// Copyright 2017 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.

#include "public/fpdf_annot.h"

#include <memory>
#include <utility>

#include "core/fpdfapi/edit/cpdf_pagecontentgenerator.h"
#include "core/fpdfapi/page/cpdf_form.h"
#include "core/fpdfapi/page/cpdf_page.h"
#include "core/fpdfapi/page/cpdf_pageobject.h"
#include "core/fpdfapi/parser/cpdf_array.h"
#include "core/fpdfapi/parser/cpdf_dictionary.h"
#include "core/fpdfapi/parser/cpdf_document.h"
#include "core/fpdfapi/parser/cpdf_name.h"
#include "core/fpdfapi/parser/cpdf_number.h"
#include "core/fpdfapi/parser/cpdf_string.h"
#include "core/fpdfdoc/cpdf_annot.h"
#include "core/fpdfdoc/cpdf_formfield.h"
#include "core/fpdfdoc/cpdf_interform.h"
#include "core/fpdfdoc/cpvt_generateap.h"
#include "core/fxge/cfx_color.h"
#include "fpdfsdk/cpdfsdk_helpers.h"

namespace {

// These checks ensure the consistency of annotation subtype values across core/
// and public.
static_assert(static_cast<int>(CPDF_Annot::Subtype::UNKNOWN) ==
                  FPDF_ANNOT_UNKNOWN,
              "CPDF_Annot::UNKNOWN value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::TEXT) == FPDF_ANNOT_TEXT,
              "CPDF_Annot::TEXT value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::LINK) == FPDF_ANNOT_LINK,
              "CPDF_Annot::LINK value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::FREETEXT) ==
                  FPDF_ANNOT_FREETEXT,
              "CPDF_Annot::FREETEXT value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::LINE) == FPDF_ANNOT_LINE,
              "CPDF_Annot::LINE value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::SQUARE) ==
                  FPDF_ANNOT_SQUARE,
              "CPDF_Annot::SQUARE value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::CIRCLE) ==
                  FPDF_ANNOT_CIRCLE,
              "CPDF_Annot::CIRCLE value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::POLYGON) ==
                  FPDF_ANNOT_POLYGON,
              "CPDF_Annot::POLYGON value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::POLYLINE) ==
                  FPDF_ANNOT_POLYLINE,
              "CPDF_Annot::POLYLINE value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::HIGHLIGHT) ==
                  FPDF_ANNOT_HIGHLIGHT,
              "CPDF_Annot::HIGHLIGHT value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::UNDERLINE) ==
                  FPDF_ANNOT_UNDERLINE,
              "CPDF_Annot::UNDERLINE value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::SQUIGGLY) ==
                  FPDF_ANNOT_SQUIGGLY,
              "CPDF_Annot::SQUIGGLY value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::STRIKEOUT) ==
                  FPDF_ANNOT_STRIKEOUT,
              "CPDF_Annot::STRIKEOUT value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::STAMP) == FPDF_ANNOT_STAMP,
              "CPDF_Annot::STAMP value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::CARET) == FPDF_ANNOT_CARET,
              "CPDF_Annot::CARET value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::INK) == FPDF_ANNOT_INK,
              "CPDF_Annot::INK value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::POPUP) == FPDF_ANNOT_POPUP,
              "CPDF_Annot::POPUP value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::FILEATTACHMENT) ==
                  FPDF_ANNOT_FILEATTACHMENT,
              "CPDF_Annot::FILEATTACHMENT value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::SOUND) == FPDF_ANNOT_SOUND,
              "CPDF_Annot::SOUND value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::MOVIE) == FPDF_ANNOT_MOVIE,
              "CPDF_Annot::MOVIE value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::WIDGET) ==
                  FPDF_ANNOT_WIDGET,
              "CPDF_Annot::WIDGET value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::SCREEN) ==
                  FPDF_ANNOT_SCREEN,
              "CPDF_Annot::SCREEN value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::PRINTERMARK) ==
                  FPDF_ANNOT_PRINTERMARK,
              "CPDF_Annot::PRINTERMARK value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::TRAPNET) ==
                  FPDF_ANNOT_TRAPNET,
              "CPDF_Annot::TRAPNET value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::WATERMARK) ==
                  FPDF_ANNOT_WATERMARK,
              "CPDF_Annot::WATERMARK value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::THREED) ==
                  FPDF_ANNOT_THREED,
              "CPDF_Annot::THREED value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::RICHMEDIA) ==
                  FPDF_ANNOT_RICHMEDIA,
              "CPDF_Annot::RICHMEDIA value mismatch");
static_assert(static_cast<int>(CPDF_Annot::Subtype::XFAWIDGET) ==
                  FPDF_ANNOT_XFAWIDGET,
              "CPDF_Annot::XFAWIDGET value mismatch");

// These checks ensure the consistency of annotation appearance mode values
// across core/ and public.
static_assert(static_cast<int>(CPDF_Annot::AppearanceMode::Normal) ==
                  FPDF_ANNOT_APPEARANCEMODE_NORMAL,
              "CPDF_Annot::AppearanceMode::Normal value mismatch");
static_assert(static_cast<int>(CPDF_Annot::AppearanceMode::Rollover) ==
                  FPDF_ANNOT_APPEARANCEMODE_ROLLOVER,
              "CPDF_Annot::AppearanceMode::Rollover value mismatch");
static_assert(static_cast<int>(CPDF_Annot::AppearanceMode::Down) ==
                  FPDF_ANNOT_APPEARANCEMODE_DOWN,
              "CPDF_Annot::AppearanceMode::Down value mismatch");

// These checks ensure the consistency of dictionary value types across core/
// and public/.
static_assert(static_cast<int>(CPDF_Object::Type::BOOLEAN) ==
                  FPDF_OBJECT_BOOLEAN,
              "CPDF_Object::BOOLEAN value mismatch");
static_assert(static_cast<int>(CPDF_Object::Type::NUMBER) == FPDF_OBJECT_NUMBER,
              "CPDF_Object::NUMBER value mismatch");
static_assert(static_cast<int>(CPDF_Object::Type::STRING) == FPDF_OBJECT_STRING,
              "CPDF_Object::STRING value mismatch");
static_assert(static_cast<int>(CPDF_Object::Type::NAME) == FPDF_OBJECT_NAME,
              "CPDF_Object::NAME value mismatch");
static_assert(static_cast<int>(CPDF_Object::Type::ARRAY) == FPDF_OBJECT_ARRAY,
              "CPDF_Object::ARRAY value mismatch");
static_assert(static_cast<int>(CPDF_Object::Type::DICTIONARY) ==
                  FPDF_OBJECT_DICTIONARY,
              "CPDF_Object::DICTIONARY value mismatch");
static_assert(static_cast<int>(CPDF_Object::Type::STREAM) == FPDF_OBJECT_STREAM,
              "CPDF_Object::STREAM value mismatch");
static_assert(static_cast<int>(CPDF_Object::Type::NULLOBJ) ==
                  FPDF_OBJECT_NULLOBJ,
              "CPDF_Object::NULLOBJ value mismatch");
static_assert(static_cast<int>(CPDF_Object::Type::REFERENCE) ==
                  FPDF_OBJECT_REFERENCE,
              "CPDF_Object::REFERENCE value mismatch");

class CPDF_AnnotContext {
 public:
  CPDF_AnnotContext(CPDF_Dictionary* pAnnotDict,
                    CPDF_Page* pPage,
                    CPDF_Stream* pStream)
      : m_pAnnotDict(pAnnotDict), m_pPage(pPage) {
    SetForm(pStream);
  }
  ~CPDF_AnnotContext() {}

  bool HasForm() const { return !!m_pAnnotForm; }

  void SetForm(CPDF_Stream* pStream) {
    if (!pStream)
      return;

    // Reset the annotation matrix to be the identity matrix, since the
    // appearance stream already takes matrix into account.
    pStream->GetDict()->SetMatrixFor("Matrix", CFX_Matrix());

    m_pAnnotForm = pdfium::MakeUnique<CPDF_Form>(
        m_pPage->m_pDocument.Get(), m_pPage->m_pResources.Get(), pStream);
    m_pAnnotForm->ParseContent();
  }

  CPDF_Form* GetForm() const { return m_pAnnotForm.get(); }
  CPDF_Dictionary* GetAnnotDict() const { return m_pAnnotDict.Get(); }
  CPDF_Page* GetPage() const { return m_pPage.Get(); }

 private:
  std::unique_ptr<CPDF_Form> m_pAnnotForm;
  UnownedPtr<CPDF_Dictionary> m_pAnnotDict;
  UnownedPtr<CPDF_Page> m_pPage;
};

CPDF_AnnotContext* CPDFAnnotContextFromFPDFAnnotation(FPDF_ANNOTATION annot) {
  return static_cast<CPDF_AnnotContext*>(annot);
}

bool HasAPStream(const CPDF_Dictionary* pAnnotDict) {
  return !!FPDFDOC_GetAnnotAP(pAnnotDict, CPDF_Annot::AppearanceMode::Normal);
}

void UpdateContentStream(CPDF_Form* pForm, CPDF_Stream* pStream) {
  ASSERT(pForm);
  ASSERT(pStream);

  CPDF_PageContentGenerator generator(pForm);
  std::ostringstream buf;
  generator.ProcessPageObjects(&buf);
  pStream->SetDataAndRemoveFilter(&buf);
}

void SetQuadPointsAtIndex(CPDF_Array* array,
                          size_t quad_index,
                          const FS_QUADPOINTSF* quad_points) {
  ASSERT(array);
  ASSERT(quad_points);
  ASSERT(IsValidQuadPointsIndex(array, quad_index));

  size_t nIndex = quad_index * 8;
  array->SetNewAt<CPDF_Number>(nIndex, quad_points->x1);
  array->SetNewAt<CPDF_Number>(++nIndex, quad_points->y1);
  array->SetNewAt<CPDF_Number>(++nIndex, quad_points->x2);
  array->SetNewAt<CPDF_Number>(++nIndex, quad_points->y2);
  array->SetNewAt<CPDF_Number>(++nIndex, quad_points->x3);
  array->SetNewAt<CPDF_Number>(++nIndex, quad_points->y3);
  array->SetNewAt<CPDF_Number>(++nIndex, quad_points->x4);
  array->SetNewAt<CPDF_Number>(++nIndex, quad_points->y4);
}

void AppendQuadPoints(CPDF_Array* array, const FS_QUADPOINTSF* quad_points) {
  ASSERT(quad_points);
  ASSERT(array);

  array->AddNew<CPDF_Number>(quad_points->x1);
  array->AddNew<CPDF_Number>(quad_points->y1);
  array->AddNew<CPDF_Number>(quad_points->x2);
  array->AddNew<CPDF_Number>(quad_points->y2);
  array->AddNew<CPDF_Number>(quad_points->x3);
  array->AddNew<CPDF_Number>(quad_points->y3);
  array->AddNew<CPDF_Number>(quad_points->x4);
  array->AddNew<CPDF_Number>(quad_points->y4);
}

void UpdateBBox(const CPDF_Dictionary* annot_dict) {
  // Update BBox entry in appearance stream based on the bounding rectangle
  // of the annotation's quadpoints.
  CPDF_Stream* pStream =
      FPDFDOC_GetAnnotAP(annot_dict, CPDF_Annot::AppearanceMode::Normal);
  if (pStream) {
    CFX_FloatRect boundingRect =
        CPDF_Annot::BoundingRectFromQuadPoints(annot_dict);
    if (boundingRect.Contains(pStream->GetDict()->GetRectFor("BBox")))
      pStream->GetDict()->SetRectFor("BBox", boundingRect);
  }
}

}  // namespace

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
FPDFAnnot_IsSupportedSubtype(FPDF_ANNOTATION_SUBTYPE subtype) {
  // The supported subtypes must also be communicated in the user doc.
  return subtype == FPDF_ANNOT_CIRCLE || subtype == FPDF_ANNOT_FREETEXT ||
         subtype == FPDF_ANNOT_HIGHLIGHT || subtype == FPDF_ANNOT_INK ||
         subtype == FPDF_ANNOT_POPUP || subtype == FPDF_ANNOT_SQUARE ||
         subtype == FPDF_ANNOT_SQUIGGLY || subtype == FPDF_ANNOT_STAMP ||
         subtype == FPDF_ANNOT_STRIKEOUT || subtype == FPDF_ANNOT_TEXT ||
         subtype == FPDF_ANNOT_UNDERLINE;
}

FPDF_EXPORT FPDF_ANNOTATION FPDF_CALLCONV
FPDFPage_CreateAnnot(FPDF_PAGE page, FPDF_ANNOTATION_SUBTYPE subtype) {
  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
  if (!pPage || !FPDFAnnot_IsSupportedSubtype(subtype))
    return nullptr;

  auto pDict = pdfium::MakeUnique<CPDF_Dictionary>(
      pPage->m_pDocument->GetByteStringPool());
  pDict->SetNewFor<CPDF_Name>("Type", "Annot");
  pDict->SetNewFor<CPDF_Name>("Subtype",
                              CPDF_Annot::AnnotSubtypeToString(
                                  static_cast<CPDF_Annot::Subtype>(subtype)));
  auto pNewAnnot =
      pdfium::MakeUnique<CPDF_AnnotContext>(pDict.get(), pPage, nullptr);

  CPDF_Array* pAnnotList = pPage->m_pFormDict->GetArrayFor("Annots");
  if (!pAnnotList)
    pAnnotList = pPage->m_pFormDict->SetNewFor<CPDF_Array>("Annots");

  pAnnotList->Add(std::move(pDict));
  return pNewAnnot.release();
}

FPDF_EXPORT int FPDF_CALLCONV FPDFPage_GetAnnotCount(FPDF_PAGE page) {
  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
  if (!pPage || !pPage->m_pFormDict)
    return 0;

  CPDF_Array* pAnnots = pPage->m_pFormDict->GetArrayFor("Annots");
  return pAnnots ? pAnnots->GetCount() : 0;
}

FPDF_EXPORT FPDF_ANNOTATION FPDF_CALLCONV FPDFPage_GetAnnot(FPDF_PAGE page,
                                                            int index) {
  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
  if (!pPage || !pPage->m_pFormDict || index < 0)
    return nullptr;

  CPDF_Array* pAnnots = pPage->m_pFormDict->GetArrayFor("Annots");
  if (!pAnnots || static_cast<size_t>(index) >= pAnnots->GetCount())
    return nullptr;

  CPDF_Dictionary* pDict = ToDictionary(pAnnots->GetDirectObjectAt(index));
  auto pNewAnnot = pdfium::MakeUnique<CPDF_AnnotContext>(pDict, pPage, nullptr);
  return pNewAnnot.release();
}

FPDF_EXPORT int FPDF_CALLCONV FPDFPage_GetAnnotIndex(FPDF_PAGE page,
                                                     FPDF_ANNOTATION annot) {
  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
  CPDF_AnnotContext* pAnnot = CPDFAnnotContextFromFPDFAnnotation(annot);
  if (!pPage || !pPage->m_pFormDict || !pAnnot || !pAnnot->GetAnnotDict())
    return -1;

  CPDF_Array* pAnnots = pPage->m_pFormDict->GetArrayFor("Annots");
  if (!pAnnots)
    return -1;

  CPDF_Dictionary* pDict = pAnnot->GetAnnotDict();
  auto it =
      std::find_if(pAnnots->begin(), pAnnots->end(),
                   [pDict](const std::unique_ptr<CPDF_Object>& candidate) {
                     return candidate->GetDirect() == pDict;
                   });

  if (it == pAnnots->end())
    return -1;

  return it - pAnnots->begin();
}

FPDF_EXPORT void FPDF_CALLCONV FPDFPage_CloseAnnot(FPDF_ANNOTATION annot) {
  delete CPDFAnnotContextFromFPDFAnnotation(annot);
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDFPage_RemoveAnnot(FPDF_PAGE page,
                                                         int index) {
  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
  if (!pPage || !pPage->m_pFormDict || index < 0)
    return false;

  CPDF_Array* pAnnots = pPage->m_pFormDict->GetArrayFor("Annots");
  if (!pAnnots || static_cast<size_t>(index) >= pAnnots->GetCount())
    return false;

  pAnnots->RemoveAt(index);
  return true;
}

FPDF_EXPORT FPDF_ANNOTATION_SUBTYPE FPDF_CALLCONV
FPDFAnnot_GetSubtype(FPDF_ANNOTATION annot) {
  if (!annot)
    return FPDF_ANNOT_UNKNOWN;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  if (!pAnnotDict)
    return FPDF_ANNOT_UNKNOWN;

  return static_cast<FPDF_ANNOTATION_SUBTYPE>(
      CPDF_Annot::StringToAnnotSubtype(pAnnotDict->GetStringFor("Subtype")));
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
FPDFAnnot_IsObjectSupportedSubtype(FPDF_ANNOTATION_SUBTYPE subtype) {
  // The supported subtypes must also be communicated in the user doc.
  return subtype == FPDF_ANNOT_INK || subtype == FPDF_ANNOT_STAMP;
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
FPDFAnnot_UpdateObject(FPDF_ANNOTATION annot, FPDF_PAGEOBJECT obj) {
  CPDF_AnnotContext* pAnnot = CPDFAnnotContextFromFPDFAnnotation(annot);
  CPDF_PageObject* pObj = CPDFPageObjectFromFPDFPageObject(obj);
  if (!pAnnot || !pAnnot->GetAnnotDict() || !pAnnot->HasForm() || !pObj)
    return false;

  // Check that the annotation type is supported by this method.
  if (!FPDFAnnot_IsObjectSupportedSubtype(FPDFAnnot_GetSubtype(annot)))
    return false;

  // Check that the annotation already has an appearance stream, since an
  // existing object is to be updated.
  CPDF_Stream* pStream = FPDFDOC_GetAnnotAP(pAnnot->GetAnnotDict(),
                                            CPDF_Annot::AppearanceMode::Normal);
  if (!pStream)
    return false;

  // Check that the object is already in this annotation's object list.
  CPDF_Form* pForm = pAnnot->GetForm();
  const CPDF_PageObjectList* pObjList = pForm->GetPageObjectList();
  auto it =
      std::find_if(pObjList->begin(), pObjList->end(),
                   [pObj](const std::unique_ptr<CPDF_PageObject>& candidate) {
                     return candidate.get() == pObj;
                   });
  if (it == pObjList->end())
    return false;

  // Update the content stream data in the annotation's AP stream.
  UpdateContentStream(pForm, pStream);
  return true;
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
FPDFAnnot_AppendObject(FPDF_ANNOTATION annot, FPDF_PAGEOBJECT obj) {
  CPDF_AnnotContext* pAnnot = CPDFAnnotContextFromFPDFAnnotation(annot);
  CPDF_PageObject* pObj = CPDFPageObjectFromFPDFPageObject(obj);
  if (!pAnnot || !pObj)
    return false;

  CPDF_Dictionary* pAnnotDict = pAnnot->GetAnnotDict();
  CPDF_Page* pPage = pAnnot->GetPage();
  if (!pAnnotDict || !pPage)
    return false;

  // Check that the annotation type is supported by this method.
  if (!FPDFAnnot_IsObjectSupportedSubtype(FPDFAnnot_GetSubtype(annot)))
    return false;

  // If the annotation does not have an AP stream yet, generate and set it.
  CPDF_Stream* pStream = FPDFDOC_GetAnnotAP(pAnnot->GetAnnotDict(),
                                            CPDF_Annot::AppearanceMode::Normal);
  if (!pStream) {
    CPVT_GenerateAP::GenerateEmptyAP(pPage->m_pDocument.Get(), pAnnotDict);
    pStream =
        FPDFDOC_GetAnnotAP(pAnnotDict, CPDF_Annot::AppearanceMode::Normal);
    if (!pStream)
      return false;
  }

  // Get the annotation's corresponding form object for parsing its AP stream.
  if (!pAnnot->HasForm())
    pAnnot->SetForm(pStream);

  // Check that the object did not come from the same annotation. If this check
  // succeeds, then it is assumed that the object came from
  // FPDFPageObj_CreateNew{Path|Rect}() or FPDFPageObj_New{Text|Image}Obj().
  // Note that an object that came from a different annotation must not be
  // passed here, since an object cannot belong to more than one annotation.
  CPDF_Form* pForm = pAnnot->GetForm();
  const CPDF_PageObjectList* pObjList = pForm->GetPageObjectList();
  auto it =
      std::find_if(pObjList->begin(), pObjList->end(),
                   [pObj](const std::unique_ptr<CPDF_PageObject>& candidate) {
                     return candidate.get() == pObj;
                   });
  if (it != pObjList->end())
    return false;

  // Append the object to the object list.
  pForm->AppendPageObject(pdfium::WrapUnique(pObj));

  // Set the content stream data in the annotation's AP stream.
  UpdateContentStream(pForm, pStream);
  return true;
}

FPDF_EXPORT int FPDF_CALLCONV FPDFAnnot_GetObjectCount(FPDF_ANNOTATION annot) {
  CPDF_AnnotContext* pAnnot = CPDFAnnotContextFromFPDFAnnotation(annot);
  if (!pAnnot || !pAnnot->GetAnnotDict())
    return 0;

  if (!pAnnot->HasForm()) {
    CPDF_Stream* pStream = FPDFDOC_GetAnnotAP(
        pAnnot->GetAnnotDict(), CPDF_Annot::AppearanceMode::Normal);
    if (!pStream)
      return 0;

    pAnnot->SetForm(pStream);
  }
  return pdfium::CollectionSize<int>(*pAnnot->GetForm()->GetPageObjectList());
}

FPDF_EXPORT FPDF_PAGEOBJECT FPDF_CALLCONV
FPDFAnnot_GetObject(FPDF_ANNOTATION annot, int index) {
  CPDF_AnnotContext* pAnnot = CPDFAnnotContextFromFPDFAnnotation(annot);
  if (!pAnnot || !pAnnot->GetAnnotDict() || index < 0)
    return nullptr;

  if (!pAnnot->HasForm()) {
    CPDF_Stream* pStream = FPDFDOC_GetAnnotAP(
        pAnnot->GetAnnotDict(), CPDF_Annot::AppearanceMode::Normal);
    if (!pStream)
      return nullptr;

    pAnnot->SetForm(pStream);
  }

  return pAnnot->GetForm()->GetPageObjectByIndex(index);
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
FPDFAnnot_RemoveObject(FPDF_ANNOTATION annot, int index) {
  CPDF_AnnotContext* pAnnot = CPDFAnnotContextFromFPDFAnnotation(annot);
  if (!pAnnot || !pAnnot->GetAnnotDict() || !pAnnot->HasForm() || index < 0)
    return false;

  // Check that the annotation type is supported by this method.
  if (!FPDFAnnot_IsObjectSupportedSubtype(FPDFAnnot_GetSubtype(annot)))
    return false;

  // Check that the annotation already has an appearance stream, since an
  // existing object is to be deleted.
  CPDF_Stream* pStream = FPDFDOC_GetAnnotAP(pAnnot->GetAnnotDict(),
                                            CPDF_Annot::AppearanceMode::Normal);
  if (!pStream)
    return false;

  if (!pAnnot->GetForm()->ErasePageObjectAtIndex(index))
    return false;

  UpdateContentStream(pAnnot->GetForm(), pStream);
  return true;
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDFAnnot_SetColor(FPDF_ANNOTATION annot,
                                                       FPDFANNOT_COLORTYPE type,
                                                       unsigned int R,
                                                       unsigned int G,
                                                       unsigned int B,
                                                       unsigned int A) {
  if (!annot || R > 255 || G > 255 || B > 255 || A > 255)
    return false;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  if (!pAnnotDict)
    return false;

  // For annotations with their appearance streams already defined, the path
  // stream's own color definitions take priority over the annotation color
  // definitions set by this method, hence this method will simply fail.
  if (HasAPStream(pAnnotDict))
    return false;

  // Set the opacity of the annotation.
  pAnnotDict->SetNewFor<CPDF_Number>("CA", A / 255.f);

  // Set the color of the annotation.
  ByteString key = type == FPDFANNOT_COLORTYPE_InteriorColor ? "IC" : "C";
  CPDF_Array* pColor = pAnnotDict->GetArrayFor(key);
  if (pColor)
    pColor->Clear();
  else
    pColor = pAnnotDict->SetNewFor<CPDF_Array>(key);

  pColor->AddNew<CPDF_Number>(R / 255.f);
  pColor->AddNew<CPDF_Number>(G / 255.f);
  pColor->AddNew<CPDF_Number>(B / 255.f);

  return true;
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDFAnnot_GetColor(FPDF_ANNOTATION annot,
                                                       FPDFANNOT_COLORTYPE type,
                                                       unsigned int* R,
                                                       unsigned int* G,
                                                       unsigned int* B,
                                                       unsigned int* A) {
  if (!annot || !R || !G || !B || !A)
    return false;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  if (!pAnnotDict)
    return false;

  // For annotations with their appearance streams already defined, the path
  // stream's own color definitions take priority over the annotation color
  // definitions retrieved by this method, hence this method will simply fail.
  if (HasAPStream(pAnnotDict))
    return false;

  CPDF_Array* pColor = pAnnotDict->GetArrayFor(
      type == FPDFANNOT_COLORTYPE_InteriorColor ? "IC" : "C");
  *A =
      (pAnnotDict->KeyExist("CA") ? pAnnotDict->GetNumberFor("CA") : 1) * 255.f;
  if (!pColor) {
    // Use default color. The default colors must be consistent with the ones
    // used to generate AP. See calls to GetColorStringWithDefault() in
    // CPVT_GenerateAP::Generate*AP().
    if (pAnnotDict->GetStringFor("Subtype") == "Highlight") {
      *R = 255;
      *G = 255;
      *B = 0;
    } else {
      *R = 0;
      *G = 0;
      *B = 0;
    }
    return true;
  }

  CFX_Color color = CFX_Color::ParseColor(*pColor);
  switch (color.nColorType) {
    case CFX_Color::kRGB:
      *R = color.fColor1 * 255.f;
      *G = color.fColor2 * 255.f;
      *B = color.fColor3 * 255.f;
      break;
    case CFX_Color::kGray:
      *R = 255.f * color.fColor1;
      *G = 255.f * color.fColor1;
      *B = 255.f * color.fColor1;
      break;
    case CFX_Color::kCMYK:
      *R = 255.f * (1 - color.fColor1) * (1 - color.fColor4);
      *G = 255.f * (1 - color.fColor2) * (1 - color.fColor4);
      *B = 255.f * (1 - color.fColor3) * (1 - color.fColor4);
      break;
    case CFX_Color::kTransparent:
      *R = 0;
      *G = 0;
      *B = 0;
      break;
  }
  return true;
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
FPDFAnnot_HasAttachmentPoints(FPDF_ANNOTATION annot) {
  if (!annot)
    return false;

  FPDF_ANNOTATION_SUBTYPE subtype = FPDFAnnot_GetSubtype(annot);
  return subtype == FPDF_ANNOT_LINK || subtype == FPDF_ANNOT_HIGHLIGHT ||
         subtype == FPDF_ANNOT_UNDERLINE || subtype == FPDF_ANNOT_SQUIGGLY ||
         subtype == FPDF_ANNOT_STRIKEOUT;
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
FPDFAnnot_SetAttachmentPoints(FPDF_ANNOTATION annot,
                              size_t quad_index,
                              const FS_QUADPOINTSF* quad_points) {
  if (!FPDFAnnot_HasAttachmentPoints(annot) || !quad_points)
    return false;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  CPDF_Array* pQuadPointsArray = GetQuadPointsArrayFromDictionary(pAnnotDict);
  if (!IsValidQuadPointsIndex(pQuadPointsArray, quad_index))
    return false;

  SetQuadPointsAtIndex(pQuadPointsArray, quad_index, quad_points);
  UpdateBBox(pAnnotDict);
  return true;
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
FPDFAnnot_AppendAttachmentPoints(FPDF_ANNOTATION annot,
                                 const FS_QUADPOINTSF* quad_points) {
  if (!FPDFAnnot_HasAttachmentPoints(annot) || !quad_points)
    return false;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  CPDF_Array* pQuadPointsArray = GetQuadPointsArrayFromDictionary(pAnnotDict);
  if (!pQuadPointsArray)
    pQuadPointsArray = AddQuadPointsArrayToDictionary(pAnnotDict);
  AppendQuadPoints(pQuadPointsArray, quad_points);
  UpdateBBox(pAnnotDict);
  return true;
}

FPDF_EXPORT size_t FPDF_CALLCONV
FPDFAnnot_CountAttachmentPoints(FPDF_ANNOTATION annot) {
  if (!FPDFAnnot_HasAttachmentPoints(annot))
    return 0;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  const CPDF_Array* pArray = GetQuadPointsArrayFromDictionary(pAnnotDict);
  return pArray ? pArray->GetCount() / 8 : 0;
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
FPDFAnnot_GetAttachmentPoints(FPDF_ANNOTATION annot,
                              size_t quad_index,
                              FS_QUADPOINTSF* quad_points) {
  if (!FPDFAnnot_HasAttachmentPoints(annot) || !quad_points)
    return false;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  if (!pAnnotDict)
    return false;

  const CPDF_Array* pArray = GetQuadPointsArrayFromDictionary(pAnnotDict);
  if (!pArray)
    return false;

  return GetQuadPointsAtIndex(pArray, quad_index, quad_points);
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDFAnnot_SetRect(FPDF_ANNOTATION annot,
                                                      const FS_RECTF* rect) {
  if (!annot || !rect)
    return false;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  if (!pAnnotDict)
    return false;

  CFX_FloatRect newRect = CFXFloatRectFromFSRECTF(*rect);

  // Update the "Rect" entry in the annotation dictionary.
  pAnnotDict->SetRectFor("Rect", newRect);

  // If the annotation's appearance stream is defined, the annotation is of a
  // type that does not have quadpoints, and the new rectangle is bigger than
  // the current bounding box, then update the "BBox" entry in the AP
  // dictionary too, since its "BBox" entry comes from annotation dictionary's
  // "Rect" entry.
  if (FPDFAnnot_HasAttachmentPoints(annot))
    return true;

  CPDF_Stream* pStream =
      FPDFDOC_GetAnnotAP(pAnnotDict, CPDF_Annot::AppearanceMode::Normal);
  if (pStream && newRect.Contains(pStream->GetDict()->GetRectFor("BBox")))
    pStream->GetDict()->SetRectFor("BBox", newRect);
  return true;
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDFAnnot_GetRect(FPDF_ANNOTATION annot,
                                                      FS_RECTF* rect) {
  if (!annot || !rect)
    return false;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  if (!pAnnotDict)
    return false;

  FSRECTFFromCFXFloatRect(pAnnotDict->GetRectFor("Rect"), rect);
  return true;
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDFAnnot_HasKey(FPDF_ANNOTATION annot,
                                                     FPDF_BYTESTRING key) {
  if (!annot)
    return false;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  if (!pAnnotDict)
    return false;

  return pAnnotDict->KeyExist(key);
}

FPDF_EXPORT FPDF_OBJECT_TYPE FPDF_CALLCONV
FPDFAnnot_GetValueType(FPDF_ANNOTATION annot, FPDF_BYTESTRING key) {
  if (!FPDFAnnot_HasKey(annot, key))
    return FPDF_OBJECT_UNKNOWN;

  auto* pAnnot = CPDFAnnotContextFromFPDFAnnotation(annot);
  CPDF_Object* pObj = pAnnot->GetAnnotDict()->GetObjectFor(key);
  return pObj ? pObj->GetType() : FPDF_OBJECT_UNKNOWN;
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
FPDFAnnot_SetStringValue(FPDF_ANNOTATION annot,
                         FPDF_BYTESTRING key,
                         FPDF_WIDESTRING value) {
  if (!annot)
    return false;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  if (!pAnnotDict)
    return false;

  pAnnotDict->SetNewFor<CPDF_String>(
      key, CFXByteStringFromFPDFWideString(value), false);
  return true;
}

FPDF_EXPORT unsigned long FPDF_CALLCONV
FPDFAnnot_GetStringValue(FPDF_ANNOTATION annot,
                         FPDF_BYTESTRING key,
                         void* buffer,
                         unsigned long buflen) {
  if (!annot)
    return 0;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  if (!pAnnotDict)
    return 0;

  return Utf16EncodeMaybeCopyAndReturnLength(pAnnotDict->GetUnicodeTextFor(key),
                                             buffer, buflen);
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
FPDFAnnot_SetAP(FPDF_ANNOTATION annot,
                FPDF_ANNOT_APPEARANCEMODE appearanceMode,
                FPDF_WIDESTRING value) {
  if (appearanceMode < 0 || appearanceMode >= FPDF_ANNOT_APPEARANCEMODE_COUNT)
    return false;

  if (!annot)
    return false;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  if (!pAnnotDict)
    return false;

  constexpr const char* modeKeyForMode[] = {"N", "R", "D"};
  static_assert(FX_ArraySize(modeKeyForMode) == FPDF_ANNOT_APPEARANCEMODE_COUNT,
                "length of modeKeyForMode should be equal to "
                "FPDF_ANNOT_APPEARANCEMODE_COUNT");
  const char* modeKey = modeKeyForMode[appearanceMode];

  CPDF_Dictionary* pApDict = pAnnotDict->GetDictFor("AP");

  // If value is null, we're in remove mode. Otherwise, we're in add/update
  // mode.
  if (value) {
    if (!pApDict)
      pApDict = pAnnotDict->SetNewFor<CPDF_Dictionary>("AP");

    ByteString newValue = CFXByteStringFromFPDFWideString(value);
    auto pNewApStream = pdfium::MakeUnique<CPDF_Stream>();
    pNewApStream->SetData(newValue.raw_str(), newValue.GetLength());
    pApDict->SetFor(modeKey, std::move(pNewApStream));
  } else {
    if (pApDict) {
      if (appearanceMode == FPDF_ANNOT_APPEARANCEMODE_NORMAL)
        pAnnotDict->RemoveFor("AP");
      else
        pApDict->RemoveFor(modeKey);
    }
  }

  return true;
}

FPDF_EXPORT unsigned long FPDF_CALLCONV
FPDFAnnot_GetAP(FPDF_ANNOTATION annot,
                FPDF_ANNOT_APPEARANCEMODE appearanceMode,
                void* buffer,
                unsigned long buflen) {
  if (appearanceMode < 0 || appearanceMode >= FPDF_ANNOT_APPEARANCEMODE_COUNT)
    return 0;

  if (!annot)
    return 0;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  if (!pAnnotDict)
    return 0;

  CPDF_Annot::AppearanceMode mode =
      static_cast<CPDF_Annot::AppearanceMode>(appearanceMode);

  CPDF_Stream* pStream = FPDFDOC_GetAnnotAPNoFallback(pAnnotDict, mode);
  return Utf16EncodeMaybeCopyAndReturnLength(
      pStream ? pStream->GetUnicodeText() : L"", buffer, buflen);
}

FPDF_EXPORT FPDF_ANNOTATION FPDF_CALLCONV
FPDFAnnot_GetLinkedAnnot(FPDF_ANNOTATION annot, FPDF_BYTESTRING key) {
  CPDF_AnnotContext* pAnnot = CPDFAnnotContextFromFPDFAnnotation(annot);
  if (!pAnnot || !pAnnot->GetAnnotDict())
    return nullptr;

  CPDF_Dictionary* pLinkedDict = pAnnot->GetAnnotDict()->GetDictFor(key);
  if (!pLinkedDict || pLinkedDict->GetStringFor("Type") != "Annot")
    return nullptr;

  auto pLinkedAnnot = pdfium::MakeUnique<CPDF_AnnotContext>(
      pLinkedDict, pAnnot->GetPage(), nullptr);
  return pLinkedAnnot.release();
}

FPDF_EXPORT int FPDF_CALLCONV FPDFAnnot_GetFlags(FPDF_ANNOTATION annot) {
  if (!annot)
    return FPDF_ANNOT_FLAG_NONE;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  return pAnnotDict ? pAnnotDict->GetIntegerFor("F") : FPDF_ANNOT_FLAG_NONE;
}

FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDFAnnot_SetFlags(FPDF_ANNOTATION annot,
                                                       int flags) {
  if (!annot)
    return false;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  if (!pAnnotDict)
    return false;

  pAnnotDict->SetNewFor<CPDF_Number>("F", flags);
  return true;
}

FPDF_EXPORT int FPDF_CALLCONV
FPDFAnnot_GetFormFieldFlags(FPDF_PAGE page, FPDF_ANNOTATION annot) {
  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
  if (!pPage || !annot)
    return FPDF_FORMFLAG_NONE;

  CPDF_Dictionary* pAnnotDict =
      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
  if (!pAnnotDict)
    return FPDF_FORMFLAG_NONE;

  CPDF_InterForm interform(pPage->m_pDocument.Get());
  CPDF_FormField* pFormField = interform.GetFieldByDict(pAnnotDict);
  return pFormField ? pFormField->GetFieldFlags() : FPDF_FORMFLAG_NONE;
}

FPDF_EXPORT FPDF_ANNOTATION FPDF_CALLCONV
FPDFAnnot_GetFormFieldAtPoint(FPDF_FORMHANDLE hHandle,
                              FPDF_PAGE page,
                              double page_x,
                              double page_y) {
  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
  if (!hHandle || !pPage)
    return nullptr;

  CPDF_InterForm interform(pPage->m_pDocument.Get());
  int annot_index = -1;
  CPDF_FormControl* pFormCtrl = interform.GetControlAtPoint(
      pPage, CFX_PointF(static_cast<float>(page_x), static_cast<float>(page_y)),
      &annot_index);
  if (!pFormCtrl || annot_index == -1)
    return nullptr;
  return FPDFPage_GetAnnot(page, annot_index);
}