// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <windows.h>
#include <psapi.h>

#include "skia/ext/bitmap_platform_device_win.h"
#include "skia/ext/bitmap_platform_device_data.h"
#include "skia/ext/platform_canvas.h"
#include "third_party/skia/include/core/SkMatrix.h"
#include "third_party/skia/include/core/SkRefCnt.h"
#include "third_party/skia/include/core/SkRegion.h"
#include "third_party/skia/include/core/SkUtils.h"

namespace {

// PlatformBitmapPixelRef is an SkPixelRef that, on Windows, is backed by an
// HBITMAP.
class SK_API PlatformBitmapPixelRef : public SkPixelRef {
 public:
  PlatformBitmapPixelRef(HBITMAP bitmap_handle, void* pixels);
  virtual ~PlatformBitmapPixelRef();

  SK_DECLARE_UNFLATTENABLE_OBJECT();

 protected:
  virtual void* onLockPixels(SkColorTable**) SK_OVERRIDE;
  virtual void onUnlockPixels() SK_OVERRIDE;

 private:
  HBITMAP bitmap_handle_;
  void* pixels_;
};

HBITMAP CreateHBitmap(int width, int height, bool is_opaque,
                             HANDLE shared_section, void** data) {
  // CreateDIBSection appears to get unhappy if we create an empty bitmap, so
  // just create a minimal bitmap
  if ((width == 0) || (height == 0)) {
    width = 1;
    height = 1;
  }

  BITMAPINFOHEADER hdr = {0};
  hdr.biSize = sizeof(BITMAPINFOHEADER);
  hdr.biWidth = width;
  hdr.biHeight = -height;  // minus means top-down bitmap
  hdr.biPlanes = 1;
  hdr.biBitCount = 32;
  hdr.biCompression = BI_RGB;  // no compression
  hdr.biSizeImage = 0;
  hdr.biXPelsPerMeter = 1;
  hdr.biYPelsPerMeter = 1;
  hdr.biClrUsed = 0;
  hdr.biClrImportant = 0;

  HBITMAP hbitmap = CreateDIBSection(NULL, reinterpret_cast<BITMAPINFO*>(&hdr),
                                     0, data, shared_section, 0);
  return hbitmap;
}

PlatformBitmapPixelRef::PlatformBitmapPixelRef(HBITMAP bitmap_handle,
                                               void* pixels)
    : bitmap_handle_(bitmap_handle),
      pixels_(pixels) {
  setPreLocked(pixels, NULL);
}

PlatformBitmapPixelRef::~PlatformBitmapPixelRef() {
  if (bitmap_handle_)
    DeleteObject(bitmap_handle_);
}

void* PlatformBitmapPixelRef::onLockPixels(SkColorTable** color_table) {
  *color_table = NULL;
  return pixels_;
}

void PlatformBitmapPixelRef::onUnlockPixels() {
  // Nothing to do.
  return;
}

}  // namespace

namespace skia {

BitmapPlatformDevice::BitmapPlatformDeviceData::BitmapPlatformDeviceData(
    HBITMAP hbitmap)
    : bitmap_context_(hbitmap),
      hdc_(NULL),
      config_dirty_(true),  // Want to load the config next time.
      transform_(SkMatrix::I()) {
  // Initialize the clip region to the entire bitmap.
  BITMAP bitmap_data;
  if (GetObject(bitmap_context_, sizeof(BITMAP), &bitmap_data)) {
    SkIRect rect;
    rect.set(0, 0, bitmap_data.bmWidth, bitmap_data.bmHeight);
    clip_region_ = SkRegion(rect);
  }
}

BitmapPlatformDevice::BitmapPlatformDeviceData::~BitmapPlatformDeviceData() {
  if (hdc_)
    ReleaseBitmapDC();

  // this will free the bitmap data as well as the bitmap handle
  DeleteObject(bitmap_context_);
}

HDC BitmapPlatformDevice::BitmapPlatformDeviceData::GetBitmapDC() {
  if (!hdc_) {
    hdc_ = CreateCompatibleDC(NULL);
    InitializeDC(hdc_);
    HGDIOBJ old_bitmap = SelectObject(hdc_, bitmap_context_);
    // When the memory DC is created, its display surface is exactly one
    // monochrome pixel wide and one monochrome pixel high. Since we select our
    // own bitmap, we must delete the previous one.
    DeleteObject(old_bitmap);
  }

  LoadConfig();
  return hdc_;
}

void BitmapPlatformDevice::BitmapPlatformDeviceData::ReleaseBitmapDC() {
  SkASSERT(hdc_);
  DeleteDC(hdc_);
  hdc_ = NULL;
}

bool BitmapPlatformDevice::BitmapPlatformDeviceData::IsBitmapDCCreated()
    const {
  return hdc_ != NULL;
}


void BitmapPlatformDevice::BitmapPlatformDeviceData::SetMatrixClip(
    const SkMatrix& transform,
    const SkRegion& region) {
  transform_ = transform;
  clip_region_ = region;
  config_dirty_ = true;
}

void BitmapPlatformDevice::BitmapPlatformDeviceData::LoadConfig() {
  if (!config_dirty_ || !hdc_)
    return;  // Nothing to do.
  config_dirty_ = false;

  // Transform.
  LoadTransformToDC(hdc_, transform_);
  LoadClippingRegionToDC(hdc_, clip_region_, transform_);
}

// We use this static factory function instead of the regular constructor so
// that we can create the pixel data before calling the constructor. This is
// required so that we can call the base class' constructor with the pixel
// data.
BitmapPlatformDevice* BitmapPlatformDevice::Create(
    int width,
    int height,
    bool is_opaque,
    HANDLE shared_section) {

  void* data;
  HBITMAP hbitmap = CreateHBitmap(width, height, is_opaque, shared_section,
                                  &data);
  if (!hbitmap)
    return NULL;

  SkBitmap bitmap;
  bitmap.setConfig(SkBitmap::kARGB_8888_Config, width, height);
  bitmap.setPixels(data);
  bitmap.setIsOpaque(is_opaque);

#ifndef NDEBUG
  // If we were given data, then don't clobber it!
  if (!shared_section && is_opaque)
    // To aid in finding bugs, we set the background color to something
    // obviously wrong so it will be noticable when it is not cleared
    bitmap.eraseARGB(255, 0, 255, 128);  // bright bluish green
#endif

  // The device object will take ownership of the HBITMAP. The initial refcount
  // of the data object will be 1, which is what the constructor expects.
  return new BitmapPlatformDevice(
      skia::AdoptRef(new BitmapPlatformDeviceData(hbitmap)), bitmap);
}

// static
BitmapPlatformDevice* BitmapPlatformDevice::Create(int width, int height,
                                                   bool is_opaque) {
  return Create(width, height, is_opaque, NULL);
}

// static
BitmapPlatformDevice* BitmapPlatformDevice::CreateAndClear(int width,
                                                           int height,
                                                           bool is_opaque) {
  BitmapPlatformDevice* device = BitmapPlatformDevice::Create(width, height,
                                                              is_opaque);
  if (device && !is_opaque)
    device->accessBitmap(true).eraseARGB(0, 0, 0, 0);
  return device;
}

// The device will own the HBITMAP, which corresponds to also owning the pixel
// data. Therefore, we do not transfer ownership to the SkDevice's bitmap.
BitmapPlatformDevice::BitmapPlatformDevice(
    const skia::RefPtr<BitmapPlatformDeviceData>& data,
    const SkBitmap& bitmap)
    : SkDevice(bitmap),
      data_(data) {
  // The data object is already ref'ed for us by create().
  SkDEBUGCODE(begin_paint_count_ = 0);
  SetPlatformDevice(this, this);
}

BitmapPlatformDevice::~BitmapPlatformDevice() {
  SkASSERT(begin_paint_count_ == 0);
}

HDC BitmapPlatformDevice::BeginPlatformPaint() {
  SkDEBUGCODE(begin_paint_count_++);
  return data_->GetBitmapDC();
}

void BitmapPlatformDevice::EndPlatformPaint() {
  SkASSERT(begin_paint_count_--);
  PlatformDevice::EndPlatformPaint();
}

void BitmapPlatformDevice::setMatrixClip(const SkMatrix& transform,
                                         const SkRegion& region,
                                         const SkClipStack&) {
  data_->SetMatrixClip(transform, region);
}

void BitmapPlatformDevice::DrawToNativeContext(HDC dc, int x, int y,
                                               const RECT* src_rect) {
  bool created_dc = !data_->IsBitmapDCCreated();
  HDC source_dc = BeginPlatformPaint();

  RECT temp_rect;
  if (!src_rect) {
    temp_rect.left = 0;
    temp_rect.right = width();
    temp_rect.top = 0;
    temp_rect.bottom = height();
    src_rect = &temp_rect;
  }

  int copy_width = src_rect->right - src_rect->left;
  int copy_height = src_rect->bottom - src_rect->top;

  // We need to reset the translation for our bitmap or (0,0) won't be in the
  // upper left anymore
  SkMatrix identity;
  identity.reset();

  LoadTransformToDC(source_dc, identity);
  if (isOpaque()) {
    BitBlt(dc,
           x,
           y,
           copy_width,
           copy_height,
           source_dc,
           src_rect->left,
           src_rect->top,
           SRCCOPY);
  } else {
    SkASSERT(copy_width != 0 && copy_height != 0);
    BLENDFUNCTION blend_function = {AC_SRC_OVER, 0, 255, AC_SRC_ALPHA};
    GdiAlphaBlend(dc,
                  x,
                  y,
                  copy_width,
                  copy_height,
                  source_dc,
                  src_rect->left,
                  src_rect->top,
                  copy_width,
                  copy_height,
                  blend_function);
  }
  LoadTransformToDC(source_dc, data_->transform());

  EndPlatformPaint();
  if (created_dc)
    data_->ReleaseBitmapDC();
}

const SkBitmap& BitmapPlatformDevice::onAccessBitmap(SkBitmap* bitmap) {
  // FIXME(brettw) OPTIMIZATION: We should only flush if we know a GDI
  // operation has occurred on our DC.
  if (data_->IsBitmapDCCreated())
    GdiFlush();
  return *bitmap;
}

SkDevice* BitmapPlatformDevice::onCreateCompatibleDevice(
    SkBitmap::Config config, int width, int height, bool isOpaque, Usage) {
  SkASSERT(config == SkBitmap::kARGB_8888_Config);
  return BitmapPlatformDevice::CreateAndClear(width, height, isOpaque);
}

// PlatformCanvas impl

SkCanvas* CreatePlatformCanvas(int width,
                               int height,
                               bool is_opaque,
                               HANDLE shared_section,
                               OnFailureType failureType) {
  skia::RefPtr<SkDevice> dev = skia::AdoptRef(
      BitmapPlatformDevice::Create(width, height, is_opaque, shared_section));
  return CreateCanvas(dev, failureType);
}

// Port of PlatformBitmap to win

PlatformBitmap::~PlatformBitmap() {
  if (surface_) {
    if (platform_extra_)
      SelectObject(surface_, reinterpret_cast<HGDIOBJ>(platform_extra_));
    DeleteDC(surface_);
  }
}

bool PlatformBitmap::Allocate(int width, int height, bool is_opaque) {
  void* data;
  HBITMAP hbitmap = CreateHBitmap(width, height, is_opaque, 0, &data);
  if (!hbitmap)
    return false;

  surface_ = CreateCompatibleDC(NULL);
  InitializeDC(surface_);
  // When the memory DC is created, its display surface is exactly one
  // monochrome pixel wide and one monochrome pixel high. Save this object
  // off, we'll restore it just before deleting the memory DC.
  HGDIOBJ stock_bitmap = SelectObject(surface_, hbitmap);
  platform_extra_ = reinterpret_cast<intptr_t>(stock_bitmap);

  bitmap_.setConfig(SkBitmap::kARGB_8888_Config, width, height);
  // PlatformBitmapPixelRef takes ownership of |hbitmap|.
  bitmap_.setPixelRef(
      skia::AdoptRef(new PlatformBitmapPixelRef(hbitmap, data)).get());
  bitmap_.setIsOpaque(is_opaque);
  bitmap_.lockPixels();

  return true;
}

}  // namespace skia