/*

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 *   - Redistributions of source code must retain the above copyright

 *     notice, this list of conditions and the following disclaimer.

 *

 *   - 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.

 *

 *   - Neither the name of Sun Microsystems 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 COPYRIGHT OWNER 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.

 */

/*

*/

using System;

using System.Runtime.InteropServices;

class jinvoker{

    public static int Main(string[] aArgs){

        // Print Hello to show we are in CLR

        Console.WriteLine("Hello from C#");

        if(aArgs.Length > 0)

            // invoke JVM

            return InvokeMain(aArgs[0]);

        else

            return -1;

    }

    // Link the JVM API functions and the wrappers

    [DllImport("jvm.dll")]      public unsafe static extern int  JNI_CreateJavaVM(void** ppVm, void** ppEnv, void* pArgs);

    [DllImport("jinvoker.dll")] public unsafe static extern int  MakeJavaVMInitArgs( void** ppArgs );

    [DllImport("jinvoker.dll")] public unsafe static extern void FreeJavaVMInitArgs( void* pArgs );

    [DllImport("jinvoker.dll")] public unsafe static extern int  FindClass( void* pEnv, String sClass, void** ppClass );

    [DllImport("jinvoker.dll")] public unsafe static extern int  GetStaticMethodID( void*  pEnv,

                                                                                    void*  pClass, 

                                                                                    String szName, 

                                                                                    String szArgs, 

                                                                                    void** ppMid);

    [DllImport("jinvoker.dll")] public unsafe static extern int NewObjectArray( void*  pEnv,

                                                                                int    nDimension,

                                                                                String sType,

                                                                                void** ppArray );

    [DllImport("jinvoker.dll")] public unsafe static extern int CallStaticVoidMethod( void* pEnv,

                                                                                      void* pClass,

                                                                                      void* pMid,

                                                                                      void* pArgs);

    [DllImport("jinvoker.dll")] public unsafe static extern int DestroyJavaVM( void* pJVM );

	public unsafe static int InvokeMain( String sClass ){

        void*  pJVM;    // JVM struct

        void*  pEnv;    // JVM environment

        void*  pVMArgs; // VM args

        void*  pClass;  // Class struct of the executed method

        void*  pMethod; // The executed method struct

        void*  pArgs;   // The executed method arguments struct

        // Fill the pVMArgs structs

        MakeJavaVMInitArgs( &pVMArgs );

        // Create JVM

        int nRes = JNI_CreateJavaVM( &pJVM, &pEnv, pVMArgs );

        if( nRes == 0 ){

            // Find the executed method class 

            if(FindClass( pEnv, sClass, &pClass) == 0 )

                // Find the executed method

                if( GetStaticMethodID( pEnv, pClass, "main", "([Ljava/lang/String;)V", &pMethod ) == 0 )

                    // Create empty String[] array to pass to the main()

                    if( NewObjectArray( pEnv, 0, "java/lang/String", &pArgs ) == 0 ){

                        // Call main()

                        nRes = CallStaticVoidMethod( pEnv, pClass, pMethod, pArgs );

                        if( nRes != -1 )

                            Console.WriteLine("Result:"+nRes);

                        else

                            Console.WriteLine("Exception");

                    }else{

                        Console.WriteLine("Error while making args array");

                        nRes = -100;

                    }

                else{

                    Console.WriteLine("can not find method main(String[])");

                    nRes = -101;

                }

            else{

                Console.WriteLine("can not find class:"+sClass);

                nRes = -102;

            }

            // Destroy the JVM

            DestroyJavaVM( pJVM );

        }else

            Console.WriteLine("Can not create Java VM");

        // Free the JVM args structs

        FreeJavaVMInitArgs(pVMArgs);

        return nRes;

    }

}