/*=============================================================================#
 # Copyright (c) 2004, 2021 TeXlipse-Project (texlipse.sf.net) and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0
 # 
 # Contributors:
 #     Tor Arne Vestbø - initial API and implementation
 #=============================================================================*/

// Compile with cl -shared -o./ddeclient.dll -I$jdk/include/ -I$jdk/include/win32 ddeclient.cpp

#ifndef UNICODE
#define UNICODE
#define _UNICODE
#endif

#include <jni.h>
#include <windows.h>
#include <ddeml.h>
#include "ddeclient.h"


// Not used for anything but must be defined
HDDEDATA CALLBACK DdeCallback(UINT uType, UINT uFmt, HCONV hconv,
		HSZ hsz1, HSZ hsz2, HDDEDATA hdata, DWORD dwData1, DWORD dwData2)
{
	return 0;
}

#ifdef __cplusplus
extern "C" {
#endif

JNIEXPORT jint JNICALL Java_org_eclipse_statet_ecommons_io_win_DDEClient_ddeExecute(
		JNIEnv* env, jclass obj, jstring server, jstring topic, jstring command)
{
	// Pull unicode strings from the java arguments
	const jchar *szServer= env->GetStringChars(server, 0);
	const jchar *szTopic=  env->GetStringChars(topic, 0);
	const jchar *szCommand= env->GetStringChars(command, 0);
	
	// Init the DDEM Library
	DWORD idInst= 0;
	UINT iReturn= DdeInitialize(&idInst, (PFNCALLBACK) DdeCallback,
			APPCLASS_STANDARD | APPCMD_CLIENTONLY, 0 );
	if (iReturn != DMLERR_NO_ERROR)
	{
		return 1;
	}
	
	// Connect to the DDE server
	HSZ hszServer= DdeCreateStringHandle(idInst, (WCHAR*) szServer, 0);
	HSZ hszTopic= DdeCreateStringHandle(idInst, (WCHAR*) szTopic, 0);
	HCONV hConv= DdeConnect(idInst, hszServer, hszTopic, NULL);
	
	// Free up some resources
	DdeFreeStringHandle(idInst, hszServer);
	env->ReleaseStringChars(server, szServer);
	DdeFreeStringHandle(idInst, hszTopic);
	env->ReleaseStringChars(topic, szTopic);
	
	// Make sure we're connected
	if (hConv == NULL)
	{
		DdeUninitialize(idInst);
		env->ReleaseStringChars(command, szCommand);
		return 2;
	}
	
	// Prepare data for transaction
	HDDEDATA hData= DdeCreateDataHandle(idInst, (LPBYTE) szCommand,
			(lstrlen((WCHAR*) szCommand) + 1) * sizeof(WCHAR), 0L, 0L, CF_UNICODETEXT, 0);
	env->ReleaseStringChars(command, szCommand);
	
	// Data is OK?
	if (hData == NULL)
	{
		DdeDisconnect(hConv);
		DdeUninitialize(idInst);
		return 3;
	}
	else
	{
		DdeClientTransaction((LPBYTE) hData, 0xFFFFFFFF, hConv, 0L, 0,
				XTYP_EXECUTE, TIMEOUT_ASYNC, NULL);
	}
	
	// Clean up
	DdeDisconnect(hConv);
	DdeUninitialize(idInst);
	
	return 0;
}

#ifdef __cplusplus
}
#endif