// Copyright (C) 2012 Jérôme Leclercq
// This file is part of the "Nazara Engine - Utility module"
// For conditions of distribution and use, see copyright notice in Config.hpp

#include <Nazara/Utility/Buffer.hpp>
#include <Nazara/Core/Error.hpp>
#include <Nazara/Utility/BufferImpl.hpp>
#include <Nazara/Utility/Config.hpp>
#include <Nazara/Utility/SoftwareBuffer.hpp>
#include <cstring>
#include <stdexcept>
#include <Nazara/Utility/Debug.hpp>

namespace
{
	NzBufferImpl* SoftwareBufferFunction(NzBuffer* parent, nzBufferType type)
	{
		return new NzSoftwareBuffer(parent, type);
	}
}

NzBuffer::NzBuffer(nzBufferType type) :
m_type(type),
m_typeSize(0),
m_impl(nullptr),
m_length(0)
{
}

NzBuffer::NzBuffer(nzBufferType type, unsigned int length, nzUInt8 typeSize, nzBufferStorage storage, nzBufferUsage usage) :
m_type(type),
m_impl(nullptr)
{
	Create(length, typeSize, storage, usage);

	#ifdef NAZARA_DEBUG
	if (!m_impl)
	{
		NazaraError("Failed to create buffer");
		throw std::runtime_error("Constructor failed");
	}
	#endif
}

NzBuffer::~NzBuffer()
{
	Destroy();
}

bool NzBuffer::CopyContent(NzBuffer& buffer)
{
	#if NAZARA_UTILITY_SAFE
	if (!m_impl)
	{
		NazaraError("Buffer must be valid");
		return false;
	}

	if (!buffer.IsValid())
	{
		NazaraError("Source buffer must be valid");
		return false;
	}

	if (!buffer.GetTypeSize() != m_typeSize)
	{
		NazaraError("Source buffer type size does not match buffer type size");
		return false;
	}
	#endif

	void* ptr = buffer.Map(nzBufferAccess_ReadOnly);
	if (!ptr)
	{
		NazaraError("Failed to map source buffer");
		return false;
	}

	bool r = Fill(ptr, 0, buffer.GetLength());

	if (!buffer.Unmap())
		NazaraWarning("Failed to unmap source buffer");

	return r;
}

bool NzBuffer::Create(unsigned int length, nzUInt8 typeSize, nzBufferStorage storage, nzBufferUsage usage)
{
	Destroy();

	// On tente d'abord de faire un buffer hardware, si supporté
	if (s_bufferFunctions[storage])
	{
		NzBufferImpl* impl = s_bufferFunctions[storage](this, m_type);
		if (!impl->Create(length*typeSize, usage))
		{
			NazaraError("Failed to create buffer");
			delete impl;

			return false;
		}

		m_impl = impl;
	}
	else
	{
		NazaraError("Buffer storage not supported");
		return false;
	}

	m_length = length;
	m_typeSize = typeSize;
	m_storage = storage;
	m_usage = usage;

	// Si on arrive ici c'est que tout s'est bien passé.
	return true;
}

void NzBuffer::Destroy()
{
	if (m_impl)
	{
		m_impl->Destroy();
		delete m_impl;
		m_impl = nullptr;
	}
}

bool NzBuffer::Fill(const void* data, unsigned int offset, unsigned int length)
{
	#if NAZARA_UTILITY_SAFE
	if (!m_impl)
	{
		NazaraError("Buffer not valid");
		return false;
	}

	if (offset+length > m_length)
	{
		NazaraError("Exceeding buffer size");
		return false;
	}
	#endif

	return m_impl->Fill(data, offset*m_typeSize, ((length == 0) ? m_length-offset : length)*m_typeSize);
}

NzBufferImpl* NzBuffer::GetImpl() const
{
	return m_impl;
}

unsigned int NzBuffer::GetLength() const
{
	return m_length;
}

void* NzBuffer::GetPointer()
{
	#if NAZARA_UTILITY_SAFE
	if (!m_impl)
	{
		NazaraError("Buffer not valid");
		return nullptr;
	}
	#endif

	return m_impl->GetPointer();
}

const void* NzBuffer::GetPointer() const
{
	#if NAZARA_UTILITY_SAFE
	if (!m_impl)
	{
		NazaraError("Buffer not valid");
		return nullptr;
	}
	#endif

	return m_impl->GetPointer();
}

unsigned int NzBuffer::GetSize() const
{
	return m_length*m_typeSize;
}

nzBufferStorage NzBuffer::GetStorage() const
{
	return m_storage;
}

nzBufferType NzBuffer::GetType() const
{
	return m_type;
}

nzUInt8 NzBuffer::GetTypeSize() const
{
	return m_typeSize;
}

nzBufferUsage NzBuffer::GetUsage() const
{
	return m_usage;
}

bool NzBuffer::IsHardware() const
{
	return m_storage == nzBufferStorage_Hardware;
}

bool NzBuffer::IsValid() const
{
	return m_impl != nullptr;
}

void* NzBuffer::Map(nzBufferAccess access, unsigned int offset, unsigned int length)
{
	#if NAZARA_UTILITY_SAFE
	if (!m_impl)
	{
		NazaraError("Buffer not valid");
		return nullptr;
	}

	if (offset+length > m_length)
	{
		NazaraError("Exceeding buffer size");
		return nullptr;
	}
	#endif

	return m_impl->Map(access, offset*m_typeSize, ((length == 0) ? m_length-offset : length)*m_typeSize);
}

bool NzBuffer::SetStorage(nzBufferStorage storage)
{
	#if NAZARA_UTILITY_SAFE
	if (!m_impl)
	{
		NazaraError("Buffer not valid");
		return false;
	}
	#endif

	if (m_storage == storage)
		return true;

	#if NAZARA_UTILITY_SAFE
	if (!IsSupported(storage))
	{
		NazaraError("Storage not supported");
		return false;
	}
	#endif

	void* ptr = m_impl->Map(nzBufferAccess_ReadOnly, 0, m_length*m_typeSize);
	if (!ptr)
	{
		NazaraError("Failed to map buffer");
		return false;
	}

	NzBufferImpl* impl = s_bufferFunctions[storage](this, m_type);
	if (!impl->Create(m_length*m_typeSize, m_usage))
	{
		NazaraError("Failed to create buffer");
		delete impl;

		if (!m_impl->Unmap())
			NazaraWarning("Failed to unmap buffer");

		return false;
	}

	if (!impl->Fill(ptr, 0, m_length*m_typeSize))
	{
		NazaraError("Failed to fill buffer");
		impl->Destroy();
		delete impl;

		if (!m_impl->Unmap())
			NazaraWarning("Failed to unmap buffer");

		return false;
	}

	m_impl->Unmap();
	m_impl->Destroy();

	delete m_impl;
	m_impl = impl;

	m_storage = storage;

	return true;
}

bool NzBuffer::Unmap()
{
	#if NAZARA_UTILITY_SAFE
	if (!m_impl)
	{
		NazaraError("Buffer not valid");
		return false;
	}
	#endif

	return m_impl->Unmap();
}

bool NzBuffer::IsSupported(nzBufferStorage storage)
{
	return s_bufferFunctions[storage] != nullptr;
}

void NzBuffer::SetBufferFunction(nzBufferStorage storage, BufferFunction func)
{
	s_bufferFunctions[storage] = func;
}

bool NzBuffer::Initialize()
{
	s_bufferFunctions[nzBufferStorage_Software] = SoftwareBufferFunction;

	return true;
}

void NzBuffer::Uninitialize()
{
	std::memset(s_bufferFunctions, 0, (nzBufferStorage_Max+1)*sizeof(NzBuffer::BufferFunction));
}

NzBuffer::BufferFunction NzBuffer::s_bufferFunctions[nzBufferStorage_Max+1] = {0};