#include <memory>
#include <cstring>
#include <openssl/dso.h>
#include <openssl/rsa.h>

#include "engine_sct.h"
#include "engine_sct_internal.h"

#ifndef ENGINE_CMD_BASE
#error did not get engine.h
#endif

#define SCT_ENGINE_ID "act"
#define SCT_ENGINE_NAME "cv act library SecureToken interface engine"

enum {
	CMD_SO_PATH = ENGINE_CMD_BASE,
	CMD_PIN,
	CMD_VERBOSE,
	CMD_QUIET,
	CMD_LOAD_CERT_CTRL,
	CMD_ENUM_CERTS,
	CMD_INIT_ARGS
};

static std::auto_ptr<SecureTokenEngine> g_engine;

static int sct_engine_construct(ENGINE *e);
static int sct_engine_destruct(ENGINE *e);
static int sct_engine_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)() );

static const ENGINE_CMD_DEFN sct_cmd_defns[] = {
	{
		CMD_SO_PATH,
		"SO_PATH",
		"Specifies the path to the 'securetoken-engine' shared library",
		ENGINE_CMD_FLAG_STRING
	},
	{
		CMD_PIN,
		"PIN",
		"Specifies the PIN to use for access",
		ENGINE_CMD_FLAG_STRING
	},
	{
		CMD_VERBOSE,
		"VERBOSE",
		"Increases the amount of progress information",
		ENGINE_CMD_FLAG_NO_INPUT
	},
	{
		CMD_LOAD_CERT_CTRL,
		"LOAD_CERT_CTRL",
		"Get the certificate from card",
		ENGINE_CMD_FLAG_INTERNAL
	},
	{
		CMD_ENUM_CERTS,
		"ENUM_CERTS",
		"Return the certificates and the ID's of the key pairs",
		ENGINE_CMD_FLAG_INTERNAL
	},
	{
		CMD_INIT_ARGS,
		"INIT_ARGS",
		"Additional initialization arguments",
		ENGINE_CMD_FLAG_STRING
	},
	{	0, NULL, NULL, 0 }
};

// Encapsule a "return function()" statement with a catch-all block which will emit an error message and return
// a predefined (error) return value in that case.
#define CATCH_ALL(rettype, retval, function) \
do { \
	rettype result = retval; \
	try \
	{ \
		result = (function); \
	} \
	catch(...) \
	{ \
		fprintf(stderr, "Unhandled exception caught!\n"); \
	} \
	return result; \
} while(0) \

static int sct_engine_construct(ENGINE *e)
{
	if(g_engine.get() != 0)
		return 1;
		
	g_engine.reset(new SecureTokenEngine());
	return 1;
}

static int sct_engine_destruct(ENGINE *e)
{
	g_engine.reset(0);
	return 1;
}

static int sct_engine_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)() )
{
	switch(cmd)
	{
	case CMD_PIN:
		return g_engine->setPin((char *) p);
	case CMD_VERBOSE:
		return g_engine->incVerbosity();
	case CMD_LOAD_CERT_CTRL:
		return g_engine->loadCertCtrl(e, (load_cert_params *)p);
	case CMD_INIT_ARGS:
		return g_engine->setInitArgs((const char *)p);
	case CMD_ENUM_CERTS:
		return g_engine->enumerate_certs(e, (enum_certs_s **)p);
	default:
		break;
	}
	
	return 0;
}

static int sct_init(ENGINE *e)
{
	CATCH_ALL(int,0,g_engine->init());
}

static int sct_finish(ENGINE *e)
{
	CATCH_ALL(int,0,g_engine->finish());
}

static int sct_rsa_finish(RSA *rsa)
{
	CATCH_ALL(int,0,g_engine->rsa_finish(rsa));
}

static EVP_PKEY *sct_load_public_key(
 ENGINE *e, const char *s_key_id, UI_METHOD *ui_method, void *callback_data)
{
	CATCH_ALL(EVP_PKEY*,NULL,g_engine->load_pubkey(s_key_id, ui_method, callback_data));
}

static EVP_PKEY *sct_load_private_key(
 ENGINE *e, const char *s_key_id, UI_METHOD *ui_method, void *callback_data)
{
	CATCH_ALL(EVP_PKEY*,NULL,g_engine->load_privkey(s_key_id, ui_method, callback_data));
}

static int sct_rsa_encrypt(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding)
{
	CATCH_ALL(int,-1,g_engine->rsa_encrypt(flen, from, to, EXTRACT_CARD_KEY(rsa), padding));
}

static int sct_rsa_decrypt(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding)
{
	CATCH_ALL(int,-1,g_engine->rsa_decrypt(flen, from, to, EXTRACT_CARD_KEY(rsa), padding));
}

static int sct_rsa_sign(int type,
	const unsigned char *msg, unsigned int msglen,
	unsigned char *sigret, unsigned int *siglen, const RSA *rsa)
{
	CATCH_ALL(int,0,g_engine->rsa_sign(type, msg, msglen, sigret, siglen, EXTRACT_CARD_KEY(rsa)));
}

static int sct_rsa_verify(int type,
	const unsigned char *msg, unsigned int msglen,
	const unsigned char *signature, unsigned int siglen, const RSA *rsa)
{
  CATCH_ALL(int,0,g_engine->rsa_verify(type, msg, msglen, const_cast<unsigned char *>(signature), siglen, EXTRACT_CARD_KEY(rsa)));
}


/*
 *  Following part is for binding the engine into OpenSSL
 */

// Overlay the standard RSA operations with smartcard based ones
RSA_METHOD* RSA_get_sct_method()
{
	static RSA_METHOD ops;
	
	if(!ops.rsa_priv_enc)
	{
		ops = *RSA_get_default_method();
		ops.rsa_pub_enc		= sct_rsa_encrypt;
		ops.rsa_priv_dec	= sct_rsa_decrypt;
		ops.rsa_pub_dec		= NULL;		// a.k.a Verify/Sign. actLibrary just allows the proper functions
		ops.rsa_priv_enc	= NULL;		// and has this 'backdoor' closed. Breaks 'rsautl', sadly.
		ops.rsa_sign		= sct_rsa_sign;
		ops.rsa_verify		= sct_rsa_verify;
		ops.finish			= sct_rsa_finish;
	}
	
	return &ops;
}

static int bind_helper(ENGINE *e)
{
	if(
		!sct_engine_construct(e) ||
		
		!ENGINE_set_id(e, SCT_ENGINE_ID) ||
		!ENGINE_set_name(e, SCT_ENGINE_NAME) ||
		!ENGINE_set_destroy_function(e, sct_engine_destruct) ||
		!ENGINE_set_init_function(e, sct_init) ||
		!ENGINE_set_finish_function(e, sct_finish) ||
		!ENGINE_set_ctrl_function(e, sct_engine_ctrl) ||
		!ENGINE_set_cmd_defns(e, sct_cmd_defns) ||

#ifndef OPENSSL_NO_RSA
	    !ENGINE_set_RSA(e, RSA_get_sct_method()) ||
#endif
#ifndef OPENSSL_NO_DSA
	    !ENGINE_set_DSA(e, DSA_get_default_method()) ||
#endif
#ifndef OPENSSL_NO_DH
	    !ENGINE_set_DH(e, DH_get_default_method()) ||
#endif
	    !ENGINE_set_RAND(e, RAND_SSLeay()) ||
#if 0
	    !ENGINE_set_BN_mod_exp(e, BN_mod_exp) ||
#endif
	    !ENGINE_set_load_pubkey_function(e, sct_load_public_key) ||
	    !ENGINE_set_load_privkey_function(e, sct_load_private_key))
	{
		return 0;
	}
	else
	{
		return 1;
	}
}

static int bind_fn(ENGINE * e, const char *id)
{

#ifndef DEBUG
	if (id && (strcmp(id, SCT_ENGINE_ID) != 0)) {
		fprintf(stderr, "bad engine id (%s vs. %s)\n", id, SCT_ENGINE_ID);
		return 0;
	}
#endif

	if (!bind_helper(e)) {
		fprintf(stderr, "bind failed\n");
		return 0;
	}
	return 1;
}

extern "C"
{

IMPLEMENT_DYNAMIC_CHECK_FN();
IMPLEMENT_DYNAMIC_BIND_FN(bind_fn);

}