// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-present 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_SCRIPT_SIGN_H
#define BITCOIN_SCRIPT_SIGN_H

#include <attributes.h>
#include <consensus/amount.h>
#include <pubkey.h>
#include <script/interpreter.h>
#include <script/keyorigin.h>
#include <script/script.h>
#include <script/signingprovider.h>
#include <uint256.h>

#include <cstdint>
#include <map>
#include <optional>
#include <set>
#include <utility>
#include <vector>

class COutPoint;
class CTxIn;
class CTxOut;
class Coin;

struct bilingual_str;
struct CMutableTransaction;
struct SignatureData;

struct SignOptions {
    int sighash_type{SIGHASH_DEFAULT};
};

/** Interface for signature creators. */
class BaseSignatureCreator {
public:
    virtual ~BaseSignatureCreator() = default;
    virtual const BaseSignatureChecker& Checker() const =0;

    /** Create a singular (non-script) signature. */
    virtual bool CreateSig(const SigningProvider& provider, std::vector<unsigned char>& vchSig, const CKeyID& keyid, const CScript& scriptCode, SigVersion sigversion) const =0;
    virtual bool CreateSchnorrSig(const SigningProvider& provider, std::vector<unsigned char>& sig, const XOnlyPubKey& pubkey, const uint256* leaf_hash, const uint256* merkle_root, SigVersion sigversion) const =0;
    virtual std::vector<uint8_t> CreateMuSig2Nonce(const SigningProvider& provider, const CPubKey& aggregate_pubkey, const CPubKey& script_pubkey, const CPubKey& part_pubkey, const uint256* leaf_hash, const uint256* merkle_root, SigVersion sigversion, const SignatureData& sigdata) const =0;
    virtual bool CreateMuSig2PartialSig(const SigningProvider& provider, uint256& partial_sig, const CPubKey& aggregate_pubkey, const CPubKey& script_pubkey, const CPubKey& part_pubkey, const uint256* leaf_hash, const std::vector<std::pair<uint256, bool>>& tweaks, SigVersion sigversion, const SignatureData& sigdata) const =0;
    virtual bool CreateMuSig2AggregateSig(const std::vector<CPubKey>& participants, std::vector<uint8_t>& sig, const CPubKey& aggregate_pubkey, const CPubKey& script_pubkey, const uint256* leaf_hash, const std::vector<std::pair<uint256, bool>>& tweaks, SigVersion sigversion, const SignatureData& sigdata) const =0;
};

/** A signature creator for transactions. */
class MutableTransactionSignatureCreator : public BaseSignatureCreator
{
    const CMutableTransaction& m_txto;
    unsigned int nIn;
    SignOptions m_options;
    CAmount amount;
    const MutableTransactionSignatureChecker checker;
    const PrecomputedTransactionData* m_txdata;

    std::optional<uint256> ComputeSchnorrSignatureHash(const uint256* leaf_hash, SigVersion sigversion) const;

public:
    MutableTransactionSignatureCreator(const CMutableTransaction& tx LIFETIMEBOUND, unsigned int input_idx, const CAmount& amount, const SignOptions& options);
    MutableTransactionSignatureCreator(const CMutableTransaction& tx LIFETIMEBOUND, unsigned int input_idx, const CAmount& amount, const PrecomputedTransactionData* txdata, const SignOptions& options);
    const BaseSignatureChecker& Checker() const override { return checker; }
    bool CreateSig(const SigningProvider& provider, std::vector<unsigned char>& vchSig, const CKeyID& keyid, const CScript& scriptCode, SigVersion sigversion) const override;
    bool CreateSchnorrSig(const SigningProvider& provider, std::vector<unsigned char>& sig, const XOnlyPubKey& pubkey, const uint256* leaf_hash, const uint256* merkle_root, SigVersion sigversion) const override;
    std::vector<uint8_t> CreateMuSig2Nonce(const SigningProvider& provider, const CPubKey& aggregate_pubkey, const CPubKey& script_pubkey, const CPubKey& part_pubkey, const uint256* leaf_hash, const uint256* merkle_root, SigVersion sigversion, const SignatureData& sigdata) const override;
    bool CreateMuSig2PartialSig(const SigningProvider& provider, uint256& partial_sig, const CPubKey& aggregate_pubkey, const CPubKey& script_pubkey, const CPubKey& part_pubkey, const uint256* leaf_hash, const std::vector<std::pair<uint256, bool>>& tweaks, SigVersion sigversion, const SignatureData& sigdata) const override;
    bool CreateMuSig2AggregateSig(const std::vector<CPubKey>& participants, std::vector<uint8_t>& sig, const CPubKey& aggregate_pubkey, const CPubKey& script_pubkey, const uint256* leaf_hash, const std::vector<std::pair<uint256, bool>>& tweaks, SigVersion sigversion, const SignatureData& sigdata) const override;
};

/** A signature checker that accepts all signatures */
extern const BaseSignatureChecker& DUMMY_CHECKER;
/** A signature creator that just produces 71-byte empty signatures. */
extern const BaseSignatureCreator& DUMMY_SIGNATURE_CREATOR;
/** A signature creator that just produces 72-byte empty signatures. */
extern const BaseSignatureCreator& DUMMY_MAXIMUM_SIGNATURE_CREATOR;

typedef std::pair<CPubKey, std::vector<unsigned char>> SigPair;

// This struct contains information from a transaction input and also contains signatures for that input.
// The information contained here can be used to create a signature and is also filled by ProduceSignature
// in order to construct final scriptSigs and scriptWitnesses.
struct SignatureData {
    bool complete = false; ///< Stores whether the scriptSig and scriptWitness are complete
    bool witness = false; ///< Stores whether the input this SigData corresponds to is a witness input
    CScript scriptSig; ///< The scriptSig of an input. Contains complete signatures or the traditional partial signatures format
    CScript redeem_script; ///< The redeemScript (if any) for the input
    CScript witness_script; ///< The witnessScript (if any) for the input. witnessScripts are used in P2WSH outputs.
    CScriptWitness scriptWitness; ///< The scriptWitness of an input. Contains complete signatures or the traditional partial signatures format. scriptWitness is part of a transaction input per BIP 144.
    TaprootSpendData tr_spenddata; ///< Taproot spending data.
    std::optional<TaprootBuilder> tr_builder; ///< Taproot tree used to build tr_spenddata.
    std::map<CKeyID, SigPair> signatures; ///< BIP 174 style partial signatures for the input. May contain all signatures necessary for producing a final scriptSig or scriptWitness.
    std::map<CKeyID, std::pair<CPubKey, KeyOriginInfo>> misc_pubkeys;
    std::vector<unsigned char> taproot_key_path_sig; /// Schnorr signature for key path spending
    std::map<std::pair<XOnlyPubKey, uint256>, std::vector<unsigned char>> taproot_script_sigs; ///< (Partial) schnorr signatures, indexed by XOnlyPubKey and leaf_hash.
    std::map<XOnlyPubKey, std::pair<std::set<uint256>, KeyOriginInfo>> taproot_misc_pubkeys; ///< Miscellaneous Taproot pubkeys involved in this input along with their leaf script hashes and key origin data. Also includes the Taproot internal and output keys (may have no leaf script hashes).
    std::map<CKeyID, XOnlyPubKey> tap_pubkeys; ///< Misc Taproot pubkeys involved in this input, by hash. (Equivalent of misc_pubkeys but for Taproot.)
    std::vector<CKeyID> missing_pubkeys; ///< KeyIDs of pubkeys which could not be found
    std::vector<CKeyID> missing_sigs; ///< KeyIDs of pubkeys for signatures which could not be found
    uint160 missing_redeem_script; ///< ScriptID of the missing redeemScript (if any)
    uint256 missing_witness_script; ///< SHA256 of the missing witnessScript (if any)
    std::map<std::vector<uint8_t>, std::vector<uint8_t>> sha256_preimages; ///< Mapping from a SHA256 hash to its preimage provided to solve a Script
    std::map<std::vector<uint8_t>, std::vector<uint8_t>> hash256_preimages; ///< Mapping from a HASH256 hash to its preimage provided to solve a Script
    std::map<std::vector<uint8_t>, std::vector<uint8_t>> ripemd160_preimages; ///< Mapping from a RIPEMD160 hash to its preimage provided to solve a Script
    std::map<std::vector<uint8_t>, std::vector<uint8_t>> hash160_preimages; ///< Mapping from a HASH160 hash to its preimage provided to solve a Script
    //! Map MuSig2 aggregate pubkeys to its participants
    std::map<CPubKey, std::vector<CPubKey>> musig2_pubkeys;
    //! Mapping from pair of MuSig2 aggregate pubkey, and tapleaf hash to map of MuSig2 participant pubkeys to MuSig2 public nonce
    std::map<std::pair<CPubKey, uint256>, std::map<CPubKey, std::vector<uint8_t>>> musig2_pubnonces;
    //! Mapping from pair of MuSig2 aggregate pubkey, and tapleaf hash to map of MuSig2 participant pubkeys to MuSig2 partial signature
    std::map<std::pair<CPubKey, uint256>, std::map<CPubKey, uint256>> musig2_partial_sigs;

    SignatureData() = default;
    explicit SignatureData(const CScript& script) : scriptSig(script) {}
    void MergeSignatureData(SignatureData sigdata);
};

/** Produce a script signature using a generic signature creator. */
bool ProduceSignature(const SigningProvider& provider, const BaseSignatureCreator& creator, const CScript& scriptPubKey, SignatureData& sigdata);

/** Extract signature data from a transaction input, and insert it. */
SignatureData DataFromTransaction(const CMutableTransaction& tx, unsigned int nIn, const CTxOut& txout);
void UpdateInput(CTxIn& input, const SignatureData& data);

/** Check whether a scriptPubKey is known to be segwit. */
bool IsSegWitOutput(const SigningProvider& provider, const CScript& script);

/** Sign the CMutableTransaction */
bool SignTransaction(CMutableTransaction& mtx, const SigningProvider* provider, const std::map<COutPoint, Coin>& coins, const SignOptions& options, std::map<int, bilingual_str>& input_errors);

#endif // BITCOIN_SCRIPT_SIGN_H
