/********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2004 Wilmer van der Gaast and others                *
  \********************************************************************/

/* SSL module - SSPI backend */

/* Copyright (C) 2005 Jelmer Vernooij <jelmer@samba.org> */

/*
  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 with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 59 Temple Place,
  Suite 330, Boston, MA  02111-1307  USA
*/

#include "ssl_client.h"
#include <windows.h>
#define SECURITY_WIN32
#include <security.h>
#include <sspi.h>
#include <schannel.h>
#include "sock.h"

static gboolean initialized = FALSE;
int ssl_errno;

struct scd
{
	int fd;
	ssl_input_function func;
	gpointer data;
	gboolean established;
  	CredHandle cred;		/* SSL credentials */
	CtxtHandle context;		/* SSL context */
	SecPkgContext_StreamSizes sizes;

	char *host;

	char *pending_raw_data;
	gsize pending_raw_data_len;
	char *pending_data;
	gsize pending_data_len;
};

static void ssl_connected(gpointer, gint, GaimInputCondition);

void sspi_global_init(void)
{
	/* FIXME */
}

void sspi_global_deinit(void)
{
	/* FIXME */
}

void *ssl_connect(char *host, int port, ssl_input_function func, gpointer data)
{
	struct scd *conn = g_new0(struct scd, 1);
		
	conn->fd = proxy_connect(host, port, ssl_connected, conn);
	sock_make_nonblocking(conn->fd);
	conn->func = func;
	conn->data = data;
	conn->host = g_strdup(host);
	
	if (conn->fd < 0)
	{
		g_free(conn);
		return NULL;
	}
	
	if (!initialized)
	{
		sspi_global_init();
		initialized = TRUE;
		atexit(sspi_global_deinit);
	}

	return conn;
}

static void ssl_connected(gpointer _conn, gint fd, GaimInputCondition cond)
{
	struct scd *conn = _conn;
	SCHANNEL_CRED ssl_cred;
	TimeStamp timestamp;
	SecBuffer ibuf[2],obuf[1];
	SecBufferDesc ibufs,obufs;
	ULONG req = ISC_REQ_REPLAY_DETECT | ISC_REQ_SEQUENCE_DETECT |
    	ISC_REQ_CONFIDENTIALITY | ISC_REQ_USE_SESSION_KEY |
      	ISC_REQ_ALLOCATE_MEMORY | ISC_REQ_STREAM | ISC_REQ_EXTENDED_ERROR |
		ISC_REQ_MANUAL_CRED_VALIDATION;
	ULONG a;
	gsize size = 0;
	gchar *data = NULL;

	memset(&ssl_cred, 0, sizeof(SCHANNEL_CRED));
	ssl_cred.dwVersion = SCHANNEL_CRED_VERSION;
	ssl_cred.grbitEnabledProtocols = SP_PROT_SSL3_CLIENT;

	SECURITY_STATUS st = AcquireCredentialsHandle(NULL, UNISP_NAME, SECPKG_CRED_OUTBOUND, NULL, &ssl_cred, NULL, NULL, &conn->cred, &timestamp);

	if (st != SEC_E_OK) {
		conn->func(conn->data, NULL, cond);
		return;
	}
	
	do {
		/* initialize buffers */
	    ibuf[0].cbBuffer = size; ibuf[0].pvBuffer = data;
	    ibuf[1].cbBuffer = 0; ibuf[1].pvBuffer = NULL;
	    obuf[0].cbBuffer = 0; obuf[0].pvBuffer = NULL;
    	ibuf[0].BufferType = obuf[0].BufferType = SECBUFFER_TOKEN;
	    ibuf[1].BufferType = SECBUFFER_EMPTY;

		/* initialize buffer descriptors */
	    ibufs.ulVersion = obufs.ulVersion = SECBUFFER_VERSION;
	    ibufs.cBuffers = 2; obufs.cBuffers = 1;
	    ibufs.pBuffers = ibuf; obufs.pBuffers = obuf;

		st = InitializeSecurityContext(&conn->cred, size?&conn->context:NULL, conn->host, req, 0, SECURITY_NETWORK_DREP, size?&ibufs:NULL, 0, &conn->context, &obufs, &a, &timestamp);  
    	if (obuf[0].pvBuffer && obuf[0].cbBuffer) {
			/* FIXME: Check return value */
			send(conn->fd, obuf[0].pvBuffer, obuf[0].cbBuffer, 0);
		}

		switch (st) {
		case SEC_I_INCOMPLETE_CREDENTIALS:
			break;
		case SEC_I_CONTINUE_NEEDED:
			break;
		case SEC_E_INCOMPLETE_MESSAGE:
			break;
		case SEC_E_OK:
			break;
		}
	
		QueryContextAttributes(&conn->context, SECPKG_ATTR_STREAM_SIZES, &conn->sizes);
	} while (1);

	conn->func(conn->data, conn, cond);
}

int ssl_read(void *conn, char *retdata, int len)
{
	struct scd *scd = conn;
	SecBufferDesc msg;
	SecBuffer buf[4];
	int ret = -1, i;
	char *data = g_malloc(scd->sizes.cbHeader + scd->sizes.cbMaximumMessage + scd->sizes.cbTrailer);

	/* FIXME: Try to read some data */

  	msg.ulVersion = SECBUFFER_VERSION;
	msg.cBuffers = 4;
	msg.pBuffers = buf;
	
	buf[0].BufferType = SECBUFFER_DATA;
	buf[0].cbBuffer = len;
	buf[0].pvBuffer = data;

	buf[1].BufferType = SECBUFFER_EMPTY;
	buf[2].BufferType = SECBUFFER_EMPTY;
	buf[3].BufferType = SECBUFFER_EMPTY;

	SECURITY_STATUS st = DecryptMessage(&scd->context, &msg, 0, NULL);

	if (st != SEC_E_OK) {
		/* FIXME */
		return -1;
	}

	for (i = 0; i < 4; i++) {
		if (buf[i].BufferType == SECBUFFER_DATA) {
			memcpy(retdata, buf[i].pvBuffer, len);
			ret = len;
		}	
	}

	g_free(data);
	return -1;
}

int ssl_write(void *conn, const char *userdata, int len)
{
	struct scd *scd = conn;
	SecBuffer buf[4];
	SecBufferDesc msg;
	char *data;
	int ret;

	msg.ulVersion = SECBUFFER_VERSION;
	msg.cBuffers = 4;
	msg.pBuffers = buf;

	data = g_malloc(scd->sizes.cbHeader + scd->sizes.cbMaximumMessage + scd->sizes.cbTrailer);
	memcpy(data + scd->sizes.cbHeader, userdata, len);

	buf[0].BufferType = SECBUFFER_STREAM_HEADER;
	buf[0].cbBuffer = scd->sizes.cbHeader;
	buf[0].pvBuffer = data;

	buf[1].BufferType = SECBUFFER_DATA;
	buf[1].cbBuffer = len;
	buf[1].pvBuffer = data + scd->sizes.cbHeader;

	buf[2].BufferType = SECBUFFER_STREAM_TRAILER;
	buf[2].cbBuffer = scd->sizes.cbTrailer;
	buf[2].pvBuffer = data + scd->sizes.cbHeader + len;
	buf[3].BufferType = SECBUFFER_EMPTY;

	SECURITY_STATUS st = EncryptMessage(&scd->context, 0, &msg, 0);

	ret = send(scd->fd, data, 
				buf[0].cbBuffer + buf[1].cbBuffer + buf[2].cbBuffer, 0);

	g_free(data);

	return ret;
}

void ssl_disconnect(void *conn)
{
	struct scd *scd = conn;

	SecBufferDesc msg;
	SecBuffer buf;
	DWORD dw;

	dw = SCHANNEL_SHUTDOWN;
	buf.cbBuffer = sizeof(dw);
	buf.BufferType = SECBUFFER_TOKEN;
	buf.pvBuffer = &dw;
	
	msg.ulVersion = SECBUFFER_VERSION;
	msg.cBuffers = 1;
	msg.pBuffers = &buf;

	SECURITY_STATUS st = ApplyControlToken(&scd->context, &msg);

	if (st != SEC_E_OK) {
		/* FIXME */
	}
	
	/* FIXME: call InitializeSecurityContext(Schannel), passing 
	 * in empty buffers*/

	DeleteSecurityContext(&scd->context);

	FreeCredentialsHandle(&scd->cred);

	closesocket(scd->fd);
	g_free(scd->host);
	g_free(scd);
}

int ssl_getfd(void *conn)
{
	return ((struct scd*)conn)->fd;
}

GaimInputCondition ssl_getdirection( void *conn )
{
	return B_EV_IO_WRITE; /* FIXME: or B_EV_IO_READ */
}