/*
 * Copyright (c) 2021, Konstantin Aladyshev <aladyshev22@gmail.com>
 *
 * SPDX-License-Identifier: MIT
 */

#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiLib.h>

#include <Protocol/AcpiSystemDescriptionTable.h>
#include <Library/ShellLib.h>
#include <IndustryStandard/Bmp.h>

EFI_STATUS WriteFile(CHAR16* FileName, VOID* Data, UINTN* Size)
{
  SHELL_FILE_HANDLE FileHandle;
  EFI_STATUS Status = ShellOpenFileByName(
    FileName,
    &FileHandle,
    EFI_FILE_MODE_CREATE | EFI_FILE_MODE_WRITE | EFI_FILE_MODE_READ,
    0
  );
  if (!EFI_ERROR(Status)) {
    Print(L"Save it to %s\n", FileName);
    UINTN ToWrite = *Size;
    Status = ShellWriteFile(
      FileHandle,
      Size,
      Data
    );
    if (EFI_ERROR(Status)) {
      Print(L"Can't write file: %r\n", Status);
    }
    if (*Size != ToWrite) {
      Print(L"Error! Not all data was written\n");
    }
    Status = ShellCloseFile(
      &FileHandle
    );
    if (EFI_ERROR(Status)) {
      Print(L"Can't close file: %r\n", Status);
    }
  } else {
    Print(L"Can't open file: %r\n", Status);
  }
  return Status;
}

EFI_STATUS
EFIAPI
UefiMain (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_ACPI_SDT_PROTOCOL* AcpiSdtProtocol;
  EFI_STATUS Status = gBS->LocateProtocol (
                  &gEfiAcpiSdtProtocolGuid,
                  NULL,
                  (VOID**)&AcpiSdtProtocol
                  );
  if (EFI_ERROR (Status)) {
    return Status;
  }

  BOOLEAN BGRT_found = FALSE;
  UINTN Index = 0;
  EFI_ACPI_SDT_HEADER* Table;
  EFI_ACPI_TABLE_VERSION Version;
  UINTN TableKey;
  while (TRUE) {
    Status = AcpiSdtProtocol->GetAcpiTable(Index,
      &Table,
      &Version,
      &TableKey
    );
    if (EFI_ERROR(Status)) {
      break;
    }
    if (((CHAR8)((Table->Signature >>  0) & 0xFF) == 'B') &&
        ((CHAR8)((Table->Signature >>  8) & 0xFF) == 'G') &&
        ((CHAR8)((Table->Signature >> 16) & 0xFF) == 'R') &&
        ((CHAR8)((Table->Signature >> 24) & 0xFF) == 'T')) {
      BGRT_found = TRUE;
      break;
    }
    Index++;
  }
  if (!BGRT_found) {
    Print(L"BGRT table is not present in the system\n");
    return EFI_UNSUPPORTED;
  }

  EFI_ACPI_6_3_BOOT_GRAPHICS_RESOURCE_TABLE* BGRT = (EFI_ACPI_6_3_BOOT_GRAPHICS_RESOURCE_TABLE*)Table;
  if (BGRT->ImageType == 0) {
    BMP_IMAGE_HEADER* BMP = (BMP_IMAGE_HEADER*)(BGRT->ImageAddress);

    if ((BMP->CharB != 'B') || (BMP->CharM != 'M')) {
      Print(L"BMP image has wrong signature!\n");
      return EFI_UNSUPPORTED;
    }
    Print(L"BGRT conatins BMP image with %dx%d resolution\n", BMP->PixelWidth, BMP->PixelHeight);
    UINTN Size = BMP->Size;
    Status = WriteFile(L"BGRT.bmp", BMP, &Size);
    if (EFI_ERROR(Status)) {
      Print(L"Error! Can't write BGRT.bmp file\n");
    }
  }
  return Status;
}