] );
         if ( offset < idx.length - 1 )
         {
            return getArrayElements ( elem, idx, offset + 1, ndims, elemType );
         }
         else
         {
            return elem;
         }
      }
      else
      {
         Class compType = elemType.getComponentType ();
         Object retval = Array.newInstance ( compType, idx[offset].length );
         for ( int i = 0; i < idx[offset].length; i++ )
         {
            Object elem = Array.get ( array, idx[offset][i] );
            if ( offset < idx.length - 1 )
            {
               elem = getArrayElements ( elem, idx, offset + 1, ndims, compType );
            }
            Array.set ( retval, i, elem );
         }
         return retval;
      }
   }


   public static Object arraySubsref ( Object obj, int[][] idx )
      throws Exception
   {
      if ( !obj.getClass ().isArray () )
      {
         throw new IllegalArgumentException ( "not a Java array" );
      }

      if ( idx.length == 1 )
      {
         if ( idx[0].length == 1 )
         {
            return Array.get ( obj, idx[0][0] );
         }
         else
         {
            Object retval = Array.newInstance ( obj.getClass ().
                                                getComponentType (),
                                                idx[0].length );
            for ( int i = 0; i < idx[0].length; i++ )
            {
               Array.set ( retval, i, Array.get ( obj, idx[0][i] ) );
            }
            return retval;
         }
      }
      else
      {
         int[] dims = new int[idx.length];
         for ( int i = 0; i < idx.length; i++ )
         {
            dims[i] = idx[i].length;
         }

         if ( dims.length != getArrayClassNDims ( obj.getClass () ) )
         {
            throw new IllegalArgumentException ( "index size mismatch" );
         }

         /* resolve leading singletons */
         Object theObj = obj;
         int offset = 0;
         while ( dims[offset] == 1 )
         {
            theObj = Array.get ( theObj, idx[offset][0] );
            offset = offset + 1;
            if ( offset >= dims.length )
            {
               return theObj;
            }
         }
         if ( offset > 0 )
         {
            int[][] new_idx = new int[idx.length - offset][];
            System.arraycopy ( idx, offset, new_idx, 0, idx.length - offset );
            return arraySubsref ( theObj, new_idx );
         }

         /* chop trailing singletons */
         int ndims = dims.length;
         while ( ndims > 1 && dims[ndims - 1] == 1 )
         {
            ndims--;
         }

         /* create result array */
         Class elemClass = theObj.getClass ();
         for ( int i = 0; i <= ( dims.length - ndims ); i++ )
         {
            elemClass = elemClass.getComponentType ();
         }
         Object retval = Array.newInstance ( elemClass, dims[0] );

         /* fill-in array */
         for ( int i = 0; i < idx[0].length; i++ )
         {
            Object elem = getArrayElements ( Array.get ( theObj, idx[0][i] ),
                                             idx, 1, ndims, elemClass );
            Array.set ( retval, i, elem );
         }

         return retval;
      }
   }


   private static Object setArrayElements ( Object array, int[][] idx,
                                            int offset, int ndims, Object rhs )
      throws Exception
   {
      if ( offset >= ndims )
      {
         if ( offset < idx.length - 1 )
         {
            setArrayElements ( Array.get ( array, idx[offset][0] ), idx,
                               offset + 1, ndims, rhs );
         }
         else
         {
            Array.set ( array, idx[offset][0], rhs );
         }
         return array;
      }
      else
      {
         for ( int i = 0; i < idx[offset].length; i++ )
         {
            if ( offset < idx.length - 1 )
            {
               setArrayElements ( Array.get ( array, idx[offset][i] ), idx,
                                  offset + 1, ndims, Array.get ( rhs, i ) );
            }
            else
            {
               Array.set ( array, idx[offset][i], Array.get ( rhs, i ) );
            }
         }
         return array;
      }
   }


   public static Object arraySubsasgn ( Object obj, int[][] idx, Object rhs )
      throws Exception
   {
      if ( !obj.getClass ().isArray () )
      {
         throw new IllegalArgumentException ( "not a Java array" );
      }

      if ( idx.length == 1 )
      {
         if ( idx[0].length == 1 )
         {
            Array.set ( obj, idx[0][0], rhs );
         }
         else
         {
            for ( int i = 0; i < idx[0].length; i++ )
            {
               Array.set ( obj, idx[0][i], Array.get ( rhs, i ) );
            }
         }
         return obj;
      }
      else
      {
         int[] dims = new int[idx.length];
         for ( int i = 0; i < idx.length; i++ )
         {
            dims[i] = idx[i].length;
         }

         if ( dims.length != getArrayClassNDims ( obj.getClass () ) )
         {
            throw new IllegalArgumentException ( "index size mismatch" );
         }

         /* resolve leading singletons */
         Object theObj = obj;
         int offset = 0;
         while ( dims[offset] == 1 && offset < ( dims.length - 1 ) )
         {
            theObj = Array.get ( theObj, idx[offset][0] );
            offset = offset + 1;
         }
         if ( offset > 0 )
         {
            int[][] new_idx = new int[idx.length - offset][];
            System.arraycopy ( idx, offset, new_idx, 0, idx.length - offset );
            arraySubsasgn ( theObj, new_idx, rhs );
            return obj;
         }

         /* chop trailing singletons */
         int ndims = dims.length;
         while ( ndims > 1 && dims[ndims - 1] == 1 )
         {
            ndims--;
         }

         for ( int i = 0; i < idx[0].length; i++ )
         {
            setArrayElements ( Array.get ( theObj, idx[0][i] ), idx, 1, ndims,
                               Array.get ( rhs, i ) );
         }

         return obj;
      }
   }


   public static Object createArray ( Object cls, int[] dims )
      throws Exception
   {
      Class theClass;
      if ( cls instanceof Class )
      {
         theClass = ( Class ) cls;
      }
      else if ( cls instanceof String )
      {
         theClass = Class.forName ( ( String ) cls, true, loader );
      }
      else
      {
         throw new IllegalArgumentException ( "invalid class specification " +
                                              cls );
      }

      return Array.newInstance ( theClass, dims );
   }


   public static Object createArray ( Object cls, int length )
      throws Exception
   {
      return createArray ( cls, new int[]
                           {length} );
   }

}