/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "RadialGradientEffectD2D1.h"

#include "Logging.h"

#include "ShadersD2D1.h"
#include "HelpersD2D.h"

#include <vector>

#define TEXTW(x) L##x
#define XML(X) TEXTW(#X) // This macro creates a single string from multiple lines of text.

static const PCWSTR kXmlDescription =
    XML(
        <?xml version='1.0'?>
        <Effect>
            <!-- System Properties -->
            <Property name='DisplayName' type='string' value='RadialGradientEffect'/>
            <Property name='Author' type='string' value='Mozilla'/>
            <Property name='Category' type='string' value='Pattern effects'/>
            <Property name='Description' type='string' value='This effect is used to render radial gradients in a manner compliant with the 2D Canvas specification.'/>
            <Inputs>
                <Input name='Geometry'/>
            </Inputs>
            <Property name='StopCollection' type='iunknown'>
              <Property name='DisplayName' type='string' value='Gradient stop collection'/>
            </Property>
            <Property name='Center1' type='vector2'>
              <Property name='DisplayName' type='string' value='Inner circle center'/>
            </Property>
            <Property name='Center2' type='vector2'>
              <Property name='DisplayName' type='string' value='Outer circle center'/>
            </Property>
            <Property name='Radius1' type='float'>
              <Property name='DisplayName' type='string' value='Inner circle radius'/>
            </Property>
            <Property name='Radius2' type='float'>
              <Property name='DisplayName' type='string' value='Outer circle radius'/>
            </Property>
            <Property name='Transform' type='matrix3x2'>
              <Property name='DisplayName' type='string' value='Transform applied to the pattern'/>
            </Property>

        </Effect>
        );

// {FB947CDA-718E-40CC-AE7B-D255830D7D14}
static const GUID GUID_SampleRadialGradientPS =
  {0xfb947cda, 0x718e, 0x40cc, {0xae, 0x7b, 0xd2, 0x55, 0x83, 0xd, 0x7d, 0x14}};
// {2C468128-6546-453C-8E25-F2DF0DE10A0F}
static const GUID GUID_SampleRadialGradientA0PS =
  {0x2c468128, 0x6546, 0x453c, {0x8e, 0x25, 0xf2, 0xdf, 0xd, 0xe1, 0xa, 0xf}};

namespace mozilla {
namespace gfx {

RadialGradientEffectD2D1::RadialGradientEffectD2D1()
  : mRefCount(0)
  , mCenter1(D2D1::Vector2F(0, 0))
  , mCenter2(D2D1::Vector2F(0, 0))
  , mRadius1(0)
  , mRadius2(0)
  , mTransform(D2D1::IdentityMatrix())

{
}

IFACEMETHODIMP
RadialGradientEffectD2D1::Initialize(ID2D1EffectContext* pContextInternal, ID2D1TransformGraph* pTransformGraph)
{
  HRESULT hr;
  
  hr = pContextInternal->LoadPixelShader(GUID_SampleRadialGradientPS, SampleRadialGradientPS, sizeof(SampleRadialGradientPS));

  if (FAILED(hr)) {
    return hr;
  }

  hr = pContextInternal->LoadPixelShader(GUID_SampleRadialGradientA0PS, SampleRadialGradientA0PS, sizeof(SampleRadialGradientA0PS));

  if (FAILED(hr)) {
    return hr;
  }

  hr = pTransformGraph->SetSingleTransformNode(this);

  if (FAILED(hr)) {
    return hr;
  }

  mEffectContext = pContextInternal;

  return S_OK;
}

IFACEMETHODIMP
RadialGradientEffectD2D1::PrepareForRender(D2D1_CHANGE_TYPE changeType)
{
  if (changeType == D2D1_CHANGE_TYPE_NONE) {
    return S_OK;
  }

  // We'll need to inverse transform our pixel, precompute inverse here.
  Matrix mat = ToMatrix(mTransform);
  if (!mat.Invert()) {
    // Singular
    return S_OK;
  }

  if (!mStopCollection) {
    return S_OK;
  }

  D2D1_POINT_2F dc = D2D1::Point2F(mCenter2.x - mCenter1.x, mCenter2.y - mCenter2.y);
  float dr = mRadius2 - mRadius1;
  float A = dc.x * dc.x + dc.y * dc.y - dr * dr;
 
  HRESULT hr;
  
  if (A == 0) {
    hr = mDrawInfo->SetPixelShader(GUID_SampleRadialGradientA0PS);
  } else {
    hr = mDrawInfo->SetPixelShader(GUID_SampleRadialGradientPS);
  }

  if (FAILED(hr)) {
    return hr;
  }

  RefPtr<ID2D1ResourceTexture> tex = CreateGradientTexture();
  hr = mDrawInfo->SetResourceTexture(1, tex);

  if (FAILED(hr)) {
    return hr;
  }

  struct PSConstantBuffer
  {
    float diff[3];
    float padding;
    float center1[2];
    float A;
    float radius1;
    float sq_radius1;
    float padding2[3];
    float transform[8];
  };

  PSConstantBuffer buffer = { { dc.x, dc.y, dr }, 0,
                              { mCenter1.x, mCenter1.y },
                              A, mRadius1, mRadius1 * mRadius1,
                              { 0, 0, 0 }, { mat._11, mat._21, mat._31, 0,
                                             mat._12, mat._22, mat._32, 0 } };

  hr = mDrawInfo->SetPixelShaderConstantBuffer((BYTE*)&buffer, sizeof(buffer));

  if (FAILED(hr)) {
    return hr;
  }

  return S_OK;
}

IFACEMETHODIMP
RadialGradientEffectD2D1::SetGraph(ID2D1TransformGraph* pGraph)
{
  return pGraph->SetSingleTransformNode(this);
}

IFACEMETHODIMP_(ULONG)
RadialGradientEffectD2D1::AddRef()
{
  return ++mRefCount;
}

IFACEMETHODIMP_(ULONG)
RadialGradientEffectD2D1::Release()
{
  if (!--mRefCount) {
    delete this;
    return 0;
  }
  return mRefCount;
}

IFACEMETHODIMP
RadialGradientEffectD2D1::QueryInterface(const IID &aIID, void **aPtr)
{
  if (!aPtr) {
    return E_POINTER;
  }

  if (aIID == IID_IUnknown) {
    *aPtr = static_cast<IUnknown*>(static_cast<ID2D1EffectImpl*>(this));
  } else if (aIID == IID_ID2D1EffectImpl) {
    *aPtr = static_cast<ID2D1EffectImpl*>(this);
  } else if (aIID == IID_ID2D1DrawTransform) {
    *aPtr = static_cast<ID2D1DrawTransform*>(this);
  } else if (aIID == IID_ID2D1Transform) {
    *aPtr = static_cast<ID2D1Transform*>(this);
  } else if (aIID == IID_ID2D1TransformNode) {
    *aPtr = static_cast<ID2D1TransformNode*>(this);
  } else {
    return E_NOINTERFACE;
  }

  static_cast<IUnknown*>(*aPtr)->AddRef();
  return S_OK;
}

IFACEMETHODIMP
RadialGradientEffectD2D1::MapInputRectsToOutputRect(const D2D1_RECT_L* pInputRects,
                                                    const D2D1_RECT_L* pInputOpaqueSubRects,
                                                    UINT32 inputRectCount,
                                                    D2D1_RECT_L* pOutputRect,
                                                    D2D1_RECT_L* pOutputOpaqueSubRect)
{
  if (inputRectCount != 1) {
    return E_INVALIDARG;
  }

  *pOutputRect = *pInputRects;
  *pOutputOpaqueSubRect = *pInputOpaqueSubRects;
  return S_OK;
}

IFACEMETHODIMP
RadialGradientEffectD2D1::MapOutputRectToInputRects(const D2D1_RECT_L* pOutputRect,
                                                    D2D1_RECT_L* pInputRects,
                                                    UINT32 inputRectCount) const
{
  if (inputRectCount != 1) {
      return E_INVALIDARG;
  }

  *pInputRects = *pOutputRect;
  return S_OK;
}

IFACEMETHODIMP
RadialGradientEffectD2D1::MapInvalidRect(UINT32 inputIndex,
                                         D2D1_RECT_L invalidInputRect,
                                         D2D1_RECT_L* pInvalidOutputRect) const
{
  MOZ_ASSERT(inputIndex = 0);

  *pInvalidOutputRect = invalidInputRect;
  return S_OK;
}

IFACEMETHODIMP
RadialGradientEffectD2D1::SetDrawInfo(ID2D1DrawInfo *pDrawInfo)
{
  mDrawInfo = pDrawInfo;
  return S_OK;
}

HRESULT
RadialGradientEffectD2D1::Register(ID2D1Factory1 *aFactory)
{
  D2D1_PROPERTY_BINDING bindings[] = {
    D2D1_VALUE_TYPE_BINDING(L"StopCollection", &RadialGradientEffectD2D1::SetStopCollection,
                            &RadialGradientEffectD2D1::GetStopCollection),
    D2D1_VALUE_TYPE_BINDING(L"Center1", &RadialGradientEffectD2D1::SetCenter1, &RadialGradientEffectD2D1::GetCenter1),
    D2D1_VALUE_TYPE_BINDING(L"Center2", &RadialGradientEffectD2D1::SetCenter2, &RadialGradientEffectD2D1::GetCenter2),
    D2D1_VALUE_TYPE_BINDING(L"Radius1", &RadialGradientEffectD2D1::SetRadius1, &RadialGradientEffectD2D1::GetRadius1),
    D2D1_VALUE_TYPE_BINDING(L"Radius2", &RadialGradientEffectD2D1::SetRadius2, &RadialGradientEffectD2D1::GetRadius2),
    D2D1_VALUE_TYPE_BINDING(L"Transform", &RadialGradientEffectD2D1::SetTransform, &RadialGradientEffectD2D1::GetTransform)
  };
  HRESULT hr = aFactory->RegisterEffectFromString(CLSID_RadialGradientEffect, kXmlDescription, bindings, ARRAYSIZE(bindings), CreateEffect);

  if (FAILED(hr)) {
    gfxWarning() << "Failed to register radial gradient effect.";
  }
  return hr;
}

HRESULT __stdcall
RadialGradientEffectD2D1::CreateEffect(IUnknown **aEffectImpl)
{
  *aEffectImpl = static_cast<ID2D1EffectImpl*>(new RadialGradientEffectD2D1());
  (*aEffectImpl)->AddRef();

  return S_OK;
}

HRESULT
RadialGradientEffectD2D1::SetStopCollection(IUnknown *aStopCollection)
{
  if (SUCCEEDED(aStopCollection->QueryInterface((ID2D1GradientStopCollection**)byRef(mStopCollection)))) {
    return S_OK;
  }

  return E_INVALIDARG;
}

TemporaryRef<ID2D1ResourceTexture>
RadialGradientEffectD2D1::CreateGradientTexture()
{
  std::vector<D2D1_GRADIENT_STOP> rawStops;
  rawStops.resize(mStopCollection->GetGradientStopCount());
  mStopCollection->GetGradientStops(&rawStops.front(), rawStops.size());

  std::vector<unsigned char> textureData;
  textureData.resize(4096 * 4);
  unsigned char *texData = &textureData.front();

  float prevColorPos = 0;
  float nextColorPos = 1.0f;
  D2D1_COLOR_F prevColor = rawStops[0].color;
  D2D1_COLOR_F nextColor = prevColor;

  if (rawStops.size() >= 2) {
    nextColor = rawStops[1].color;
    nextColorPos = rawStops[1].position;
  }

  uint32_t stopPosition = 2;

  // Not the most optimized way but this will do for now.
  for (int i = 0; i < 4096; i++) {
    // The 4095 seems a little counter intuitive, but we want the gradient
    // color at offset 0 at the first pixel, and at offset 1.0f at the last
    // pixel.
    float pos = float(i) / 4095;

    while (pos > nextColorPos) {
      prevColor = nextColor;
      prevColorPos = nextColorPos;
      if (rawStops.size() > stopPosition) {
        nextColor = rawStops[stopPosition].color;
        nextColorPos = rawStops[stopPosition++].position;
      } else {
        nextColorPos = 1.0f;
      }
    }

    float interp;
    
    if (nextColorPos != prevColorPos) {
      interp = (pos - prevColorPos) / (nextColorPos - prevColorPos);
    } else {
      interp = 0;
    }

    Color newColor(prevColor.r + (nextColor.r - prevColor.r) * interp,
                    prevColor.g + (nextColor.g - prevColor.g) * interp,
                    prevColor.b + (nextColor.b - prevColor.b) * interp,
                    prevColor.a + (nextColor.a - prevColor.a) * interp);

    // Note D2D expects RGBA here!!
    texData[i * 4] = (char)(255.0f * newColor.r);
    texData[i * 4 + 1] = (char)(255.0f * newColor.g);
    texData[i * 4 + 2] = (char)(255.0f * newColor.b);
    texData[i * 4 + 3] = (char)(255.0f * newColor.a);
  }

  RefPtr<ID2D1ResourceTexture> tex;

  UINT32 width = 4096;
  UINT32 stride = 4096 * 4;
  D2D1_RESOURCE_TEXTURE_PROPERTIES props;
  props.dimensions = 1;
  props.extents = &width;
  props.channelDepth = D2D1_CHANNEL_DEPTH_4;
  props.bufferPrecision = D2D1_BUFFER_PRECISION_8BPC_UNORM;
  props.filter = D2D1_FILTER_MIN_MAG_MIP_LINEAR;
  D2D1_EXTEND_MODE extendMode = mStopCollection->GetExtendMode();
  props.extendModes = &extendMode;

  HRESULT hr = mEffectContext->CreateResourceTexture(nullptr, &props, &textureData.front(), &stride, 4096 * 4, byRef(tex));

  if (FAILED(hr)) {
    gfxWarning() << "Failed to create resource texture: " << hr;
  }

  return tex;
}

}
}
