// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2013 The Bitcoin Core developers
// Copyright (c) 2016-2024 The Hush developers
// Distributed under the GPLv3 software license, see the accompanying
// file COPYING or https://www.gnu.org/licenses/gpl-3.0.en.html

/******************************************************************************
 * Copyright © 2014-2019 The SuperNET Developers.                             *
 *                                                                            *
 * See the AUTHORS, DEVELOPER-AGREEMENT and LICENSE files at                  *
 * the top-level directory of this distribution for the individual copyright  *
 * holder information and the developer policies on copyright and licensing.  *
 *                                                                            *
 * Unless otherwise agreed in a custom licensing agreement, no part of the    *
 * SuperNET software, including this file may be copied, modified, propagated *
 * or distributed except according to the terms contained in the LICENSE file *
 *                                                                            *
 * Removal or modification of this copyright notice is prohibited.            *
 *                                                                            *
 ******************************************************************************/

#ifndef HUSH_STREAMS_H
#define HUSH_STREAMS_H

#include "support/allocators/zeroafterfree.h"
#include "serialize.h"

#include <algorithm>
#include <assert.h>
#include <ios>
#include <limits>
#include <map>
#include <set>
#include <stdint.h>
#include <stdio.h>
#include <string>
#include <string.h>
#include <utility>
#include <vector>

template<typename Stream>
class OverrideStream
{
    Stream* stream;

    const int nType;
    const int nVersion;

public:
    OverrideStream(Stream* stream_, int nType_, int nVersion_) : stream(stream_), nType(nType_), nVersion(nVersion_) {}

    template<typename T>
    OverrideStream<Stream>& operator<<(const T& obj)
    {
        // Serialize to this stream
        ::Serialize(*this, obj);
        return (*this);
    }

    template<typename T>
    OverrideStream<Stream>& operator>>(T&& obj)
    {
        // Unserialize from this stream
        ::Unserialize(*this, obj);
        return (*this);
    }

    void write(const char* pch, size_t nSize)
    {
        stream->write(pch, nSize);
    }

    void read(char* pch, size_t nSize)
    {
        stream->read(pch, nSize);
    }

    int GetVersion() const { return nVersion; }
    int GetType() const { return nType; }
    size_t size() const { return stream->size(); }
    void ignore(size_t size) { return stream->ignore(size); }
};

template<typename S>
OverrideStream<S> WithVersion(S* s, int nVersion)
{
    return OverrideStream<S>(s, s->GetType(), nVersion);
}

/* Minimal stream for overwriting and/or appending to an existing byte vector
 *
 * The referenced vector will grow as necessary
 */
class CVectorWriter
{
 public:

/*
 * @param[in]  nTypeIn Serialization Type
 * @param[in]  nVersionIn Serialization Version (including any flags)
 * @param[in]  vchDataIn  Referenced byte vector to overwrite/append
 * @param[in]  nPosIn Starting position. Vector index where writes should start. The vector will initially
 *                    grow as necessary to max(nPosIn, vec.size()). So to append, use vec.size().
*/
    CVectorWriter(int nTypeIn, int nVersionIn, std::vector<unsigned char>& vchDataIn, size_t nPosIn) : nType(nTypeIn), nVersion(nVersionIn), vchData(vchDataIn), nPos(nPosIn)
    {
        if(nPos > vchData.size())
            vchData.resize(nPos);
    }
/*
 * (other params same as above)
 * @param[in]  args  A list of items to serialize starting at nPosIn.
*/
    template <typename... Args>
    CVectorWriter(int nTypeIn, int nVersionIn, std::vector<unsigned char>& vchDataIn, size_t nPosIn, Args&&... args) : CVectorWriter(nTypeIn, nVersionIn, vchDataIn, nPosIn)
    {
        ::SerializeMany(*this, std::forward<Args>(args)...);
    }
    void write(const char* pch, size_t nSize)
    {
        assert(nPos <= vchData.size());
        size_t nOverwrite = std::min(nSize, vchData.size() - nPos);
        if (nOverwrite) {
            memcpy(vchData.data() + nPos, reinterpret_cast<const unsigned char*>(pch), nOverwrite);
        }
        if (nOverwrite < nSize) {
            vchData.insert(vchData.end(), reinterpret_cast<const unsigned char*>(pch) + nOverwrite, reinterpret_cast<const unsigned char*>(pch) + nSize);
        }
        nPos += nSize;
    }
    template<typename T>
    CVectorWriter& operator<<(const T& obj)
    {
        // Serialize to this stream
        ::Serialize(*this, obj);
        return (*this);
    }
    int GetVersion() const
    {
        return nVersion;
    }
    int GetType() const
    {
        return nType;
    }
private:
    const int nType;
    const int nVersion;
    std::vector<unsigned char>& vchData;
    size_t nPos;
};


/** Double ended buffer combining vector and stream-like interfaces.
 *
 * >> and << read and write unformatted data using the above serialization templates.
 * Fills with data in linear time; some stringstream implementations take N^2 time.
 */
template<typename SerializeType>
class CBaseDataStream
{
protected:
    typedef SerializeType vector_type;
    vector_type vch;
    unsigned int nReadPos;

    int nType;
    int nVersion;
public:

    typedef typename vector_type::allocator_type   allocator_type;
    typedef typename vector_type::size_type        size_type;
    typedef typename vector_type::difference_type  difference_type;
    typedef typename vector_type::reference        reference;
    typedef typename vector_type::const_reference  const_reference;
    typedef typename vector_type::value_type       value_type;
    typedef typename vector_type::iterator         iterator;
    typedef typename vector_type::const_iterator   const_iterator;
    typedef typename vector_type::reverse_iterator reverse_iterator;

    explicit CBaseDataStream(int nTypeIn, int nVersionIn)
    {
        Init(nTypeIn, nVersionIn);
    }

    CBaseDataStream(const_iterator pbegin, const_iterator pend, int nTypeIn, int nVersionIn) : vch(pbegin, pend)
    {
        Init(nTypeIn, nVersionIn);
    }

#if !defined(_MSC_VER) || _MSC_VER >= 1300
    CBaseDataStream(const char* pbegin, const char* pend, int nTypeIn, int nVersionIn) : vch(pbegin, pend)
    {
        Init(nTypeIn, nVersionIn);
    }
#endif

    CBaseDataStream(const vector_type& vchIn, int nTypeIn, int nVersionIn) : vch(vchIn.begin(), vchIn.end())
    {
        Init(nTypeIn, nVersionIn);
    }

    CBaseDataStream(const std::vector<char>& vchIn, int nTypeIn, int nVersionIn) : vch(vchIn.begin(), vchIn.end())
    {
        Init(nTypeIn, nVersionIn);
    }

    CBaseDataStream(const std::vector<unsigned char>& vchIn, int nTypeIn, int nVersionIn) : vch(vchIn.begin(), vchIn.end())
    {
        Init(nTypeIn, nVersionIn);
    }

    template <typename... Args>
    CBaseDataStream(int nTypeIn, int nVersionIn, Args&&... args)
    {
        Init(nTypeIn, nVersionIn);
        ::SerializeMany(*this, std::forward<Args>(args)...);
    }

    void Init(int nTypeIn, int nVersionIn)
    {
        nReadPos = 0;
        nType = nTypeIn;
        nVersion = nVersionIn;
    }

    CBaseDataStream& operator+=(const CBaseDataStream& b)
    {
        vch.insert(vch.end(), b.begin(), b.end());
        return *this;
    }

    friend CBaseDataStream operator+(const CBaseDataStream& a, const CBaseDataStream& b)
    {
        CBaseDataStream ret = a;
        ret += b;
        return (ret);
    }

    std::string str() const
    {
        return (std::string(begin(), end()));
    }


    //
    // Vector subset
    //
    const_iterator begin() const                     { return vch.begin() + nReadPos; }
    iterator begin()                                 { return vch.begin() + nReadPos; }
    const_iterator end() const                       { return vch.end(); }
    iterator end()                                   { return vch.end(); }
    size_type size() const                           { return vch.size() - nReadPos; }
    bool empty() const                               { return vch.size() == nReadPos; }
    void resize(size_type n, value_type c=0)         { vch.resize(n + nReadPos, c); }
    void reserve(size_type n)                        { vch.reserve(n + nReadPos); }
    const_reference operator[](size_type pos) const  { return vch[pos + nReadPos]; }
    reference operator[](size_type pos)              { return vch[pos + nReadPos]; }
    void clear()                                     { vch.clear(); nReadPos = 0; }
    iterator insert(iterator it, const char& x=char()) { return vch.insert(it, x); }
    void insert(iterator it, size_type n, const char& x) { vch.insert(it, n, x); }

    void insert(iterator it, std::vector<char>::const_iterator first, std::vector<char>::const_iterator last)
    {
        if (last == first) return;
        assert(last - first > 0);
        if (it == vch.begin() + nReadPos && (unsigned int)(last - first) <= nReadPos)
        {
            // special case for inserting at the front when there's room
            nReadPos -= (last - first);
            memcpy(&vch[nReadPos], &first[0], last - first);
        }
        else
            vch.insert(it, first, last);
    }

#if !defined(_MSC_VER) || _MSC_VER >= 1300
    void insert(iterator it, const char* first, const char* last)
    {
        if (last == first) return;
        assert(last - first > 0);
        if (it == vch.begin() + nReadPos && (unsigned int)(last - first) <= nReadPos)
        {
            // special case for inserting at the front when there's room
            nReadPos -= (last - first);
            memcpy(&vch[nReadPos], &first[0], last - first);
        }
        else
            vch.insert(it, first, last);
    }
#endif

    iterator erase(iterator it)
    {
        if (it == vch.begin() + nReadPos)
        {
            // special case for erasing from the front
            if (++nReadPos >= vch.size())
            {
                // whenever we reach the end, we take the opportunity to clear the buffer
                nReadPos = 0;
                return vch.erase(vch.begin(), vch.end());
            }
            return vch.begin() + nReadPos;
        }
        else
            return vch.erase(it);
    }

    iterator erase(iterator first, iterator last)
    {
        if (first == vch.begin() + nReadPos)
        {
            // special case for erasing from the front
            if (last == vch.end())
            {
                nReadPos = 0;
                return vch.erase(vch.begin(), vch.end());
            }
            else
            {
                nReadPos = (last - vch.begin());
                return last;
            }
        }
        else
            return vch.erase(first, last);
    }

    inline void Compact()
    {
        vch.erase(vch.begin(), vch.begin() + nReadPos);
        nReadPos = 0;
    }

    bool Rewind(size_type n)
    {
        // Rewind by n characters if the buffer hasn't been compacted yet
        if (n > nReadPos)
            return false;
        nReadPos -= n;
        return true;
    }


    //
    // Stream subset
    //
    bool eof() const             { return size() == 0; }
    CBaseDataStream* rdbuf()         { return this; }
    int in_avail()               { return size(); }

    void SetType(int n)          { nType = n; }
    int GetType() const          { return nType; }
    void SetVersion(int n)       { nVersion = n; }
    int GetVersion() const       { return nVersion; }

    void read(char* pch, size_t nSize)
    {
        if (nSize == 0) return;

        if (pch == nullptr) {
            throw std::ios_base::failure("CBaseDataStream::read(): cannot read from null pointer");
        }

        // Read from the beginning of the buffer
        unsigned int nReadPosNext = nReadPos + nSize;
        if (nReadPosNext >= vch.size())
        {
            if (nReadPosNext > vch.size())
            {
                throw std::ios_base::failure("CBaseDataStream::read(): end of data");
            }
            memcpy(pch, &vch[nReadPos], nSize);
            nReadPos = 0;
            vch.clear();
            return;
        }
        memcpy(pch, &vch[nReadPos], nSize);
        nReadPos = nReadPosNext;
    }

    void ignore(int nSize)
    {
        // Ignore from the beginning of the buffer
        if (nSize < 0) {
            throw std::ios_base::failure("CDataStream::ignore(): nSize negative");
        }
        unsigned int nReadPosNext = nReadPos + nSize;
        if (nReadPosNext >= vch.size())
        {
            if (nReadPosNext > vch.size())
                throw std::ios_base::failure("CBaseDataStream::ignore(): end of data");
            nReadPos = 0;
            vch.clear();
            return;
        }
        nReadPos = nReadPosNext;
    }

    void write(const char* pch, size_t nSize)
    {
        // Write to the end of the buffer
        vch.insert(vch.end(), pch, pch + nSize);
    }

    template<typename Stream>
    void Serialize(Stream& s) const
    {
        // Special case: stream << stream concatenates like stream += stream
        if (!vch.empty())
            s.write((char*)&vch[0], vch.size() * sizeof(vch[0]));
    }

    template<typename T>
    CBaseDataStream& operator<<(const T& obj)
    {
        // Serialize to this stream
        ::Serialize(*this, obj);
        return (*this);
    }

    template<typename T>
    CBaseDataStream& operator>>(T&& obj)
    {
        // Unserialize from this stream
        ::Unserialize(*this, obj);
        return (*this);
    }

    void GetAndClear(CSerializeData &d) {
        d.insert(d.end(), begin(), end());
        clear();
    }
};

class CDataStream : public CBaseDataStream<CSerializeData>
{
public:
    explicit CDataStream(int nTypeIn, int nVersionIn) : CBaseDataStream(nTypeIn, nVersionIn) { }

    CDataStream(const_iterator pbegin, const_iterator pend, int nTypeIn, int nVersionIn) :
            CBaseDataStream(pbegin, pend, nTypeIn, nVersionIn) { }

#if !defined(_MSC_VER) || _MSC_VER >= 1300
    CDataStream(const char* pbegin, const char* pend, int nTypeIn, int nVersionIn) :
            CBaseDataStream(pbegin, pend, nTypeIn, nVersionIn) { }
#endif

    CDataStream(const vector_type& vchIn, int nTypeIn, int nVersionIn) :
            CBaseDataStream(vchIn, nTypeIn, nVersionIn) { }

    CDataStream(const std::vector<char>& vchIn, int nTypeIn, int nVersionIn) :
            CBaseDataStream(vchIn, nTypeIn, nVersionIn) { }

    CDataStream(const std::vector<unsigned char>& vchIn, int nTypeIn, int nVersionIn) :
            CBaseDataStream(vchIn, nTypeIn, nVersionIn) { }

    template <typename... Args>
    CDataStream(int nTypeIn, int nVersionIn, Args&&... args) :
            CBaseDataStream(nTypeIn, nVersionIn, args...) { }

};










/** Non-refcounted RAII wrapper for FILE*
 *
 * Will automatically close the file when it goes out of scope if not null.
 * If you're returning the file pointer, return file.release().
 * If you need to close the file early, use file.fclose() instead of fclose(file).
 */
class CAutoFile
{
private:
    // Disallow copies
    CAutoFile(const CAutoFile&);
    CAutoFile& operator=(const CAutoFile&);

    const int nType;
    const int nVersion;

    FILE* file;	

public:
    CAutoFile(FILE* filenew, int nTypeIn, int nVersionIn) : nType(nTypeIn), nVersion(nVersionIn)
    {
        file = filenew;
    }

    ~CAutoFile()
    {
        fclose();
    }

    void fclose()
    {
        if (file) {
            ::fclose(file);
            file = NULL;
        }
    }

    /** Get wrapped FILE* with transfer of ownership.
     * @note This will invalidate the CAutoFile object, and makes it the responsibility of the caller
     * of this function to clean up the returned FILE*.
     */
    FILE* release()             { FILE* ret = file; file = NULL; return ret; }

    /** Get wrapped FILE* without transfer of ownership.
     * @note Ownership of the FILE* will remain with this class. Use this only if the scope of the
     * CAutoFile outlives use of the passed pointer.
     */
    FILE* Get() const           { return file; }

    /** Return true if the wrapped FILE* is NULL, false otherwise.
     */
    bool IsNull() const         { return (file == NULL); }

    //
    // Stream subset
    //
    int GetType() const          { return nType; }
    int GetVersion() const       { return nVersion; }

    void read(char* pch, size_t nSize)
    {
        if (!file)
            throw std::ios_base::failure("CAutoFile::read: file handle is NULL");
        if (fread(pch, 1, nSize, file) != nSize)
            throw std::ios_base::failure(feof(file) ? "CAutoFile::read: end of file" : "CAutoFile::read: fread failed");
    }

    void ignore(size_t nSize)
    {
        if (!file)
            throw std::ios_base::failure("CAutoFile::ignore: file handle is NULL");
        unsigned char data[4096];
        while (nSize > 0) {
            size_t nNow = std::min<size_t>(nSize, sizeof(data));
            if (fread(data, 1, nNow, file) != nNow)
                throw std::ios_base::failure(feof(file) ? "CAutoFile::ignore: end of file" : "CAutoFile::read: fread failed");
            nSize -= nNow;
        }
    }

    void write(const char* pch, size_t nSize)
    {
        if (!file)
            throw std::ios_base::failure("CAutoFile::write: file handle is NULL");
        if (fwrite(pch, 1, nSize, file) != nSize)
            throw std::ios_base::failure("CAutoFile::write: write failed");
    }

    template<typename T>
    CAutoFile& operator<<(const T& obj)
    {
        // Serialize to this stream
        if (!file)
            throw std::ios_base::failure("CAutoFile::operator<<: file handle is NULL");
        ::Serialize(*this, obj);
        return (*this);
    }

    template<typename T>
    CAutoFile& operator>>(T& obj)
    {
        // Unserialize from this stream
        if (!file)
            throw std::ios_base::failure("CAutoFile::operator>>: file handle is NULL");
        ::Unserialize(*this, obj);
        return (*this);
    }
};

/** Non-refcounted RAII wrapper around a FILE* that implements a ring buffer to
 *  deserialize from. It guarantees the ability to rewind a given number of bytes.
 *
 *  Will automatically close the file when it goes out of scope if not null.
 *  If you need to close the file early, use file.fclose() instead of fclose(file).
 */
class CBufferedFile
{
private:
    // Disallow copies
    CBufferedFile(const CBufferedFile&);
    CBufferedFile& operator=(const CBufferedFile&);

    const int nType;
    const int nVersion;

    FILE *src;            // source file
    uint64_t nSrcPos;     // how many bytes have been read from source
    uint64_t nReadPos;    // how many bytes have been read from this
    uint64_t nReadLimit;  // up to which position we're allowed to read
    uint64_t nRewind;     // how many bytes we guarantee to rewind
    std::vector<char> vchBuf; // the buffer

protected:
    // read data from the source to fill the buffer
    bool Fill() {
        unsigned int pos = nSrcPos % vchBuf.size();
        unsigned int readNow = vchBuf.size() - pos;
        unsigned int nAvail = vchBuf.size() - (nSrcPos - nReadPos) - nRewind;
        if (nAvail < readNow)
            readNow = nAvail;
        if (readNow == 0)
            return false;
        size_t nBytes = fread((void*)&vchBuf[pos], 1, readNow, src);
        if (nBytes == 0) {
            throw std::ios_base::failure(feof(src) ? "CBufferedFile::Fill: end of file" : "CBufferedFile::Fill: fread failed");
        }
        nSrcPos += nBytes;
            return true;
    }

public:
    CBufferedFile(FILE *fileIn, uint64_t nBufSize, uint64_t nRewindIn, int nTypeIn, int nVersionIn) :
        nType(nTypeIn), nVersion(nVersionIn), nSrcPos(0), nReadPos(0), nReadLimit((uint64_t)(-1)), nRewind(nRewindIn), vchBuf(nBufSize, 0)
    {
        if (nRewindIn >= nBufSize)
            throw std::ios_base::failure("Rewind limit must be less than buffer size");
        src = fileIn;
    }

    ~CBufferedFile()
    {
        fclose();
    }

    int GetVersion() const { return nVersion; }
    int GetType() const { return nType; }

    void fclose()
    {
        if (src) {
            ::fclose(src);
            src = NULL;
        }
    }

    // check whether we're at the end of the source file
    bool eof() const {
        return nReadPos == nSrcPos && feof(src);
    }

    // read a number of bytes
    void read(char *pch, size_t nSize) {
        if (nSize == 0) return;

        if (pch == nullptr) {
            throw std::ios_base::failure("CBufferedFile::read(): cannot read from null pointer");
        }

        if (nSize + nReadPos > nReadLimit)
            throw std::ios_base::failure("Read attempted past buffer limit");
        while (nSize > 0) {
            if (nReadPos == nSrcPos)
                Fill();
            unsigned int pos = nReadPos % vchBuf.size();
            size_t nNow = nSize;
            if (nNow + pos > vchBuf.size())
                nNow = vchBuf.size() - pos;
            if (nNow + nReadPos > nSrcPos)
                nNow = nSrcPos - nReadPos;
            memcpy(pch, &vchBuf[pos], nNow);
            nReadPos += nNow;
            pch += nNow;
            nSize -= nNow;
        }
    }

    // return the current reading position
    uint64_t GetPos() {
        return nReadPos;
    }

    // rewind to a given reading position
    bool SetPos(uint64_t nPos) {
        size_t bufsize = vchBuf.size();
        if (nPos + bufsize < nSrcPos) {
            // rewinding too far, rewind as far as possible
            nReadPos = nSrcPos - bufsize;
            return false;
        }
        if (nPos > nSrcPos) {
            // can't go this far forward, go as far as possible
            nReadPos = nSrcPos;
            return false;
        }
        nReadPos = nPos;
        return true;
    }

    bool Seek(uint64_t nPos) {
        long nLongPos = nPos;
        if (nPos != (uint64_t)nLongPos)
            return false;
        if (fseek(src, nLongPos, SEEK_SET))
            return false;
        nLongPos = ftell(src);
        nSrcPos = nLongPos;
        nReadPos = nLongPos;
        return true;
    }

    // prevent reading beyond a certain position
    // no argument removes the limit
    bool SetLimit(uint64_t nPos = (uint64_t)(-1)) {
        if (nPos < nReadPos)
            return false;
        nReadLimit = nPos;
        return true;
    }

    template<typename T>
    CBufferedFile& operator>>(T& obj) {
        // Unserialize from this stream
        ::Unserialize(*this, obj);
        return (*this);
    }

    // search for a given byte in the stream, and remain positioned on it
    void FindByte(char ch) {
        while (true) {
            if (nReadPos == nSrcPos)
                Fill();
            if (vchBuf[nReadPos % vchBuf.size()] == ch)
                break;
            nReadPos++;
        }
    }
};

#endif // HUSH_STREAMS_H