#include <string.h>
#include <filesystem>
#include <dlfcn.h>
#include <fstream>
#include <iostream>
#include <vector>

#include "Logging.hpp"

#include "PLCObject.hpp"

#include "beremiz.h"


// File name of the last transferred PLC md5 hex digest
// with typo in the name, for compatibility with Python runtime
#define LastTransferredPLC "lasttransferedPLC.md5"

// File name of the extra files list
#define ExtraFilesList "extra_files.txt"



PLCObject::PLCObject(void)
{
    m_status.PLCstatus = Empty;
    m_handle = NULL;
    m_debugToken = 0;
    m_argc = 0;
    m_argv = NULL;
    m_PSK_ID = "";
    m_PSK_secret = "";
}

PLCObject::~PLCObject(void)
{
}

uint32_t PLCObject::AppendChunkToBlob(
    const binary_t *data, const binary_t *blobID, binary_t *newBlobID)
{
    // Append data to blob with given blobID
    // Output new blob's md5 into newBlobID
    // Return 0 if success

    newBlobID->data = (uint8_t *)malloc(MD5::digestsize);
    if (newBlobID->data == NULL)
    {
        return ENOMEM;
    }

    std::vector<uint8_t> k(blobID->data, blobID->data + blobID->dataLength);

    auto nh = m_mapBlobIDToBlob.extract(k);
    if (nh.empty())
    {
        return ENOENT;
    }

    Blob *blob = nh.mapped();

    uint32_t res = blob->appendChunk(data->data, data->dataLength);
    if (res != 0)
    {
        return res;
    }

    MD5::digest_t digest = blob->digest();

    std::vector<uint8_t> nk((uint8_t*)digest.data, (uint8_t*)digest.data + MD5::digestsize);
    nh.key() = nk;

    m_mapBlobIDToBlob.insert(std::move(nh));

    memcpy(newBlobID->data, digest.data, MD5::digestsize);
    newBlobID->dataLength = MD5::digestsize;

    return 0;
}

uint32_t PLCObject::AutoLoad()
{
    // Load PLC object
    uint32_t res = LoadPLC();
    if (res != 0)
    {
        return res;
    }

    // Start PLC object
    res = StartPLC();
    if (res != 0)
    {
        return res;
    }

    return 0;
}


#define LOG_READ_BUFFER_SIZE 1 << 10 // 1KB

uint32_t PLCObject::GetLogMessage(
    uint8_t level, uint32_t msgID, log_message *message)
{
    char buf[LOG_READ_BUFFER_SIZE];
    uint32_t tick;
    uint32_t tv_sec;
    uint32_t tv_nsec;

    uint32_t resultLen;
    if(m_status.PLCstatus == Empty){
        resultLen = 0;
    } else {
        resultLen = m_PLCSyms.GetLogMessage(
            level, msgID, buf, LOG_READ_BUFFER_SIZE - 1,
            &tick, &tv_sec, &tv_nsec);
    }

    // Get log message with given msgID
    message->msg = (char *)malloc(resultLen + 1);
    if (message->msg == NULL)
    {
        return ENOMEM;
    }
    // Copy the log message into eRPC message
    memcpy(message->msg, buf, resultLen);
    message->msg[resultLen] = '\0';

    message->tick = tick;
    message->sec = tv_sec;
    message->nsec = tv_nsec;

    return 0;
}

uint32_t PLCObject::GetPLCID(PSKID *plcID)
{
    // Get PSK ID
    plcID->ID = (char *)malloc(m_PSK_ID.size() + 1);
    if (plcID->ID == NULL)
    {
        return ENOMEM;
    }
    memcpy(plcID->ID, m_PSK_ID.c_str(), m_PSK_ID.size());
    plcID->ID[m_PSK_ID.size()] = '\0';

    // Get PSK secret
    plcID->PSK = (char *)malloc(m_PSK_secret.size() + 1);
    if (plcID->PSK == NULL)
    {
        free(plcID->ID);
        return ENOMEM;
    }
    memcpy(plcID->PSK, m_PSK_secret.c_str(), m_PSK_secret.size());
    plcID->PSK[m_PSK_secret.size()] = '\0';

    return 0;
}

uint32_t PLCObject::GetPLCstatus(PLCstatus *status)
{
    if(m_status.PLCstatus == Empty){        
        for(int lvl = 0; lvl < 4; lvl++){
            m_status.logcounts[lvl] = 0;
        }
    } else {
        // Get log counts
        for(int lvl = 0; lvl < 4; lvl++){
            m_status.logcounts[lvl] = m_PLCSyms.GetLogCount(lvl);
        }
    }
    // Get PLC status
    *status = m_status;
    return 0;
}

uint32_t PLCObject::GetTraceVariables(
    uint32_t debugToken, TraceVariables *traces)
{
    if(debugToken != m_debugToken)
    {
        return EINVAL;
    }

    // Check if there are any traces
    m_tracesMutex.lock();
    size_t sz = m_traces.size();
    if(sz > 0)
    {
        // Allocate memory for traces
        traces->traces.elements = (trace_sample *)malloc(sz * sizeof(trace_sample));
        if(traces->traces.elements == NULL)
        {
            m_tracesMutex.unlock();
            return ENOMEM;
        }
        // Copy traces from vector
        memcpy(traces->traces.elements, m_traces.data(), sz * sizeof(trace_sample));

        // Clear the vector
        // note that the data is not freed here, it is meant to be freed by eRPC server code
        m_traces.clear();
    }
    m_tracesMutex.unlock();

    traces->traces.elementsCount = sz;
    traces->PLCstatus = m_status.PLCstatus;

    return 0;
}

uint32_t PLCObject::MatchMD5(const char *MD5, bool *match)
{
    // an empty PLC is never considered to match
    if(m_status.PLCstatus == Empty)
    {
        *match = false;
        return 0;
    }

    // Load the last transferred PLC md5 hex digest
    std::string md5sum;
    try {
        std::ifstream(std::string(LastTransferredPLC), std::ios::binary) >> md5sum;
    } catch (std::exception e) {
        *match = false;
        return 0;
    }

    // Compare the given MD5 with the last transferred PLC md5
    *match = (md5sum == MD5);

    return 0;
}

#if defined(_WIN32) || defined(_WIN64)
// For Windows platform
#define SHARED_OBJECT_EXT ".dll"
#elif defined(__APPLE__) || defined(__MACH__)
// For MacOS platform
#define SHARED_OBJECT_EXT ".dylib"
#else
// For Linux/Unix platform
#define SHARED_OBJECT_EXT ".so"
#endif

uint32_t PLCObject::BlobAsFile(
    const binary_t *BlobID, std::filesystem::path filename)
{
    // Extract the blob from the map
    auto nh = m_mapBlobIDToBlob.extract(
        std::vector<uint8_t>(BlobID->data, BlobID->data + BlobID->dataLength));
    if (nh.empty())
    {
        return ENOENT;
    }
    Blob *blob = nh.mapped();

    // Realize the blob into a file
    uint32_t res = blob->asFile(filename);

    delete blob;

    if (res != 0)
    {
        return res;
    }
    return 0;
}

uint32_t PLCObject::NewPLC(
    const char *md5sum, const binary_t *plcObjectBlobID,
    const list_extra_file_1_t *extrafiles, bool *success)
{
    if(m_status.PLCstatus == Started)
    {
        *success = false;
        return EBUSY;
    }

    if(m_status.PLCstatus == Broken)
    {
        *success = false;
        return EINVAL;
    }

    // Unload the PLC object
    UnLoadPLC();

    // Purge the PLC object
    PurgePLC();

    // Concatenate md5sum and shared object extension to obtain filename
    std::filesystem::path filename =
        std::filesystem::path(md5sum) += SHARED_OBJECT_EXT;

    // Create the PLC object shared object file
    BlobAsFile(plcObjectBlobID, filename);

    // create "lasttransferedPLC.md5" file and Save md5sum in it
    std::ofstream(std::string(LastTransferredPLC), std::ios::binary) << md5sum;

    // create "extra_files.txt" file
    std::ofstream extra_files_log(std::string(ExtraFilesList), std::ios::binary);

    // Create extra files
    for (int i = 0; i < extrafiles->elementsCount; i++)
    {
        extra_file *extrafile = extrafiles->elements + i;

        BlobAsFile(plcObjectBlobID, extrafile->fname);

        // Save the extra file name in "extra_files.txt"
        extra_files_log << extrafile->fname << std::endl;
    }

    // Load the PLC object
    uint32_t res = LoadPLC();
    if (res != 0)
    {
        *success = false;
        return res;
    }

    m_status.PLCstatus = Stopped;
    *success = true;

    return 0;
}

#define DLSYM(sym)                                                           \
    do                                                                       \
    {                                                                        \
        m_PLCSyms.sym = (decltype(m_PLCSyms.sym))dlsym(m_handle, #sym);      \
        if (m_PLCSyms.sym == NULL)                                           \
        {                                                                    \
            /* TODO: use log instead */                                      \
            std::cout << "Error dlsym " #sym ": " << dlerror() << std::endl; \
            return errno;                                                    \
        }                                                                    \
    } while (0);

uint32_t PLCObject::LoadPLC(void)
{
    // Load the last transferred PLC md5 hex digest
    std::string md5sum;
    try {
        std::ifstream(std::string(LastTransferredPLC), std::ios::binary) >> md5sum;
    } catch (std::exception e) {
        return ENOENT;
    }

    // Concatenate md5sum and shared object extension to obtain filename
    std::filesystem::path filename(md5sum + SHARED_OBJECT_EXT);

    // Load the shared object file
    m_handle = dlopen(std::filesystem::absolute(filename).c_str(), RTLD_NOW);
    if (m_handle == NULL)
    {
        std::cout << "Error: " << dlerror() << std::endl;
        return errno;
    }

    // Resolve shared object symbols
    FOR_EACH_PLC_SYMBOLS_DO(DLSYM);

    // Set content of PLC_ID to md5sum
    m_PLCSyms.PLC_ID = (uint8_t *)malloc(md5sum.size() + 1);
    if (m_PLCSyms.PLC_ID == NULL)
    {
        return ENOMEM;
    }
    memcpy(m_PLCSyms.PLC_ID, md5sum.c_str(), md5sum.size());
    m_PLCSyms.PLC_ID[md5sum.size()] = '\0';

    return 0;
}

#define ULSYM(sym)            \
    do                        \
    {                         \
        m_PLCSyms.sym = NULL; \
    } while (0);

uint32_t PLCObject::UnLoadPLC(void)
{
    // Unload the shared object file
    FOR_EACH_PLC_SYMBOLS_DO(ULSYM);
    if(m_handle != NULL)
    {
        dlclose(m_handle);
        m_handle = NULL;
    }
    return 0;
}

uint32_t PLCObject::PurgeBlobs(void)
{
    // Purge all blobs

    for (auto &blob : m_mapBlobIDToBlob)
    {
        delete blob.second;
    }
    m_mapBlobIDToBlob.clear();

    return 0;
}

uint32_t PLCObject::PurgePLC(void)
{

    // Open the extra files list
    std::ifstream extra_files_log(std::string(ExtraFilesList), std::ios::binary);

    // Remove extra files
    std::string extra_file;
    while (std::getline(extra_files_log, extra_file))
    {
        std::filesystem::remove(extra_file);
    }

    // Load the last transferred PLC md5 hex digest
    std::string md5sum;
    try {
        std::ifstream(std::string(LastTransferredPLC), std::ios::binary) >> md5sum;

        // Remove the PLC object shared object file
        std::filesystem::remove(md5sum + SHARED_OBJECT_EXT);
    } catch (std::exception e) {
        // ignored
    }

    try {
        // Remove the last transferred PLC md5 hex digest
        std::filesystem::remove(std::string(LastTransferredPLC));

        // Remove the extra files list
        std::filesystem::remove(std::string(ExtraFilesList));
    } catch (std::exception e) {
        // ignored
    }

    return 0;
}

uint32_t PLCObject::RepairPLC(void)
{
    // Repair the PLC object

    if(m_status.PLCstatus == Broken)
    {
        // Unload the PLC object
        UnLoadPLC();

        // Purge the PLC object
        PurgePLC();
    }


    LogMessage(LOG_WARNING, "RepairPLC not implemented");
    return 0;
}

uint32_t PLCObject::ResetLogCount(void)
{
    m_PLCSyms.ResetLogCount();
    return 0;
}

uint32_t PLCObject::SeedBlob(const binary_t *seed, binary_t *blobID)
{
    // Create a blob with given seed
    // Output new blob's md5 into blobID
    // Return 0 if success

    Blob *blob = NULL;
    try
    {
        blob = new Blob(seed->data, seed->dataLength);
    }
    catch (int e)
    {
        return e;
    }

    MD5::digest_t digest = blob->digest();

    std::vector<uint8_t> k((uint8_t*)digest.data, (uint8_t*)digest.data + MD5::digestsize);

    m_mapBlobIDToBlob[k] = blob;

    blobID->data = (uint8_t *)malloc(MD5::digestsize);
    if (blobID->data == NULL)
    {
        return ENOMEM;
    }
    memcpy(blobID->data, digest.data, MD5::digestsize);
    blobID->dataLength = MD5::digestsize;

    return 0;
}
void PLCObject::PurgeTraceBuffer(void)
{
    // Free trace buffer
    m_tracesMutex.lock();
    for(trace_sample s : m_traces){
        free(s.TraceBuffer.data);
    }
    m_traces.clear();
    m_tracesMutex.unlock();
}

uint32_t PLCObject::SetTraceVariablesList(
    const list_trace_order_1_t *orders, int32_t *debugtoken)
{
    if(m_status.PLCstatus == Empty)
    {
        return EINVAL;
    }

    // increment debug token
    m_debugToken++;

    if(orders->elementsCount == 0)
    {
        // actually disables debug
        m_PLCSyms.suspendDebug(1);
        *debugtoken = -5; // DEBUG_SUSPENDED
        return 0;
    }

    // suspend debug before any operation
    int res = m_PLCSyms.suspendDebug(0);
    if(res == 0)
    {
        // forget about all previous debug variables
        m_PLCSyms.ResetDebugVariables();

        // call RegisterTraceVariables for each trace order
        for (int i = 0; i < orders->elementsCount; i++)
        {
            trace_order *order = orders->elements + i;
            res = m_PLCSyms.RegisterDebugVariable(order->idx, order->force.data, order->force.dataLength);
            if(res != 0)
            {
                // if any error, disable debug
                // since debug is already suspended, resume it first
                m_PLCSyms.resumeDebug();
                m_PLCSyms.suspendDebug(1);
                *debugtoken = -res;
                return EINVAL;
            }
        }

        // old traces are not valid anymore
        PurgeTraceBuffer();

        // Start debug thread if not already started
        if(!m_traceThread.joinable())
        {
            m_traceThread = std::thread(&PLCObject::TraceThreadProc, this);
        }

        m_PLCSyms.resumeDebug();
        *debugtoken = m_debugToken;
        return 0;
    }
    return res;
}

uint32_t PLCObject::StartPLC(void)
{
    LogMessage(LOG_INFO, "Starting PLC");
    uint32_t res = m_PLCSyms.startPLC(m_argc, m_argv);
    if(res != 0)
    {
        m_status.PLCstatus = Broken;
        return res;
    }
    m_status.PLCstatus = Started;

    return 0;
}

uint32_t PLCObject::StopPLC(bool *success)
{
    LogMessage(LOG_INFO, "Stopping PLC");
    uint32_t res = m_PLCSyms.stopPLC();
    if(res == 0)
    {
        m_status.PLCstatus = Stopped;
    } else {
        m_status.PLCstatus = Broken;
    }

    // Stop debug thread
    if(m_traceThread.joinable())
    {
        m_traceThread.join();
    }

    return res;
}

uint32_t PLCObject::LogMessage(uint8_t level, std::string message)
{
    // if PLC isn't loaded, log to stdout
    if(m_PLCSyms.LogMessage == NULL)
    {
        std::cout << level << message << std::endl;
        return ENOSYS;
    }

    // Log std::string message with given level
    return m_PLCSyms.LogMessage(level, (char *)message.c_str(), message.size());
}

void PLCObject::TraceThreadProc(void)
{
    uint32_t err = 0;

    m_PLCSyms.resumeDebug();

    while(m_status.PLCstatus == Started)
    {
        unsigned int tick;
        unsigned int size;
        void * buff;

        // Data allocated here is meant to be freed by eRPC server code
        uint8_t* ourData = NULL;

        m_PLClibMutex.lock();

        int res = m_PLCSyms.GetDebugData(&tick, &size, &buff);

        if(res == 0)
        {   
            ourData = (uint8_t *)malloc(size);
            if(ourData != NULL)
            {
                memcpy(ourData, buff, size);
            }
            m_PLCSyms.FreeDebugData();
        }

        m_PLClibMutex.unlock();

        if(ourData == NULL)
        {
            err = res == 0 ? ENOMEM : res;
            break;

        } else {   

            m_tracesMutex.lock();

            m_traces.push_back(trace_sample{tick, binary_t{ourData, size}});

            m_tracesMutex.unlock();
        }
    }

    PurgeTraceBuffer();

    LogMessage(err ? LOG_CRITICAL : LOG_INFO,
        err == ENOMEM ? "Out of memory in TraceThreadProc" : 
        err ? "TraceThreadProc ended because of error" : 
        "TraceThreadProc ended normally");
}