#include "kabufuda/Card.hpp"
#include "kabufuda/SRAM.hpp"
#include <stdio.h>
#include <string.h>
#include <algorithm>
#include <memory>

namespace kabufuda
{

IFileHandle::~IFileHandle()
{
}

class FileHandle : public IFileHandle
{
    friend class Card;
    const char* game;
    const char* maker;
    const char* filename;
    int32_t offset =0;
public:
    FileHandle() = default;
    FileHandle(const char* game, const char* maker, const char* filename)
        : game(game),
          maker(maker),
          filename(filename)
    {}
    virtual ~FileHandle();
};

FileHandle::~FileHandle()
{}


void Card::swapEndian()
{
    m_formatTime = SBig(m_formatTime);
    m_sramBias = SBig(m_sramBias);
    m_sramLanguage = SBig(m_sramLanguage);
    m_unknown = SBig(m_unknown);
    m_deviceId = SBig(m_deviceId);
    m_sizeMb = SBig(m_sizeMb);
    m_encoding = SBig(m_encoding);
    m_updateCounter = SBig(m_updateCounter);
    m_checksum = SBig(m_checksum);
    m_checksumInv = SBig(m_checksumInv);
}

Card::Card()
{
    memset(__raw, 0xFF, BlockSize);
}

Card::Card(const SystemString& filename, const char* game, const char* maker)
    : m_filename(filename)
{
    memset(__raw, 0xFF, BlockSize);
    if (game && strlen(game) == 4)
        memcpy(m_game, game, 4);
    if (maker && strlen(maker) == 2)
        memcpy(m_maker, maker, 2);

    m_fileHandle = Fopen(m_filename.c_str(), _S("rb"));
    if (m_fileHandle)
    {
        fread(__raw, 1, BlockSize, m_fileHandle);
        m_maxBlock = m_sizeMb * MbitToBlocks;
        swapEndian();
        fread(m_dir.__raw, 1, BlockSize, m_fileHandle);
        fread(m_dirBackup.__raw, 1, BlockSize, m_fileHandle);
        fread(m_bat.__raw, 1, BlockSize, m_fileHandle);
        fread(m_batBackup.__raw, 1, BlockSize, m_fileHandle);

        m_dir.swapEndian();
        m_dirBackup.swapEndian();
        m_bat.swapEndian();
        m_batBackup.swapEndian();

        /* Check for data integrity, restoring valid data in case of corruption if possible */
        if (!m_dir.valid() && m_dirBackup.valid())
            m_dir = m_dirBackup;
        else if (!m_dirBackup.valid() && m_dir.valid())
            m_dirBackup = m_dir;
        if (!m_bat.valid() && m_batBackup.valid())
            m_bat = m_batBackup;
        else if (!m_batBackup.valid() && m_bat.valid())
            m_batBackup = m_bat;

        if (m_dir.m_updateCounter > m_dirBackup.m_updateCounter)
        {
            m_currentDir = &m_dir;
            m_previousDir = &m_dirBackup;
        }
        else
        {
            m_currentDir = &m_dirBackup;
            m_previousDir = &m_dir;
        }

        if (m_bat.m_updateCounter > m_batBackup.m_updateCounter)
        {
            m_currentBat = &m_bat;
            m_previousBat = &m_batBackup;
        }
        else
        {
            m_currentBat = &m_batBackup;
            m_previousBat = &m_bat;
        }

        /* Close and reopen in read/write mode */
        fclose(m_fileHandle);
        m_fileHandle = Fopen(m_filename.c_str(), _S("r+"));
    }
}

Card::~Card()
{
    commit();
    if (m_fileHandle)
        fclose(m_fileHandle);
    m_fileHandle = nullptr;
}

std::unique_ptr<IFileHandle> Card::openFile(const char* filename)
{
    File* f = m_currentDir->getFile(m_game, m_maker, filename);
    if (f)
        return std::unique_ptr<IFileHandle>(new FileHandle(m_game, m_maker, filename));
    return nullptr;
}

void Card::updateDirAndBat()
{
    Directory updateDir = *m_currentDir;
    updateDir.m_updateCounter++;
    *m_previousDir = updateDir;
    std::swap(m_currentDir, m_previousDir);

    BlockAllocationTable updateBat = *m_currentBat;
    updateBat.m_updateCounter++;
    *m_previousBat = updateBat;
    std::swap(m_currentBat, m_previousBat);
}

std::unique_ptr<IFileHandle> Card::createFile(const char* filename, size_t size)
{
    updateDirAndBat();
    File* f = m_currentDir->getFirstFreeFile(m_game, m_maker, filename);
    uint16_t block = m_currentBat->allocateBlocks(uint16_t(size / BlockSize), m_maxBlock);
    if (f && block != 0xFFFF)
    {
        f->m_modifiedTime = uint32_t(getGCTime());
        f->m_firstBlock = block;
        f->m_blockCount = uint16_t(size / BlockSize);


        return std::unique_ptr<FileHandle>(new FileHandle(m_game, m_maker, filename));
    }
    return nullptr;
}

void Card::deleteFile(const std::unique_ptr<IFileHandle> &fh)
{
    updateDirAndBat();
    if (!fh)
        return;
    FileHandle* f = dynamic_cast<FileHandle*>(fh.get());
    uint16_t block = m_currentDir->getFile(f->game, f->maker, f->filename)->m_firstBlock;

    while(block != 0xFFFF)
    {
        /* TODO: add a fragmentation check */
        uint16_t nextBlock = m_currentBat->getNextBlock(block);
        m_currentBat->clear(block, 1);
        block = nextBlock;
    }
    *m_currentDir->getFile(f->game, f->maker, f->filename) = File();

}

void Card::write(const std::unique_ptr<IFileHandle>& fh, const void* buf, size_t size)
{
    if (!fh)
        return;

    if (m_fileHandle)
    {
        FileHandle* f = dynamic_cast<FileHandle*>(fh.get());
        File* file = m_currentDir->getFile(f->game, f->maker, f->filename);
        if (!file)
            return;

        /* Block handling is a little different from cache handling,
         * since each block can be in an arbitrary location we must
         * first find our starting block.
         */
        const uint16_t blockId = uint16_t(f->offset / BlockSize);
        uint16_t block = file->m_firstBlock;
        for (uint16_t i = 0; i < blockId; i++)
            block = m_currentBat->getNextBlock(block);

        const uint8_t* tmpBuf = reinterpret_cast<const uint8_t*>(buf);
        uint16_t curBlock = block;
        uint32_t blockOffset = f->offset % BlockSize;
        size_t rem = size;
        while (rem)
        {
            if (curBlock == 0xFFFF)
                return;

            size_t cacheSize = rem;
            if (cacheSize + blockOffset > BlockSize)
                cacheSize = BlockSize - blockOffset;
            uint32_t offset = (curBlock * BlockSize) + blockOffset;
            fseek(m_fileHandle, offset, SEEK_SET);
            fwrite(tmpBuf, 1, cacheSize, m_fileHandle);
            tmpBuf += cacheSize;
            rem -= cacheSize;
            blockOffset += cacheSize;
            if (blockOffset >= BlockSize)
            {
                curBlock = m_currentBat->getNextBlock(curBlock);
                blockOffset = 0;
            }
        }
        f->offset += size;
    }
}

void Card::read(const std::unique_ptr<IFileHandle> &fh, void *dst, size_t size)
{
    if (!fh)
        return;

    if (m_fileHandle)
    {
        FileHandle* f = dynamic_cast<FileHandle*>(fh.get());
        File* file = m_currentDir->getFile(f->game, f->maker, f->filename);
        if (!file)
            return;
        /* Block handling is a little different from cache handling,
         * since each block can be in an arbitrary location we must
         * first find our starting block.
         */
        const uint16_t blockId = uint16_t(f->offset / BlockSize);
        uint16_t block = file->m_firstBlock;
        for (uint16_t i = 0; i < blockId; i++)
            block = m_currentBat->getNextBlock(block);

        uint8_t* tmpBuf = reinterpret_cast<uint8_t*>(dst);
        uint16_t curBlock = block;
        uint32_t blockOffset = f->offset % BlockSize;
        size_t rem = size;
        while (rem)
        {
            if (curBlock == 0xFFFF)
                return;

            size_t cacheSize = rem;
            if (cacheSize + blockOffset > BlockSize)
                cacheSize = BlockSize - blockOffset;
            uint32_t offset = (curBlock * BlockSize) + blockOffset;
            fseek(m_fileHandle, offset, SEEK_SET);
            fread(tmpBuf, 1, cacheSize, m_fileHandle);
            tmpBuf += cacheSize;
            rem -= cacheSize;
            blockOffset += cacheSize;
            if (blockOffset >= BlockSize)
            {
                curBlock = m_currentBat->getNextBlock(curBlock);
                blockOffset = 0;
            }
        }
        f->offset += size;
    }
}

void Card::seek(const std::unique_ptr<IFileHandle> &fh, int32_t pos, SeekOrigin whence)
{
    if (!fh)
        return;

    FileHandle* f = dynamic_cast<FileHandle*>(fh.get());
    File* file = m_currentDir->getFile(f->game, f->maker, f->filename);
    if (!file)
        return;

    switch(whence)
    {
    case SeekOrigin::Begin:
        f->offset = pos;
        break;
    case SeekOrigin::Current:
        f->offset += pos;
        break;
    case SeekOrigin::End:
        f->offset = int32_t(file->m_blockCount * BlockSize) - pos;
        break;
    }
}

void Card::setGame(const char* game)
{
    if (game == nullptr)
    {
        memset(m_game, 0, 2);
        return;
    }

    if (strlen(game) != 4)
        return;

    memcpy(m_game, game, 4);
}

const uint8_t* Card::getGame() const
{
    if (strlen(m_game) == 4)
        return reinterpret_cast<const uint8_t*>(m_game);

    return nullptr;
}

void Card::setMaker(const char* maker)
{
    if (maker == nullptr)
    {
        memset(m_maker, 0, 2);
        return;
    }

    if (strlen(maker) != 2)
        return;

    memcpy(m_maker, maker, 2);
}

const uint8_t* Card::getMaker() const
{
    if (strlen(m_maker) == 2)
        return reinterpret_cast<const uint8_t*>(m_maker);
    return nullptr;
}

void Card::getSerial(uint32_t *s0, uint32_t *s1)
{
    uint32_t serial[8];
    for (uint32_t i = 0; i < 8; i++)
        memcpy(&serial[i], reinterpret_cast<uint8_t*>(m_serial + (i * 4)), 4);
    *s0 = serial[0] ^ serial[2] ^ serial[4] ^ serial[6];
    *s1 = serial[1] ^ serial[3] ^ serial[5] ^ serial[7];
}

void Card::getChecksum(uint16_t* checksum, uint16_t* inverse)
{
    *checksum = m_checksum;
    *inverse = m_checksumInv;
}

void Card::format(EDeviceId id, ECardSize size, EEncoding encoding)
{
    memset(__raw, 0xFF, BlockSize);
    uint64_t rand = uint64_t(getGCTime());
    m_formatTime = rand;
    for (int i = 0; i < 12; i++)
    {
        rand = (((rand * uint64_t(0x41c64e6d)) + uint64_t(0x3039)) >> 16);
        m_serial[i] = uint8_t(g_SRAM.flash_id[uint32_t(id)][i] + uint32_t(rand));
        rand = (((rand * uint64_t(0x41c64e6d)) + uint64_t(0x3039)) >> 16);
        rand &= uint64_t(0x7fffULL);
    }

    m_sramBias   = int32_t(SBig(g_SRAM.counter_bias));
    m_sramLanguage = uint32_t(SBig(g_SRAM.lang));
    m_unknown    = 0; /* 1 works for slot A, 0 both */
    m_deviceId    = 0;
    m_sizeMb      = uint16_t(size);
    m_maxBlock    = m_sizeMb * MbitToBlocks;
    m_encoding    = uint16_t(encoding);
    calculateChecksum(reinterpret_cast<uint16_t*>(__raw), 0xFE, &m_checksum, &m_checksumInv);
    m_dir         = Directory();
    m_dirBackup   = m_dir;
    m_bat         = BlockAllocationTable(uint32_t(size) * MbitToBlocks);
    m_batBackup   = m_bat;
    m_currentDir  = &m_dirBackup;
    m_previousDir = &m_dir;
    m_currentBat  = &m_batBackup;
    m_previousBat = &m_bat;

    if (!m_fileHandle)
        m_fileHandle = Fopen(m_filename.c_str(), _S("wb"));

    if (m_fileHandle)
    {
        swapEndian();
        fwrite(__raw, 1, BlockSize, m_fileHandle);
        swapEndian();
        Directory tmpDir = m_dir;
        tmpDir.swapEndian();
        fwrite(tmpDir.__raw, 1, BlockSize, m_fileHandle);
        tmpDir = m_dirBackup;
        tmpDir.swapEndian();
        fwrite(tmpDir.__raw, 1, BlockSize, m_fileHandle);
        BlockAllocationTable tmpBat = m_bat;
        tmpBat.swapEndian();
        fwrite(tmpBat.__raw, 1, BlockSize, m_fileHandle);
        tmpBat = m_batBackup;
        tmpBat.swapEndian();
        fwrite(tmpBat.__raw, 1, BlockSize, m_fileHandle);
        uint32_t dataLen = ((uint32_t(size) * MbitToBlocks) - 5) * BlockSize;
        std::unique_ptr<uint8_t[]> data(new uint8_t[dataLen]);
        memset(data.get(), 0xFF, dataLen);
        fwrite(data.get(), 1, dataLen, m_fileHandle);
        fclose(m_fileHandle);
        m_fileHandle = Fopen(m_filename.c_str(), _S("r+"));
    }
}

uint32_t Card::getSizeMbitFromFile(const SystemString& filename)
{
    Sstat stat;
    Stat(filename.c_str(), &stat);
    return uint32_t(stat.st_size / BlockSize) / MbitToBlocks;
}

void Card::commit()
{
    if (m_fileHandle)
    {
        rewind(m_fileHandle);

        swapEndian();
        fwrite(__raw, 1, BlockSize, m_fileHandle);
        swapEndian();
        Directory tmpDir = m_dir;
        tmpDir.updateChecksum();
        tmpDir.swapEndian();
        fwrite(tmpDir.__raw, 1, BlockSize, m_fileHandle);
        tmpDir = m_dirBackup;
        tmpDir.updateChecksum();
        tmpDir.swapEndian();
        fwrite(tmpDir.__raw, 1, BlockSize, m_fileHandle);
        BlockAllocationTable tmpBat = m_bat;
        tmpBat.updateChecksum();
        tmpBat.swapEndian();
        fwrite(tmpBat.__raw, 1, BlockSize, m_fileHandle);
        tmpBat = m_batBackup;
        tmpBat.updateChecksum();
        tmpBat.swapEndian();
        fwrite(tmpBat.__raw, 1, BlockSize, m_fileHandle);
    }
}

Card::operator bool() const
{
    if (m_fileHandle == nullptr)
        return false;

    uint16_t ckSum, ckSumInv;
    calculateChecksum(reinterpret_cast<const uint16_t*>(__raw), 0xFE, &ckSum, &ckSumInv);
    if (ckSum != m_checksum || ckSumInv != m_checksumInv)
        return false;
    if (!m_dir.valid() && !m_dirBackup.valid())
        return false;
    if (!m_bat.valid() && !m_batBackup.valid())
        return false;

    return true;
}

File::File(char data[])
{
    memcpy(__raw, data, 0x40);
}

File::File(const char* filename)
{
    memset(__raw, 0xFF, 0x40);
    memset(m_filename, 0, 32);
    size_t len = strlen(filename);
    len = std::min<size_t>(len, 32);
    memcpy(m_filename, filename, len);
}
void File::swapEndian()
{
    m_modifiedTime = SBig(m_modifiedTime);
    m_imageOffset = SBig(m_imageOffset);
    m_iconFmt = SBig(m_iconFmt);
    m_animSpeed = SBig(m_animSpeed);
    m_firstBlock = SBig(m_firstBlock);
    m_blockCount = SBig(m_blockCount);
    m_reserved2 = SBig(m_reserved2);
    m_commentAddr = SBig(m_commentAddr);
}

File::File()
{
    memset(__raw, 0xFF, 0x40);
}

void BlockAllocationTable::swapEndian()
{
    m_checksum = SBig(m_checksum);
    m_checksumInv = SBig(m_checksumInv);
    m_updateCounter = SBig(m_updateCounter);
    m_freeBlocks = SBig(m_freeBlocks);
    m_lastAllocated = SBig(m_lastAllocated);
    std::for_each(std::begin(m_map), std::end(m_map), [](uint16_t& val){
        val = SBig(val);
    });
}

void BlockAllocationTable::updateChecksum()
{
    calculateChecksum(reinterpret_cast<uint16_t*>(__raw + 4), 0xFFE, &m_checksum, &m_checksumInv);
}

bool BlockAllocationTable::valid() const
{
    uint16_t ckSum, ckSumInv;
    calculateChecksum(reinterpret_cast<const uint16_t*>(__raw + 4), 0xFFE, &ckSum, &ckSumInv);
    return (ckSum == m_checksum && ckSumInv == m_checksumInv);
}

BlockAllocationTable::BlockAllocationTable(uint32_t blockCount)
{
    memset(__raw, 0, BlockSize);
    m_freeBlocks = uint16_t(blockCount - FSTBlocks);
    m_lastAllocated = 4;
    updateChecksum();
}

uint16_t BlockAllocationTable::getNextBlock(uint16_t block) const
{
    if ((block < FSTBlocks) || (block > (BATSize - FSTBlocks)))
        return 0;

    return m_map[block - FSTBlocks];
}

uint16_t BlockAllocationTable::nextFreeBlock(uint16_t maxBlock, uint16_t startingBlock) const
{
    if (m_freeBlocks > 0)
    {
        maxBlock = std::min(maxBlock, uint16_t(BATSize));
        for (uint16_t i = startingBlock; i < maxBlock; ++i)
            if (m_map[i - FSTBlocks] == 0)
                return i;

        for (uint16_t i = FSTBlocks; i < startingBlock; ++i)
            if (m_map[i - FSTBlocks] == 0)
                return i;
    }

    return 0xFFFF;
}

bool BlockAllocationTable::clear(uint16_t first, uint16_t count)
{
    std::vector<uint16_t> blocks;
    while (first != 0xFFFF && first != 0)
    {
        blocks.push_back(first);
        first = getNextBlock(first);
    }
    if (first > 0)
    {
        size_t length = blocks.size();
        if (length != count)
            return false;

        for (size_t i= 0 ; i < length ; ++i)
            m_map[blocks.at(i) - FSTBlocks] = 0;
        m_freeBlocks += count;
        return true;
    }
    return false;
}

uint16_t BlockAllocationTable::allocateBlocks(uint16_t count, uint16_t maxBlocks)
{
    uint16_t firstBlock = nextFreeBlock(maxBlocks - FSTBlocks, m_lastAllocated + 1);
    uint16_t freeBlock = firstBlock;
    if (freeBlock != 0xFFFF)
    {
        uint16_t tmpCount = count;
        while ((count--) > 0)
        {
            m_map[(freeBlock - FSTBlocks)] = 0xFFFF;
            if (count != 0)
            {
                m_map[(freeBlock - FSTBlocks)] = nextFreeBlock(maxBlocks - FSTBlocks, m_lastAllocated + 1);
                freeBlock = m_map[(freeBlock - FSTBlocks)];
            }
            m_lastAllocated = freeBlock;
        }

        m_freeBlocks -= tmpCount;
    }
    return firstBlock;
}

void Directory::swapEndian()
{
    std::for_each(std::begin(m_files), std::end(m_files), [](File& f){
        f.swapEndian();
    });

    m_updateCounter = SBig(m_updateCounter);
    m_checksum = SBig(m_checksum);
    m_checksumInv = SBig(m_checksumInv);
}

void Directory::updateChecksum()
{
    calculateChecksum(reinterpret_cast<uint16_t*>(__raw), 0xFFE, &m_checksum, &m_checksumInv);
}

bool Directory::valid() const
{
    uint16_t ckSum, ckSumInv;
    calculateChecksum(reinterpret_cast<const uint16_t*>(__raw), 0xFFE, &ckSum, &ckSumInv);
    return (ckSum == m_checksum && ckSumInv == m_checksumInv);
}

Directory::Directory()
{
    memset(__raw, 0xFF, BlockSize);
    m_updateCounter = 0;
    updateChecksum();
}

Directory::Directory(uint8_t data[])
{
    memcpy(__raw, data, BlockSize);
}

Directory::Directory(const Directory& other)
{
    memcpy(__raw, other.__raw, BlockSize);
}

void Directory::operator=(const Directory& other)
{
    memcpy(__raw, other.__raw, BlockSize);
}

File* Directory::getFirstFreeFile(const char* game, const char* maker, const char* filename)
{
    for (uint16_t i = 0 ; i < 127 ; i++)
    {
        if (m_files[i].m_id[0] == 0xFF)
        {
            File* ret = &m_files[i];
            *ret = File(filename);
            if (game && strlen(game) == 4)
                memcpy(ret->m_id, game, 4);
            if (maker && strlen(maker) == 2)
                memcpy(ret->m_maker, maker, 2);
            return ret;
        }
    }

    return nullptr;
}

File* Directory::getFile(const char* game, const char* maker, const char* filename)
{
    for (uint16_t i = 0 ; i < 127 ; i++)
    {
        if (game && strlen(game) == 4 && memcmp(m_files[i].m_id, game, 4))
            continue;
        if (maker && strlen(maker) == 2 && memcmp(m_files[i].m_maker, maker, 2))
            continue;
        if (!strcmp(m_files[i].m_filename, filename))
            return &m_files[i];
    }

    return nullptr;
}

void calculateChecksum(const uint16_t* data, size_t len, uint16_t* checksum, uint16_t* checksumInv)
{
    *checksum = 0;
    *checksumInv = 0;
    for (size_t i = 0; i < len; ++i)
    {
        *checksum += data[i];
        *checksumInv += data[i] ^ 0xFFFF;
    }
    *checksum = *checksum;
    *checksumInv = *checksumInv;
    if (*checksum == 0xFFFF)
        *checksum = 0;
    if (*checksumInv == 0xFFFF)
        *checksumInv = 0;
}
}