#include <fitsio.h>
#include <cmath>
#include <filesystem>
#include "raptor_eagle_ccd.h"


/*******************************************************************************/
/*  =======  RaptorEagleCCD::AcquisitionProcess CLASS IMPLEMENTATION  =======  */
/*******************************************************************************/


namespace details
{

double JulianDay(const std::chrono::utc_clock::time_point& tm)
{
    auto stp = std::chrono::time_point{std::chrono::utc_clock::to_sys(tm)};

    const auto stp_days = std::chrono::floor<std::chrono::days>(stp);

    const std::chrono::year_month_day ymd{stp_days};

    int y = (int)ymd.year();
    unsigned m = (unsigned)ymd.month();
    unsigned D = (unsigned)ymd.day();

    if (m < 3) {
        m += 12;
        y -= 1;
    }

    // fraction of day
    double df = std::chrono::duration<double, std::ratio<86400>>(stp - stp_days).count();

    int C = static_cast<int>(2.0 - y / 100.0 + y / 400.0);
    int E = static_cast<int>(365.25 * (y + 4716.0)), F = static_cast<int>(30.6001 * (m + 1.0));

    return C + D + E + F - 1524.5 + df;
}

}  // namespace details

RaptorEagleCCD::AcquisitionProcess::AcquisitionProcess(RaptorEagleCCD* manager) : _manager(manager)
{
    std::stringstream st;
    st << std::this_thread::get_id();
    _manager->logDebug("Create acquisition process (thread id: {})", st.str());
}


RaptorEagleCCD::AcquisitionProcess::~AcquisitionProcess()
{
    std::stringstream st;
    st << std::this_thread::get_id();
    _manager->logDebug("Delete acquisition process (thread id: {})", st.str());
}


void RaptorEagleCCD::AcquisitionProcess::start(const std::shared_ptr<acq_params_t>& params)
{
    // if (isAcqInProgress) {
    //     throw std::system_error(RaptorEagleCCDError::ERROR_ACQUISITION_IN_PROGRESS);
    // }

    isAcqInProgress = true;

    // _acqParams = std::move(params);
    _acqParams = params;
    // _acqParams->abortTime = std::chrono::utc_clock::time_point();  // to ensure the time point is in past

    _snapAndCopyFuture = std::async(std::launch::async, [self = shared_from_this(), this]() {
        std::chrono::milliseconds timeout =
            CAMERA_CAPTURE_TIMEOUT_ADD_CONSTANT +
            std::chrono::milliseconds(static_cast<std::chrono::milliseconds::rep>(_acqParams->expTime * 1000));

        static char color_space[] = "Gray";
        std::stringstream st;
        st << std::this_thread::get_id();

        _manager->logDebug("Arm grabber and wait for acquisition starting trigger (thread id: {}) ...", st.str());

        _manager->xclibApiCall(pxd_doSnap(_manager->_cameraUnitmap, 1, timeout.count()),
                               std::format("pxd_doSnap({}, 1, {})", _manager->_cameraUnitmap, timeout.count()));

        _manager->logDebug("Capture is finished  (thread id: {})!", st.str());

        if ((_acqParams->abortTime > _acqParams->startTime) &&
            !_acqParams->saveInAbort) {  // abort acquisition was occured! just exit
            _manager->logInfo("It seems the acquisition was aborted! Do not save acquired image!");

            isAcqInProgress = false;

            _status = STATUS_IDLE;
            // _status = std::string(CAMERA_ATTR_CAMERA_STATUS_IDLE.begin(), CAMERA_ATTR_CAMERA_STATUS_IDLE.end());

            // _manager->_cameraStatus = CAMERA_ATTR_CAMERA_STATUS_IDLE;

            return;
        }

        _manager->logDebug("Image ROI [{}, {}, {}, {}] (binned {}x{})", _acqParams->roiStartX, _acqParams->roiStartY,
                           _acqParams->roiWidth, _acqParams->roiHeight, _acqParams->binX, _acqParams->binY);
        _manager->logDebug("Copy image from grabber to buffer (thread id: {}) ...", st.str());

        // compute image dimension
        // NOTE:  _acqParams->roiWidth and _acqParams->roiHeight are expected in CCD pixels (not binned)!!!

        // auto div = std::div(_acqParams->roiWidth - _acqParams->roiStartX, _acqParams->binX);
        auto div = std::div(_acqParams->roiWidth, _acqParams->binX);
        auto dimx = div.quot + (div.rem ? 1 : 0);
        // div = std::div(_acqParams->roiHeight - _acqParams->roiStartY, _acqParams->binY);
        div = std::div(_acqParams->roiHeight, _acqParams->binY);
        auto dimy = div.quot + (div.rem ? 1 : 0);

        // LONGLONG npix = _acqParams->roiWidth * _acqParams->roiHeight;
        LONGLONG npix = dimx * dimy;

        // NOTE:
        auto ldiv = std::lldiv(npix, _manager->_dimCCD[0]);
        _imageBufferRows = ldiv.quot + (ldiv.rem ? 1 : 0);

        bool gap = false;
        if ((_acqParams->roiWidth + _acqParams->roiStartX) < _manager->_dimCCD[0]) {
            /*  IT SEEMS IF MAX ROI X-COORDINATE IS LESS THAN CCD DIM
             *  EAGLE CAMERA CONTROLLER SETUP READING FOR WIDTH+1 ROI!!! */
            gap = true;
            ++_imageBufferRows;
        }

        // _imageBufferRows = static_cast<size_t>(std::ceil(npix / _manager->_dimCCD[0]));

        // read size
        size_t sz = _imageBufferRows * _manager->_dimCCD[0];

        try {
            // sz = _manager->_dimCCD[0] * _manager->_dimCCD[1];
            if (_imageBufferSize < sz) {
                _manager->logDebug("Reallocate image buffer to {} elements", sz);
                _imageBufferSize = sz;
                _imageBuffer.reset(new ushort[sz]);  // may thow std::bad_alloc here!
            }

            auto log_str = std::format("pxd_readushort({}, 1, 0, 0, -1, {}, {}, {}, \"{}\")", _manager->_cameraUnitmap,
                                       _imageBufferRows, (void*)_imageBuffer.get(), _imageBufferSize, color_space);

            // _manager->xclibApiCall(pxd_readushort(_manager->_cameraUnitmap, 1, 0, 0, -1, -1,
            //                                       (ushort*)_imageBuffer.get(), _imageBufferSize, (char*)color_space),
            //                        log_str);
            _manager->xclibApiCall(pxd_readushort(_manager->_cameraUnitmap, 1, 0, 0, -1, _imageBufferRows,
                                                  (ushort*)_imageBuffer.get(), _imageBufferSize, (char*)color_space),
                                   log_str);

            isAcqInProgress = false;
        } catch (...) {
            isAcqInProgress = false;

            _status = STATUS_IDLE;
            // _status = std::string(CAMERA_ATTR_CAMERA_STATUS_IDLE.begin(), CAMERA_ATTR_CAMERA_STATUS_IDLE.end());

            // _manager->_cameraStatus = CAMERA_ATTR_CAMERA_STATUS_IDLE;

            throw;
        }


        // -------   save to FITS file   --------

        if (_acqParams->filename.empty()) {
            _manager->logWarn("An empty FITS filename is given! Do not save acquired image!");

            _status = STATUS_IDLE;
            // _status = std::string(CAMERA_ATTR_CAMERA_STATUS_IDLE.begin(), CAMERA_ATTR_CAMERA_STATUS_IDLE.end());

            // _manager->_cameraStatus = CAMERA_ATTR_CAMERA_STATUS_IDLE;

            return;
        }

        _status = STATUS_SAVE;
        // _status = std::string(CAMERA_ATTR_CAMERA_STATUS_IDLE.begin(), CAMERA_ATTR_CAMERA_STATUS_IDLE.end()) +
        //           std::format(" {}", _acqParams->filename);

        // _manager->_cameraStatus = CAMERA_ATTR_CAMERA_STATUS_SAVE;

        std::string fname{"!"};  // to overwrite existing file
        fname += _acqParams->filename;

        _manager->logInfo("Try to save FITS file with name '{}'", _acqParams->filename);
        _manager->logTrace("Actual saving filename: {}", fname);

        fitsfile* fitsFilePtr;
        int status = 0;

        const int naxis = 2;
        long naxes[naxis] = {dimx, dimy};
        // long naxes[2];
        // naxes[0] = _acqParams->roiWidth;
        // naxes[1] = _acqParams->roiHeight;

        char err_str[100];

        fits_clear_errmsg();

        _manager->logDebug("Create an empty FITS file ...");
        fits_create_file(&fitsFilePtr, fname.c_str(), &status);

        _manager->logDebug("Create primary FITS HDU (dim = [{}, {}])", naxes[0], naxes[1]);
        fits_create_img(fitsFilePtr, USHORT_IMG, 2, naxes, &status);

        _manager->logDebug("Write {} pixels to the HDU ...", npix);
        if (gap) {
            /*  IT SEEMS IF MAX ROI X-COORDINATE IS LESS THAN CCD DIM
             *  EAGLE CAMERA CONTROLLER SETUP READING FOR WIDTH+1 ROI!!!
             *  SO ONE NEEDS TO WRITE IMAGE PER ROW WITH SKIPPING EXTRA PIXEL
             *  AT THE END OF EACH ROW
             */
            auto ptr = _imageBuffer.get();
            for (size_t i = 0; i < dimy; ++i) {
                fits_write_img(fitsFilePtr, TUSHORT, i * dimx + 1, dimx, _imageBuffer.get(), &status);
            }
        } else {
            fits_write_img(fitsFilePtr, TUSHORT, 1, npix, (void*)_imageBuffer.get(), &status);
        }


        // helper to convert std::string_view to C-lang null-terminated string
        auto sv2cstr = [](const std::string_view& sv) {
            static char buffer[72];
            size_t i = 0;
            for (const char& el : sv) {
                buffer[i++] = el;
            }
            buffer[i] = '\0';

            return (const char*)buffer;
        };



        // the hardcoded camera setup-related keywords

        fits_update_key_str(fitsFilePtr, "ORIGIN", "SAO RAS", NULL, &status);
        fits_update_key_str(fitsFilePtr, "CREATOR", "RaptorEagleV control software", NULL, &status);

        // fits_update_key_str(fitsFilePtr, "FILE", _acqParams->filename.c_str(), "Original filename", &status);
        std::filesystem::path pt = _acqParams->filename;
        fits_update_key_str(fitsFilePtr, "FILE", pt.filename().c_str(), "Original filename", &status);
        fits_write_date(fitsFilePtr, &status);


        std::string comm;
        std::string str = std::format("{0:%F}T{0:%H}:{0:%M}:{0:%S}", _acqParams->startTime);
        double jd = details::JulianDay(_acqParams->startTime);

        fits_update_key_str(fitsFilePtr, "DATE-OBS", str.c_str(), "Start of the exposure in UTC", &status);
        fits_update_key_dbl(fitsFilePtr, "JD", jd, -15, "Julian day of exposure start time", &status);
        fits_update_key_dbl(fitsFilePtr, "MJD", jd - 2400000.5, -15, "Modified Julian day of exposure start time",
                            &status);

        if (_acqParams->startTime < _acqParams->abortTime) {  // acquisition was aborted
            std::chrono::duration<double> real_exp = _acqParams->abortTime - _acqParams->startTime;
            _manager->logTrace("Acq. start time: {}; acq. abort time: {}", _acqParams->startTime,
                               _acqParams->abortTime);
            _manager->logDebug("Exposure was stopped! Recompute the exposure duration to {} secs", real_exp.count());
            _acqParams->expTime = real_exp.count();
        }

        fits_update_key_dbl(fitsFilePtr, "EXPTIME", _acqParams->expTime, -3, "Integration time in seconds", &status);


        fits_update_key_lng(fitsFilePtr, "CRPIX1", 1, "Reference pixel along X-axis", &status);
        fits_update_key_lng(fitsFilePtr, "CRVAL1", 1, "Physical value of the reference pixel", &status);
        fits_update_key_lng(fitsFilePtr, "STARTX", _acqParams->roiStartX + 1,  // "+1" to convert to FITS notation
                            "Image area start pixel along X-axis [CCD pixel]", &status);


        fits_update_key_lng(fitsFilePtr, "CRPIX2", 1, "Reference pixel along Y-axis", &status);
        fits_update_key_lng(fitsFilePtr, "CRVAL2", 1, "Physical value of the reference pixel", &status);
        fits_update_key_lng(fitsFilePtr, "STARTY", _acqParams->roiStartY + 1,  // "+1" to convert to FITS notation
                            "Image area start pixel along Y-axis [CCD pixel]", &status);

        fits_update_key_lng(fitsFilePtr, "XBIN", _acqParams->binX, "Horizontal binning", &status);
        fits_update_key_lng(fitsFilePtr, "YBIN", _acqParams->binY, "Vertical binning", &status);
        str = std::format("{}x{}", _acqParams->binX, _acqParams->binY);
        fits_update_key_str(fitsFilePtr, "BINNING", str.c_str(), "Binning mode (XBINxYBIN)", &status);

        comm = "Shutter state: ";
        comm += _acqParams->shutterState == CAMERA_ATTR_SHUTTER_STATE_CLOSED ? "always closed"
                : _acqParams->shutterState == CAMERA_ATTR_SHUTTER_STATE_OPEN ? "always open"
                : _acqParams->shutterState == CAMERA_ATTR_SHUTTER_STATE_EXP  ? "open for exposure duration time"
                                                                             : "unknown";
        fits_update_key_str(fitsFilePtr, "SHUTTER", sv2cstr(_acqParams->shutterState), comm.c_str(), &status);

        comm = "Camera readout rate ";
        comm += _acqParams->readRate == CAMERA_ATTR_READ_RATE_FAST   ? "(2 MHz)"
                : _acqParams->readRate == CAMERA_ATTR_READ_RATE_SLOW ? "(75 kHz)"
                                                                     : "unknown";
        fits_update_key_str(fitsFilePtr, "READRATE", sv2cstr(_acqParams->readRate), comm.c_str(), &status);

        fits_update_key_str(fitsFilePtr, "READMODE", sv2cstr(_acqParams->readMode), "Camera readout mode", &status);

        fits_update_key_str(fitsFilePtr, "GAIN", sv2cstr(_acqParams->gain), "Preamp gain", &status);

        str = _acqParams->tecState ? "ON" : "OFF";
        fits_update_key_str(fitsFilePtr, "TECSTATE", str.c_str(), "Thermoelectrical cooler state", &status);

        fits_update_key_dbl(fitsFilePtr, "CCDTEMP", _acqParams->ccdTemp, -2, "CCD chip temperature in Celsius",
                            &status);
        fits_update_key_dbl(fitsFilePtr, "PCBTEMP", _acqParams->pcbTemp, -2, "PCB temperature in Celsius", &status);
        fits_update_key_dbl(fitsFilePtr, "TECSETPT", _acqParams->tecSetPoint, -5,
                            "TEC set point temperature in Celsius", &status);

        if (!status) {
            // keywords from user template file
            if (_acqParams->templateFilename.size() && !status) {
                _manager->logDebug("Copy keywords from '{}' template file", _acqParams->templateFilename);
                fits_write_key_template(fitsFilePtr, _acqParams->templateFilename.c_str(), &status);
                if (status) {  // ignore possible errors
                    fits_get_errstatus(status, err_str);
                    _manager->logWarn(
                        "An error occured while copy keywords from the template file '{}' (err = {}, msg = {})! "
                        "Ignore!",
                        _acqParams->templateFilename, status, err_str);

                    status = 0;
                }
            }

            // permanent keywords (may update keywords from template file!)
            char card[80];
            char kname[8];
            int k_type;

            for (auto& s : _manager->_permanentFitsKeywords) {
                fits_parse_template(s.data(), card, &k_type, &status);
                if (status) {  // ignore possible errors
                    fits_get_errstatus(status, err_str);
                    _manager->logWarn(
                        "An error occured while writing permanent keyword card [{}] (err = {}, msg = {})! "
                        "Ignore!",
                        s, status, err_str);

                    status = 0;
                } else {
                    for (int i = 0; i < 8; ++i) {
                        kname[i] = card[i];
                    }
                }
                fits_update_card(fitsFilePtr, kname, card, &status);
            }

            // keyword from user (may update template file and permanent keywords!)
            for (auto& s : _manager->_currentFitsKeywords) {
                fits_parse_template(s.data(), card, &k_type, &status);
                if (status) {  // ignore possible errors
                    fits_get_errstatus(status, err_str);
                    _manager->logWarn(
                        "An error occured while writing user keyword card [{}] (err = {}, msg = {})! "
                        "Ignore!",
                        s, status, err_str);

                    status = 0;
                } else {
                    for (int i = 0; i < 8; ++i) {
                        kname[i] = card[i];
                    }
                }
                fits_update_card(fitsFilePtr, kname, card, &status);
            }
        }

        // hardcoded camera hardware version info keywords

        fits_update_key_ulng(fitsFilePtr, "SERNUM", (ULONGLONG)_manager->_cameraSerialNumber, "Camera serial number",
                             &status);

        str = std::format("{}.{}", _manager->_microVersion[0], _manager->_microVersion[1]);
        fits_update_key_str(fitsFilePtr, "MICROVER", str.c_str(), "Camera microcontroller version", &status);

        str = std::format("{}.{}", _manager->_FPGAVersion[0], _manager->_FPGAVersion[1]);
        fits_update_key_str(fitsFilePtr, "FPGAVER", str.c_str(), "Camera FPGA version", &status);

        str = std::format("{}", _manager->_buildDate);
        fits_update_key_str(fitsFilePtr, "BUILDDAT", str.c_str(), "Camera build date, YY-MM-DD", &status);

        fits_update_key_str(fitsFilePtr, "BUILDCOD", sv2cstr(_manager->_buildCode), "Camera build code", &status);


        fits_close_file(fitsFilePtr, &status);

        _status = STATUS_IDLE;
        // _status = std::string(CAMERA_ATTR_CAMERA_STATUS_IDLE.begin(), CAMERA_ATTR_CAMERA_STATUS_IDLE.end());
        // _manager->_cameraStatus = CAMERA_ATTR_CAMERA_STATUS_IDLE;

        fits_get_errstatus(status, err_str);

        if (status) {
            _manager->logError("An error occured while writing FITS file '{}'! FITS status = {} ({})",
                               _acqParams->filename, status, err_str);
        } else {
            _manager->logInfo("FITS file '{}' is saved", _acqParams->filename);
        }
    });
}


void RaptorEagleCCD::AcquisitionProcess::stop(bool save)
{
    if (isAcqInProgress) {
        _manager->logInfo("Abort current acquisition process!");

        _acqParams->saveInAbort = save;

        auto bytes = _manager->readRegisters({0xD4});  // curent trigger mode register

        bytes[0] |= CL_ABORT_CURRENT_EXP;  // set abort acquisition bit

        _acqParams->abortTime = std::chrono::utc_clock::now();
        _manager->writeRegisters({0xD4}, bytes);

    } else {
        _manager->logWarn("There was no active acquisition process! Ignore!");
    }
}


std::string RaptorEagleCCD::AcquisitionProcess::status()
{
    std::lock_guard lock(_statusMutex);

    switch (_status) {
        case STATUS_IDLE:
            _statusString = std::format("{}", CAMERA_ATTR_CAMERA_STATUS_IDLE);
            break;
        case STATUS_ACQ: {
            std::chrono::duration<double> curr_exp = std::chrono::utc_clock::now() - _acqParams->startTime;
            auto remain_exp = _acqParams->expTime - curr_exp.count();
            if (remain_exp < 0) {
                _status = STATUS_READ;
                _statusString = std::format("{} {}", CAMERA_ATTR_CAMERA_STATUS_READ, _acqParams->filename);
            } else {
                _statusString = std::format("{} {}", CAMERA_ATTR_CAMERA_STATUS_ACQ, remain_exp);
            }
            break;
        }
        case STATUS_READ:
            _statusString = std::format("{} {}", CAMERA_ATTR_CAMERA_STATUS_READ, _acqParams->filename);
            break;
        case STATUS_SAVE:
            _statusString = std::format("{} {}", CAMERA_ATTR_CAMERA_STATUS_SAVE, _acqParams->filename);
            break;
        default:
            _statusString = "UNKNOWN";  // is should not be!!!
    }

    return _statusString;
}