#include <cstdint>
#include <thread>
#include <array>
#include <string>
#include <tuple>
#include <sstream>
#include <Windows.h>
#include <chrono>
#include <vector>
using namespace std::literals::chrono_literals;
#include "firmware_update.h"
#include "ihex_loader.h"
#include "SHA512.h"
#include <filesystem>
#include "utils.h"
#include "libusb.h"
#include "dfu_utilities.h"

// *** CRC calculation for DFU files ***
static const unsigned long crc32_table[] = {
    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
    0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
    0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
    0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
    0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
    0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
    0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
    0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
    0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
    0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
    0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
    0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
    0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
    0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
    0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
    0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
    0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
    0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
    0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
    0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
    0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
    0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
    0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
    0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
    0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
    0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
    0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
    0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
    0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
    0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
    0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
    0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
    0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
    0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
    0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
    0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
    0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
    0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
    0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
    0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d };

static uint32_t crc32_byte(uint32_t accum, uint8_t delta)
{
    return crc32_table[(accum ^ delta) & 0xff] ^ (accum >> 8);
}

bool firmware_update::mcu_update_available(std::string current_version)
{
    // simply compare to the saved "newest_mcu_fw" to see if an update is needed
    // version strings use semantic versioning (major.minor.patch) 
    // the semver is converted to an integer 
    semver_decode curver(current_version);
    semver_decode updatever(latest_firmware_version);

    return (updatever > curver);
}

bool firmware_update::dfu_update_available(std::string current_version)
{
    // No semantic versioning
    // Check if latest file is greater than current
    int current = 0;
    int latest = 0;

    if (!current_version.empty() && !latest_dfu_version.empty())
    {
        // Convert to integers
        try
        {
            current = std::stoi(current_version);
            latest = std::stoi(latest_dfu_version);
        }
        catch (...) {}
    }

    return (latest > current);
}

// File format:
// - 1st byte: length of version string
// - next bytes are the version string (variable length)
// - then 4 bytes for the Flash start address of the firmware (little-endian,
//		where the least significant byte is first)
// - then 4 more bytes for the length of the binary blob
// - then the binary blob itself
// - and finally, SHA512 hash of the whole file to this point, up to
//		and including the binary blob (64 bytes total for the hash)

bool firmware_update::load_firmware_file(std::wstring filepath)
{
    std::ifstream in(filepath.c_str(), std::ios::binary);
    if (in.is_open())
    {
        std::stringstream fws;
        fws << in.rdbuf();
        in.close();
        auto version_string_length = fws.str().at(0);
        auto version_string = fws.str().substr(1, version_string_length);
        uint32_t app_start_addr = 0;
        uint32_t app_binary_length = 0;
        for (uint8_t i = 0; i < 4; i++)
        {
            app_start_addr += static_cast<uint8_t>(fws.str().at(1 + version_string_length + i)) << (8 * i);
            app_binary_length += static_cast<uint8_t>(fws.str().at(5 + version_string_length + i)) << (8 * i);
        }

        //auto computed_filehash = sha512.hash(fws.str().substr(0, version_string_length + app_binary_length + 9));
        auto hash_vec = sha512_v(fws.str().substr(0, version_string_length + app_binary_length + 9));
        std::string computed_filehash(hash_vec.begin(), hash_vec.end());
        auto stored_filehash = fws.str().substr(version_string_length + app_binary_length + 9, 64);
        if (computed_filehash == stored_filehash)
        {
            auto fwdata = fws.str().substr(version_string_length + 9, app_binary_length);
            app_data = std::vector<uint8_t>(fwdata.begin(), fwdata.end());
            start_addr = app_start_addr;
            latest_firmware_version = version_string;
            return true;
        }
    }

    return false;
}

void firmware_update::update_firmware(HidHandler& hid)
{
    /*
    std::wstring wbinfile(newest_mcu_file.begin(), newest_mcu_file.end());
    bool valid_path = !((INVALID_FILE_ATTRIBUTES == GetFileAttributes(wbinfile.c_str()) ||
        GetLastError() == ERROR_FILE_NOT_FOUND));
    if (!valid_path)
    {
        firmware_status.store(Firmware_Status::File_Not_Found);
        return;
    }
    */

    hid.bl_got_status.store(false);
    hid.bl_status.store(0);

    firmware_status.store(Firmware_Status::In_Progress);
    // Get the raw data from the hex file
    /*
    ihex_loader ihx;
    if (!ihx.load_ihex(newest_mcu_file))
    {
        // Loading file failed
        firmware_status.store(Firmware_Status::File_Load_Failed);
        return;
    }

    start_addr = ihx.get_start_address();
    app_data = ihx.get_application_data();
    */
    // sanity checks
    if ((start_addr != APP_ADDRESS) || (app_data.size() > ALLOWED_APP_SIZE))
    {
        firmware_status.store(Firmware_Status::Firmware_Params_Incorrect);
        return;
    }
    if (mythread.joinable()) mythread.join();

    mythread = std::thread([&]()
        {
            // try to erase by chunks first, but if that fails erase the whole app region
            if (!erase_app_by_blocks(hid, start_addr, app_data.size()))
            {
                if (!erase_app_region(hid)) return;
            }

            for (uint32_t current_addr = 0; current_addr < app_data.size(); current_addr += PAGE_SIZE)
            {
                std::vector<uint8_t> page;
                if ((current_addr + PAGE_SIZE) < app_data.size())
                {
                    page.insert(page.begin(), app_data.begin() + current_addr, app_data.begin() + current_addr + PAGE_SIZE);
                }
                else
                {
                    page.insert(page.begin(), app_data.begin() + current_addr, app_data.end());
                    if (page.size() < PAGE_SIZE)
                    {
                        page.insert(page.end(), PAGE_SIZE - page.size(), 0xFF);
                    }
                }

                if (!load_page(hid, start_addr + current_addr, page))
                {
                    firmware_status.store(Firmware_Status::Page_Write_Failed);
                    return;
                }
                // Update the progress
                firmware_progress.store(static_cast<double>(current_addr) / static_cast<double>(app_data.size()));
            }

            firmware_status.store(Firmware_Status::Success);
        });

}

bool firmware_update::get_dfu_version(std::wstring filepath)
{
    std::ifstream in(filepath.c_str(), std::ios::binary | std::ios::ate);
    if (in.is_open())
    {
        std::streamsize file_length = in.tellg();
        if (file_length < 16 + 2)
            return false;

        in.seekg(file_length - 16);
        uint16_t version_raw = 0;
        in.read(reinterpret_cast<char*>(&version_raw), sizeof(version_raw));
        in.close();

        std::ostringstream ss;
        ss << std::hex << version_raw;

        latest_dfu_version = ss.str();
        return true;
    }

    return false;
}

void firmware_update::abort_dfu_update()
{
    dfu_load_status.store(DFU_Load_Status::Failure);

    // End the DFU command process
    if (dfu_upload_process.hProcess != NULL && dfu_upload_process.hProcess != INVALID_HANDLE_VALUE)
    {
        TerminateProcess(dfu_upload_process.hProcess, 0);

        CloseHandle(dfu_upload_process.hThread);
        CloseHandle(dfu_upload_process.hProcess);
        dfu_upload_process.hProcess = NULL;
        dfu_upload_process.hThread = NULL;
    }
}

bool firmware_update::check_dfu_file(std::wstring firmwarePath) {
    hid_handler.log << "Running integrity check on the firmware file" << std::endl;

    if (((INVALID_FILE_ATTRIBUTES == GetFileAttributes(firmwarePath.c_str()) || GetLastError() == ERROR_FILE_NOT_FOUND)))
    {
        hid_handler.log << "Unable to find DFU file" << std::endl;
        return false;
    }

    std::ifstream in(firmwarePath.c_str(), std::ios::binary | std::ios::ate);
    std::streamsize file_length = in.tellg();

    hid_handler.log << "Checking crc on file" << std::endl;

    // check the final 16 bytes to see if this is a dfu formatted file and crc passes
    unsigned char dfu_suffix[16];
    in.seekg(file_length - 16);
    in.read(reinterpret_cast<char*>(dfu_suffix), 16);

    // contains magic characters 'D', 'F', 'U' ?
    if (dfu_suffix[8] != 'U' || dfu_suffix[9] != 'F' || dfu_suffix[10] != 'D') {
        in.close();
        hid_handler.log << "Unable to verify DFU file" << std::endl;
        return false;
    }

    // size needs to be 16
    if (dfu_suffix[11] != 16) {
        in.close();
        hid_handler.log << "Unable to verify DFU file" << std::endl;
        return false;
    }

    // compute and check crc
    uint32_t file_crc = dfu_suffix[12] + (dfu_suffix[13] << 8) + (dfu_suffix[14] << 16) + (dfu_suffix[15] << 24);
    uint32_t crc = 0xffffffff;
    in.seekg(0);
    for (int i = 0; i < file_length - 4; i++) {
        char chr;
        in.read(&chr, 1);
        crc = crc32_byte(crc, static_cast<uint8_t>(chr));
    }

    in.close();

    if (file_crc != crc) {
        return false;
    }

    return true;
}

void firmware_update::load_dfu_firmware(HidHandler& hid, std::wstring firmwarePath)
{
    hid_handler.log << "Loading DFU firmware" << std::endl;
    bool firmware_valid = !((INVALID_FILE_ATTRIBUTES == GetFileAttributes(firmwarePath.c_str()) || GetLastError() == ERROR_FILE_NOT_FOUND));

    if (!firmware_valid)
    {
        dfu_load_status.store(DFU_Load_Status::Firmware_Not_Found);
        return;
    }

    if (!check_dfu_file(firmwarePath)) {
        // TODO: new failure flag?
        dfu_load_status.store(DFU_Load_Status::DFU_File_Invalid);
        return;
    }

    hid_handler.log << "DFU file is valid. Continuing with update" << std::endl;
    last_dfu_change = std::chrono::duration_cast<std::chrono::seconds>(std::chrono::system_clock::now().time_since_epoch()).count();
    previous_dfu_progress.store(0);
    dfu_progress.store(0);
    dfu_load_status.store(DFU_Load_Status::In_Progress);

    if (dfuthread.joinable()) dfuthread.join();

    dfuthread = std::thread([this, firmwarePath]()
        {
            hid_handler.log << "Reading DFU file" << std::endl;
            std::ifstream in(firmwarePath.c_str(), std::ios::binary | std::ios::ate);
            std::streamsize firmware_length = in.tellg();
            if (in.is_open())
            {
                in.seekg(0);
                std::stringstream dfu_file;
                int bytes_done = 0;
                dfu_file << in.rdbuf();
                auto dfd = dfu_file.str();
                std::vector<uint8_t> dfu_file_data(dfd.begin(), dfd.end());

                int data_length = firmware_length - 16;

                dfu_utilities dfu_util;
                dfu_device eye_dfu;
                eye_dfu.dev = nullptr;

                hid_handler.log << "Getting DFU device" << std::endl;
                std::vector<dfu_device> dfu_list = dfu_util.list_devices();
                for (auto& dev : dfu_list) {
                    if (dev.vid == 0x35bd && dev.pid == 0x0282) {
                        hid_handler.log << "Got device" << std::endl;
                        eye_dfu = dev;
                    }
                }
                if (eye_dfu.dev == nullptr) {
                    hid_handler.log << "No eyetracking dfu device detected" << std::endl;

                    dfu_load_status.store(DFU_Load_Status::Failure);
                    in.close();
                    return;
                }

                hid_handler.log << "Opening dfu device" << std::endl;
                int ret = dfu_util.open(eye_dfu);
                if (ret != LIBUSB_SUCCESS) {
                    hid_handler.log << "Could not open eyetracking DFU" << std::endl;

                    dfu_load_status.store(DFU_Load_Status::Failure);
                    in.close();
                    return;
                }

                while (bytes_done < data_length) {

                    // read 32kB chunks of the file
                    int chunk_length;
                    if ((data_length - bytes_done) > 32768) {
                        chunk_length = 32768;
                    }
                    else {
                        chunk_length = data_length - bytes_done;
                    }

                    std::vector<uint8_t> data_sector(dfu_file_data.begin() + bytes_done, dfu_file_data.begin() + bytes_done + chunk_length);

                    bool sector_success = false;
                    int sector_retry_count = 0;
                    do {
                        sector_retry_count++;
                        hid_handler.log << "Attempting to write sector data" << std::endl;
                        int ret = dfu_util.download(eye_dfu, data_sector, bytes_done);
                        if (ret != LIBUSB_SUCCESS) {
                            hid_handler.log << "Failed to download sector at " << std::hex << std::setw(8) << std::setfill(L'0') << bytes_done << " of " << std::hex << std::setw(8) << std::setfill(L'0') << data_length << std::endl;
                            hid_handler.log << "Attempt " << sector_retry_count << std::endl;
                            // skip to the end of the loop and try again
                            continue;
                        }
                        std::vector<uint8_t> bytes_read = dfu_util.upload(eye_dfu, 32768, bytes_done); // always read a full sector, even if final chunk of file is less than sector length
                        if (bytes_read.size() != 32768) {
                            continue;
                        }
                        if (std::equal(data_sector.begin(), data_sector.end(), bytes_read.begin())) {
                            sector_success = true;
                        }
                        else 
                        {
                            hid_handler.log << "Failed to validate sector at " << std::hex << std::setw(8) << std::setfill(L'0') << bytes_done << " of " << std::hex << std::setw(8) << std::setfill(L'0') << data_length << std::endl;
                            hid_handler.log << "Attempt " << sector_retry_count << std::endl;
                        };

                    } while (!sector_success && sector_retry_count < 10);

                    if (!sector_success) {
                        hid_handler.log << "Failed to write starting at address 0x" << std::hex << std::setw(8) << std::setfill(L'0') << bytes_done << std::endl;

                        dfu_load_status.store(DFU_Load_Status::Failure);
                        dfu_util.close(eye_dfu);
                        in.close();
                        return;
                    }

                    bytes_done += chunk_length;
                    dfu_progress.store(((float)bytes_done) / ((float)data_length));

                    hid_handler.log << "Successfully wrote " << std::dec << bytes_done << " bytes." << std::endl;
                }

                dfu_progress.store(1.0);
                dfu_load_status.store(DFU_Load_Status::Success);
                dfu_util.close(eye_dfu);
                in.close();
            }
        });
}

void firmware_update::clear_status()
{
    firmware_progress.store(0);
    firmware_status.store(Firmware_Status::Idle);
}

void firmware_update::clear_dfu_status()
{
    dfu_load_status.store(DFU_Load_Status::Idle);
}

double firmware_update::get_update_progress()
{
    return firmware_progress.load();
}

int firmware_update::get_update_status()
{
    return firmware_status.load();
}

int firmware_update::get_dfu_status()
{
    return dfu_load_status.load();
}

uint8_t firmware_update::crc8(uint8_t initval, std::vector<uint8_t>& data)
{
    const uint8_t CRC8_POLY = 0x07;

    for (auto& bb : data)
    {
        initval = initval ^ bb;
        for (uint8_t k = 0; k < 8; k++)
        {
            if ((initval & 0x80) != 0)
            {
                initval = (0xFF & (initval << 1)) ^ CRC8_POLY;
            }
            else
            {
                initval = (0xFF & (initval << 1));
            }
        }
    }
    return initval;
}

std::vector<uint8_t> firmware_update::create_hid_message(uint8_t type, uint8_t len, uint32_t addr, const std::vector<uint8_t>& data)
{
    std::vector<uint8_t> msg;
    msg.push_back(type);
    msg.push_back(len);
    msg.push_back(addr & 0xFF);
    msg.push_back((addr & 0xFF00) >> 8);
    msg.push_back((addr & 0xFF0000) >> 16);
    msg.push_back((addr & 0xFF000000) >> 24);
    msg.insert(msg.end(), data.begin(), data.end());
    msg.push_back(crc8(0, msg));

    msg.insert(msg.begin(), 0); // initial byte for the HID report page (always zero)
    return msg;
}

std::vector<uint8_t> firmware_update::create_hid_message_nodata(uint8_t type, uint8_t len, uint32_t addr)
{
    std::vector<uint8_t> msg;
    msg.push_back(type);
    msg.push_back(len);
    msg.push_back(addr & 0xFF);
    msg.push_back((addr & 0xFF00) >> 8);
    msg.push_back((addr & 0xFF0000) >> 16);
    msg.push_back((addr & 0xFF000000) >> 24);
    msg.push_back(crc8(0, msg));

    msg.insert(msg.begin(), 0); // initial byte for the HID report page (always zero)
    return msg;
}

bool firmware_update::load_page(HidHandler& hid, uint32_t addr, const std::vector<uint8_t>& data)
{
    if ((addr % PAGE_SIZE) != 0)
    {
        return false;
    }
    // load the chunks
    for (int dataptr = 0; dataptr < data.size(); dataptr += CHUNK_SIZE)
    {
        // slice the page data into chunks
        std::vector<uint8_t> chunk;
        // if less than CHUNK_SIZE remains, just go until the end of data
        if (dataptr + CHUNK_SIZE > data.size())
        {
            chunk.insert(chunk.begin(), data.begin() + dataptr, data.end());
        }
        else
        {
            chunk.insert(chunk.begin(), data.begin() + dataptr, data.begin() + dataptr + CHUNK_SIZE);
        }

        if (!load_chunk(hid, addr + dataptr, chunk)) return false;
    }

    // Check status one last time, make sure it's cleared
    if (hid.bl_got_status.load())
    {
        hid.bl_got_status.store(false);
        if (hid.bl_status.load() != 0)
        {
            return false;
        }
    }
    // program the page full of loaded data
    hid.blcommand_program_data(addr);
    // wait for status
    while (!hid.bl_got_status.load())
    {
        Sleep(1);
        if (hid.awaiting_device.load()) return false;
        //std::this_thread::sleep_for(100us);
    }

    hid.bl_got_status.store(false);
    return (hid.bl_status.load() == 0);
}

bool firmware_update::load_chunk(HidHandler& hid, uint32_t addr, const std::vector<uint8_t>& data)
{
    if ((addr % CHUNK_SIZE) != 0)
    {
        return false;
    }
    uint8_t chunk[CHUNK_SIZE];
    uint8_t i = 0;
    for (uint8_t i = 0; i < data.size(); i++)
    {
        chunk[i] = data[i];
    }

    hid.blcommand_write_data(addr, data.size(), chunk);
    // Sending the write data command doesn't return a status
    // unless the result is a failure. Just check for failures.
    if (hid.bl_got_status.load())
    {
        hid.bl_got_status.store(false);
        if (hid.bl_status.load() != 0)
        {
            return false;
        }
    }
    return true;
}

bool firmware_update::erase_app_region(HidHandler& hid)
{
    if (hid.bl_got_status.load())
    {
        hid.bl_got_status.store(false);
    }
    hid.blcommand_erase_app();
    while (!hid.bl_got_status.load())
    {
        Sleep(1);
        if (hid.awaiting_device.load()) return false;
        //std::this_thread::sleep_for(100us);
    }
    hid.bl_got_status.store(false);
    return (hid.bl_status.load() == 0);

}

bool firmware_update::erase_app_by_blocks(HidHandler& hid, uint32_t erase_addr, uint32_t bytes_to_erase)
{
    bool retval = false;

    const std::array<uint32_t, 4> divisions{ LARGE_SUBSECTOR_SIZE, SECTOR_SIZE, SECTOR_SIZE, SECTOR_SIZE };

    for (auto& div : divisions)
    {
        if (bytes_to_erase > div)
        {
            // Erase this sector and move to the next
            retval = erase_sector(hid, erase_addr);
            if (!retval) return false;
            erase_addr += div;
            bytes_to_erase -= div;
        }
        else if (bytes_to_erase > 0)
        {
            // Erase blocks in this sector
            retval = erase_blocks(hid, erase_addr, bytes_to_erase);
            if (!retval) return false;
            erase_addr -= bytes_to_erase;
            bytes_to_erase = 0;
        }
    }

    return retval;
}
bool firmware_update::erase_sector(HidHandler& hid, uint32_t erase_addr)
{
    if ((erase_addr % 0x2000) != 0) return false; // aligns on 8kB boundary

    if (hid.bl_got_status.load())
    {
        hid.bl_got_status.store(false);
    }

    hid.blcommand_erase_flash(2, erase_addr); // size code 2 = sector

    while (!hid.bl_got_status.load())
    {
        Sleep(1);
        if (hid.awaiting_device.load()) return false;
        //std::this_thread::sleep_for(100us);
    }
    hid.bl_got_status.store(false);
    return (hid.bl_status.load() == 0);
}

bool firmware_update::erase_blocks(HidHandler& hid, uint32_t erase_addr, uint32_t bytes_to_erase)
{
    bool retval = false;
    int32_t i_bytes_to_erase = bytes_to_erase;
    while (i_bytes_to_erase > (2 * MIN_ERASABLE_SIZE))
    {
        retval = erase_16kB_block(hid, erase_addr);
        if (!retval) return false;
        erase_addr += 2 * MIN_ERASABLE_SIZE;
        i_bytes_to_erase -= 2 * MIN_ERASABLE_SIZE;
    }
    if (i_bytes_to_erase > MIN_ERASABLE_SIZE)
    {
        retval = erase_16kB_block(hid, erase_addr);
        erase_addr += 2 * MIN_ERASABLE_SIZE;
        i_bytes_to_erase -= 2 * MIN_ERASABLE_SIZE;
    }
    if (i_bytes_to_erase > 0)
    {
        retval = erase_8kB_block(hid, erase_addr);
        erase_addr += MIN_ERASABLE_SIZE;
        i_bytes_to_erase -= MIN_ERASABLE_SIZE;
    }

    return retval;
}

bool firmware_update::erase_8kB_block(HidHandler& hid, uint32_t erase_addr)
{
    if ((erase_addr % 0x2000) != 0) return false; // aligns on 8kB boundary

    if (hid.bl_got_status.load())
    {
        hid.bl_got_status.store(false);
    }

    hid.blcommand_erase_flash(0, erase_addr); // size code 0 = 8kB

    while (!hid.bl_got_status.load())
    {
        Sleep(1);
        if (hid.awaiting_device.load()) return false;
        //std::this_thread::sleep_for(100us);
    }
    hid.bl_got_status.store(false);
    return (hid.bl_status.load() == 0);
}

bool firmware_update::erase_16kB_block(HidHandler& hid, uint32_t erase_addr)
{
    if ((erase_addr % 0x4000) != 0) return false; // aligns on 16kB boundary

    if (hid.bl_got_status.load())
    {
        hid.bl_got_status.store(false);
    }

    hid.blcommand_erase_flash(1, erase_addr); // size code 1 = 16kB

    while (!hid.bl_got_status.load())
    {
        Sleep(1);
        if (hid.awaiting_device.load()) return false;
        //std::this_thread::sleep_for(100us);
    }
    hid.bl_got_status.store(false);
    return (hid.bl_status.load() == 0);
}