// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2015 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_PRIMITIVES_TRANSACTION_H
#define BITCOIN_PRIMITIVES_TRANSACTION_H

#include "amount.h"
#include "script/script.h"
#include "serialize.h"
#include "uint256.h"

/** Transaction types */
enum {
    TRANSACTION_NORMAL = 0,
    TRANSACTION_PROVIDER_REGISTER = 1,
    TRANSACTION_PROVIDER_UPDATE_SERVICE = 2,
    TRANSACTION_PROVIDER_UPDATE_REGISTRAR = 3,
    TRANSACTION_PROVIDER_UPDATE_REVOKE = 4,
    TRANSACTION_COINBASE = 5,
    TRANSACTION_QUORUM_COMMITMENT = 6,
};

/** An outpoint - a combination of a transaction hash and an index n into its vout */
class COutPoint
{
public:
    uint256 hash;
    uint32_t n;

    COutPoint() { SetNull(); }
    COutPoint(uint256 hashIn, uint32_t nIn) { hash = hashIn; n = nIn; }

    ADD_SERIALIZE_METHODS;

    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action) {
        READWRITE(hash);
        READWRITE(n);
    }

    void SetNull() { hash.SetNull(); n = (uint32_t) -1; }
    bool IsNull() const { return (hash.IsNull() && n == (uint32_t) -1); }

    friend bool operator<(const COutPoint& a, const COutPoint& b)
    {
        int cmp = a.hash.Compare(b.hash);
        return cmp < 0 || (cmp == 0 && a.n < b.n);
    }

    friend bool operator==(const COutPoint& a, const COutPoint& b)
    {
        return (a.hash == b.hash && a.n == b.n);
    }

    friend bool operator!=(const COutPoint& a, const COutPoint& b)
    {
        return !(a == b);
    }

    std::string ToString() const;
    std::string ToStringShort() const;
};

/** An input of a transaction.  It contains the location of the previous
 * transaction's output that it claims and a signature that matches the
 * output's public key.
 */
class CTxIn
{
public:
    COutPoint prevout;
    CScript scriptSig;
    uint32_t nSequence;

    /* Setting nSequence to this value for every input in a transaction
     * disables nLockTime. */
    static const uint32_t SEQUENCE_FINAL = 0xffffffff;

    /* Below flags apply in the context of BIP 68*/
    /* If this flag set, CTxIn::nSequence is NOT interpreted as a
     * relative lock-time. */
    static const uint32_t SEQUENCE_LOCKTIME_DISABLE_FLAG = (1 << 31);

    /* If CTxIn::nSequence encodes a relative lock-time and this flag
     * is set, the relative lock-time has units of 512 seconds,
     * otherwise it specifies blocks with a granularity of 1. */
    static const uint32_t SEQUENCE_LOCKTIME_TYPE_FLAG = (1 << 22);

    /* If CTxIn::nSequence encodes a relative lock-time, this mask is
     * applied to extract that lock-time from the sequence field. */
    static const uint32_t SEQUENCE_LOCKTIME_MASK = 0x0000ffff;

    /* In order to use the same number of bits to encode roughly the
     * same wall-clock duration, and because blocks are naturally
     * limited to occur every 600s on average, the minimum granularity
     * for time-based relative lock-time is fixed at 512 seconds.
     * Converting from CTxIn::nSequence to seconds is performed by
     * multiplying by 512 = 2^9, or equivalently shifting up by
     * 9 bits. */
    static const int SEQUENCE_LOCKTIME_GRANULARITY = 9;

    CTxIn()
    {
        nSequence = SEQUENCE_FINAL;
    }

    explicit CTxIn(COutPoint prevoutIn, CScript scriptSigIn=CScript(), uint32_t nSequenceIn=SEQUENCE_FINAL);
    CTxIn(uint256 hashPrevTx, uint32_t nOut, CScript scriptSigIn=CScript(), uint32_t nSequenceIn=SEQUENCE_FINAL);

    ADD_SERIALIZE_METHODS;

    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action) {
        READWRITE(prevout);
        READWRITE(*(CScriptBase*)(&scriptSig));
        READWRITE(nSequence);
    }

    friend bool operator==(const CTxIn& a, const CTxIn& b)
    {
        return (a.prevout   == b.prevout &&
                a.scriptSig == b.scriptSig &&
                a.nSequence == b.nSequence);
    }

    friend bool operator!=(const CTxIn& a, const CTxIn& b)
    {
        return !(a == b);
    }

    friend bool operator<(const CTxIn& a, const CTxIn& b)
    {
        return a.prevout<b.prevout;
    }

    std::string ToString() const;
};

/** An output of a transaction.  It contains the public key that the next input
 * must be able to sign with to claim it.
 */
class CTxOut
{
public:
    CAmount nValue;
    CScript scriptPubKey;
    int nRounds;

    CTxOut()
    {
        SetNull();
    }

    CTxOut(const CAmount& nValueIn, CScript scriptPubKeyIn, int nRoundsIn = -10);

    ADD_SERIALIZE_METHODS;

    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action) {
        READWRITE(nValue);
        READWRITE(*(CScriptBase*)(&scriptPubKey));
    }

    void SetNull()
    {
        nValue = -1;
        scriptPubKey.clear();
        nRounds = -10; // an initial value, should be no way to get this by calculations
    }

    bool IsNull() const
    {
        return (nValue == -1);
    }

    bool IsEmpty() const
    {
        return (nValue == 0 && scriptPubKey.empty());
    }
    void SetEmpty()
    {
        nValue = 0;
        scriptPubKey.clear();
    }


    CAmount GetDustThreshold(const CFeeRate &minRelayTxFee) const
    {
        // "Dust" is defined in terms of CTransaction::minRelayTxFee, which has units politoshis-per-kilobyte.
        // If you'd pay more than 1/3 in fees to spend something, then we consider it dust.
        // A typical spendable txout is 34 bytes big, and will need a CTxIn of at least 148 bytes to spend
        // i.e. total is 148 + 34 = 182 bytes. Default -minrelaytxfee is 1000 duffs per kB
        // and that means that fee per spendable txout is 182 * 1000 / 1000 = 182 politoshis.
        // So dust is a spendable txout less than 546 * minRelayTxFee / 1000 (in politoshis)
        // i.e. 182 * 3 = 546 politoshis with default -minrelaytxfee = minRelayTxFee = 1000 politoshis per kB.
        if (scriptPubKey.IsUnspendable())
            return 0;

        size_t nSize = GetSerializeSize(*this, SER_DISK, 0)+148u;
        return 3*minRelayTxFee.GetFee(nSize);
    }

    bool IsDust(const CFeeRate &minRelayTxFee) const
    {
        return (nValue < GetDustThreshold(minRelayTxFee));
    }

    friend bool operator==(const CTxOut& a, const CTxOut& b)
    {
        return (a.nValue       == b.nValue &&
                a.scriptPubKey == b.scriptPubKey &&
                a.nRounds      == b.nRounds);
    }

    friend bool operator!=(const CTxOut& a, const CTxOut& b)
    {
        return !(a == b);
    }

    std::string ToString() const;
};

struct CMutableTransaction;

/** The basic transaction that is broadcasted on the network and contained in
 * blocks.  A transaction can contain multiple inputs and outputs.
 */
class CTransaction
{
public:
    // Default transaction version.
    static const int32_t CURRENT_VERSION=2;

    // Changing the default transaction version requires a two step process: first
    // adapting relay policy by bumping MAX_STANDARD_VERSION, and then later date
    // bumping the default CURRENT_VERSION at which point both CURRENT_VERSION and
    // MAX_STANDARD_VERSION will be equal.
    static const int32_t MAX_STANDARD_VERSION=3;

    // The local variables are made const to prevent unintended modification
    // without updating the cached hash value. However, CTransaction is not
    // actually immutable; deserialization and assignment are implemented,
    // and bypass the constness. This is safe, as they update the entire
    // structure, including the hash.
    const int16_t nVersion;
    const int16_t nType;
    const std::vector<CTxIn> vin;
    const std::vector<CTxOut> vout;
    const uint32_t nLockTime;
    const std::vector<uint8_t> vExtraPayload; // only available for special transaction types

private:
    /** Memory only. */
    const uint256 hash;

    uint256 ComputeHash() const;

public:
    /** Construct a CTransaction that qualifies as IsNull() */
    CTransaction();

    /** Convert a CMutableTransaction into a CTransaction. */
    CTransaction(const CMutableTransaction &tx);
    CTransaction(CMutableTransaction &&tx);

    template <typename Stream>
    inline void Serialize(Stream& s) const {
        int32_t n32bitVersion = this->nVersion | (this->nType << 16);
        s << n32bitVersion;
        s << vin;
        s << vout;
        s << nLockTime;
        if (this->nVersion == 3 && this->nType != TRANSACTION_NORMAL)
            s << vExtraPayload;
    }

    /** This deserializing constructor is provided instead of an Unserialize method.
     *  Unserialize is not possible, since it would require overwriting const fields. */
    template <typename Stream>
    CTransaction(deserialize_type, Stream& s) : CTransaction(CMutableTransaction(deserialize, s)) {}

    bool IsNull() const {
        return vin.empty() && vout.empty();
    }

    const uint256& GetHash() const {
        return hash;
    }

    // Return sum of txouts.
    CAmount GetValueOut() const;
    // GetValueIn() is a method on CCoinsViewCache, because
    // inputs must be known to compute value in.

    /**
     * Get the total transaction size in bytes, including witness data.
     * "Total Size" defined in BIP141 and BIP144.
     * @return Total transaction size in bytes
     */
    unsigned int GetTotalSize() const;

    bool IsCoinBase() const
    {
        return (vin.size() == 1 && vin[0].prevout.IsNull());
    }

    bool IsCoinStake() const
    {
        // ppcoin: the coin stake transaction is marked with the first output empty
        return (vin.size() > 0 && (!vin[0].prevout.IsNull()) && vout.size() >= 2 && vout[0].IsEmpty());
    }

    friend bool operator==(const CTransaction& a, const CTransaction& b)
    {
        return a.hash == b.hash;
    }

    friend bool operator!=(const CTransaction& a, const CTransaction& b)
    {
        return a.hash != b.hash;
    }

    std::string ToString() const;
};

/** A mutable version of CTransaction. */
struct CMutableTransaction
{
    int16_t nVersion;
    int16_t nType;
    std::vector<CTxIn> vin;
    std::vector<CTxOut> vout;
    uint32_t nLockTime;
    std::vector<uint8_t> vExtraPayload; // only available for special transaction types

    CMutableTransaction();
    CMutableTransaction(const CTransaction& tx);

    ADD_SERIALIZE_METHODS;

    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action) {
        int32_t n32bitVersion = this->nVersion | (this->nType << 16);
        READWRITE(n32bitVersion);
        if (ser_action.ForRead()) {
            this->nVersion = (int16_t) (n32bitVersion & 0xffff);
            this->nType = (int16_t) ((n32bitVersion >> 16) & 0xffff);
        }
        READWRITE(vin);
        READWRITE(vout);
        READWRITE(nLockTime);
        if (this->nVersion == 3 && this->nType != TRANSACTION_NORMAL) {
            READWRITE(vExtraPayload);
        }
    }

    template <typename Stream>
    CMutableTransaction(deserialize_type, Stream& s) {
        Unserialize(s);
    }

    /** Compute the hash of this CMutableTransaction. This is computed on the
     * fly, as opposed to GetHash() in CTransaction, which uses a cached result.
     */
    uint256 GetHash() const;

    std::string ToString() const;

    friend bool operator==(const CMutableTransaction& a, const CMutableTransaction& b)
    {
        return a.GetHash() == b.GetHash();
    }

    friend bool operator!=(const CMutableTransaction& a, const CMutableTransaction& b)
    {
        return !(a == b);
    }

};

typedef std::shared_ptr<const CTransaction> CTransactionRef;
static inline CTransactionRef MakeTransactionRef() { return std::make_shared<const CTransaction>(); }
template <typename Tx> static inline CTransactionRef MakeTransactionRef(Tx&& txIn) { return std::make_shared<const CTransaction>(std::forward<Tx>(txIn)); }

/** Implementation of BIP69
 * https://github.com/bitcoin/bips/blob/master/bip-0069.mediawiki
 */
struct CompareInputBIP69
{
    inline bool operator()(const CTxIn& a, const CTxIn& b) const
    {
        if (a.prevout.hash == b.prevout.hash) return a.prevout.n < b.prevout.n;

        uint256 hasha = a.prevout.hash;
        uint256 hashb = b.prevout.hash;

        typedef std::reverse_iterator<const unsigned char*> rev_it;
        rev_it rita = rev_it(hasha.end());
        rev_it ritb = rev_it(hashb.end());

        return std::lexicographical_compare(rita, rita + hasha.size(), ritb, ritb + hashb.size());
    }
};

struct CompareOutputBIP69
{
    inline bool operator()(const CTxOut& a, const CTxOut& b) const
    {
        return a.nValue < b.nValue || (a.nValue == b.nValue && a.scriptPubKey < b.scriptPubKey);
    }
};

#endif // BITCOIN_PRIMITIVES_TRANSACTION_H
