// Copyright (c) 2017 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#include <Graphic3d_LightSet.hxx>

#include <NCollection_LocalArray.hxx>

IMPLEMENT_STANDARD_RTTIEXT(Graphic3d_LightSet, Standard_Transient)

namespace
{
  //! Suffixes identifying light source type.
  static const char THE_LIGHT_KEY_LETTERS[Graphic3d_TypeOfLightSource_NB] =
  {
    'a', // Graphic3d_TOLS_AMBIENT
    'd', // Graphic3d_TOLS_DIRECTIONAL
    'p', // Graphic3d_TOLS_POSITIONAL
    's'  // Graphic3d_TOLS_SPOT
  };
}

// =======================================================================
// function : Graphic3d_LightSet
// purpose  :
// =======================================================================
Graphic3d_LightSet::Graphic3d_LightSet()
: myAmbient (0.0f, 0.0f, 0.0f, 0.0f),
  myNbEnabled (0),
  myRevision (1),
  myCacheRevision (0)
{
  memset (myLightTypes,        0, sizeof(myLightTypes));
  memset (myLightTypesEnabled, 0, sizeof(myLightTypesEnabled));
}

// =======================================================================
// function : Add
// purpose  :
// =======================================================================
Standard_Boolean Graphic3d_LightSet::Add (const Handle(Graphic3d_CLight)& theLight)
{
  if (theLight.IsNull())
  {
    throw Standard_ProgramError ("Graphic3d_LightSet::Add(), NULL argument");
  }

  const Standard_Integer anOldExtent = myLights.Extent();
  const Standard_Integer anIndex     = myLights.Add (theLight, 0);
  if (anIndex <= anOldExtent)
  {
    return Standard_False;
  }

  myLightTypes[theLight->Type()] += 1;
  myLights.ChangeFromIndex (anIndex) = theLight->Revision();
  ++myRevision;
  return Standard_True;
}

// =======================================================================
// function : Remove
// purpose  :
// =======================================================================
Standard_Boolean Graphic3d_LightSet::Remove (const Handle(Graphic3d_CLight)& theLight)
{
  const Standard_Integer anIndToRemove = myLights.FindIndex (theLight);
  if (anIndToRemove <= 0)
  {
    return Standard_False;
  }

  ++myRevision;
  myLights.RemoveFromIndex (anIndToRemove);
  myLightTypes[theLight->Type()] -= 1;
  return Standard_True;
}

// =======================================================================
// function : UpdateRevision
// purpose  :
// =======================================================================
Standard_Size Graphic3d_LightSet::UpdateRevision()
{
  if (myCacheRevision == myRevision)
  {
    // check implicit updates of light sources
    for (NCollection_IndexedDataMap<Handle(Graphic3d_CLight), Standard_Size>::Iterator aLightIter (myLights); aLightIter.More(); aLightIter.Next())
    {
      const Handle(Graphic3d_CLight)& aLight = aLightIter.Key();
      if (aLightIter.Value() != aLight->Revision())
      {
        ++myRevision;
        break;
      }
    }
  }
  if (myCacheRevision == myRevision)
  {
    return myRevision;
  }

  myCacheRevision = myRevision;
  myAmbient.SetValues (0.0f, 0.0f, 0.0f, 0.0f);
  memset (myLightTypesEnabled, 0, sizeof(myLightTypesEnabled));
  NCollection_LocalArray<char, 32> aKeyLong (myLights.Extent() + 1);
  Standard_Integer aLightLast = 0;
  for (NCollection_IndexedDataMap<Handle(Graphic3d_CLight), Standard_Size>::Iterator aLightIter (myLights); aLightIter.More(); aLightIter.Next())
  {
    const Handle(Graphic3d_CLight)& aLight = aLightIter.Key();
    aLightIter.ChangeValue() = aLight->Revision();
    if (!aLight->IsEnabled())
    {
      continue;
    }

    myLightTypesEnabled[aLight->Type()] += 1;
    if (aLight->Type() == Graphic3d_TOLS_AMBIENT)
    {
      myAmbient += aLight->PackedColor() * aLight->Intensity();
    }
    else
    {
      aKeyLong[aLightLast++] = THE_LIGHT_KEY_LETTERS[aLight->Type()];
    }
  }
  aKeyLong[aLightLast] = '\0';
  myAmbient.a() = 1.0f;
  myNbEnabled = myLightTypesEnabled[Graphic3d_TOLS_DIRECTIONAL]
              + myLightTypesEnabled[Graphic3d_TOLS_POSITIONAL]
              + myLightTypesEnabled[Graphic3d_TOLS_SPOT];
  myKeyEnabledLong  = aKeyLong;
  myKeyEnabledShort = TCollection_AsciiString (myLightTypesEnabled[Graphic3d_TOLS_DIRECTIONAL] > 0 ? THE_LIGHT_KEY_LETTERS[Graphic3d_TOLS_DIRECTIONAL] : '\0')
                    + TCollection_AsciiString (myLightTypesEnabled[Graphic3d_TOLS_POSITIONAL]  > 0 ? THE_LIGHT_KEY_LETTERS[Graphic3d_TOLS_POSITIONAL]  : '\0')
                    + TCollection_AsciiString (myLightTypesEnabled[Graphic3d_TOLS_SPOT]        > 0 ? THE_LIGHT_KEY_LETTERS[Graphic3d_TOLS_SPOT]        : '\0');
  return myRevision;
}