#pragma once

#include "Color.h"

#include <stdint.h>

#include <glm/glm.hpp>
#include <glm/ext.hpp>
#include <glm/ext/quaternion_float.hpp>
#include <math.h>
#include <vector>

#include "Entity.h"

#include "Texture.h"
#include "Shader.h"
#include "Mesh.h"

struct VertexData {
	glm::vec3 position;
	glm::vec3 normal;
	glm::vec2 uv0;
	glm::vec3 tangent;
	glm::vec3 bitangent;
	Color color;

	VertexData(const glm::vec3& position, const glm::vec3& normal, const glm::vec2 uv0, Color color) : position(position), color(color), normal(normal), uv0(uv0), tangent(0.0f), bitangent(0.0f) {
		
	}
};

class PartitionedCubeMesh : public Mesh<VertexData> {
private:
	static Shader _shader;
	static Texture _diffuse;
	static Texture _roughness;
	static Texture _normal;

	GLuint _uniformDiffuse;
	GLuint _uniformRoughness;
	GLuint _uniformNormal;

public:
	PartitionedCubeMesh() : Mesh(&_shader) { 
		_shader.Use();

		glBindVertexArray(_vba);
		glBindBuffer(GL_ARRAY_BUFFER, _vbo);

		int shd = shader->Reference();

		_uniformDiffuse = glGetUniformLocation(shd, "diffuse");
		_uniformRoughness = glGetUniformLocation(shd, "roughness");
		_uniformNormal = glGetUniformLocation(shd, "normal");

		glUniform1i(_uniformDiffuse, 0);
		glUniform1i(_uniformRoughness, 1);
		glUniform1i(_uniformNormal, 2);

		glVertexAttribPointer(glGetAttribLocation(shd, "position"), 3, GL_FLOAT, GL_FALSE, sizeof(VertexData), (void*)offsetof(VertexData, position));
		glVertexAttribPointer(glGetAttribLocation(shd, "normal"), 3, GL_FLOAT, GL_FALSE, sizeof(VertexData), (void*)offsetof(VertexData, normal));
		glVertexAttribPointer(glGetAttribLocation(shd, "uv0"), 2, GL_FLOAT, GL_FALSE, sizeof(VertexData), (void*)offsetof(VertexData, uv0));
		glVertexAttribPointer(glGetAttribLocation(shd, "tangent"), 3, GL_FLOAT, GL_FALSE, sizeof(VertexData), (void*)offsetof(VertexData, tangent));
		glVertexAttribPointer(glGetAttribLocation(shd, "bitangent"), 3, GL_FLOAT, GL_FALSE, sizeof(VertexData), (void*)offsetof(VertexData, bitangent));
		glVertexAttribPointer(glGetAttribLocation(shd, "color"), 4, GL_FLOAT, GL_FALSE, sizeof(VertexData), (void*)offsetof(VertexData, color));
		glEnableVertexAttribArray(0);
		glEnableVertexAttribArray(1);
		glEnableVertexAttribArray(2);
		glEnableVertexAttribArray(3);
		glEnableVertexAttribArray(4);
		glEnableVertexAttribArray(5);

		glBindBuffer(GL_ARRAY_BUFFER, 0);
		glBindVertexArray(0);

		_shader.Disable();
	}

	virtual void Render(const DefaultUniform& uniform) override {
		_shader.Use();

		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, _diffuse.Reference());

		glActiveTexture(GL_TEXTURE1);
		glBindTexture(GL_TEXTURE_2D, _roughness.Reference());

		glActiveTexture(GL_TEXTURE2);
		glBindTexture(GL_TEXTURE_2D, _normal.Reference());

		_shader.Disable();

		Mesh::Render(uniform);
	}

	static void LoadResources() {
		_diffuse = Texture("diffuse.png");
		_roughness = Texture("roughness.png");
		_normal = Texture("normal.png");
	}

	void CalculateTangents() {
		for(int i=0;i<_vertexData.size();i += 3) {
			VertexData& d0 = _vertexData.at(i + 0);
			VertexData& d1 = _vertexData.at(i + 1);
			VertexData& d2 = _vertexData.at(i + 2);

			glm::vec3 deltaPos1 = d1.position - d0.position;
			glm::vec3 deltaPos2 = d2.position - d0.position;

			glm::vec2 deltaUV1 = d1.uv0 - d0.uv0;
			glm::vec2 deltaUV2 = d2.uv0 - d0.uv0;

			float r = 1.0f / (deltaUV1.x * deltaUV2.y - deltaUV1.y * deltaUV2.x);
			d0.tangent = (deltaPos1 * deltaUV2.y - deltaPos2 * deltaUV1.y) * r;
			d0.bitangent = (deltaPos2 * deltaUV1.x - deltaPos1 * deltaUV2.x) * r;
			d1.tangent = (deltaPos1 * deltaUV2.y - deltaPos2 * deltaUV1.y) * r;
			d1.bitangent = (deltaPos2 * deltaUV1.x - deltaPos1 * deltaUV2.x) * r;
			d2.tangent = (deltaPos1 * deltaUV2.y - deltaPos2 * deltaUV1.y) * r;
			d2.bitangent = (deltaPos2 * deltaUV1.x - deltaPos1 * deltaUV2.x) * r;
		}
	}
};

enum Side {
	Left, Right, Bottom, Top, Back, Forward
};

constexpr glm::vec3 SideToDirection[6] = { 
	glm::vec3(-1.0f, 0.0f, 0.0f),
	glm::vec3(1.0f, 0.0f, 0.0f),
	glm::vec3(0.0f, -1.0f, 0.0f),
	glm::vec3(0.0f, 1.0f, 0.0f),
	glm::vec3(0.0f, 0.0f, -1.0f),
	glm::vec3(0.0f, 0.0f, 1.0f),
};

class Cube;

class PartitionedCube : public Entity
{
private:
	glm::mat4 _transformTem;
	
	glm::quat _animationTransform;
	float _animationTime;
	float _animationTimeExtend;
	bool _animationFinished;

	Color _faces[6];
	PartitionedCubeMesh _mesh;

public:
	PartitionedCube(Cube* parent, const glm::vec3& position, Color* sideColors);

	void Update(double deltaTime) override;
	void Render(DefaultUniform& uniform) override;

	const glm::mat4 TransformCustom() const {
		// Need to use slerp since rotations are non-linear and would not interpolate this way
		// 
		// However a lerp can be used and then normalized, with not that much of an 
		// error but being much more performant thus preferred function
		if (false == _animationFinished) {
			float lerpFactor = 1.0f - ( _animationTime / _animationTimeExtend);

			glm::mat4 animationView = glm::mat4_cast(glm::normalize(glm::lerp(glm::quat(1.0f, 0.0f, 0.0f, 0.0f), _animationTransform, lerpFactor)));

			return Parent()->LocalToWorld() * animationView * LocalObjectTransform();
		}
		
		return Parent()->LocalToWorld() * _transformTem * LocalObjectTransform();
	}

	void TransformData(const glm::ivec3& axis, int turns);
	void TransformAnimation(const glm::quat& transform, float duration);
	void TransformTemp(const glm::mat4& transform);
	void UndoTransformTemp();
};