#include <efi.h>
#include <efilib.h>
#include <stddef.h>

EFI_SYSTEM_TABLE * g_system_table;

static void write_string(uint16_t * string)
{
    g_system_table->ConOut->OutputString(g_system_table->ConOut, string);
}

static void write_uint(uint32_t n)
{
    uint16_t s[12] = {0};
    size_t i = 0u;
    while ((n != 0u) || (i == 0u))
    {
        s[10u - i] = '0' + (n % 10u);
        n /= 10u;
        i++;
    }
    write_string(&s[11u - i]);
}

EFI_STATUS
efi_main(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE * system_table)
{
    EFI_STATUS status;
    EFI_INPUT_KEY key;

    g_system_table = system_table;

    write_string(L"My first EFI loader\r\n");
    if (EFI_ERROR(status))
        return status;

    status = system_table->ConIn->Reset(system_table->ConIn, FALSE);
    if (EFI_ERROR(status))
        return status;

    EFI_HANDLE buffer[10];
    UINTN buffer_size = sizeof(buffer);
    status = system_table->BootServices->LocateHandle(ByProtocol,
            &(EFI_GUID)EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID,
            NULL,
            &buffer_size,
            buffer);
    write_string(L"status = ");
    write_uint(status);
    write_string(L", num entries = ");
    write_uint(buffer_size / sizeof(EFI_HANDLE));
    write_string(L"\r\n");

    write_string(L"Press any key...\r\n");
    while ((status = system_table->ConIn->ReadKeyStroke(system_table->ConIn, &key)) == EFI_NOT_READY)
    {
    }

    return status;
}