/** @file
  This is an instance of the Unit Test Persistence Lib that will utilize
  the filesystem that a test application is running from to save a serialized
  version of the internal test state in case the test needs to quit and restore.

  Copyright (c) Microsoft Corporation.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent
**/

#include <PiDxe.h>
#include <Library/UnitTestPersistenceLib.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/DevicePathLib.h>
#include <Library/ShellLib.h>
#include <Protocol/LoadedImage.h>

#define CACHE_FILE_SUFFIX  L"_Cache.dat"

/**
  Generate the device path to the cache file.

  @param[in]  FrameworkHandle  A pointer to the framework that is being persisted.

  @retval  !NULL  A pointer to the EFI_FILE protocol instance for the filesystem.
  @retval  NULL   Filesystem could not be found or an error occurred.

**/
STATIC
EFI_DEVICE_PATH_PROTOCOL *
GetCacheFileDevicePath (
  IN UNIT_TEST_FRAMEWORK_HANDLE  FrameworkHandle
  )
{
  EFI_STATUS                 Status;
  UNIT_TEST_FRAMEWORK        *Framework;
  EFI_LOADED_IMAGE_PROTOCOL  *LoadedImage;
  CHAR16                     *AppPath;
  CHAR16                     *CacheFilePath;
  CHAR16                     *TestName;
  UINTN                      DirectorySlashOffset;
  UINTN                      CacheFilePathLength;
  EFI_DEVICE_PATH_PROTOCOL   *CacheFileDevicePath;

  Framework           = (UNIT_TEST_FRAMEWORK *)FrameworkHandle;
  AppPath             = NULL;
  CacheFilePath       = NULL;
  TestName            = NULL;
  CacheFileDevicePath = NULL;

  //
  // First, we need to get some information from the loaded image.
  //
  Status = gBS->HandleProtocol (
                  gImageHandle,
                  &gEfiLoadedImageProtocolGuid,
                  (VOID **)&LoadedImage
                  );
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_WARN, "%a - Failed to locate DevicePath for loaded image. %r\n", __FUNCTION__, Status));
    return NULL;
  }

  //
  // Before we can start, change test name from ASCII to Unicode.
  //
  CacheFilePathLength = AsciiStrLen (Framework->ShortTitle) + 1;
  TestName            = AllocatePool (CacheFilePathLength * sizeof (CHAR16));
  if (!TestName) {
    goto Exit;
  }

  AsciiStrToUnicodeStrS (Framework->ShortTitle, TestName, CacheFilePathLength);

  //
  // Now we should have the device path of the root device and a file path for the rest.
  // In order to target the directory for the test application, we must process
  // the file path a little.
  //
  // NOTE: This may not be necessary... Path processing functions exist...
  // PathCleanUpDirectories (FileNameCopy);
  //     if (PathRemoveLastItem (FileNameCopy)) {
  //
  AppPath              = ConvertDevicePathToText (LoadedImage->FilePath, TRUE, TRUE); // NOTE: This must be freed.
  DirectorySlashOffset = StrLen (AppPath);
  //
  // Make sure we didn't get any weird data.
  //
  if (DirectorySlashOffset == 0) {
    DEBUG ((DEBUG_ERROR, "%a - Weird 0-length string when processing app path.\n", __FUNCTION__));
    goto Exit;
  }

  //
  // Now that we know we have a decent string, let's take a deeper look.
  //
  do {
    if (AppPath[DirectorySlashOffset] == L'\\') {
      break;
    }

    DirectorySlashOffset--;
  } while (DirectorySlashOffset > 0);

  //
  // After that little maneuver, DirectorySlashOffset should be pointing at the last '\' in AppString.
  // That would be the path to the parent directory that the test app is executing from.
  // Let's check and make sure that's right.
  //
  if (AppPath[DirectorySlashOffset] != L'\\') {
    DEBUG ((DEBUG_ERROR, "%a - Could not find a single directory separator in app path.\n", __FUNCTION__));
    goto Exit;
  }

  //
  // Now we know some things, we're ready to produce our output string, I think.
  //
  CacheFilePathLength  = DirectorySlashOffset + 1;
  CacheFilePathLength += StrLen (TestName);
  CacheFilePathLength += StrLen (CACHE_FILE_SUFFIX);
  CacheFilePathLength += 1;   // Don't forget the NULL terminator.
  CacheFilePath        = AllocateZeroPool (CacheFilePathLength * sizeof (CHAR16));
  if (!CacheFilePath) {
    goto Exit;
  }

  //
  // Let's produce our final path string, shall we?
  //
  StrnCpyS (CacheFilePath, CacheFilePathLength, AppPath, DirectorySlashOffset + 1);  // Copy the path for the parent directory.
  StrCatS (CacheFilePath, CacheFilePathLength, TestName);                            // Copy the base name for the test cache.
  StrCatS (CacheFilePath, CacheFilePathLength, CACHE_FILE_SUFFIX);                   // Copy the file suffix.

  //
  // Finally, try to create the device path for the thing thing.
  //
  CacheFileDevicePath = FileDevicePath (LoadedImage->DeviceHandle, CacheFilePath);

Exit:
  //
  // Free allocated buffers.
  //
  if (AppPath != NULL) {
    FreePool (AppPath);
  }

  if (CacheFilePath != NULL) {
    FreePool (CacheFilePath);
  }

  if (TestName != NULL) {
    FreePool (TestName);
  }

  return CacheFileDevicePath;
}

/**
  Determines whether a persistence cache already exists for
  the given framework.

  @param[in]  FrameworkHandle  A pointer to the framework that is being persisted.

  @retval  TRUE
  @retval  FALSE  Cache doesn't exist or an error occurred.

**/
BOOLEAN
EFIAPI
DoesCacheExist (
  IN UNIT_TEST_FRAMEWORK_HANDLE  FrameworkHandle
  )
{
  EFI_DEVICE_PATH_PROTOCOL  *FileDevicePath;
  EFI_STATUS                Status;
  SHELL_FILE_HANDLE         FileHandle;

  //
  // NOTE: This devpath is allocated and must be freed.
  //
  FileDevicePath = GetCacheFileDevicePath (FrameworkHandle);

  //
  // Check to see whether the file exists.  If the file can be opened for
  // reading, it exists.  Otherwise, probably not.
  //
  Status = ShellOpenFileByDevicePath (
             &FileDevicePath,
             &FileHandle,
             EFI_FILE_MODE_READ,
             0
             );
  if (!EFI_ERROR (Status)) {
    ShellCloseFile (&FileHandle);
  }

  if (FileDevicePath != NULL) {
    FreePool (FileDevicePath);
  }

  DEBUG ((DEBUG_VERBOSE, "%a - Returning %d\n", __FUNCTION__, !EFI_ERROR (Status)));

  return (!EFI_ERROR (Status));
}

/**
  Will save the data associated with an internal Unit Test Framework
  state in a manner that can persist a Unit Test Application quit or
  even a system reboot.

  @param[in]  FrameworkHandle  A pointer to the framework that is being persisted.
  @param[in]  SaveData         A pointer to the buffer containing the serialized
                               framework internal state.

  @retval  EFI_SUCCESS  Data is persisted and the test can be safely quit.
  @retval  Others       Data is not persisted and test cannot be resumed upon exit.

**/
EFI_STATUS
EFIAPI
SaveUnitTestCache (
  IN UNIT_TEST_FRAMEWORK_HANDLE  FrameworkHandle,
  IN UNIT_TEST_SAVE_HEADER       *SaveData
  )
{
  EFI_DEVICE_PATH_PROTOCOL  *FileDevicePath;
  EFI_STATUS                Status;
  SHELL_FILE_HANDLE         FileHandle;
  UINTN                     WriteCount;

  //
  // Check the inputs for sanity.
  //
  if ((FrameworkHandle == NULL) || (SaveData == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  //
  // Determine the path for the cache file.
  // NOTE: This devpath is allocated and must be freed.
  //
  FileDevicePath = GetCacheFileDevicePath (FrameworkHandle);

  //
  // First lets open the file if it exists so we can delete it...This is the work around for truncation
  //
  Status = ShellOpenFileByDevicePath (
             &FileDevicePath,
             &FileHandle,
             (EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE),
             0
             );

  if (!EFI_ERROR (Status)) {
    //
    // If file handle above was opened it will be closed by the delete.
    //
    Status = ShellDeleteFile (&FileHandle);
    if (EFI_ERROR (Status)) {
      DEBUG ((DEBUG_ERROR, "%a failed to delete file %r\n", __FUNCTION__, Status));
    }
  }

  //
  // Now that we know the path to the file... let's open it for writing.
  //
  Status = ShellOpenFileByDevicePath (
             &FileDevicePath,
             &FileHandle,
             (EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE | EFI_FILE_MODE_CREATE),
             0
             );
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "%a - Opening file for writing failed! %r\n", __FUNCTION__, Status));
    goto Exit;
  }

  //
  // Write the data to the file.
  //
  WriteCount = SaveData->SaveStateSize;
  DEBUG ((DEBUG_INFO, "%a - Writing %d bytes to file...\n", __FUNCTION__, WriteCount));
  Status = ShellWriteFile (
             FileHandle,
             &WriteCount,
             SaveData
             );

  if (EFI_ERROR (Status) || (WriteCount != SaveData->SaveStateSize)) {
    DEBUG ((DEBUG_ERROR, "%a - Writing to file failed! %r\n", __FUNCTION__, Status));
  } else {
    DEBUG ((DEBUG_INFO, "%a - SUCCESS!\n", __FUNCTION__));
  }

  //
  // No matter what, we should probably close the file.
  //
  ShellCloseFile (&FileHandle);

Exit:
  if (FileDevicePath != NULL) {
    FreePool (FileDevicePath);
  }

  return Status;
}

/**
  Will retrieve any cached state associated with the given framework.
  Will allocate a buffer to hold the loaded data.

  @param[in]  FrameworkHandle  A pointer to the framework that is being persisted.
  @param[in]  SaveData         A pointer pointer that will be updated with the address
                               of the loaded data buffer.

  @retval  EFI_SUCCESS  Data has been loaded successfully and SaveData is updated
                        with a pointer to the buffer.
  @retval  Others       An error has occurred and no data has been loaded. SaveData
                        is set to NULL.

**/
EFI_STATUS
EFIAPI
LoadUnitTestCache (
  IN  UNIT_TEST_FRAMEWORK_HANDLE  FrameworkHandle,
  OUT UNIT_TEST_SAVE_HEADER       **SaveData
  )
{
  EFI_STATUS                Status;
  EFI_DEVICE_PATH_PROTOCOL  *FileDevicePath;
  SHELL_FILE_HANDLE         FileHandle;
  BOOLEAN                   IsFileOpened;
  UINT64                    LargeFileSize;
  UINTN                     FileSize;
  UNIT_TEST_SAVE_HEADER     *Buffer;

  IsFileOpened = FALSE;
  Buffer       = NULL;

  //
  // Check the inputs for sanity.
  //
  if ((FrameworkHandle == NULL) || (SaveData == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  //
  // Determine the path for the cache file.
  // NOTE: This devpath is allocated and must be freed.
  //
  FileDevicePath = GetCacheFileDevicePath (FrameworkHandle);

  //
  // Now that we know the path to the file... let's open it for writing.
  //
  Status = ShellOpenFileByDevicePath (
             &FileDevicePath,
             &FileHandle,
             EFI_FILE_MODE_READ,
             0
             );
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "%a - Opening file for writing failed! %r\n", __FUNCTION__, Status));
    goto Exit;
  } else {
    IsFileOpened = TRUE;
  }

  //
  // Now that the file is opened, we need to determine how large a buffer we need.
  //
  Status = ShellGetFileSize (FileHandle, &LargeFileSize);
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "%a - Failed to determine file size! %r\n", __FUNCTION__, Status));
    goto Exit;
  }

  //
  // Now that we know the size, let's allocated a buffer to hold the contents.
  //
  FileSize = (UINTN)LargeFileSize;    // You know what... if it's too large, this lib don't care.
  Buffer   = AllocatePool (FileSize);
  if (Buffer == NULL) {
    DEBUG ((DEBUG_ERROR, "%a - Failed to allocate a pool to hold the file contents! %r\n", __FUNCTION__, Status));
    Status = EFI_OUT_OF_RESOURCES;
    goto Exit;
  }

  //
  // Finally, let's read the data.
  //
  Status = ShellReadFile (FileHandle, &FileSize, Buffer);
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "%a - Failed to read the file contents! %r\n", __FUNCTION__, Status));
  }

Exit:
  //
  // Free allocated buffers
  //
  if (FileDevicePath != NULL) {
    FreePool (FileDevicePath);
  }

  if (IsFileOpened) {
    ShellCloseFile (&FileHandle);
  }

  //
  // If we're returning an error, make sure
  // the state is sane.
  if (EFI_ERROR (Status) && (Buffer != NULL)) {
    FreePool (Buffer);
    Buffer = NULL;
  }

  *SaveData = Buffer;
  return Status;
}