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

#include "Init_Engine.h"

#include "CardObject.h"
#include "CardKey.h"
#include "SlotList.h"
#include "CertificateList.h"
#include "SecOpGuard.h"

#include <actIToken.h>
#include <actITokenKey.h>
#include <actITokenPIN.h>
#include <actMode.h>
#include <actState.h>
#include <actUtility.h>
#include <actDebug.h>
#include <actSlotManager.h>
#include <actAlgorithm.h>
#include <actISlot.h>

// Provide thread synchronization
#include <SyncObject.h>

#include <cstring>

EVP_PKEY *SecureTokenEngine::encapsule_CardKey(CardKey *ck)
{
	EVP_PKEY* pk(EVP_PKEY_new());
	RSA* rsa(RSA_new());
	
	if(pk == NULL || rsa == NULL)
		return NULL;

	// Initialize the RSA structure
	{	

		RSA_set_method(rsa, RSA_get_sct_method());
		RSA_set_app_data(rsa, ck);

		// We need (at least) the public exponent and the modulus for OpenSSL itself because
		// it calculates the I/O buffer sizes out of it.
		act::ITokenKey* key = ck->getKey();
	
		act::Blob publicExponent;
		act::Blob modulus;
	
		key->GetParam(act::PUBLICKEY, publicExponent);
		key->GetParam(act::MODULO, modulus);
		act::I2OSP(modulus);
		act::I2OSP(publicExponent);
		rsa->n = BN_bin2bn(&modulus[0], modulus.size(), rsa->n);
		rsa->e = BN_bin2bn(&publicExponent[0], publicExponent.size(), rsa->e);
		
		// Meh. Set it here. If we don't, OpenSSL tries to emulate sign/verify with
		// private_encrypt and public_decrypt which we can't do.
		rsa->flags |= RSA_FLAG_SIGN_VER;
		
	}
	
	EVP_PKEY_set1_RSA(pk, rsa);

	// Decreases refcount by one, i.e. transfers sole ownership to EVP_PKEY struct
	RSA_free(rsa);
	
	return pk;
}

int SecureTokenEngine::setPin(char *pin)
{
	int plen = strlen(pin);
	act::Blob(pin, pin+plen).swap(m_pin);
	std::fill(pin, pin+plen, '*');
	return 1;
}

int SecureTokenEngine::incVerbosity()
{
	return 0;
}

int SecureTokenEngine::setInitArgs(const char *args)
{
	return 0;
}


int SecureTokenEngine::init()
{
	act::Init(true);
	
	act::SlotManager slot_manager;
	
	try
	{
		slot_manager.Install(act::SubsystemReg::CreateSubsystem("PCSC", 0));
		slot_manager.Refresh();
	}
	catch(act::Exception& ACT_DEBUG_PARAM(e))
	{
		ACT_TRACE(e, "SecureTokenEngine::Init");
		return 0;
	}
	
	int slots = slot_manager.GetSlotNumber();

	for(int i = 0; i < slots; i++)
	{
		act::ISlot* slot(slot_manager.GetSlot(i)->Clone());
		m_slot_list.addSlot(slot);
	}
		
	return 1;
}

int SecureTokenEngine::finish()
{
	m_slot_list.clear();
	return 1;
}

int SecureTokenEngine::rsa_finish(RSA *rsa)
{
	// This function is only called on freeing of 'our' own RSA keys which have been generated
	// by encapsule_CardKey
	
	// NB: If you use something like
	//
	// EVP_PKEY* pk_pub = ENGINE_load_public_key(e, key_id, NULL, NULL);
	// RSA* pubkey = EVP_PKEY_get1_RSA(pk_pub);
	//
	// in the user code, you have to use both EVP_PKEY_free() and RSA_free() until the last traces are gone.

	CardKey* ck(EXTRACT_CARD_KEY(rsa));

	ACT_ASSERT(ck != 0);
	
	delete ck;
	return 1;
}

int SecureTokenEngine::loadCertCtrl(ENGINE *e, load_cert_params *p)
{
	CardObject co(&m_slot_list);
	
	ACT_ASSERT(p != NULL);
	ACT_ASSERT(p->s_token_cert_id != NULL);
	
	if(p == NULL || p->s_token_cert_id == NULL)
		return NULL;
		
	if(!co.searchFor(act::CERTIFICATE, p->s_token_cert_id))
		return NULL;
	
	const act::Blob& certblob = co.getCertBlob();
	const unsigned char *cbp = &certblob[0];
	
	p->cert = d2i_X509(NULL, &cbp, certblob.size());

	return p->cert != NULL ? 1 : 0;
}

EVP_PKEY *SecureTokenEngine::load_privkey(const char *s_key_id, UI_METHOD *ui_method, void *callback_data)
{
	CardObject co(&m_slot_list);
	
	if(!co.searchFor(act::PRIVATEKEY, s_key_id))
		return NULL;
	
	std::auto_ptr<CardKey> ck(new CardKey(co.getKey()));

	// Ask for the PIN if not already passed into the module	
	if(m_pin.empty())
		ck->setPin(ui_method, callback_data);
	else
		ck->setPin(m_pin);

	// Try to authenticate with the provided PIN. If we fail, don't return the key at all.
	act::IToken* token = ck->getKey()->GetToken();
	SecOpGuard guard(token);
	act::Synchronize lock(*token);
	
	if(!ck->Authenticate(guard))
		return NULL;

	EVP_PKEY* pk = encapsule_CardKey(ck.get());
	
	if(pk != NULL)
	{
		ck.release();
		return pk;
	}
	
	return NULL;
}

EVP_PKEY *SecureTokenEngine::load_pubkey(const char *s_key_id, UI_METHOD *ui_method, void *callback_data)
{
	// Really. Same as above, but without asking/setting a PIN. Simply because one can use an instance of
	// act::ITokenKey for both ways since private and public keys are interlinked internally.
	CardObject co(&m_slot_list);
	
	if(!co.searchFor(act::PUBLICKEY, s_key_id))
		return NULL;
	
	std::auto_ptr<CardKey> ck(new CardKey(co.getKey()));

	EVP_PKEY* pk = encapsule_CardKey(ck.get());
	
	if(pk != NULL)
	{
		ck.release();
		return pk;
	}
	
	return NULL;
}

int SecureTokenEngine::rsa_encrypt(int flen, const unsigned char *from, unsigned char *to, const CardKey* ck, int padding)
{
	if(padding != RSA_PKCS1_PADDING)
	{
		ACT_TRACE("SecureTokenEngine::rsa_encrypt: Only RSA_PKCS1_PADDING allowed so far\n");
		return -1;
	}
	
	if(ck == NULL)
	{
		ACT_TRACE("SecureTokenEngine::rsa_encrypt: No CardKey given\n");
		return -1;
	}
	
	act::Blob _plaintext(from, from+flen);
	act::Blob _ciphertext;
	int retlen = -1;

	act::IToken* token = ck->getKey()->GetToken();
	SecOpGuard guard(token);
	act::Synchronize lock(*token);

	try
	{
		act::Algorithm alg(ck->getKey(), act::ENCRYPT);
		alg << _plaintext << act::final >> _ciphertext;
		retlen = _ciphertext.size();
		
		// OpenSSL uses these operations for just one round and determines the buffer size from the
		// key length. Still I'm not happy with it.
		std::copy(_ciphertext.begin(), _ciphertext.end(), to);
	}
	catch(act::Exception& ACT_DEBUG_PARAM(e))
	{
		ACT_TRACE(e, "SecureTokenEngine::rsa_encrypt");
	}
	
	return retlen;
}

int SecureTokenEngine::rsa_decrypt(int flen, const unsigned char *from, unsigned char *to, CardKey* ck, int padding)
{
	if(padding != RSA_PKCS1_PADDING)
	{
		ACT_TRACE("SecureTokenEngine::rsa_decrypt: Only RSA_PKCS1_PADDING allowed so far\n");
		return -1;
	}
	
	if(ck == NULL)
	{
		ACT_TRACE("SecureTokenEngine::rsa_decrypt: No CardKey given\n");
		return -1;
	}
	
	act::IToken* token = ck->getKey()->GetToken();
	SecOpGuard guard(token);
	act::Synchronize lock(*token);
	
	if(!ck->Authenticate(guard))
		return -1;
		
	act::Blob _ciphertext(from, from+flen);
	act::Blob _plaintext;
	int retlen = -1;

	try
	{
		act::Algorithm alg(ck->getKey(), act::DECRYPT);
		alg << _ciphertext << act::final >> _plaintext;
		retlen = _plaintext.size();

		// Same as with rsa_encrypt
		std::copy(_plaintext.begin(), _plaintext.end(), to);
	}
	catch(act::Exception& ACT_DEBUG_PARAM(e))
	{
		ACT_TRACE(e, "SecureTokenEngine::rsa_decrypt");
	}
	
	return retlen;
}

int SecureTokenEngine::rsa_sign(int type, const unsigned char *msg, unsigned int msglen, unsigned char *sigret, unsigned int *siglen, CardKey* ck)
{
	if(ck == NULL)
	{
		ACT_TRACE("SecureTokenEngine::rsa_sign: No CardKey given\n");
		return 0;
	}
	
	act::IToken* token = ck->getKey()->GetToken();
	SecOpGuard guard(ck->getKey()->GetToken());
	act::Synchronize lock(*token);

	if(!ck->Authenticate(guard))
		return 0;

	act::Blob _plaintext(msg, msg+msglen);
	act::Blob _signature;
	unsigned int _siglen = 0;

	// In that case the hashing is already done and we just need the lowlevel key operation
	bool ssl = (type == NID_md5_sha1);

	act::ITokenKey* key = ck->getKey();
	act::Blob oldhash;
	key->GetParam(act::HASH, oldhash);

	if(ssl)
		key->SetParam(act::HASH, "DummyHash");

	try
	{
		act::Algorithm alg(ck->getKey(), act::SIGN);
		alg << _plaintext << act::final >> _signature;
		_siglen = _signature.size();

		// I won't repeat myself here....
		std::copy(_signature.begin(), _signature.end(), sigret);
	}
	catch(act::Exception& ACT_DEBUG_PARAM(e))
	{
		ACT_TRACE(e, "SecureTokenEngine::rsa_sign");
	}
	
	key->SetParam(act::HASH, oldhash);

	*siglen = _siglen;
	return _siglen > 0 ? 1 : 0;
}

int SecureTokenEngine::rsa_verify(int type, const unsigned char *msg, unsigned int msglen, unsigned char *signature, unsigned int siglen, const CardKey* ck)
{
	if(ck == NULL)
	{
		ACT_TRACE("SecureTokenEngine::rsa_verify: No CardKey given\n");
		return 0;
	}
	
	act::IToken* token = ck->getKey()->GetToken();
	SecOpGuard guard(token);
	act::Synchronize lock(*token);

	act::Blob _plaintext(msg, msg+msglen);
	act::Blob _signature(signature, signature+siglen);
	bool sig_ok = false;

	try
	{
		act::Algorithm alg(ck->getKey(), act::VERIFY, _signature);
		alg << _plaintext << act::final;
		sig_ok = alg.GetStatus() == act::SIGNATURE_OK;
	}
	catch(act::Exception& ACT_DEBUG_PARAM(e))
	{
		ACT_TRACE(e, "SecureTokenEngine::rsa_verify");
	}

	if(!sig_ok)
		RSAerr(RSA_F_RSA_VERIFY, RSA_R_BAD_SIGNATURE);

	return sig_ok ? 1 : 0;
}
	
int SecureTokenEngine::enumerate_certs(ENGINE *e, enum_certs_s **p)
{
	if(p == NULL)
		return 0;
		
	// Drop and free old instance (if present) and create a fresh one.
	m_cert_list.reset(new CertificateList());
	
	m_cert_list->init(m_slot_list);
	
	*p = m_cert_list->getEnumList();
	
	// Only way to return 0 would be that we ran out of memory. If there are no certificates to be found
	// we would return successful, but with an empty list (num_certs == 0)
	return *p ? 1 : 0;
}