#include "fatfs.h"
#include "string.h"

#define RAM_LOADER_BUFFER_SIZE 15*1024
#define RAM_LOADER_ADDRESS 0x38000000
#define APP_START_ADDRESS RAM_LOADER_ADDRESS
uint8_t * ram_loader_buffer = (uint8_t *) RAM_LOADER_ADDRESS;

void _app_start(void)
{
    __disable_irq();
    // Reset USB

    //De-init all peripherals
    //HAL_ADC_DeInit(&hadc1);

    // Disable Systick
    SysTick->CTRL = 0;
    SysTick->LOAD = 0;
    SysTick->VAL = 0;

    // Reset clock to default
    HAL_RCC_DeInit();

    // Clear all interrupt bits
    for (uint8_t i = 0; i < sizeof(NVIC->ICER) / sizeof(NVIC->ICER[0]); i++)
    {
        NVIC->ICER[i] = 0xFFFFFFFF;
        NVIC->ICPR[i] = 0xFFFFFFFF;
    }

    __enable_irq();


    // set the vector table offset register
    SCB->VTOR = APP_START_ADDRESS;

    // get the application stack pointer
    __set_MSP(((uint32_t *)APP_START_ADDRESS)[0]);


    // jump to the application
    ((void (*)(void))((uint32_t *)APP_START_ADDRESS)[1])();

    // the application should never return
    // ULOG_ERROR("Failed to start application");
    while (1) {}

}

static uint8_t buffer[512];

void RamLoader_LoadApplication()
{

    // check if the file "load.bin" exists
    FIL file;
    FRESULT res = f_open(&file, "load.bin", FA_READ);
    if (res != FR_OK) {
        // ULOG_ERROR("Failed to open file load.bin");
        return;
    }

    UINT size =  f_size(&file);
    // ensure the file is not larger than the buffer
    if (size > RAM_LOADER_BUFFER_SIZE ) {
        // ULOG_ERROR("File load.bin is too large");
        return;
    }

    // read the file into the buffer
    UINT bytes_read;
    uint32_t remaining_bytes = size;
    uint8_t *destination_ptr = ram_loader_buffer;
    uint8_t *buffer_ptr = buffer;
    while (remaining_bytes > 0) {
        UINT read_size = remaining_bytes > 512 ? 512 : remaining_bytes;
        res = f_read(&file, buffer_ptr, read_size, &bytes_read);
        if (res != FR_OK) {
            // ULOG_ERROR("Failed to read file load.bin");
            return;
        }
        if (bytes_read != read_size) {
            // ULOG_ERROR("Failed to read file load.bin completely");
            return;
        }

        memcpy(destination_ptr, buffer_ptr, read_size);
        remaining_bytes -= read_size;
        destination_ptr += read_size;
    }

    // close the file
    f_close(&file);


    // check that the file to flash exists ("firm.bin")
    res = f_open(&file, "firm.bin", FA_READ);
    if (res != FR_OK) {
        // ULOG_ERROR("Failed to open file firm.bin");
        return;
    }
    //close the file
    f_close(&file);


    _app_start();


}