/** @file
  Functions to deal with file buffer.

  Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved. <BR>
  This program and the accompanying materials
  are licensed and made available under the terms and conditions of the BSD License
  which accompanies this distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/

#include "HexEditor.h"

extern EFI_HANDLE                 HImageHandleBackup;
extern HEFI_EDITOR_BUFFER_IMAGE   HBufferImage;

extern BOOLEAN                    HBufferImageNeedRefresh;
extern BOOLEAN                    HBufferImageOnlyLineNeedRefresh;
extern BOOLEAN                    HBufferImageMouseNeedRefresh;

extern HEFI_EDITOR_GLOBAL_EDITOR  HMainEditor;

HEFI_EDITOR_FILE_IMAGE            HFileImage;
HEFI_EDITOR_FILE_IMAGE            HFileImageBackupVar;

//
// for basic initialization of HFileImage
//
HEFI_EDITOR_BUFFER_IMAGE          HFileImageConst = {
  NULL,
  0,
  FALSE
};

/**
  Initialization function for HFileImage
 
  @retval EFI_SUCCESS     The operation was successful.
**/
EFI_STATUS
HFileImageInit (
  VOID
  )
{
  //
  // basically initialize the HFileImage
  //
  CopyMem (&HFileImage, &HFileImageConst, sizeof (HFileImage));

  CopyMem (
    &HFileImageBackupVar,
    &HFileImageConst,
    sizeof (HFileImageBackupVar)
    );

  return EFI_SUCCESS;
}

/**
  Backup function for HFileImage. Only a few fields need to be backup. 
  This is for making the file buffer refresh as few as possible.

  @retval EFI_SUCCESS           The operation was successful.
  @retval EFI_OUT_OF_RESOURCES  A memory allocation failed.
**/
EFI_STATUS
HFileImageBackup (
  VOID
  )
{
  SHELL_FREE_NON_NULL (HFileImageBackupVar.FileName);
  HFileImageBackupVar.FileName = CatSPrint(NULL, L"%s", HFileImage.FileName);
  if (HFileImageBackupVar.FileName == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  return EFI_SUCCESS;
}

/**
  Cleanup function for HFileImage.

  @retval EFI_SUCCESS           The operation was successful.
**/
EFI_STATUS
HFileImageCleanup (
  VOID
  )
{

  SHELL_FREE_NON_NULL (HFileImage.FileName);
  SHELL_FREE_NON_NULL (HFileImageBackupVar.FileName);

  return EFI_SUCCESS;
}

/**
  Set FileName field in HFileImage

  @param[in] Str  File name to set.

  @retval EFI_SUCCESS           The operation was successful.
  @retval EFI_OUT_OF_RESOURCES  A memory allocation failed.
**/
EFI_STATUS
HFileImageSetFileName (
  IN CONST CHAR16 *Str
  )
{
  if (Str == HFileImage.FileName) {
    //
    // This function might be called using HFileImage.FileName as Str.
    // Directly return without updating HFileImage.FileName.
    //
    return EFI_SUCCESS;
  }
  //
  // free the old file name
  //
  SHELL_FREE_NON_NULL (HFileImage.FileName);
  HFileImage.FileName = AllocateCopyPool (StrSize (Str), Str);
  if (HFileImage.FileName == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  return EFI_SUCCESS;
}

/**
  Read a file from disk into HBufferImage.

  @param[in] FileName     filename to read.
  @param[in] Recover      if is for recover, no information print.

  @retval EFI_SUCCESS           The operation was successful.
  @retval EFI_OUT_OF_RESOURCES  A memory allocation failed.
  @retval EFI_LOAD_ERROR        A load error occured.
**/
EFI_STATUS
HFileImageRead (
  IN CONST CHAR16  *FileName,
  IN BOOLEAN Recover
  )
{
  HEFI_EDITOR_LINE                *Line;
  UINT8                           *Buffer;
  CHAR16                          *UnicodeBuffer;
  EFI_STATUS                      Status;

  //
  // variable initialization
  //
  Line                    = NULL;

  //
  // in this function, when you return error ( except EFI_OUT_OF_RESOURCES )
  // you should set status string
  // since this function maybe called before the editorhandleinput loop
  // so any error will cause editor return
  // so if you want to print the error status
  // you should set the status string
  //
  Status = ReadFileIntoBuffer (FileName, (VOID**)&Buffer, &HFileImage.Size, &HFileImage.ReadOnly);
  //
  // NULL pointer is only also a failure for a non-zero file size.
  //
  if ((EFI_ERROR(Status)) || (Buffer == NULL && HFileImage.Size != 0)) {
    UnicodeBuffer = CatSPrint(NULL, L"Read error on file %s: %r", FileName, Status);
    if (UnicodeBuffer == NULL) {
      SHELL_FREE_NON_NULL(Buffer);
      return EFI_OUT_OF_RESOURCES;
    }

    StatusBarSetStatusString (UnicodeBuffer);
    FreePool (UnicodeBuffer);
    return EFI_OUT_OF_RESOURCES;
  }

  HFileImageSetFileName (FileName);

  //
  // free the old lines
  //
  HBufferImageFree ();

  Status = HBufferImageBufferToList (Buffer, HFileImage.Size);
  SHELL_FREE_NON_NULL (Buffer);
  if (EFI_ERROR (Status)) {
    StatusBarSetStatusString (L"Error parsing file.");
    return Status;
  }

  HBufferImage.DisplayPosition.Row    = 2;
  HBufferImage.DisplayPosition.Column = 10;
  HBufferImage.MousePosition.Row      = 2;
  HBufferImage.MousePosition.Column   = 10;
  HBufferImage.LowVisibleRow          = 1;
  HBufferImage.HighBits               = TRUE;
  HBufferImage.BufferPosition.Row     = 1;
  HBufferImage.BufferPosition.Column  = 1;
  HBufferImage.BufferType = FileTypeFileBuffer;

  if (!Recover) {
    UnicodeBuffer = CatSPrint(NULL, L"%d Lines Read", HBufferImage.NumLines);
    if (UnicodeBuffer == NULL) {
      SHELL_FREE_NON_NULL(Buffer);
      return EFI_OUT_OF_RESOURCES;
    }

    StatusBarSetStatusString (UnicodeBuffer);
    FreePool (UnicodeBuffer);

    HMainEditor.SelectStart = 0;
    HMainEditor.SelectEnd   = 0;
  }

  //
  // has line
  //
  if (HBufferImage.Lines != 0) {
    HBufferImage.CurrentLine = CR (HBufferImage.ListHead->ForwardLink, HEFI_EDITOR_LINE, Link, EFI_EDITOR_LINE_LIST);
  } else {
    //
    // create a dummy line
    //
    Line = HBufferImageCreateLine ();
    if (Line == NULL) {
      SHELL_FREE_NON_NULL(Buffer);
      return EFI_OUT_OF_RESOURCES;
    }

    HBufferImage.CurrentLine = Line;
  }

  HBufferImage.Modified           = FALSE;
  HBufferImageNeedRefresh         = TRUE;
  HBufferImageOnlyLineNeedRefresh = FALSE;
  HBufferImageMouseNeedRefresh    = TRUE;

  return EFI_SUCCESS;
}

/**
  Save lines in HBufferImage to disk.

  @param[in] FileName     The file name.

  @retval EFI_SUCCESS           The operation was successful.
  @retval EFI_OUT_OF_RESOURCES  A memory allocation failed.
  @retval EFI_LOAD_ERROR        A load error occured.
**/
EFI_STATUS
HFileImageSave (
  IN CHAR16 *FileName
  )
{

  LIST_ENTRY                      *Link;
  HEFI_EDITOR_LINE                *Line;
  CHAR16                          *Str;
  EFI_STATUS                      Status;
  UINTN                           NumLines;
  SHELL_FILE_HANDLE                 FileHandle;
  UINTN                           TotalSize;
  UINT8                           *Buffer;
  UINT8                           *Ptr;
  EDIT_FILE_TYPE                  BufferTypeBackup;

  BufferTypeBackup        = HBufferImage.BufferType;
  HBufferImage.BufferType = FileTypeFileBuffer;

  //
  // if is the old file
  //
  if (HFileImage.FileName != NULL && FileName != NULL && StrCmp (FileName, HFileImage.FileName) == 0) {
    //
    // check whether file exists on disk
    //
    if (ShellIsFile(FileName) == EFI_SUCCESS) {
      //
      // current file exists on disk
      // so if not modified, then not save
      //
      if (HBufferImage.Modified == FALSE) {
        return EFI_SUCCESS;
      }
      //
      // if file is read-only, set error
      //
      if (HFileImage.ReadOnly == TRUE) {
        StatusBarSetStatusString (L"Read Only File Can Not Be Saved");
        return EFI_SUCCESS;
      }
    }
  }

   if (ShellIsDirectory(FileName) == EFI_SUCCESS) {
    StatusBarSetStatusString (L"Directory Can Not Be Saved");
    return EFI_LOAD_ERROR;
  }

  Status = ShellOpenFileByName (FileName, &FileHandle, EFI_FILE_MODE_READ|EFI_FILE_MODE_WRITE, 0);

  if (!EFI_ERROR (Status)) {
    //
    // the file exits, delete it
    //
    Status = ShellDeleteFile (&FileHandle);
    if (EFI_ERROR (Status) || Status == EFI_WARN_DELETE_FAILURE) {
      StatusBarSetStatusString (L"Write File Failed");
      return EFI_LOAD_ERROR;
    }
 }

  //
  // write all the lines back to disk
  //
  NumLines  = 0;
  TotalSize = 0;
  for (Link = HBufferImage.ListHead->ForwardLink; Link != HBufferImage.ListHead; Link = Link->ForwardLink) {
    Line = CR (Link, HEFI_EDITOR_LINE, Link, EFI_EDITOR_LINE_LIST);

    if (Line->Size != 0) {
      TotalSize += Line->Size;
    }
    //
    // end of if Line -> Size != 0
    //
    NumLines++;
  }
  //
  // end of for Link
  //
  Buffer = AllocateZeroPool (TotalSize);
  if (Buffer == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  Ptr = Buffer;
  for (Link = HBufferImage.ListHead->ForwardLink; Link != HBufferImage.ListHead; Link = Link->ForwardLink) {
    Line = CR (Link, HEFI_EDITOR_LINE, Link, EFI_EDITOR_LINE_LIST);

    if (Line->Size != 0) {
      CopyMem (Ptr, Line->Buffer, Line->Size);
      Ptr += Line->Size;
    }
    //
    // end of if Line -> Size != 0
    //
  }


  Status = ShellOpenFileByName (FileName, &FileHandle, EFI_FILE_MODE_READ|EFI_FILE_MODE_WRITE|EFI_FILE_MODE_CREATE, 0);

  if (EFI_ERROR (Status)) {
    StatusBarSetStatusString (L"Create File Failed");
    return EFI_LOAD_ERROR;
  }

  Status = ShellWriteFile (FileHandle, &TotalSize, Buffer);
  FreePool (Buffer);
  if (EFI_ERROR (Status)) {
    ShellDeleteFile (&FileHandle);
    return EFI_LOAD_ERROR;
  }

  ShellCloseFile(&FileHandle);

  HBufferImage.Modified = FALSE;

  //
  // set status string
  //
  Str = CatSPrint(NULL, L"%d Lines Wrote", NumLines);
  StatusBarSetStatusString (Str);
  FreePool (Str);

  //
  // now everything is ready , you can set the new file name to filebuffer
  //
  if ((BufferTypeBackup != FileTypeFileBuffer && FileName != NULL) ||
     (FileName != NULL && HFileImage.FileName != NULL && StringNoCaseCompare (&FileName, &HFileImage.FileName) != 0)){
    //
    // not the same
    //
    HFileImageSetFileName (FileName);
    if (HFileImage.FileName == NULL) {
      return EFI_OUT_OF_RESOURCES;
    }
  }

  HFileImage.ReadOnly = FALSE;

  return EFI_SUCCESS;
}