#pragma region CPL License
/*
Nuclex Native Framework
Copyright (C) 2002-2013 Nuclex Development Labs

This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
IBM Common Public License for more details.

You should have received a copy of the IBM Common Public
License along with this library
*/
#pragma endregion // CPL License

// If the library is compiled as a DLL, this ensures symbols are exported
#define NUCLEX_GRAPHICS_SOURCE 1

#include "Nuclex/Graphics/Rasterization/Buffer.h"

#include <stdexcept>
#include <cassert>
#include <algorithm>

#undef min
#undef max

namespace Nuclex { namespace Graphics { namespace Rasterization {

  // ------------------------------------------------------------------------------------------- //

  Buffer::Buffer(std::size_t capacityInBytes) :
    CapacityBytes(capacityInBytes),
    usedBytes(0),
    firstChangeOffset(0),
    lastChangeOffset(0),
    Contents(new std::uint8_t[capacityInBytes]) {}

  // ------------------------------------------------------------------------------------------- //

  Buffer::Buffer(const Buffer &other) :
    CapacityBytes(other.CapacityBytes),
    usedBytes(other.usedBytes),
    firstChangeOffset(0),
    lastChangeOffset(0),
    Contents(new std::uint8_t[this->CapacityBytes]) {
    std::copy_n(other.Contents, this->usedBytes, this->Contents);
  }

  // ------------------------------------------------------------------------------------------- //

  Buffer::~Buffer() {
    delete []this->Contents;
  }

  // ------------------------------------------------------------------------------------------- //

  void Buffer::SuppressChangeNotifications() {
    this->firstChangeOffset = static_cast<std::size_t>(-1);
    this->lastChangeOffset = 0;
  }

  // ------------------------------------------------------------------------------------------- //

  void Buffer::PermitChangeNotifications() {
    std::size_t firstChangeOffset = this->firstChangeOffset;
    std::size_t lastChangeOffset = this->lastChangeOffset;

    this->firstChangeOffset = 0;
    this->lastChangeOffset = 0;

    if(firstChangeOffset < lastChangeOffset) {
      OnChanged(firstChangeOffset, lastChangeOffset);
    }
  }

  // ------------------------------------------------------------------------------------------- //

  Buffer::Observer *Buffer::GetObserver(const void *owner) const {
    return this->observers.Get(owner);
  }

  // ------------------------------------------------------------------------------------------- //

  void Buffer::AttachObserver(const void *owner, Observer *observer) {
    using namespace std;

    bool wasUnique = this->observers.AttachUnique(owner, observer);

    // Observer management should be accurate and error-free!
    assert(wasUnique && "Only one observer can be attached per owner");
    wasUnique; // avoid unreferenced parameter warning
  }

  // ------------------------------------------------------------------------------------------- //

  void Buffer::DetachObserver(const void *owner) {
    using namespace std;

    bool wasAttached = this->observers.Detach(owner);

    // Observer management should be accurate and error-free!
    assert(wasAttached && "Attempted to detach an observer that was not attached");
    wasAttached; // avoid unreferenced parameter warning
  }

  // ------------------------------------------------------------------------------------------- //

  Buffer &Buffer::operator =(const Buffer &other) {
    if(other.usedBytes > this->CapacityBytes) {
      throw std::runtime_error("Other buffer is too large for this buffer's capacity");
    }

    std::copy_n(other.Contents, this->usedBytes, this->Contents);
    this->usedBytes = other.usedBytes;

    OnChanged(0, this->usedBytes);

    return *this;
  }

  // ------------------------------------------------------------------------------------------- //

  void Buffer::OnDestroying() {
    std::vector<Observer *> copy = this->observers.Copy();
    for(std::size_t index = 0; index < copy.size(); ++index) {
      copy[index]->Destroying();
    }
  }

  // ------------------------------------------------------------------------------------------- //

  void Buffer::OnCleared() {
    std::vector<Observer *> copy = this->observers.Copy();
    for(std::size_t index = 0; index < copy.size(); ++index) {
      copy[index]->Cleared();
    }
  }

  // ------------------------------------------------------------------------------------------- //

  void Buffer::OnChanged(std::size_t offset, std::size_t count) {
    std::size_t lastOffset = offset + count;

    if(this->firstChangeOffset == this->lastChangeOffset) {
      std::vector<Observer *> copy = this->observers.Copy();
      for(std::size_t index = 0; index < copy.size(); ++index) {
        copy[index]->Changed(offset, count);
      }
    } else { // Change notifications are currently suppressed
      this->firstChangeOffset = std::min(offset, this->firstChangeOffset);
      this->lastChangeOffset = std::max(lastOffset, this->lastChangeOffset);
    }

    this->usedBytes = std::max(this->usedBytes, lastOffset);
  }

  // ------------------------------------------------------------------------------------------- //

}}} // namespace Nuclex::Graphics::Rasterization