// Copyright (C) 2022 Jérôme "Lynix" Leclercq (lynix680@gmail.com)
// This file is part of the "Nazara Engine - Graphics module"
// For conditions of distribution and use, see copyright notice in Config.hpp

#include <Nazara/Graphics/LinearSlicedSprite.hpp>
#include <Nazara/Graphics/BasicMaterial.hpp>
#include <Nazara/Graphics/Material.hpp>
#include <Nazara/Graphics/RenderSpriteChain.hpp>
#include <Nazara/Graphics/Debug.hpp>

namespace Nz
{
	LinearSlicedSprite::LinearSlicedSprite(std::shared_ptr<Material> material, Orientation orientation) :
	m_material(std::move(material)),
	m_sectionCount(0),
	m_spriteCount(0),
	m_color(Color::White),
	m_orientation(orientation),
	m_textureCoords(0.f, 0.f, 1.f, 1.f),
	m_size(64.f, 64.f)
	{
		UpdateVertices();
	}

	void LinearSlicedSprite::BuildElement(std::size_t passIndex, const WorldInstance& worldInstance, const SkeletonInstance* skeletonInstance, std::vector<std::unique_ptr<RenderElement>>& elements, const Recti& scissorBox) const
	{
		const auto& materialPass = m_material->GetPass(passIndex);
		if (!materialPass)
			return;

		const std::shared_ptr<VertexDeclaration>& vertexDeclaration = VertexDeclaration::Get(VertexLayout::XYZ_Color_UV);

		std::vector<RenderPipelineInfo::VertexBufferData> vertexBufferData = {
			{
				{
					0,
					vertexDeclaration
				}
			}
		};
		const auto& renderPipeline = materialPass->GetPipeline()->GetRenderPipeline(vertexBufferData);

		const auto& whiteTexture = Graphics::Instance()->GetDefaultTextures().whiteTextures[UnderlyingCast(ImageType::E2D)];

		elements.emplace_back(std::make_unique<RenderSpriteChain>(GetRenderLayer(), materialPass, renderPipeline, worldInstance, vertexDeclaration, whiteTexture, m_spriteCount, m_vertices.data(), scissorBox));
	}

	const std::shared_ptr<Material>& LinearSlicedSprite::GetMaterial(std::size_t i) const
	{
		assert(i == 0);
		NazaraUnused(i);

		return m_material;
	}

	std::size_t LinearSlicedSprite::GetMaterialCount() const
	{
		return 1;
	}

	Vector3ui LinearSlicedSprite::GetTextureSize() const
	{
		assert(m_material);

		//TODO: Cache index in registry?
		if (const auto& material = m_material->FindPass("ForwardPass"))
		{
			BasicMaterial mat(*material);
			if (mat.HasBaseColorMap())
			{
				// Material should always have textures but we're better safe than sorry
				if (const auto& texture = mat.GetBaseColorMap())
					return texture->GetSize();
			}
		}

		// Couldn't get material pass or texture
		return Vector3ui::Unit(); //< prevents division by zero
	}

	void LinearSlicedSprite::UpdateVertices()
	{
		VertexStruct_XYZ_Color_UV* vertices = m_vertices.data();

		Vector3f origin = Vector3f::Zero();
		Vector2f topLeftUV = m_textureCoords.GetCorner(RectCorner::LeftTop);

		m_spriteCount = 0;

		for (std::size_t i = 0; i < m_sectionCount; ++i)
		{
			const auto& section = m_sections[i];
			if (section.size <= 0.f)
				continue;

			Vector2f dir;
			Vector2f size;
			Vector2f texCoords;
			if (m_orientation == Orientation::Horizontal)
			{
				dir = Vector2(1.f, 0.f);
				size = Vector2f(section.size, m_size.y);
				texCoords = Vector2f(section.textureCoord, m_textureCoords.height);
			}
			else
			{
				dir = Vector2(0.f, 1.f);
				size = Vector2f(m_size.x, section.size);
				texCoords = Vector2f(m_textureCoords.width, section.textureCoord);
			}
			
			vertices->color = m_color;
			vertices->position = origin;
			vertices->uv = topLeftUV;
			vertices++;

			vertices->color = m_color;
			vertices->position = origin + size.x * Vector3f::Right();
			vertices->uv = topLeftUV + Vector2f(texCoords.x, 0.f);
			vertices++;

			vertices->color = m_color;
			vertices->position = origin + size.y * Vector3f::Up();
			vertices->uv = topLeftUV + Vector2f(0.f, texCoords.y);
			vertices++;

			vertices->color = m_color;
			vertices->position = origin + size.x * Vector3f::Right() + size.y * Vector3f::Up();
			vertices->uv = topLeftUV + Vector2f(texCoords.x, texCoords.y);
			vertices++;

			origin += dir * section.size;
			topLeftUV += dir * section.textureCoord;
			m_spriteCount++;
		}

		Boxf aabb = Boxf::Zero();

		std::size_t vertexCount = 4 * m_spriteCount;
		if (vertexCount > 0)
		{
			// Reverse texcoords Y
			for (std::size_t i = 0; i < vertexCount; ++i)
				m_vertices[i].uv.y = m_textureCoords.height - m_vertices[i].uv.y;

			aabb.Set(m_vertices[0].position);
			for (std::size_t i = 1; i < vertexCount; ++i)
				aabb.ExtendTo(m_vertices[i].position);
		}

		UpdateAABB(aabb);
		OnElementInvalidated(this);
	}
}