// Copyright 2016 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com

#include "core/fpdfapi/render/cpdf_progressiverenderer.h"

#include "core/fpdfapi/page/cpdf_pageobject.h"
#include "core/fpdfapi/page/cpdf_pageobjectholder.h"
#include "core/fpdfapi/render/cpdf_pagerendercache.h"
#include "core/fpdfapi/render/cpdf_renderoptions.h"
#include "core/fpdfapi/render/cpdf_renderstatus.h"
#include "core/fxge/cfx_renderdevice.h"
#include "third_party/base/ptr_util.h"

CPDF_ProgressiveRenderer::CPDF_ProgressiveRenderer(
    CPDF_RenderContext* pContext,
    CFX_RenderDevice* pDevice,
    const CPDF_RenderOptions* pOptions)
    : m_Status(Ready),
      m_pContext(pContext),
      m_pDevice(pDevice),
      m_pOptions(pOptions),
      m_LayerIndex(0),
      m_pCurrentLayer(nullptr) {}

CPDF_ProgressiveRenderer::~CPDF_ProgressiveRenderer() {
  if (m_pRenderStatus)
    m_pDevice->RestoreState(false);
}

void CPDF_ProgressiveRenderer::Start(IFX_Pause* pPause) {
  if (!m_pContext || !m_pDevice || m_Status != Ready) {
    m_Status = Failed;
    return;
  }
  m_Status = ToBeContinued;
  Continue(pPause);
}

void CPDF_ProgressiveRenderer::Continue(IFX_Pause* pPause) {
  while (m_Status == ToBeContinued) {
    if (!m_pCurrentLayer) {
      if (m_LayerIndex >= m_pContext->CountLayers()) {
        m_Status = Done;
        return;
      }
      m_pCurrentLayer = m_pContext->GetLayer(m_LayerIndex);
      m_LastObjectRendered =
          m_pCurrentLayer->m_pObjectHolder->GetPageObjectList()->end();
      m_pRenderStatus = pdfium::MakeUnique<CPDF_RenderStatus>();
      m_pRenderStatus->Initialize(
          m_pContext, m_pDevice, nullptr, nullptr, nullptr, nullptr, m_pOptions,
          m_pCurrentLayer->m_pObjectHolder->m_Transparency, false, nullptr);
      m_pDevice->SaveState();
      m_ClipRect = CFX_FloatRect(m_pDevice->GetClipBox());
      CFX_Matrix device2object;
      device2object.SetReverse(m_pCurrentLayer->m_Matrix);
      device2object.TransformRect(m_ClipRect);
    }
    CPDF_PageObjectList::iterator iter;
    CPDF_PageObjectList::iterator iterEnd =
        m_pCurrentLayer->m_pObjectHolder->GetPageObjectList()->end();
    if (m_LastObjectRendered != iterEnd) {
      iter = m_LastObjectRendered;
      ++iter;
    } else {
      iter = m_pCurrentLayer->m_pObjectHolder->GetPageObjectList()->begin();
    }
    int nObjsToGo = kStepLimit;
    while (iter != iterEnd) {
      CPDF_PageObject* pCurObj = iter->get();
      if (pCurObj && pCurObj->m_Left <= m_ClipRect.right &&
          pCurObj->m_Right >= m_ClipRect.left &&
          pCurObj->m_Bottom <= m_ClipRect.top &&
          pCurObj->m_Top >= m_ClipRect.bottom) {
        if (m_pRenderStatus->ContinueSingleObject(
                pCurObj, &m_pCurrentLayer->m_Matrix, pPause)) {
          return;
        }
        if (pCurObj->IsImage() &&
            m_pRenderStatus->m_Options.m_Flags & RENDER_LIMITEDIMAGECACHE) {
          m_pContext->GetPageCache()->CacheOptimization(
              m_pRenderStatus->m_Options.m_dwLimitCacheSize);
        }
        if (pCurObj->IsForm() || pCurObj->IsShading())
          nObjsToGo = 0;
        else
          --nObjsToGo;
      }
      m_LastObjectRendered = iter;
      if (nObjsToGo == 0) {
        if (pPause && pPause->NeedToPauseNow())
          return;
        nObjsToGo = kStepLimit;
      }
      ++iter;
    }
    if (m_pCurrentLayer->m_pObjectHolder->IsParsed()) {
      m_pRenderStatus.reset();
      m_pDevice->RestoreState(false);
      m_pCurrentLayer = nullptr;
      m_LayerIndex++;
      if (pPause && pPause->NeedToPauseNow()) {
        return;
      }
    } else {
      m_pCurrentLayer->m_pObjectHolder->ContinueParse(pPause);
      if (!m_pCurrentLayer->m_pObjectHolder->IsParsed())
        return;
    }
  }
}