#ifndef __TRANSACTIONENGINE__
#define __TRANSACTIONENGINE__

#include <boost/tuple/tuple.hpp>
#include <boost/tuple/tuple_comparison.hpp>
#include <boost/unordered_set.hpp>
#include <boost/unordered_map.hpp>

#include "Ledger.h"
#include "SerializedTransaction.h"
#include "SerializedLedger.h"
#include "LedgerEntrySet.h"
#include "TransactionErr.h"

// A TransactionEngine applies serialized transactions to a ledger
// It can also, verify signatures, verify fees, and give rejection reasons

enum TransactionEngineParams
{
	tapNONE				= 0x00,

	tapNO_CHECK_SIGN	= 0x01,	// Signature already checked

	tapOPEN_LEDGER		= 0x10,	// Transaction is running against an open ledger
		// true = failures are not forwarded, check transaction fee
		// false = debit ledger for consumed funds

	tapRETRY			= 0x20,	// This is not the transaction's last pass
		// Transaction can be retried, soft failures allowed
};

class PaymentNode {
protected:
	friend class TransactionEngine;
	friend class PathState;

	uint16							uFlags;				// --> From path.

	uint160							uAccountID;			// --> Accounts: Recieving/sending account.
	uint160							uCurrencyID;		// --> Accounts: Receive and send, Offers: send.
														// --- For offer's next has currency out.
	uint160							uIssuerID;			// --> Currency's issuer

	STAmount						saTransferRate;		// Transfer rate for uIssuerID.

	// Computed by Reverse.
	STAmount						saRevRedeem;		// <-- Amount to redeem to next.
	STAmount						saRevIssue;			// <-- Amount to issue to next limited by credit and outstanding IOUs.
														//     Issue isn't used by offers.
	STAmount						saRevDeliver;		// <-- Amount to deliver to next regardless of fee.

	// Computed by forward.
	STAmount						saFwdRedeem;		// <-- Amount node will redeem to next.
	STAmount						saFwdIssue;			// <-- Amount node will issue to next.
														//	   Issue isn't used by offers.
	STAmount						saFwdDeliver;		// <-- Amount to deliver to next regardless of fee.

	// For offers:

	STAmount						saRateMax;			// XXX Should rate be sticky for forward too?

	// Directory
	uint256							uDirectTip;			// Current directory.
	uint256							uDirectEnd;			// Next order book.
	bool							bDirectAdvance;		// Need to advance directory.
	SLE::pointer					sleDirectDir;
	STAmount						saOfrRate;			// For correct ratio.

	// Node
	bool							bEntryAdvance;		// Need to advance entry.
	unsigned int					uEntry;
	uint256							uOfferIndex;
	SLE::pointer					sleOffer;
	uint160							uOfrOwnerID;
	bool							bFundsDirty;		// Need to refresh saOfferFunds, saTakerPays, & saTakerGets.
	STAmount						saOfferFunds;
	STAmount						saTakerPays;
	STAmount						saTakerGets;
};

// account id, currency id, issuer id :: node
typedef boost::tuple<uint160, uint160, uint160> aciSource;
typedef boost::unordered_map<aciSource, unsigned int>					curIssuerNode;	// Map of currency, issuer to node index.
typedef boost::unordered_map<aciSource, unsigned int>::const_iterator	curIssuerNodeConstIterator;

extern std::size_t hash_value(const aciSource& asValue);

// Holds a path state under incremental application.
class PathState
{
protected:
	Ledger::pointer				mLedger;

	TER		pushNode(const int iType, const uint160& uAccountID, const uint160& uCurrencyID, const uint160& uIssuerID);
	TER		pushImply(const uint160& uAccountID, const uint160& uCurrencyID, const uint160& uIssuerID);

public:
	typedef boost::shared_ptr<PathState> pointer;

	TER							terStatus;
	std::vector<PaymentNode>	vpnNodes;

	// When processing, don't want to complicate directory walking with deletion.
	std::vector<uint256>		vUnfundedBecame;	// Offers that became unfunded or were completely consumed.

	// First time scanning foward, as part of path contruction, a funding source was mentioned for accounts. Source may only be
	// used there.
	curIssuerNode				umForward;			// Map of currency, issuer to node index.

	// First time working in reverse a funding source was used.
	// Source may only be used there if not mentioned by an account.
	curIssuerNode				umReverse;			// Map of currency, issuer to node index.

	LedgerEntrySet				lesEntries;

	int							mIndex;
	uint64						uQuality;			// 0 = none.
	STAmount					saInReq;			// Max amount to spend by sender
	STAmount					saInAct;			// Amount spent by sender (calc output)
	STAmount					saOutReq;			// Amount to send (calc input)
	STAmount					saOutAct;			// Amount actually sent (calc output).

	PathState(
		Ledger::ref				lpLedger,
		const int				iIndex,
		const LedgerEntrySet&	lesSource,
		const STPath&			spSourcePath,
		const uint160&			uReceiverID,
		const uint160&			uSenderID,
		const STAmount&			saSend,
		const STAmount&			saSendMax
		);

	Json::Value	getJson() const;

	static PathState::pointer createPathState(
		Ledger::ref				lpLedger,
		const int				iIndex,
		const LedgerEntrySet&	lesSource,
		const STPath&			spSourcePath,
		const uint160&			uReceiverID,
		const uint160&			uSenderID,
		const STAmount&			saSend,
		const STAmount&			saSendMax
		)
	{
		return boost::make_shared<PathState>(lpLedger, iIndex, lesSource, spSourcePath, uReceiverID, uSenderID, saSend, saSendMax);
	}

	static bool lessPriority(const PathState::pointer& lhs, const PathState::pointer& rhs);
};

// One instance per ledger.
// Only one transaction applied at a time.
class TransactionEngine
{
private:
	LedgerEntrySet						mNodes;

	TER	setAuthorized(const SerializedTransaction& txn, bool bMustSetGenerator);

	TER takeOffers(
		bool				bPassive,
		const uint256&		uBookBase,
		const uint160&		uTakerAccountID,
		const SLE::pointer&	sleTakerAccount,
		const STAmount&		saTakerPays,
		const STAmount&		saTakerGets,
		STAmount&			saTakerPaid,
		STAmount&			saTakerGot);

protected:
	Ledger::pointer		mLedger;

	uint160				mTxnAccountID;
	SLE::pointer		mTxnAccount;

	// First time working in reverse a funding source was mentioned.  Source may only be used there.
	curIssuerNode		mumSource;	// Map of currency, issuer to node index.

	// When processing, don't want to complicate directory walking with deletion.
	std::vector<uint256>			mvUnfundedBecame;	// Offers that became unfunded.

	// If the transaction fails to meet some constraint, still need to delete unfunded offers.
	boost::unordered_set<uint256>	musUnfundedFound;	// Offers that were found unfunded.

	SLE::pointer		entryCreate(LedgerEntryType type, const uint256& index)		{ return mNodes.entryCreate(type, index); }
	SLE::pointer		entryCache(LedgerEntryType type, const uint256& index)		{ return mNodes.entryCache(type, index); }
	void				entryDelete(SLE::ref sleEntry)								{ mNodes.entryDelete(sleEntry); }
	void				entryModify(SLE::ref sleEntry)								{ mNodes.entryModify(sleEntry); }

	TER					offerDelete(const uint256& uOfferIndex);
	TER					offerDelete(const SLE::pointer& sleOffer, const uint256& uOfferIndex, const uint160& uOwnerID);

	uint32				rippleTransferRate(const uint160& uIssuerID);
	STAmount			rippleOwed(const uint160& uToAccountID, const uint160& uFromAccountID, const uint160& uCurrencyID);
	STAmount			rippleLimit(const uint160& uToAccountID, const uint160& uFromAccountID, const uint160& uCurrencyID);
	uint32				rippleQualityIn(const uint160& uToAccountID, const uint160& uFromAccountID, const uint160& uCurrencyID, const SOE_Field sfLow=sfLowQualityIn, const SOE_Field sfHigh=sfHighQualityIn);
	uint32				rippleQualityOut(const uint160& uToAccountID, const uint160& uFromAccountID, const uint160& uCurrencyID)
	{ return rippleQualityIn(uToAccountID, uFromAccountID, uCurrencyID, sfLowQualityOut, sfHighQualityOut); }

	STAmount			rippleHolds(const uint160& uAccountID, const uint160& uCurrencyID, const uint160& uIssuerID);
	STAmount			rippleTransferFee(const uint160& uSenderID, const uint160& uReceiverID, const uint160& uIssuerID, const STAmount& saAmount);
	void				rippleCredit(const uint160& uSenderID, const uint160& uReceiverID, const STAmount& saAmount, bool bCheckIssuer=true);
	STAmount			rippleSend(const uint160& uSenderID, const uint160& uReceiverID, const STAmount& saAmount);

	STAmount			accountHolds(const uint160& uAccountID, const uint160& uCurrencyID, const uint160& uIssuerID);
	void				accountSend(const uint160& uSenderID, const uint160& uReceiverID, const STAmount& saAmount);
	STAmount			accountFunds(const uint160& uAccountID, const STAmount& saDefault);

	PathState::pointer	pathCreate(const STPath& spPath);
	void				pathNext(const PathState::pointer& pspCur, const int iPaths, const LedgerEntrySet& lesCheckpoint);
	TER					calcNode(const unsigned int uIndex, const PathState::pointer& pspCur, const bool bMultiQuality);
	TER					calcNodeRev(const unsigned int uIndex, const PathState::pointer& pspCur, const bool bMultiQuality);
	TER					calcNodeFwd(const unsigned int uIndex, const PathState::pointer& pspCur, const bool bMultiQuality);
	TER					calcNodeOfferRev(const unsigned int uIndex, const PathState::pointer& pspCur, const bool bMultiQuality);
	TER					calcNodeOfferFwd(const unsigned int uIndex, const PathState::pointer& pspCur, const bool bMultiQuality);
	TER					calcNodeAccountRev(const unsigned int uIndex, const PathState::pointer& pspCur, const bool bMultiQuality);
	TER					calcNodeAccountFwd(const unsigned int uIndex, const PathState::pointer& pspCur, const bool bMultiQuality);
	TER					calcNodeAdvance(const unsigned int uIndex, const PathState::pointer& pspCur, const bool bMultiQuality, const bool bReverse);
	TER					calcNodeDeliverRev(
							const unsigned int			uIndex,
							const PathState::pointer&	pspCur,
							const bool					bMultiQuality,
							const uint160&				uOutAccountID,
							const STAmount&				saOutReq,
							STAmount&					saOutAct);

	TER					calcNodeDeliverFwd(
							const unsigned int			uIndex,
							const PathState::pointer&	pspCur,
							const bool					bMultiQuality,
							const uint160&				uInAccountID,
							const STAmount&				saInFunds,
							const STAmount&				saInReq,
							STAmount&					saInAct,
							STAmount&					saInFees);

	void				calcNodeRipple(const uint32 uQualityIn, const uint32 uQualityOut,
							const STAmount& saPrvReq, const STAmount& saCurReq,
							STAmount& saPrvAct, STAmount& saCurAct,
							uint64& uRateMax);

	void				txnWrite();

	TER					doAccountSet(const SerializedTransaction& txn);
	TER					doClaim(const SerializedTransaction& txn);
	TER					doCreditSet(const SerializedTransaction& txn);
	TER					doInvoice(const SerializedTransaction& txn);
	TER					doOfferCreate(const SerializedTransaction& txn);
	TER					doOfferCancel(const SerializedTransaction& txn);
	TER					doNicknameSet(const SerializedTransaction& txn);
	TER					doPasswordFund(const SerializedTransaction& txn);
	TER					doPasswordSet(const SerializedTransaction& txn);
	TER					doPayment(const SerializedTransaction& txn);
	TER					doWalletAdd(const SerializedTransaction& txn);
	TER					doContractAdd(const SerializedTransaction& txn);
	TER					doContractRemove(const SerializedTransaction& txn);

public:
	TransactionEngine() { ; }
	TransactionEngine(Ledger::ref ledger) : mLedger(ledger) { assert(mLedger); }

	Ledger::pointer getLedger()			{ return mLedger; }
	void setLedger(Ledger::ref ledger)	{ assert(ledger); mLedger = ledger; }

	TER applyTransaction(const SerializedTransaction&, TransactionEngineParams);
};

inline TransactionEngineParams operator|(const TransactionEngineParams& l1, const TransactionEngineParams& l2)
{
	return static_cast<TransactionEngineParams>(static_cast<int>(l1) | static_cast<int>(l2));
}

inline TransactionEngineParams operator&(const TransactionEngineParams& l1, const TransactionEngineParams& l2)
{
	return static_cast<TransactionEngineParams>(static_cast<int>(l1) & static_cast<int>(l2));
}

#endif
// vim:ts=4